5
This document describes the Bazaar internals and the development process.
6
It's meant for people interested in developing Bazaar, and some parts will
7
also be useful to people developing Bazaar plugins.
9
If you have any questions or something seems to be incorrect, unclear or
10
missing, please talk to us in ``irc://irc.freenode.net/#bzr``, or write to
11
the Bazaar mailing list. To propose a correction or addition to this
12
document, send a merge request or new text to the mailing list.
14
The current version of this document is available in the file
15
``doc/developers/HACKING.txt`` in the source tree, or at
16
http://doc.bazaar-vcs.org/bzr.dev/en/developer-guide/HACKING.html
24
Exploring the Bazaar Platform
25
=============================
27
Before making changes, it's a good idea to explore the work already
28
done by others. Perhaps the new feature or improvement you're looking
29
for is available in another plug-in already? If you find a bug,
30
perhaps someone else has already fixed it?
32
To answer these questions and more, take a moment to explore the
33
overall Bazaar Platform. Here are some links to browse:
35
* The Plugins page on the Wiki - http://bazaar-vcs.org/BzrPlugins
37
* The Bazaar product family on Launchpad - https://launchpad.net/bazaar
39
* Bug Tracker for the core product - https://bugs.launchpad.net/bzr/
41
* Blueprint Tracker for the core product - https://blueprints.launchpad.net/bzr/
43
If nothing else, perhaps you'll find inspiration in how other developers
44
have solved their challenges.
47
Planning and Discussing Changes
48
===============================
50
There is a very active community around Bazaar. Mostly we meet on IRC
51
(#bzr on irc.freenode.net) and on the mailing list. To join the Bazaar
52
community, see http://bazaar-vcs.org/BzrSupport.
54
If you are planning to make a change, it's a very good idea to mention it
55
on the IRC channel and/or on the mailing list. There are many advantages
56
to involving the community before you spend much time on a change.
59
* you get to build on the wisdom on others, saving time
61
* if others can direct you to similar code, it minimises the work to be done
63
* it assists everyone in coordinating direction, priorities and effort.
65
In summary, maximising the input from others typically minimises the
66
total effort required to get your changes merged. The community is
67
friendly, helpful and always keen to welcome newcomers.
70
Bazaar Development in a Nutshell
71
================================
73
Looking for a 10 minute introduction to submitting a change?
74
See http://bazaar-vcs.org/BzrGivingBack.
76
TODO: Merge that Wiki page into this document.
79
Understanding the Development Process
80
=====================================
82
The development team follows many best-practices including:
84
* a public roadmap and planning process in which anyone can participate
86
* time based milestones everyone can work towards and plan around
88
* extensive code review and feedback to contributors
90
* complete and rigorous test coverage on any code contributed
92
* automated validation that all tests still pass before code is merged
93
into the main code branch.
95
The key tools we use to enable these practices are:
97
* Launchpad - https://launchpad.net/
99
* Bazaar - http://bazaar-vcs.org/
101
* Bundle Buggy - http://bundlebuggy.aaronbentley.com/
103
* Patch Queue Manager - https://launchpad.net/pqm/
105
For further information, see http://bazaar-vcs.org/BzrDevelopment.
108
A Closer Look at the Merge & Review Process
109
===========================================
111
If you'd like to propose a change, please post to the
112
bazaar@lists.canonical.com list with a bundle, patch, or link to a
113
branch. Put '[PATCH]' or '[MERGE]' in the subject so Bundle Buggy
114
can pick it out, and explain the change in the email message text.
115
Remember to update the NEWS file as part of your change if it makes any
116
changes visible to users or plugin developers. Please include a diff
117
against mainline if you're giving a link to a branch.
119
You can generate a bundle like this::
121
bzr bundle > mybundle.patch
123
A .patch extension is recommended instead of .bundle as many mail clients
124
will send the latter as a binary file. If a bundle would be too long or your
125
mailer mangles whitespace (e.g. implicitly converts Unix newlines to DOS
126
newlines), use the merge-directive command instead like this::
128
bzr merge-directive http://bazaar-vcs.org http://example.org/my_branch > my_directive.patch
130
See the help for details on the arguments to merge-directive.
132
Please do **NOT** put [PATCH] or [MERGE] in the subject line if you don't
133
want it to be merged. If you want comments from developers rather than
134
to be merged, you can put '[RFC]' in the subject line.
136
Anyone is welcome to review code. There are broadly three gates for
139
* Doesn't reduce test coverage: if it adds new methods or commands,
140
there should be tests for them. There is a good test framework
141
and plenty of examples to crib from, but if you are having trouble
142
working out how to test something feel free to post a draft patch
145
* Doesn't reduce design clarity, such as by entangling objects
146
we're trying to separate. This is mostly something the more
147
experienced reviewers need to help check.
149
* Improves bugs, features, speed, or code simplicity.
151
Code that goes in should pass all three. The core developers take care
152
to keep the code quality high and understandable while recognising that
153
perfect is sometimes the enemy of good. (It is easy for reviews to make
154
people notice other things which should be fixed but those things should
155
not hold up the original fix being accepted. New things can easily be
156
recorded in the Bug Tracker instead.)
158
Anyone can "vote" on the mailing list. Core developers can also vote using
159
Bundle Buggy. Here are the voting codes and their explanations.
161
:approve: Reviewer wants this submission merged.
162
:tweak: Reviewer wants this submission merged with small changes. (No
164
:abstain: Reviewer does not intend to vote on this patch.
165
:resubmit: Please make changes and resubmit for review.
166
:reject: Reviewer doesn't want this kind of change merged.
167
:comment: Not really a vote. Reviewer just wants to comment, for now.
169
If a change gets two approvals from core reviewers, and no rejections,
170
then it's OK to come in. Any of the core developers can bring it into the
171
bzr.dev trunk and backport it to maintenance branches if required. The
172
Release Manager will merge the change into the branch for a pending
173
release, if any. As a guideline, core developers usually merge their own
174
changes and volunteer to merge other contributions if they were the second
175
reviewer to agree to a change.
177
To track the progress of proposed changes, use Bundle Buggy. See
178
http://bundlebuggy.aaronbentley.com/help for a link to all the
179
outstanding merge requests together with an explanation of the columns.
180
Bundle Buggy will also mail you a link to track just your change.
183
Preparing a Sandbox for Making Changes to Bazaar
184
================================================
186
Bazaar supports many ways of organising your work. See
187
http://bazaar-vcs.org/SharedRepositoryLayouts for a summary of the
188
popular alternatives.
190
Of course, the best choice for you will depend on numerous factors:
191
the number of changes you may be making, the complexity of the changes, etc.
192
As a starting suggestion though:
194
* create a local copy of the main development branch (bzr.dev) by using
197
bzr branch http://bazaar-vcs.org/bzr/bzr.dev/ bzr.dev
199
* keep your copy of bzr.dev prestine (by not developing in it) and keep
200
it up to date (by using bzr pull)
202
* create a new branch off your local bzr.dev copy for each issue
203
(bug or feature) you are working on.
205
This approach makes it easy to go back and make any required changes
206
after a code review. Resubmitting the change is then simple with no
207
risk of accidentially including edits related to other issues you may
208
be working on. After the changes for an issue are accepted and merged,
209
the associated branch can be deleted or archived as you wish.
212
Navigating the Code Base
213
========================
215
TODO: List and describe in one line the purpose of each directory
216
inside an installation of bzr.
218
TODO: Refer to a central location holding an up to date copy of the API
219
documentation generated by epydoc, e.g. something like
220
http://starship.python.net/crew/mwh/bzrlibapi/bzrlib.html.
226
The Importance of Testing
227
=========================
229
Reliability is a critical success factor for any Version Control System.
230
We want Bazaar to be highly reliable across multiple platforms while
231
evolving over time to meet the needs of its community.
233
In a nutshell, this is want we expect and encourage:
235
* New functionality should have test cases. Preferably write the
236
test before writing the code.
238
In general, you can test at either the command-line level or the
239
internal API level. See Writing tests below for more detail.
241
* Try to practice Test-Driven Development: before fixing a bug, write a
242
test case so that it does not regress. Similarly for adding a new
243
feature: write a test case for a small version of the new feature before
244
starting on the code itself. Check the test fails on the old code, then
245
add the feature or fix and check it passes.
247
By doing these things, the Bazaar team gets increased confidence that
248
changes do what they claim to do, whether provided by the core team or
249
by community members. Equally importantly, we can be surer that changes
250
down the track do not break new features or bug fixes that you are
253
As of May 2007, Bazaar ships with a test suite containing over 6000 tests
254
and growing. We are proud of it and want to remain so. As community
255
members, we all benefit from it. Would you trust version control on
256
your project to a product *without* a test suite like Bazaar has?
259
Running the Test Suite
260
======================
262
Currently, bzr selftest is used to invoke tests.
263
You can provide a pattern argument to run a subset. For example,
264
to run just the blackbox tests, run::
266
./bzr selftest -v blackbox
268
To skip a particular test (or set of tests), use the --exclude option
269
(shorthand -x) like so::
271
./bzr selftest -v -x blackbox
273
To ensure that all tests are being run and succeeding, you can use the
274
--strict option which will fail if there are any missing features or known
277
./bzr selftest --strict
279
To list tests without running them, use the --list-only option like so::
281
./bzr selftest --list-only
283
This option can be combined with other selftest options (like -x) and
284
filter patterns to understand their effect.
290
In general tests should be placed in a file named test_FOO.py where
291
FOO is the logical thing under test. That file should be placed in the
292
tests subdirectory under the package being tested.
294
For example, tests for merge3 in bzrlib belong in bzrlib/tests/test_merge3.py.
295
See bzrlib/tests/test_sampler.py for a template test script.
297
Tests can be written for the UI or for individual areas of the library.
298
Choose whichever is appropriate: if adding a new command, or a new command
299
option, then you should be writing a UI test. If you are both adding UI
300
functionality and library functionality, you will want to write tests for
301
both the UI and the core behaviours. We call UI tests 'blackbox' tests
302
and they are found in ``bzrlib/tests/blackbox/*.py``.
304
When writing blackbox tests please honour the following conventions:
306
1. Place the tests for the command 'name' in
307
bzrlib/tests/blackbox/test_name.py. This makes it easy for developers
308
to locate the test script for a faulty command.
310
2. Use the 'self.run_bzr("name")' utility function to invoke the command
311
rather than running bzr in a subprocess or invoking the
312
cmd_object.run() method directly. This is a lot faster than
313
subprocesses and generates the same logging output as running it in a
314
subprocess (which invoking the method directly does not).
316
3. Only test the one command in a single test script. Use the bzrlib
317
library when setting up tests and when evaluating the side-effects of
318
the command. We do this so that the library api has continual pressure
319
on it to be as functional as the command line in a simple manner, and
320
to isolate knock-on effects throughout the blackbox test suite when a
321
command changes its name or signature. Ideally only the tests for a
322
given command are affected when a given command is changed.
324
4. If you have a test which does actually require running bzr in a
325
subprocess you can use ``run_bzr_subprocess``. By default the spawned
326
process will not load plugins unless ``--allow-plugins`` is supplied.
332
We make selective use of doctests__. In general they should provide
333
*examples* within the API documentation which can incidentally be tested. We
334
don't try to test every important case using doctests -- regular Python
335
tests are generally a better solution.
337
Most of these are in ``bzrlib/doc/api``. More additions are welcome.
339
__ http://docs.python.org/lib/module-doctest.html
342
Skipping tests and test requirements
343
------------------------------------
345
In our enhancements to unittest we allow for some addition results beyond
346
just success or failure.
348
If a test can't be run, it can say that it's skipped. This is typically
349
used in parameterized tests - for example if a transport doesn't support
350
setting permissions, we'll skip the tests that relating to that. ::
353
return self.branch_format.initialize(repo.bzrdir)
354
except errors.UninitializableFormat:
355
raise tests.TestSkipped('Uninitializable branch format')
357
Raising TestSkipped is a good idea when you want to make it clear that the
358
test was not run, rather than just returning which makes it look as if it
361
Several different cases are distinguished:
364
Generic skip; the only type that was present up to bzr 0.18.
367
The test doesn't apply to the parameters with which it was run.
368
This is typically used when the test is being applied to all
369
implementations of an interface, but some aspects of the interface
370
are optional and not present in particular concrete
371
implementations. (Some tests that should raise this currently
372
either silently return or raise TestSkipped.) Another option is
373
to use more precise parameterization to avoid generating the test
377
**(Not implemented yet)**
378
The test can't be run because of an inherent limitation of the
379
environment, such as not having symlinks or not supporting
383
The test can't be run because a dependency (typically a Python
384
library) is not available in the test environment. These
385
are in general things that the person running the test could fix
386
by installing the library. It's OK if some of these occur when
387
an end user runs the tests or if we're specifically testing in a
388
limited environment, but a full test should never see them.
391
The test exists but is known to fail, for example because the
392
code to fix it hasn't been run yet. Raising this allows
393
you to distinguish these failures from the ones that are not
394
expected to fail. This could be conditionally raised if something
395
is broken on some platforms but not on others.
397
We plan to support three modes for running the test suite to control the
398
interpretation of these results. Strict mode is for use in situations
399
like merges to the mainline and releases where we want to make sure that
400
everything that can be tested has been tested. Lax mode is for use by
401
developers who want to temporarily tolerate some known failures. The
402
default behaviour is obtained by ``bzr selftest`` with no options, and
403
also (if possible) by running under another unittest harness.
405
======================= ======= ======= ========
406
result strict default lax
407
======================= ======= ======= ========
408
TestSkipped pass pass pass
409
TestNotApplicable pass pass pass
410
TestPlatformLimit pass pass pass
411
TestDependencyMissing fail pass pass
412
KnownFailure fail pass pass
413
======================= ======= ======= ========
416
Test feature dependencies
417
-------------------------
419
Rather than manually checking the environment in each test, a test class
420
can declare its dependence on some test features. The feature objects are
421
checked only once for each run of the whole test suite.
423
For historical reasons, as of May 2007 many cases that should depend on
424
features currently raise TestSkipped.)
428
class TestStrace(TestCaseWithTransport):
430
_test_needs_features = [StraceFeature]
432
This means all tests in this class need the feature. The feature itself
433
should provide a ``_probe`` method which is called once to determine if
436
These should generally be equivalent to either TestDependencyMissing or
437
sometimes TestPlatformLimit.
443
Known failures are when a test exists but we know it currently doesn't
444
work, allowing the test suite to still pass. These should be used with
445
care, we don't want a proliferation of quietly broken tests. It might be
446
appropriate to use them if you've committed a test for a bug but not the
447
fix for it, or if something works on Unix but not on Windows.
450
Testing exceptions and errors
451
-----------------------------
453
It's important to test handling of errors and exceptions. Because this
454
code is often not hit in ad-hoc testing it can often have hidden bugs --
455
it's particularly common to get NameError because the exception code
456
references a variable that has since been renamed.
458
.. TODO: Something about how to provoke errors in the right way?
460
In general we want to test errors at two levels:
462
1. A test in ``test_errors.py`` checking that when the exception object is
463
constructed with known parameters it produces an expected string form.
464
This guards against mistakes in writing the format string, or in the
465
``str`` representations of its parameters. There should be one for
466
each exception class.
468
2. Tests that when an api is called in a particular situation, it raises
469
an error of the expected class. You should typically use
470
``assertRaises``, which in the Bazaar test suite returns the exception
471
object to allow you to examine its parameters.
473
In some cases blackbox tests will also want to check error reporting. But
474
it can be difficult to provoke every error through the commandline
475
interface, so those tests are only done as needed -- eg in response to a
476
particular bug or if the error is reported in an unusual way(?) Blackbox
477
tests should mostly be testing how the command-line interface works, so
478
should only test errors if there is something particular to the cli in how
479
they're displayed or handled.
485
The Python ``warnings`` module is used to indicate a non-fatal code
486
problem. Code that's expected to raise a warning can be tested through
489
The test suite can be run with ``-Werror`` to check no unexpected errors
492
However, warnings should be used with discretion. It's not an appropriate
493
way to give messages to the user, because the warning is normally shown
494
only once per source line that causes the problem. You should also think
495
about whether the warning is serious enought that it should be visible to
496
users who may not be able to fix it.
499
Interface implementation testing and test scenarios
500
---------------------------------------------------
502
There are several cases in Bazaar of multiple implementations of a common
503
conceptual interface. ("Conceptual" because
504
it's not necessary for all the implementations to share a base class,
505
though they often do.) Examples include transports and the working tree,
506
branch and repository classes.
508
In these cases we want to make sure that every implementation correctly
509
fulfils the interface requirements. For example, every Transport should
510
support the ``has()`` and ``get()`` and ``clone()`` methods. We have a
511
sub-suite of tests in ``test_transport_implementations``. (Most
512
per-implementation tests are in submodules of ``bzrlib.tests``, but not
513
the transport tests at the moment.)
515
These tests are repeated for each registered Transport, by generating a
516
new TestCase instance for the cross product of test methods and transport
517
implementations. As each test runs, it has ``transport_class`` and
518
``transport_server`` set to the class it should test. Most tests don't
519
access these directly, but rather use ``self.get_transport`` which returns
520
a transport of the appropriate type.
522
The goal is to run per-implementation only tests that relate to that
523
particular interface. Sometimes we discover a bug elsewhere that happens
524
with only one particular transport. Once it's isolated, we can consider
525
whether a test should be added for that particular implementation,
526
or for all implementations of the interface.
528
The multiplication of tests for different implementations is normally
529
accomplished by overriding the ``test_suite`` function used to load
530
tests from a module. This function typically loads all the tests,
531
then applies a TestProviderAdapter to them, which generates a longer
532
suite containing all the test variations.
538
Some utilities are provided for generating variations of tests. This can
539
be used for per-implementation tests, or other cases where the same test
540
code needs to run several times on different scenarios.
542
The general approach is to define a class that provides test methods,
543
which depend on attributes of the test object being pre-set with the
544
values to which the test should be applied. The test suite should then
545
also provide a list of scenarios in which to run the tests.
547
Typically ``multiply_tests_from_modules`` should be called from the test
548
module's ``test_suite`` function.
551
Essential Domain Classes
552
########################
554
Introducing the Object Model
555
============================
557
The core domain objects within the bazaar model are:
567
Transports are explained below. See http://bazaar-vcs.org/Classes/
568
for an introduction to the other key classes.
573
The ``Transport`` layer handles access to local or remote directories.
574
Each Transport object acts like a logical connection to a particular
575
directory, and it allows various operations on files within it. You can
576
*clone* a transport to get a new Transport connected to a subdirectory or
579
Transports are not used for access to the working tree. At present
580
working trees are always local and they are accessed through the regular
581
Python file io mechanisms.
586
Transports work in URLs. Take note that URLs are by definition only
587
ASCII - the decision of how to encode a Unicode string into a URL must be
588
taken at a higher level, typically in the Store. (Note that Stores also
589
escape filenames which cannot be safely stored on all filesystems, but
590
this is a different level.)
592
The main reason for this is that it's not possible to safely roundtrip a
593
URL into Unicode and then back into the same URL. The URL standard
594
gives a way to represent non-ASCII bytes in ASCII (as %-escapes), but
595
doesn't say how those bytes represent non-ASCII characters. (They're not
596
guaranteed to be UTF-8 -- that is common but doesn't happen everywhere.)
598
For example if the user enters the url ``http://example/%e0`` there's no
599
way to tell whether that character represents "latin small letter a with
600
grave" in iso-8859-1, or "latin small letter r with acute" in iso-8859-2
601
or malformed UTF-8. So we can't convert their URL to Unicode reliably.
603
Equally problematic if we're given a url-like string containing non-ascii
604
characters (such as the accented a) we can't be sure how to convert that
605
to the correct URL, because we don't know what encoding the server expects
606
for those characters. (Although this is not totally reliable we might still
607
accept these and assume they should be put into UTF-8.)
609
A similar edge case is that the url ``http://foo/sweet%2Fsour`` contains
610
one directory component whose name is "sweet/sour". The escaped slash is
611
not a directory separator. If we try to convert URLs to regular Unicode
612
paths this information will be lost.
614
This implies that Transports must natively deal with URLs; for simplicity
615
they *only* deal with URLs and conversion of other strings to URLs is done
616
elsewhere. Information they return, such as from ``list_dir``, is also in
617
the form of URL components.
626
We have a commitment to 6 months API stability - any supported symbol in a
627
release of bzr MUST NOT be altered in any way that would result in
628
breaking existing code that uses it. That means that method names,
629
parameter ordering, parameter names, variable and attribute names etc must
630
not be changed without leaving a 'deprecated forwarder' behind. This even
631
applies to modules and classes.
633
If you wish to change the behaviour of a supported API in an incompatible
634
way, you need to change its name as well. For instance, if I add an optional keyword
635
parameter to branch.commit - that's fine. On the other hand, if I add a
636
keyword parameter to branch.commit which is a *required* transaction
637
object, I should rename the API - i.e. to 'branch.commit_transaction'.
639
When renaming such supported API's, be sure to leave a deprecated_method (or
640
_function or ...) behind which forwards to the new API. See the
641
bzrlib.symbol_versioning module for decorators that take care of the
642
details for you - such as updating the docstring, and issuing a warning
643
when the old api is used.
645
For unsupported API's, it does not hurt to follow this discipline, but it's
646
not required. Minimally though, please try to rename things so that
647
callers will at least get an AttributeError rather than weird results.
650
Deprecation decorators
651
----------------------
653
``bzrlib.symbol_versioning`` provides decorators that can be attached to
654
methods, functions, and other interfaces to indicate that they should no
657
To deprecate a static method you must call ``deprecated_function``
658
(**not** method), after the staticmethod call::
661
@deprecated_function(zero_ninetyone)
662
def create_repository(base, shared=False, format=None):
664
When you deprecate an API, you should not just delete its tests, because
665
then we might introduce bugs in them. If the API is still present at all,
666
it should still work. The basic approach is to use
667
``TestCase.applyDeprecated`` which in one step checks that the API gives
668
the expected deprecation message, and also returns the real result from
669
the method, so that tests can keep running.
671
Coding Style Guidelines
672
=======================
677
``hasattr`` should not be used because it swallows exceptions including
678
``KeyboardInterrupt``. Instead, say something like ::
680
if getattr(thing, 'name', None) is None
686
Please write PEP-8__ compliant code.
688
__ http://www.python.org/peps/pep-0008.html
690
One often-missed requirement is that the first line of docstrings
691
should be a self-contained one-sentence summary.
693
We use 4 space indents for blocks, and never use tab characters. (In vim,
696
Lines should be no more than 79 characters if at all possible.
697
Lines that continue a long statement may be indented in either of
700
within the parenthesis or other character that opens the block, e.g.::
706
or indented by four spaces::
712
The first is considered clearer by some people; however it can be a bit
713
harder to maintain (e.g. when the method name changes), and it does not
714
work well if the relevant parenthesis is already far to the right. Avoid
717
self.legbone.kneebone.shinbone.toebone.shake_it(one,
723
self.legbone.kneebone.shinbone.toebone.shake_it(one,
729
self.legbone.kneebone.shinbone.toebone.shake_it(
732
For long lists, we like to add a trailing comma and put the closing
733
character on the following line. This makes it easier to add new items in
736
from bzrlib.goo import (
742
There should be spaces between function paramaters, but not between the
743
keyword name and the value::
745
call(1, 3, cheese=quark)
749
;(defface my-invalid-face
750
; '((t (:background "Red" :underline t)))
751
; "Face used to highlight invalid constructs or other uglyties"
754
(defun my-python-mode-hook ()
755
;; setup preferred indentation style.
756
(setq fill-column 79)
757
(setq indent-tabs-mode nil) ; no tabs, never, I will not repeat
758
; (font-lock-add-keywords 'python-mode
759
; '(("^\\s *\t" . 'my-invalid-face) ; Leading tabs
760
; ("[ \t]+$" . 'my-invalid-face) ; Trailing spaces
761
; ("^[ \t]+$" . 'my-invalid-face)); Spaces only
765
(add-hook 'python-mode-hook 'my-python-mode-hook)
767
The lines beginning with ';' are comments. They can be activated
768
if one want to have a strong notice of some tab/space usage
775
* Imports should be done at the top-level of the file, unless there is
776
a strong reason to have them lazily loaded when a particular
777
function runs. Import statements have a cost, so try to make sure
778
they don't run inside hot functions.
780
* Module names should always be given fully-qualified,
781
i.e. ``bzrlib.hashcache`` not just ``hashcache``.
787
Functions, methods or members that are "private" to bzrlib are given
788
a leading underscore prefix. Names without a leading underscore are
789
public not just across modules but to programmers using bzrlib as an
790
API. As a consequence, a leading underscore is appropriate for names
791
exposed across modules but that are not to be exposed to bzrlib API
794
We prefer class names to be concatenated capital words (``TestCase``)
795
and variables, methods and functions to be lowercase words joined by
796
underscores (``revision_id``, ``get_revision``).
798
For the purposes of naming some names are treated as single compound
799
words: "filename", "revno".
801
Consider naming classes as nouns and functions/methods as verbs.
803
Try to avoid using abbreviations in names, because there can be
804
inconsistency if other people use the full name.
810
``revision_id`` not ``rev_id`` or ``revid``
812
Functions that transform one thing to another should be named ``x_to_y``
813
(not ``x2y`` as occurs in some old code.)
819
Python destructors (``__del__``) work differently to those of other
820
languages. In particular, bear in mind that destructors may be called
821
immediately when the object apparently becomes unreferenced, or at some
822
later time, or possibly never at all. Therefore we have restrictions on
823
what can be done inside them.
825
0. Never use a __del__ method without asking Martin/Robert first.
827
1. Never rely on a ``__del__`` method running. If there is code that
828
must run, do it from a ``finally`` block instead.
830
2. Never ``import`` from inside a ``__del__`` method, or you may crash the
833
3. In some places we raise a warning from the destructor if the object
834
has not been cleaned up or closed. This is considered OK: the warning
835
may not catch every case but it's still useful sometimes.
841
In some places we have variables which point to callables that construct
842
new instances. That is to say, they can be used a lot like class objects,
843
but they shouldn't be *named* like classes:
845
> I think that things named FooBar should create instances of FooBar when
846
> called. Its plain confusing for them to do otherwise. When we have
847
> something that is going to be used as a class - that is, checked for via
848
> isinstance or other such idioms, them I would call it foo_class, so that
849
> it is clear that a callable is not sufficient. If it is only used as a
850
> factory, then yes, foo_factory is what I would use.
856
Several places in Bazaar use (or will use) a registry, which is a
857
mapping from names to objects or classes. The registry allows for
858
loading in registered code only when it's needed, and keeping
859
associated information such as a help string or description.
865
To make startup time faster, we use the ``bzrlib.lazy_import`` module to
866
delay importing modules until they are actually used. ``lazy_import`` uses
867
the same syntax as regular python imports. So to import a few modules in a
870
from bzrlib.lazy_import import lazy_import
871
lazy_import(globals(), """
880
revision as _mod_revision,
882
import bzrlib.transport
886
At this point, all of these exist as a ``ImportReplacer`` object, ready to
887
be imported once a member is accessed. Also, when importing a module into
888
the local namespace, which is likely to clash with variable names, it is
889
recommended to prefix it as ``_mod_<module>``. This makes it clearer that
890
the variable is a module, and these object should be hidden anyway, since
891
they shouldn't be imported into other namespaces.
894
Modules versus Members
895
~~~~~~~~~~~~~~~~~~~~~~
897
While it is possible for ``lazy_import()`` to import members of a module
898
when using the ``from module import member`` syntax, it is recommended to
899
only use that syntax to load sub modules ``from module import submodule``.
900
This is because variables and classes can frequently be used without
901
needing a sub-member for example::
903
lazy_import(globals(), """
904
from module import MyClass
908
return isinstance(x, MyClass)
910
This will incorrectly fail, because ``MyClass`` is a ``ImportReplacer``
911
object, rather than the real class.
914
Passing to Other Variables
915
~~~~~~~~~~~~~~~~~~~~~~~~~~
917
It also is incorrect to assign ``ImportReplacer`` objects to other variables.
918
Because the replacer only knows about the original name, it is unable to
919
replace other variables. The ``ImportReplacer`` class will raise an
920
``IllegalUseOfScopeReplacer`` exception if it can figure out that this
921
happened. But it requires accessing a member more than once from the new
922
variable, so some bugs are not detected right away.
928
The null revision is the ancestor of all revisions. Its revno is 0, its
929
revision-id is ``null:``, and its tree is the empty tree. When referring
930
to the null revision, please use ``bzrlib.revision.NULL_REVISION``. Old
931
code sometimes uses ``None`` for the null revision, but this practice is
938
Processing Command Lines
939
------------------------
941
bzrlib has a standard framework for parsing command lines and calling
942
processing routines associated with various commands. See builtins.py
943
for numerous examples.
946
Standard Parameter Types
947
------------------------
949
There are some common requirements in the library: some parameters need to be
950
unicode safe, some need byte strings, and so on. At the moment we have
951
only codified one specific pattern: Parameters that need to be unicode
952
should be checked via ``bzrlib.osutils.safe_unicode``. This will coerce the
953
input into unicode in a consistent fashion, allowing trivial strings to be
954
used for programmer convenience, but not performing unpredictably in the
955
presence of different locales.
961
(The strategy described here is what we want to get to, but it's not
962
consistently followed in the code at the moment.)
964
bzrlib is intended to be a generically reusable library. It shouldn't
965
write messages to stdout or stderr, because some programs that use it
966
might want to display that information through a GUI or some other
969
We can distinguish two types of output from the library:
971
1. Structured data representing the progress or result of an
972
operation. For example, for a commit command this will be a list
973
of the modified files and the finally committed revision number
976
These should be exposed either through the return code or by calls
977
to a callback parameter.
979
A special case of this is progress indicators for long-lived
980
operations, where the caller should pass a ProgressBar object.
982
2. Unstructured log/debug messages, mostly for the benefit of the
983
developers or users trying to debug problems. This should always
984
be sent through ``bzrlib.trace`` and Python ``logging``, so that
985
it can be redirected by the client.
987
The distinction between the two is a bit subjective, but in general if
988
there is any chance that a library would want to see something as
989
structured data, we should make it so.
991
The policy about how output is presented in the text-mode client
992
should be only in the command-line tool.
999
Bazaar has online help for various topics through ``bzr help COMMAND`` or
1000
equivalently ``bzr command -h``. We also have help on command options,
1001
and on other help topics. (See ``help_topics.py``.)
1003
As for python docstrings, the first paragraph should be a single-sentence
1004
synopsis of the command.
1006
The help for options should be one or more proper sentences, starting with
1007
a capital letter and finishing with a full stop (period).
1009
All help messages and documentation should have two spaces between
1016
In general tests should be placed in a file named test_FOO.py where
1017
FOO is the logical thing under test. That file should be placed in the
1018
tests subdirectory under the package being tested.
1020
For example, tests for merge3 in bzrlib belong in bzrlib/tests/test_merge3.py.
1021
See bzrlib/tests/test_sampler.py for a template test script.
1023
Tests can be written for the UI or for individual areas of the library.
1024
Choose whichever is appropriate: if adding a new command, or a new command
1025
option, then you should be writing a UI test. If you are both adding UI
1026
functionality and library functionality, you will want to write tests for
1027
both the UI and the core behaviours. We call UI tests 'blackbox' tests
1028
and they are found in ``bzrlib/tests/blackbox/*.py``.
1030
When writing blackbox tests please honour the following conventions:
1032
1. Place the tests for the command 'name' in
1033
bzrlib/tests/blackbox/test_name.py. This makes it easy for developers
1034
to locate the test script for a faulty command.
1036
2. Use the 'self.run_bzr("name")' utility function to invoke the command
1037
rather than running bzr in a subprocess or invoking the
1038
cmd_object.run() method directly. This is a lot faster than
1039
subprocesses and generates the same logging output as running it in a
1040
subprocess (which invoking the method directly does not).
1042
3. Only test the one command in a single test script. Use the bzrlib
1043
library when setting up tests and when evaluating the side-effects of
1044
the command. We do this so that the library api has continual pressure
1045
on it to be as functional as the command line in a simple manner, and
1046
to isolate knock-on effects throughout the blackbox test suite when a
1047
command changes its name or signature. Ideally only the tests for a
1048
given command are affected when a given command is changed.
1050
4. If you have a test which does actually require running bzr in a
1051
subprocess you can use ``run_bzr_subprocess``. By default the spawned
1052
process will not load plugins unless ``--allow-plugins`` is supplied.
1058
We have a rich collection of tools to support writing tests. Please use
1059
them in preference to ad-hoc solutions as they provide portability and
1060
performance benefits.
1065
The ``TreeBuilder`` interface allows the construction of arbitrary trees
1066
with a declarative interface. A sample session might look like::
1068
tree = self.make_branch_and_tree('path')
1069
builder = TreeBuilder()
1070
builder.start_tree(tree)
1071
builder.build(['foo', "bar/", "bar/file"])
1072
tree.commit('commit the tree')
1073
builder.finish_tree()
1075
Please see bzrlib.treebuilder for more details.
1080
The ``BranchBuilder`` interface allows the creation of test branches in a
1081
quick and easy manner. A sample session::
1083
builder = BranchBuilder(self.get_transport().clone('relpath'))
1084
builder.build_commit()
1085
builder.build_commit()
1086
builder.build_commit()
1087
branch = builder.get_branch()
1089
Please see bzrlib.branchbuilder for more details.
1094
We make selective use of doctests__. In general they should provide
1095
*examples* within the API documentation which can incidentally be tested. We
1096
don't try to test every important case using doctests -- regular Python
1097
tests are generally a better solution.
1099
Most of these are in ``bzrlib/doc/api``. More additions are welcome.
1101
__ http://docs.python.org/lib/module-doctest.html
1106
Currently, bzr selftest is used to invoke tests.
1107
You can provide a pattern argument to run a subset. For example,
1108
to run just the blackbox tests, run::
1110
./bzr selftest -v blackbox
1112
To skip a particular test (or set of tests), use the --exclude option
1113
(shorthand -x) like so::
1115
./bzr selftest -v -x blackbox
1117
To list tests without running them, use the --list-only option like so::
1119
./bzr selftest --list-only
1121
This option can be combined with other selftest options (like -x) and
1122
filter patterns to understand their effect.
1125
Handling Errors and Exceptions
1126
==============================
1128
Commands should return non-zero when they encounter circumstances that
1129
the user should really pay attention to - which includes trivial shell
1132
Recommended values are:
1135
1. Conflicts in merge-like operations, or changes are present in
1136
diff-like operations.
1137
2. Unrepresentable diff changes (i.e. binary files that we cannot show
1139
3. An error or exception has occurred.
1140
4. An internal error occurred (one that shows a traceback.)
1142
Errors are handled through Python exceptions. Exceptions should be defined
1143
inside bzrlib.errors, so that we can see the whole tree at a glance.
1145
We broadly classify errors as either being either internal or not,
1146
depending on whether ``internal_error`` is set or not. If we think it's our
1147
fault, we show a backtrace, an invitation to report the bug, and possibly
1148
other details. This is the default for errors that aren't specifically
1149
recognized as being caused by a user error. Otherwise we show a briefer
1150
message, unless -Derror was given.
1152
Many errors originate as "environmental errors" which are raised by Python
1153
or builtin libraries -- for example IOError. These are treated as being
1154
our fault, unless they're caught in a particular tight scope where we know
1155
that they indicate a user errors. For example if the repository format
1156
is not found, the user probably gave the wrong path or URL. But if one of
1157
the files inside the repository is not found, then it's our fault --
1158
either there's a bug in bzr, or something complicated has gone wrong in
1159
the environment that means one internal file was deleted.
1161
Many errors are defined in ``bzrlib/errors.py`` but it's OK for new errors
1162
to be added near the place where they are used.
1164
Exceptions are formatted for the user by conversion to a string
1165
(eventually calling their ``__str__`` method.) As a convenience the
1166
``._fmt`` member can be used as a template which will be mapped to the
1167
error's instance dict.
1169
New exception classes should be defined when callers might want to catch
1170
that exception specifically, or when it needs a substantially different
1173
Exception strings should start with a capital letter and should not have a
1174
final fullstop. If long, they may contain newlines to break the text.
1180
Do not use the Python ``assert`` statement, either in tests or elsewhere.
1181
A source test checks that it is not used. It is ok to explicitly raise
1186
* It makes the behaviour vary depending on whether bzr is run with -O
1187
or not, therefore giving a chance for bugs that occur in one case or
1188
the other, several of which have already occurred: assertions with
1189
side effects, code which can't continue unless the assertion passes,
1190
cases where we should give the user a proper message rather than an
1192
* It's not that much shorter than an explicit if/raise.
1193
* It tends to lead to fuzzy thinking about whether the check is
1194
actually needed or not, and whether it's an internal error or not
1195
* It tends to cause look-before-you-leap patterns.
1196
* It's unsafe if the check is needed to protect the integrity of the
1198
* It tends to give poor messages since the developer can get by with
1199
no explanatory text at all.
1200
* We can't rely on people always running with -O in normal use, so we
1201
can't use it for tests that are actually expensive.
1202
* Expensive checks that help developers are better turned on from the
1203
test suite or a -D flag.
1204
* If used instead of ``self.assert*()`` in tests it makes them falsely pass with -O.
1210
When you change bzrlib, please update the relevant documentation for the
1211
change you made: Changes to commands should update their help, and
1212
possibly end user tutorials; changes to the core library should be
1213
reflected in API documentation.
1218
If you make a user-visible change, please add a note to the NEWS file.
1219
The description should be written to make sense to someone who's just
1220
a user of bzr, not a developer: new functions or classes shouldn't be
1221
mentioned, but new commands, changes in behaviour or fixed nontrivial
1222
bugs should be listed. See the existing entries for an idea of what
1225
Within each release, entries in the news file should have the most
1226
user-visible changes first. So the order should be approximately:
1228
* changes to existing behaviour - the highest priority because the
1229
user's existing knowledge is incorrect
1230
* new features - should be brought to their attention
1231
* bug fixes - may be of interest if the bug was affecting them, and
1232
should include the bug number if any
1233
* major documentation changes
1234
* changes to internal interfaces
1236
People who made significant contributions to each change are listed in
1237
parenthesis. This can include reporting bugs (particularly with good
1238
details or reproduction recipes), submitting patches, etc.
1243
The docstring of a command is used by ``bzr help`` to generate help output
1244
for the command. The list 'takes_options' attribute on a command is used by
1245
``bzr help`` to document the options for the command - the command
1246
docstring does not need to document them. Finally, the '_see_also'
1247
attribute on a command can be used to reference other related help topics.
1252
Functions, methods, classes and modules should have docstrings
1253
describing how they are used.
1255
The first line of the docstring should be a self-contained sentence.
1257
For the special case of Command classes, this acts as the user-visible
1258
documentation shown by the help command.
1260
The docstrings should be formatted as reStructuredText_ (like this
1261
document), suitable for processing using the epydoc_ tool into HTML
1264
.. _reStructuredText: http://docutils.sourceforge.net/rst.html
1265
.. _epydoc: http://epydoc.sourceforge.net/
1274
The copyright policy for bzr was recently made clear in this email (edited
1275
for grammatical correctness)::
1277
The attached patch cleans up the copyright and license statements in
1278
the bzr source. It also adds tests to help us remember to add them
1279
with the correct text.
1281
We had the problem that lots of our files were "Copyright Canonical
1282
Development Ltd" which is not a real company, and some other variations
1283
on this theme. Also, some files were missing the GPL statements.
1285
I want to be clear about the intent of this patch, since copyright can
1286
be a little controversial.
1288
1) The big motivation for this is not to shut out the community, but
1289
just to clean up all of the invalid copyright statements.
1291
2) It has been the general policy for bzr that we want a single
1292
copyright holder for all of the core code. This is following the model
1293
set by the FSF, which makes it easier to update the code to a new
1294
license in case problems are encountered. (For example, if we want to
1295
upgrade the project universally to GPL v3 it is much simpler if there is
1296
a single copyright holder). It also makes it clearer if copyright is
1297
ever debated, there is a single holder, which makes it easier to defend
1298
in court, etc. (I think the FSF position is that if you assign them
1299
copyright, they can defend it in court rather than you needing to, and
1300
I'm sure Canonical would do the same).
1301
As such, Canonical has requested copyright assignments from all of the
1304
3) If someone wants to add code and not attribute it to Canonical, there
1305
is a specific list of files that are excluded from this check. And the
1306
test failure indicates where that is, and how to update it.
1308
4) If anyone feels that I changed a copyright statement incorrectly, just
1309
let me know, and I'll be happy to correct it. Whenever you have large
1310
mechanical changes like this, it is possible to make some mistakes.
1312
Just to reiterate, this is a community project, and it is meant to stay
1313
that way. Core bzr code is copyright Canonical for legal reasons, and
1314
the tests are just there to help us maintain that.
1317
Miscellaneous Topics
1318
####################
1323
Bazaar has a few facilities to help debug problems by going into pdb_, the
1326
.. _pdb: http://docs.python.org/lib/debugger-commands.html
1328
If the ``BZR_PDB`` environment variable is set
1329
then bzr will go into pdb post-mortem mode when an unhandled exception
1332
If you send a SIGQUIT signal to bzr, which can be done by pressing
1333
Ctrl-\\ on Unix, bzr will go into the debugger immediately. You can
1334
continue execution by typing ``c``. This can be disabled if necessary
1335
by setting the environment variable ``BZR_SIGQUIT_PDB=0``.
1342
Integer identifier for a revision on the main line of a branch.
1343
Revision 0 is always the null revision; others are 1-based
1344
indexes into the branch's revision history.
1347
Unicode and Encoding Support
1348
============================
1350
This section discusses various techniques that Bazaar uses to handle
1351
characters that are outside the ASCII set.
1356
When a ``Command`` object is created, it is given a member variable
1357
accessible by ``self.outf``. This is a file-like object, which is bound to
1358
``sys.stdout``, and should be used to write information to the screen,
1359
rather than directly writing to ``sys.stdout`` or calling ``print``.
1360
This file has the ability to translate Unicode objects into the correct
1361
representation, based on the console encoding. Also, the class attribute
1362
``encoding_type`` will effect how unprintable characters will be
1363
handled. This parameter can take one of 3 values:
1366
Unprintable characters will be represented with a suitable replacement
1367
marker (typically '?'), and no exception will be raised. This is for
1368
any command which generates text for the user to review, rather than
1369
for automated processing.
1370
For example: ``bzr log`` should not fail if one of the entries has text
1371
that cannot be displayed.
1374
Attempting to print an unprintable character will cause a UnicodeError.
1375
This is for commands that are intended more as scripting support, rather
1376
than plain user review.
1377
For exampl: ``bzr ls`` is designed to be used with shell scripting. One
1378
use would be ``bzr ls --null --unknows | xargs -0 rm``. If ``bzr``
1379
printed a filename with a '?', the wrong file could be deleted. (At the
1380
very least, the correct file would not be deleted). An error is used to
1381
indicate that the requested action could not be performed.
1384
Do not attempt to automatically convert Unicode strings. This is used
1385
for commands that must handle conversion themselves.
1386
For example: ``bzr diff`` needs to translate Unicode paths, but should
1387
not change the exact text of the contents of the files.
1390
``bzrlib.urlutils.unescape_for_display``
1391
----------------------------------------
1393
Because Transports work in URLs (as defined earlier), printing the raw URL
1394
to the user is usually less than optimal. Characters outside the standard
1395
set are printed as escapes, rather than the real character, and local
1396
paths would be printed as ``file://`` urls. The function
1397
``unescape_for_display`` attempts to unescape a URL, such that anything
1398
that cannot be printed in the current encoding stays an escaped URL, but
1399
valid characters are generated where possible.
1405
The ``bzrlib.osutils`` module has many useful helper functions, including
1406
some more portable variants of functions in the standard library.
1408
In particular, don't use ``shutil.rmtree`` unless it's acceptable for it
1409
to fail on Windows if some files are readonly or still open elsewhere.
1410
Use ``bzrlib.osutils.rmtree`` instead.
1416
We write some extensions in C using pyrex. We design these to work in
1419
* User with no C compiler
1420
* User with C compiler
1423
The recommended way to install bzr is to have a C compiler so that the
1424
extensions can be built, but if no C compiler is present, the pure python
1425
versions we supply will work, though more slowly.
1427
For developers we recommend that pyrex be installed, so that the C
1428
extensions can be changed if needed.
1430
For the C extensions, the extension module should always match the
1431
original python one in all respects (modulo speed). This should be
1432
maintained over time.
1434
To create an extension, add rules to setup.py for building it with pyrex,
1435
and with distutils. Now start with an empty .pyx file. At the top add
1436
"include 'yourmodule.py'". This will import the contents of foo.py into this
1437
file at build time - remember that only one module will be loaded at
1438
runtime. Now you can subclass classes, or replace functions, and only your
1439
changes need to be present in the .pyx file.
1441
Note that pyrex does not support all 2.4 programming idioms, so some
1442
syntax changes may be required. I.e.
1444
- 'from foo import (bar, gam)' needs to change to not use the brackets.
1445
- 'import foo.bar as bar' needs to be 'import foo.bar; bar = foo.bar'
1447
If the changes are too dramatic, consider
1448
maintaining the python code twice - once in the .pyx, and once in the .py,
1449
and no longer including the .py file.
1452
Making Installers for OS Windows
1453
================================
1454
To build a win32 installer, see the instructions on the wiki page:
1455
http://bazaar-vcs.org/BzrWin32Installer
1458
Core Developer Tasks
1459
####################
1464
What is a Core Developer?
1465
-------------------------
1467
While everyone in the Bazaar community is welcome and encouraged to
1468
propose and submit changes, a smaller team is reponsible for pulling those
1469
changes together into a cohesive whole. In addition to the general developer
1470
stuff covered above, "core" developers have responsibility for:
1473
* reviewing blueprints
1475
* managing releases.
1478
Removing barriers to community participation is a key reason for adopting
1479
distributed VCS technology. While DVCS removes many technical barriers,
1480
a small number of social barriers are often necessary instead.
1481
By documenting how the above things are done, we hope to
1482
encourage more people to participate in these activities, keeping the
1483
differences between core and non-core contributors to a minimum.
1486
The Development Lifecycle
1487
-------------------------
1489
As a rule, Bazaar development follows a 4 week cycle:
1491
* 2 weeks - general changes
1492
* 1 week - feature freeze
1493
* 1 week+ - Release Candidate stabilization
1495
During the FeatureFreeze week, the trunk (bzr.dev) is open in a limited
1496
way: only low risk changes, critical and high priority fixes are accepted
1497
during this time. At the end of FeatureFreeze, a branch is created for the
1498
first Release Candidate and the trunk is reopened for general development
1499
on the *next* release. A week or so later, the final release is packaged
1500
assuming no serious problems were encountered with the one or more Release
1504
There is a one week overlap between the start of one release and
1505
the end of the previous one.
1508
Communicating and Coordinating
1509
------------------------------
1511
While it has many advantages, one of the challenges of distributed
1512
development is keeping everyone else aware of what you're working on.
1513
There are numerous ways to do this:
1515
#. Assign bugs to yourself in Launchpad
1516
#. Mention it on the mailing list
1517
#. Mention it on IRC
1519
As well as the email notifcations that occur when merge requests are sent
1520
and reviewed, you can keep others informed of where you're spending your
1521
energy by emailing the **bazaar-commits** list implicitly. To do this,
1522
install and configure the Email plugin. One way to do this is add these
1523
configuration settings to your central configuration file (e.g.
1524
``~/.bazaar/bazaar.conf`` on Linux)::
1527
email = Joe Smith <joe.smith@internode.on.net>
1528
smtp_server = mail.internode.on.net:25
1530
Then add these lines for the relevant branches in ``locations.conf``::
1532
post_commit_to = bazaar-commits@lists.canonical.com
1533
post_commit_mailer = smtplib
1535
While attending a sprint, RobertCollins' Dbus plugin is useful for the
1536
same reason. See the documentation within the plugin for information on
1537
how to set it up and configure it.
1543
Setting Up Your Workspace for Reviews
1544
-------------------------------------
1546
TODO: Incorporate John Arbash Meinel's detailed email to Ian C on the
1547
numerous ways of setting up integration branches.
1550
The Review Checklist
1551
--------------------
1553
See `A Closer Look at the Merge & Review Process`_
1554
for information on the gates used to decide whether code can be merged
1555
or not and details on how review results are recorded and communicated.
1558
The Importance of Timely Reviews
1559
--------------------------------
1561
Good reviews do take time. They also regularly require a solid
1562
understanding of the overall code base. In practice, this means a small
1563
number of people often have a large review burden - with knowledge comes
1564
responsibility. No one like their merge requests sitting in a queue going
1565
nowhere, so reviewing sooner rather than later is strongly encouraged.
1574
Of the many workflows supported by Bazaar, the one adopted for Bazaar
1575
development itself is known as "Decentralized with automatic gatekeeper".
1576
To repeat the explanation of this given on
1577
http://bazaar-vcs.org/Workflows:
1580
In this workflow, each developer has their own branch or
1581
branches, plus read-only access to the mainline. A software gatekeeper
1582
(e.g. PQM) has commit rights to the main branch. When a developer wants
1583
their work merged, they request the gatekeeper to merge it. The gatekeeper
1584
does a merge, a compile, and runs the test suite. If the code passes, it
1585
is merged into the mainline.
1587
In a nutshell, here's the overall submission process:
1589
#. get your work ready (including review except for trivial changes)
1590
#. push to a public location
1591
#. ask PQM to merge from that location
1594
At present, PQM always takes the changes to merge from a branch
1595
at a URL that can be read by it. For Bazaar, that means a public,
1596
typically http, URL.
1598
As a result, the following things are needed to use PQM for submissions:
1600
#. A publicly available web server
1601
#. Your OpenPGP key registered with PQM (contact RobertCollins for this)
1602
#. The PQM plugin installed and configured (not strictly required but
1603
highly recommended).
1606
Selecting a Public Branch Location
1607
----------------------------------
1609
If you don't have your own web server running, branches can always be
1610
pushed to Launchpad. Here's the process for doing that:
1612
Depending on your location throughout the world and the size of your
1613
repository though, it is often quicker to use an alternative public
1614
location to Launchpad, particularly if you can set up your own repo and
1615
push into that. By using an existing repo, push only needs to send the
1616
changes, instead of the complete repository every time. Note that it is
1617
easy to register branches in other locations with Launchpad so no benefits
1618
are lost by going this way.
1621
For Canonical staff, http://people.ubuntu.com/~<user>/ is one
1622
suggestion for public http branches. Contact your manager for information
1623
on accessing this system if required.
1625
It should also be noted that best practice in this area is subject to
1626
change as things evolve. For example, once the Bazaar smart server on
1627
Launchpad supports server-side branching, the performance situation will
1628
be very different to what it is now (Jun 2007).
1631
Configuring the PQM Plug-In
1632
---------------------------
1634
While not strictly required, the PQM plugin automates a few things and
1635
reduces the chance of error. Before looking at the plugin, it helps to
1636
understand a little more how PQM operates. Basically, PQM requires an
1637
email indicating what you want it to do. The email typically looks like
1640
star-merge source-branch target-branch
1644
star-merge http://bzr.arbash-meinel.com/branches/bzr/jam-integration http://bazaar-vcs.org/bzr/bzr.dev
1646
Note that the command needs to be on one line. The subject of the email
1647
will be used for the commit message. The email also needs to be ``gpg``
1648
signed with a key that PQM accepts.
1650
The advantages of using the PQM plugin are:
1652
#. You can use the config policies to make it easy to set up public
1653
branches, so you don't have to ever type the full paths you want to merge
1656
#. It checks to make sure the public branch last revision matches the
1657
local last revision so you are submitting what you think you are.
1659
#. It uses the same public_branch and smtp sending settings as bzr-email,
1660
so if you have one set up, you have the other mostly set up.
1662
#. Thunderbird refuses to not wrap lines, and request lines are usually
1663
pretty long (you have 2 long URLs in there).
1665
Here are sample configuration settings for the PQM plugin. Here are the
1666
lines in bazaar.conf::
1669
email = Joe Smith <joe.smith@internode.on.net>
1670
smtp_server=mail.internode.on.net:25
1672
And here are the lines in ``locations.conf`` (or ``branch.conf`` for
1673
dirstate-tags branches)::
1675
[/home/joe/bzr/my-integration]
1676
push_location = sftp://joe-smith@bazaar.launchpad.net/%7Ejoe-smith/bzr/my-integration/
1677
push_location:policy = norecurse
1678
public_branch = http://bazaar.launchpad.net/~joe-smith/bzr/my-integration/
1679
public_branch:policy = appendpath
1680
pqm_email = Bazaar PQM <pqm@bazaar-vcs.org>
1681
pqm_branch = http://bazaar-vcs.org/bzr/bzr.dev
1683
Note that the push settings will be added by the first ``push`` on
1684
a branch. Indeed the preferred way to generate the lines above is to use
1685
``push`` with an argument, then copy-and-paste the other lines into
1692
Here is one possible recipe once the above environment is set up:
1694
#. pull bzr.dev => my-integration
1695
#. merge patch => my-integration
1696
#. fix up any final merge conflicts (NEWS being the big killer here).
1702
The ``push`` step is not required if ``my-integration`` is a checkout of
1705
Because of defaults, you can type a single message into commit and
1706
pqm-commit will reuse that.
1709
Tracking Change Acceptance
1710
--------------------------
1712
The web interface to PQM is https://pqm.bazaar-vcs.org/. After submitting
1713
a change, you can visit this URL to confirm it was received and placed in
1716
When PQM completes processing a change, an email is sent to you with the
1720
Reviewing Blueprints
1721
====================
1723
Blueprint Tracking Using Launchpad
1724
----------------------------------
1726
New features typically require a fair amount of discussion, design and
1727
debate. For Bazaar, that information is often captured in a so-called
1728
"blueprint" on our Wiki. Overall tracking of blueprints and their status
1729
is done using Launchpad's relevant tracker,
1730
https://blueprints.launchpad.net/bzr/. Once a blueprint for ready for
1731
review, please announce it on the mailing list.
1733
Alternatively, send an email begining with [RFC] with the proposal to the
1734
list. In some cases, you may wish to attach proposed code or a proposed
1735
developer document if that best communicates the idea. Debate can then
1736
proceed using the normal merge review processes.
1739
Recording Blueprint Review Feedback
1740
-----------------------------------
1742
Unlike its Bug Tracker, Launchpad's Blueprint Tracker doesn't currently
1743
(Jun 2007) support a chronological list of comment responses. Review
1744
feedback can either be recorded on the Wiki hosting the blueprints or by
1745
using Launchpad's whiteboard feature.
1754
As the two senior developers, Martin Pool and Robert Collins coordinate
1755
the overall Bazaar product development roadmap. Core developers provide
1756
input and review into this, particularly during sprints. It's totally
1757
expected that community members ought to be working on things that
1758
interest them the most. The roadmap is valuable though because it provides
1759
context for understanding where the product is going as a whole and why.
1762
Using Releases and Milestones in Launchpad
1763
------------------------------------------
1765
TODO ... (Exact policies still under discussion)
1771
Keeping on top of bugs reported is an important part of ongoing release
1772
planning. Everyone in the community is welcome and encouraged to raise
1773
bugs, confirm bugs raised by others, and nominate a priority. Practically
1774
though, a good percentage of bug triage is often done by the core
1775
developers, partially because of their depth of product knowledge.
1777
With respect to bug triage, core developers are encouraged to play an
1778
active role with particular attention to the following tasks:
1780
* keeping the number of unconfirmed bugs low
1781
* ensuring the priorities are generally right (everything as critical - or
1782
medium - is meaningless)
1783
* looking out for regressions and turning those around sooner rather than later.
1786
As well as prioritizing bugs and nominating them against a
1787
target milestone, Launchpad lets core developers offer to mentor others in
1797
To start a new release cycle:
1799
#. Send mail to the list with the key dates, who will be the release
1800
manager, and the main themes or targetted bugs. Ask people to nominate
1801
objectives, or point out an high-risk things that are best done early,
1802
or that interact with other changes.
1804
#. Add a new "series" in Launchpad at <https://launchpad.net/bzr/+addseries>. There is one
1805
series for every *x.y* release.
1807
Weekly Status Updates
1808
---------------------
1810
TODO: Things to cover:
1812
* Early communication to downstream teams (e.g. Launchpad) about changes in dependencies.
1813
* Reminder re lifecycle and where we're up to right now
1814
* Summary of recent successes and pending work
1815
* Reminder re release objectives
1816
* Reminder re things needing attention, e.g. bug triage, reviews, testing of certain things, etc.
1822
TODO: Get material from http://bazaar-vcs.org/FeatureFreeze.
1826
Making a Release or Release Candidate
1827
-------------------------------------
1829
.. Was previously at http://bazaar-vcs.org/ReleaseChecklist
1831
.. TODO: Still needs more clarity on what's in a RC versus a final
1834
.. TODO: Too much of this is manual but could be automated...
1836
This is the procedure for making a new bzr release:
1838
#. If the release is the first candidate, make a new branch in PQM. (Contact RobertCollins for this step).
1840
Register the branch at https://launchpad.net/products/bzr/+addbranch
1842
#. Run the automatic test suite and any non-automated tests. (For example, try a download over http; these should eventually be scripted though not automatically run.). Try to have all optional dependencies installed so that there are no tests skipped. Also make sure that you have the c extensions compiled (``make`` or ``python setup.py build_ext -i``).
1844
#. In the release branch, update ``version_info`` in ``./bzrlib/__init__.py``
1846
#. Add the date and release number to ``./NEWS``.
1848
#. Update the release number in the README. (It's not there as of 0.15, but please check).
1850
#. Commit these changes to the release branch, using a command like::
1852
bzr commit -m "(jam) Release 0.12rc1."
1854
The diff before you commit will be something like::
1856
=== modified file 'NEWS'
1857
--- NEWS 2006-10-23 13:11:17 +0000
1858
+++ NEWS 2006-10-23 22:50:50 +0000
1861
+bzr 0.12rc1 2006-10-23
1866
=== modified file 'bzrlib/__init__.py'
1867
--- bzrlib/__init__.py 2006-10-16 01:47:43 +0000
1868
+++ bzrlib/__init__.py 2006-10-23 22:49:46 +0000
1870
# Python version 2.0 is (2, 0, 0, 'final', 0)." Additionally we use a
1871
# releaselevel of 'dev' for unreleased under-development code.
1873
-version_info = (0, 12, 0, 'dev', 0)
1874
+version_info = (0, 12, 0, 'candidate', 1)
1876
if version_info[3] == 'final':
1877
version_string = '%d.%d.%d' % version_info[:3]
1879
#. Send the changes to PQM, to update the official master branch.
1881
#. When PQM succeeds, pull down the master release branch.
1883
#. Merge the release branch back into the trunk. Check that changes in NEWS were merged into the right sections. If it's not already done, advance the version number in bzr and bzrlib/__init__.py Submit this back into pqm for bzr.dev.
1885
#. Make a distribution directory by running e.g. ``bzr export /tmp/bzr-<version>/`` in the working directory.
1887
#. Run make in /tmp/bzr-<version>. This creates the extensions from the pyrex source.
1889
#. Run the test suite in the distribution directory
1891
#. Run ``setup.py install`` --root=prefix to do a test install into your system directory, home directory, or some other prefix. Check the install worked and that the installed version is usable. (run the bzr script from the installed path with PYTHONPATH set to the site-packages directory it created). i.e. ::
1893
python setup.py install --root=installed
1894
PYTHONPATH=installed/usr/lib/python2.4/site-packages installed/usr/bin/bzr
1896
#. Clean the tree to get rid of .pyc files etc: make clean && rm -rf build && rm bzrlib/_*.c bzrlib/_*.so
1898
#. Generate the reference documentation in text format: make doc/en/user-reference/bzr_man.txt.
1900
#. Change back to your original branch and then run: make clean && make to create the compiled pyrex extensions. You then need to copy the .c files over to the exported directory.
1902
``find . -name "*.c"`` will tell you which files you need.
1904
#. Create the release tarball::
1906
cd /tmp && tar czf bzr-<version>.tar.gz bzr-<version>
1908
#. Sign the tarball with e.g. ``gpg --detach-sign -a bzr-0.10rc1.tar.gz``
1911
Publishing the release
1912
----------------------
1914
Now you have the releasable product. The next step is making it
1915
available to the world.
1917
#. In <https://launchpad.net/bzr/> click the "Release series" for this
1918
series, to take you to e.g. <https://launchpad.net/bzr/1.1>. Then
1919
click "Register a release", and add information about this release.
1921
#. Within that release, upload the source tarball and the GPG signature.
1923
(These used to also be uploaded to
1924
<sftp://escudero.ubuntu.com/srv/bazaar.canonical.com/www/releases/src>
1925
but that's not accessible to all developers, and gets some mime types
1928
#. Link from http://bazaar-vcs.org/Download to the tarball and signature.
1930
#. Update http://doc.bazaar-vcs.org/ to have a directory of documentation
1931
for this release. (Controlled by the ``update-bzr-docs`` script on
1932
escudero, and also update the ``latest`` symlink in
1933
``/srv/bazaar.canonical.com/doc/``.)
1935
#. Announce on the `Bazaar home page`__
1937
__ http://bazaar-vcs.org/
1940
Announcing the release
1941
----------------------
1943
Now that the release is publicly available, tell people about it.
1945
#. Announce to ``bazaar-announce`` and ``bazaar`` mailing lists.
1946
The announce mail will look something like this:
1948
| Subject: bzr 0.11 release candidate 1
1950
| INTRO HERE. Mention the release number and date, and why the release. (i.e. release candidate for testing, final release of a version, backport/bugfix etc).
1953
| http://bazaar-vcs.org/releases/src/bzr-VERSION.tar.gz
1954
| and GPG signature:
1955
| http://bazaar-vcs.org/releases/src/bzr-VERSION.tar.gz.sig
1957
| DESCRIBE-CHANGES-IN-OVERVIEW-HERE
1959
| DESCRIBE-when the next release will be (if there is another - i.e. this is a release candidate)
1961
| Many thanks to all the contributors to this release! I've included the
1962
| contents of NEWS for VERSION below:
1964
To generate the data from NEWS, just copy and paste the relevant news section and clean it up as appropriate. The main clean-up task is to confirm that all major changes are indeed covered. This can be done by running ``bzr log`` back to the point when the branch was opened and cross checking the changes against the NEWS entries.
1966
(RC announcements should remind plugin maintainers to update their plugins.)
1968
* For point releases (i.e. a release candidate, or an incremental fix to a released version) take everything in the relevant NEWS secion : for 0.11rc2 take everything in NEWS from the bzr 0.11rc2 line to the bzr 0.11rc1 line further down.
1970
* For major releases (i.e. 0.11, 0.12 etc), take all the combined NEWS sections from within that version: for 0.11 take all of the 0.11 specific section, plus 0.11rc2, plus 0.11rc1 etc.
1972
#. Update the `news side menu`__ -- this currently requires downloading the file, editing it, deleting it, and uploading a replacement.
1974
__ http://bazaar-vcs.org/site/menu?action=AttachFile&do=view&target=news.html
1976
#. Update the IRC channel topic. Use the ``/topic`` command to do this, ensuring the new topic text keeps the project name, web site link, etc.
1978
#. Announce on http://freshmeat.net/projects/bzr/
1980
This should be done for both release candidates and final releases. If you do not have a Freshmeat account yet, ask one of the existing admins.
1982
#. Update http://en.wikipedia.org/wiki/Bzr -- this should be done for final releases but not Release Candidates.
1984
#. Package maintainers should update packages when they see the
1989
#. Post to http://mail.python.org/mailman/listinfo/python-announce-list for major releases
1991
#. Update the python package index: <http://pypi.python.org/pypi/bzr> - best
1994
python setup.py register
1996
Remember to check the results afterwards.
1999
Making Win32 installers
2000
-----------------------
2002
**XXX:** This information is now probably obsolete, as Alexander uploads
2003
direct to Launchpad. --mbp 20080116
2005
Alexander Belchenko has been very good about getting packaged installers compiled (see Win32ReleaseChecklist for details). He generally e-mails John Arbash Meinel when they are ready. This is just a brief checklist of what needs to be done.
2007
#. Download and verify the sha1 sums and gpg signatures. Frequently the sha1 files are in dos mode, and need to be converted to unix mode (strip off the trailing ``\r``) before they veryify correctly.
2009
#. Upload to the Launchpad page for this release.
2011
#. Upload to escudero (to the b.c.c/www/releases/win32 directory) using sftp, lftp or rsync
2013
#. Cat the contents of the .sha1 files into the SHA1SUM.
2015
#. Update the SHA1SUM and MD5SUM files using something like ``md5sum bzr-0.14.0.win32.exe >> MD5SUM``. Make sure you use append (>>) rather than overwrite (>).
2017
#. Verify once again that everything is correct with ``sha1sum -c SHA1SUM`` and ``md5sum -c MD5SUM``.
2019
#. Update ``.htaccess`` so that the 'bzr-latest.win32.exe' links point to the latest release. This is not done for candidate releases, only for final releases. (example: bzr-0.14.0, but not bzr-0.14.0rc1).
2021
#. Make sure these urls work as expected:
2023
http://bazaar-vcs.org/releases/win32/bzr-latest.win32-py2.5.exe
2025
http://bazaar-vcs.org/releases/win32/bzr-latest.win32-py2.5.exe.asc
2027
http://bazaar-vcs.org/releases/win32/bzr-latest.win32-py2.4.exe
2029
http://bazaar-vcs.org/releases/win32/bzr-latest.win32-py2.4.exe.asc
2031
http://bazaar-vcs.org/releases/win32/bzr-setup-latest.exe
2033
http://bazaar-vcs.org/releases/win32/bzr-setup-latest.exe.asc
2035
They should all try to download a file with the correct version number.
2037
#. Update http://bazaar-vcs.org/Download to indicate the newly available versions.
2039
#. Update http://bazaar-vcs.org/WindowsDownloads to have the correct version number as well as the correct sha1sum displayed.
2042
The Bazaar PPA archive
2043
----------------------
2045
We build Ubuntu ``.deb`` packages for Bazaar as an important part of the release
2046
process. These packages are hosted in a `Personal Package Archive (PPA)`__ on
2047
Launchpad, at <https://launchpad.net/~bzr/+archive>.
2049
__ https://help.launchpad.net/PPAQuickStart
2051
We build packages for every supported Ubuntu release
2052
<https://wiki.ubuntu.com/Releases>. Packages need no longer be updated
2053
when the release passes end-of-life because all users should have then
2056
The ``debian/`` directory containing the packaging information is kept in
2057
branches on Launchpad, named like
2058
<https://code.launchpad.net/~bzr/bzrtools/packaging-dapper>
2060
Updating the PPA for a new release
2061
----------------------------------
2063
Preconditions for building these packages:
2065
* You must have a Launchpad account and be a member of the `~bzr`__ team
2067
__ https://edge.launchpad.net/~bzr/+members>
2069
* You must have a GPG key registered to your Launchpad account.
2071
* Configure ``dput`` to upload to our PPA with this section in your
2075
fqdn = ppa.launchpad.net
2077
incoming = ~bzr/ubuntu
2079
allow_unsigned_uploads = 0
2081
* You need a Ubuntu (or probably Debian) machine, and ::
2083
sudo apt-get install build-essential devscripts dput
2085
Here is the process; there are some steps which should be automated in
2088
#. You will need a working directory for each supported release, such as
2089
``~/bzr/Packaging/dapper``
2091
#. Download the official tarball of the release to e.g. ``~/bzr/Releases``
2093
#. Copy the original tarball into your per-disto directory, then untar it
2094
and if necessary rename it::
2096
cp -l ~/bzr/Releases/bzrtools-1.3.0.tar.gz bzrtools_1.3.0.orig.tar.gz
2097
tar xfvz bzrtools_1.3.0.orig.tar.gz
2098
mv bzrtools bzrtools-1.3.0
2100
#. Change into that directory and check out the packaging branch::
2104
bzr+ssh://bazaar.launchpad.net/~bzr/bzrtools/packaging-dapper \
2107
#. For Bazaar plugins, change the ``debian/control`` file to express a
2108
dependency on the correct version of ``bzr``.
2110
For bzrtools this is typically::
2112
Build-Depends-Indep: bzr (>= 1.3~), rsync
2113
Depends: ${python:Depends}, bzr (>= 1.3~), bzr (<< 1.4~), patch
2115
#. Make a new ``debian/changelog`` entry for the new release,
2116
either by using ``dch`` or just editing the file::
2118
dch -v '1.3.0-1~bazaar1~dapper1' -D dapper
2120
dch will default to the distro you're working in and this isn't checked
2121
against the version number (which is just our conversion). So make
2124
Make sure you have the correct email address for yourself, version
2125
number, and distribution. It should look something like this::
2127
> bzrtools (1.3.0-1~bazaar1~dapper1) dapper; urgency=low
2129
> * New upstream release.
2131
> -- John Sample <sample@example.com> Mon, 31 Mar 2008 12:36:27 +1100
2133
If you need to upload the package again to fix a problem, normally you
2134
should increment the last number in the version number, following the
2135
distro name. Make sure not to omit the initial ``-1``, and make sure
2136
that the distro name in the version is consistent with the target name
2137
outside the parenthesis.
2139
#. Commit these changes into the packaging branch::
2141
bzr ci -m '1.3.0-1~bazaar1~dapper1: New upstream release.' debian
2143
#. Build a source package::
2147
This will create a ``.changes`` file in the per-distro directory,
2148
and should invoke gpg to sign it with your key.
2149
Check that file is reasonable: it should be uploading to the intended
2150
distribution, have a .orig file included, and the right version number.
2152
#. Upload into the PPA::
2154
dput bzr-ppa ../bzrtools__1.3.0-1\~bazaar1\~dapper1_source.changes
2156
Don't forget the ``bzr-ppa`` component or dput will try to upload into
2157
the main archive by default. You can disable this by adding this
2158
section to your ``.dput.cf``::
2161
fqdn = SPECIFY.A.PPA.NAME
2163
#. You should soon get an "upload accepted" mail from Launchpad, which
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means that your package is waiting to be built. You can then track its
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progress in <https://launchpad.net/~bzr/+archive> and
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<https://launchpad.net/~bzr/+archive/+builds>.
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vim: ft=rst tw=74 ai
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removed
doc/developers/HACKING.txt
