/brz/remove-bazaar

--------------------

Bazaar Release Notes

--------------------

.. contents::

IN DEVELOPMENT

--------------

  CHANGES:

   * The syntax ``bzr diff branch1 branch2`` is no longer supported.

     Use ``bzr diff branch1 --new branch2`` instead. This change has

     been made to remove the ambiguity where ``branch2`` is in fact a

     specific file to diff within ``branch1``.

  FEATURES:

   * New option to use custom template-based formats in  ``bzr version-info``.

     (Lukáš Lalinský)

   * New smart method, ``Repository.stream_revisions_chunked``, for fetching

     revision data that streams revision data via a chunked encoding.  This

     avoids buffering large amounts of revision data on the server and on the

     client.  (Andrew Bennetts, #178353)

   * diff '--using' allows an external diff tool to be used for files.

     (Aaron Bentley)

   * New "lca" merge-type for fast everyday merging that also supports

     criss-cross merges.  (Aaron Bentley)

  IMPROVEMENTS:

   * ``annotate`` now doesn't require a working tree. (Lukáš Lalinský,

     #90049)

   * ``branch`` and ``checkout`` can now use files from a working tree to

     to speed up the process.  For checkout, this requires the new

     --files-from flag.  (Aaron Bentley)

   * ``bzr diff`` now sorts files in alphabetical order.  (Aaron Bentley)

   * ``bzr diff`` now works on branches without working trees. Tree-less

     branches can also be compared to each other and to working trees using

     the new diff options ``--old`` and ``--new``. Diffing between branches,

     with or without trees, now supports specific file filtering as well.

     (Ian Clatworthy, #6700)

   * ``bzr pack`` now orders revision texts in topological order, with newest

     at the start of the file, promoting linear reads for ``bzr log`` and the

     like. This partially fixes #154129. (Robert Collins)

   * Fetching between different repository formats with compatible models now

     takes advantage of the smart method to stream revisions.  (Andrew Bennetts)

   * Merge directives now fetch prerequisites from the target branch if

     needed.  (Aaron Bentley)

   * pycurl now handles digest authentication.

     (Vincent Ladeuil)

   * ``reconfigure`` can now convert from repositories.  (Aaron Bentley)

   * ``-l`` is now a short form for ``--limit`` in ``log``.  (Matt Nordhoff)

   * ``merge`` now warns when merge directives cause cherrypicks.

     (Aaron Bentley)

   * ``split`` now supported, to enable splitting large trees into smaller

     pieces.  (Aaron Bentley)

  BUGFIXES:

   * Avoid AttributeError when unlocking a pack repository when an error occurs.

     (Martin Pool, #180208)

   * Better handle short reads when processing multiple range requests.

     (Vincent Ladeuil, #179368)

   * build_tree acceleration uses the correct path when a file has been moved.

     (Aaron Bentley)

   * ``commit`` now succeeds when a checkout and its master branch share a

     repository.  (Aaron Bentley, #177592)

   * Fixed error reporting of unsupported timezone format in

     ``log --timezone``. (Lukáš Lalinský, #178722)

   * Fixed Unicode encoding error in ``ignored`` when the output is

     redirected to a pipe. (Lukáš Lalinský)

   * Fix traceback when sending large response bodies over the smart protocol

     on Windows. (Andrew Bennetts, #115781)

   * Fix ``urlutils.relative_url`` for the case of two ``file:///`` URLs

     pointed to different logical drives on Windows.

     (Alexander Belchenko, #90847)

   * HTTP test servers are now compatible with the http protocol version 1.1.

     (Vincent Ladeuil, #175524)

   * _KnitParentsProvider.get_parent_map now handles requests for ghosts

     correctly, instead of erroring or attributing incorrect parents to ghosts.

     (Aaron Bentley)

   * ``merge --weave --uncommitted`` now works.  (Aaron Bentley)

   * pycurl authentication handling was broken and incomplete. Fix handling of

     user:pass embedded in the urls.

     (Vincent Ladeuil, #177643)

   * Files inside non-directories are now handled like other conflict types.

     (Aaron Bentley, #177390)

   * ``reconfigure`` is able to convert trees into lightweight checkouts.

     (Aaron Bentley)

   * ``reconfigure`` can safely be interrupted while fetching.

     (Aaron Bentley, #179316)

   * Reduce lockdir timeout to 0 when running ``bzr serve``.  (Andrew Bennetts,

     #148087)

   * Test that the old ``version_info_format`` functions still work, even

     though they are deprecated. (John Arbash Meinel, ShenMaq, #177872)

   * Transform failures no longer cause ImmortalLimbo errors (Aaron Bentley,

     #137681)

   * ``uncommit`` works even when the commit messages of revisions to be

     removed use characters not supported in the terminal encoding.

     (Aaron Bentley)

   * When dumb http servers return whole files instead of the requested ranges,

     read the remaining bytes by chunks to avoid overflowing network buffers.

     (Vincent Ladeuil, #175886)

  DOCUMENTATION:

   * Minor tweaks made to the bug tracker integration documentation.

     (Ian Clatworthy)

   * Reference material has now be moved out of the User Guide and added

     to the User Reference. The User Reference has gained 4 sections as

     a result: Authenication Settings, Configuration Settings, Conflicts

     and Hooks. All help topics are now dumped into text format in the

     doc/en/user-reference directory for those who like browsing that

     information in their editor. (Ian Clatworthy)

   * *Using Bazaar with Launchpad* tutorial added. (Ian Clatworthy)

  INTERNALS:

   * Add -Dtimes debug flag, which records a timestamp against each mutter to

     the trace file, relative to the first mutter.  (Andrew Bennetts)

   * find_* methods available for BzrDirs, Branches and WorkingTrees.

     (Aaron Bentley)

   * Help topics can now be loaded from files. 

     (Ian Clatworthy, Alexander Belchenko)

   * get_parent_map now always provides tuples as its output.  (Aaron Bentley)

   * New method ``iter_inventories`` on Repository for access to many

     inventories. This is primarily used by the ``revision_trees`` method, as

     direct access to inventories is discouraged. (Robert Collins)

   * Parent Providers should now implement ``get_parent_map`` returning a

     dictionary instead of ``get_parents`` returning a list.

     ``Graph.get_parents`` is now deprecated. (John Arbash Meinel,

     Robert Collins)

   * Patience Diff now supports arbitrary python objects, as long as they

     support ``hash()``. (John Arbash Meinel)

   * Reduce selftest overhead to establish test names by memoization.

     (Vincent Ladeuil)

   * Repository has a new method ``has_revisions`` which signals the presence

     of many revisions by returning a set of the revisions listed which are

     present. This can be done by index queries without reading data for parent

     revision names etc. (Robert Collins)

  API BREAKS:

  TESTING:

   * Modules can now customise their tests by defining a ``load_tests``

     attribute. ``pydoc bzrlib.tests.TestUtil.TestLoader.loadTestsFromModule``

     for the documentation on this attribute. (Robert Collins)

   * New helper function ``bzrlib.tests.condition_id_re`` which helps

     filter tests based on a regular expression search on the tests id.

     (Robert Collins)

   * New helper function ``bzrlib.tests.condition_isinstance`` which helps

     filter tests based on class. (Robert Collins)

   * New helper function ``bzrlib.tests.exclude_suite_by_condition`` which

     generalises the ``exclude_suite_by_re`` function. (Robert Collins)

   * New helper function ``bzrlib.tests.filter_suite_by_condition`` which

     generalises the ``filter_suite_by_re`` function. (Robert Collins)

   * New helper method ``bzrlib.tests.exclude_tests_by_re`` which gives a new

     TestSuite that does not contain tests from the input that matched a

     regular expression. (Robert Collins)

   * New helper method ``bzrlib.tests.randomize_suite`` which returns a

     randomized copy of the input suite. (Robert Collins)

   * New helper method ``bzrlib.tests.split_suite_by_re`` which splits a test

     suite into two according to a regular expression. (Robert Collins)

   * Parametrize all http tests for the transport implementations, the http

     protocol versions (1.0 and 1.1) and the authentication schemes.

     (Vincent Ladeuil) 

   * The ``exclude_pattern`` and ``random_order`` parameters to the function

     ``bzrlib.tests.filter_suite_by_re`` have been deprecated. (Robert Collins)

   * The method ``bzrlib.tests.sort_suite_by_re`` has been deprecated. It is 

     replaced by the new helper methods added in this release. (Robert Collins)

bzr 1.0 2007-12-14

------------------

  DOCUMENTATION:

   * More improvements and fixes to the User Guide.  (Ian Clatworthy)

   * Add information on cherrypicking/rebasing to the User Guide.

     (Ian Clatworthy)

   * Improve bug tracker integration documentation. (Ian Clatworthy)

   * Minor edits to ``Bazaar in five minutes`` from David Roberts and

     to the rebasing section of the User Guide from Aaron Bentley.

     (Ian Clatworthy)

bzr 1.0rc3 2007-12-11

---------------------

  CHANGES:

   * If a traceback occurs, users are now asked to report the bug 

     through Launchpad (https://bugs.launchpad.net/bzr/), rather than 

     by mail to the mailing list.

     (Martin Pool)

  BUGFIXES:

   * Fix Makefile rules for doc generation. (Ian Clatworthy, #175207)

   * Give more feedback during long http downloads by making readv deliver data

     as it arrives for urllib, and issue more requests for pycurl. High latency

     networks are better handled by urllib, the pycurl implementation give more

     feedback but also incur more latency.

     (Vincent Ladeuil, #173010)

   * Implement _make_parents_provider on RemoteRepository, allowing generating

     bundles against branches on a smart server.  (Andrew Bennetts, #147836)

  DOCUMENTATION:

   * Improved user guide.  (Ian Clatworthy)

   * The single-page quick reference guide is now available as a PDF.

     (Ian Clatworthy)

  INTERNALS:

    * readv urllib http implementation is now a real iterator above the

      underlying socket and deliver data as soon as it arrives. 'get' still

      wraps its output in a StringIO.

      (Vincent Ladeuil)

bzr 1.0rc2 2007-12-07

---------------------

  IMPROVEMENTS:

   * Added a --coverage option to selftest. (Andrew Bennetts)

   * Annotate merge (merge-type=weave) now supports cherrypicking.

     (Aaron Bentley)

   * ``bzr commit`` now doesn't print the revision number twice. (Matt

     Nordhoff, #172612)

   * New configuration option ``bugtracker_<tracker_abbrevation>_url`` to

     define locations of bug trackers that are not directly supported by

     bzr or a plugin. The URL will be treated as a template and ``{id}``

     placeholders will be replaced by specific bug IDs.  (Lukáš Lalinský)

   * Support logging single merge revisions with short and line log formatters.

     (Kent Gibson)

   * User Guide enhanced with suggested readability improvements from

     Matt Revell and corrections from John Arbash Meinel. (Ian Clatworthy)

   * Quick Start Guide renamed to Quick Start Card, moved down in

     the catalog, provided in pdf and png format and updated to refer

     to ``send`` instead of ``bundle``. (Ian Clatworthy, #165080)

   * ``switch`` can now be used on heavyweight checkouts as well as

     lightweight ones. After switching a heavyweight checkout, the

     local branch is a mirror/cache of the new bound branch and

     uncommitted changes in the working tree are merged. As a safety

     check, if there are local commits in a checkout which have not

     been committed to the previously bound branch, then ``switch``

     fails unless the ``--force`` option is given. This option is

     now also required if the branch a lightweight checkout is pointing

     to has been moved. (Ian Clatworthy)

  INTERNALS:

    * New -Dhttp debug option reports http connections, requests and responses.

      (Vincent Ladeuil)

    * New -Dmerge debug option, which emits merge plans for merge-type=weave.

  BUGFIXES:

   * Better error message when running ``bzr cat`` on a non-existant branch.

     (Lukáš Lalinský, #133782)

   * Catch OSError 17 (file exists) in final phase of tree transform and show

     filename to user.

     (Alexander Belchenko, #111758)

   * Catch ShortReadvErrors while using pycurl. Also make readv more robust by

     allowing multiple GET requests to be issued if too many ranges are

     required.

     (Vincent Ladeuil, #172701)

   * Check for missing basis texts when fetching from packs to packs.

     (John Arbash Meinel, #165290)

   * Fall back to showing e-mail in ``log --short/--line`` if the 

     committer/author has only e-mail. (Lukáš Lalinský, #157026)

  API BREAKS:

   * Deprecate not passing a ``location`` argument to commit reporters'

     ``started`` methods. (Matt Nordhoff)

bzr 1.0rc1 2007-11-30

---------------------

  NOTES WHEN UPGRADING:

   * The default repository format is now ``pack-0.92``.  This 

     default is used when creating new repositories with ``init`` and 

     ``init-repo``, and when branching over bzr+ssh or bzr+hpss. 

     (See https://bugs.launchpad.net/bugs/164626)

     This format can be read and written by Bazaar 0.92 and later, and 

     data can be transferred to and from older formats.

     To upgrade, please reconcile your repository (``bzr reconcile``), and then

     upgrade (``bzr upgrade``). 

     ``pack-0.92`` offers substantially better scaling and performance than the

     previous knits format. Some operations are slower where the code already

     had bad scaling characteristics under knits, the pack format makes such

     operations more visible as part of being more scalable overall. We will

     correct such operations over the coming releases and encourage the filing

     of bugs on any operation which you observe to be slower in a packs

     repository. One particular case that we do not intend to fix is pulling

     data from a pack repository into a knit repository over a high latency

     link;  downgrading such data requires reinsertion of the file texts, and

     this is a classic space/time tradeoff. The current implementation is

     conservative on memory usage because we need to support converting data

     from any tree without problems.  

     (Robert Collins, Martin Pool, #164476)

  CHANGES:

   * Disable detection of plink.exe as possible ssh vendor. Plink vendor

     still available if user selects it explicitly with BZR_SSH environment

     variable. (Alexander Belchenko, workaround for bug #107593)

   * The pack format is now accessible as "pack-0.92", or "pack-0.92-subtree" 

     to enable the subtree functions (for example, for bzr-svn).  

     See http://doc.bazaar-vcs.org/latest/developer/packrepo.html

     (Martin Pool)

  FEATURES:

   * New ``authentication.conf`` file holding the password or other credentials

     for remote servers. This can be used for ssh, sftp, smtp and other 

     supported transports.

     (Vincent Ladeuil)

   * New rich-root and rich-root-pack formats, recording the same data about

     tree roots that's recorded for all other directories.

     (Aaron Bentley, #164639)

   * ``pack-0.92`` repositories can now be reconciled.

     (Robert Collins, #154173)

   * ``switch`` command added for changing the branch a lightweight checkout

     is associated with and updating the tree to reflect the latest content

     accordingly. This command was previously part of the BzrTools plug-in.

     (Ian Clatworthy, Aaron Bentley, David Allouche)

   * ``reconfigure`` command can now convert branches, trees, or checkouts to

     lightweight checkouts.  (Aaron Bentley)

  PERFORMANCE:

   * Commit updates the state of the working tree via a delta rather than

     supplying entirely new basis trees. For commit of a single specified file

     this reduces the wall clock time for commit by roughly a 30%.

     (Robert Collins, Martin Pool)

   * Commit with many automatically found deleted paths no longer performs

     linear scanning for the children of those paths during inventory

     iteration. This should fix commit performance blowing out when many such

     paths occur during commit. (Robert Collins, #156491)

   * Fetch with pack repositories will no longer read the entire history graph.

     (Robert Collins, #88319)

   * Revert takes out an appropriate lock when reverting to a basis tree, and

     does not read the basis inventory twice. (Robert Collins)

   * Diff does not require an inventory to be generated on dirstate trees.

     (Aaron Bentley, #149254)

   * New annotate merge (--merge-type=weave) implementation is fast on

     versionedfiles withough cached annotations, e.g. pack-0.92.

     (Aaron Bentley)

  IMPROVEMENTS:

   * ``bzr merge`` now warns when it encounters a criss-cross merge.

     (Aaron Bentley)

   * ``bzr send`` now doesn't require the target e-mail address to be

     specified on the command line if an interactive e-mail client is used.

     (Lukáš Lalinský)

   * ``bzr tags`` now prints the revision number for each tag, instead of

     the revision id, unless --show-ids is passed. In addition, tags can be

     sorted chronologically instead of lexicographically with --sort=time.

     (Adeodato Simó, #120231)

   * Windows standalone version of bzr is able to load system-wide plugins from

     "plugins" subdirectory in installation directory. In addition standalone

     installer write to the registry (HKLM\SOFTWARE\Bazaar) useful info 

     about paths and bzr version. (Alexander Belchenko, #129298)

  DOCUMENTATION:

  BUG FIXES:

   * A progress bar has been added for knitpack -> knitpack fetching.

     (Robert Collins, #157789, #159147)

   * Branching from a branch via smart server now preserves the repository

     format. (Andrew Bennetts,  #164626)

   * ``commit`` is now able to invoke an external editor in a non-ascii

     directory. (Daniel Watkins, #84043)

   * Catch connection errors for ftp.

     (Vincent Ladeuil, #164567)

   * ``check`` no longer reports spurious unreferenced text versions.

     (Robert Collins, John A Meinel, #162931, #165071)

   * Conflicts are now resolved recursively by ``revert``.

     (Aaron Bentley, #102739)

   * Detect invalid transport reuse attempts by catching invalid URLs.

     (Vincent Ladeuil, #161819)

   * Deleting a file without removing it shows a correct diff, not a traceback.

     (Aaron Bentley)

   * Do no use timeout in HttpServer anymore.

     (Vincent Ladeuil, #158972).

   * Don't catch the exceptions related to the http pipeline status before

     retrying an http request or some programming errors may be masked.

     (Vincent Ladeuil, #160012)

   * Fix ``bzr rm`` to not delete modified and ignored files.

     (Lukáš Lalinský, #172598)

   * Fix exception when revisionspec contains merge revisons but log

     formatter doesn't support merge revisions. (Kent Gibson, #148908)

   * Fix exception when ScopeReplacer is assigned to before any members have

     been retrieved.  (Aaron Bentley)

   * Fix multiple connections during checkout --lightweight.

     (Vincent Ladeuil, #159150)

   * Fix possible error in insert_data_stream when copying between 

     pack repositories over bzr+ssh or bzr+http.  

     KnitVersionedFile.get_data_stream now makes sure that requested

     compression parents are sent before any delta hunks that depend 

     on them.

     (Martin Pool, #164637)

   * Fix typo in limiting offsets coalescing for http, leading to

     whole files being downloaded instead of parts.

     (Vincent Ladeuil, #165061)

   * FTP server errors don't error in the error handling code.

     (Robert Collins, #161240)

   * Give a clearer message when a pull fails because the source needs

     to be reconciled.

     (Martin Pool, #164443)

   * It is clearer when a plugin cannot be loaded because of its name, and a

     suggestion for an acceptable name is given. (Daniel Watkins, #103023)

   * Leave port as None in transport objects if user doesn't

     specify a port in urls.

     (vincent Ladeuil, #150860)

   * Make sure Repository.fetch(self) is properly a no-op for all

     Repository implementations. (John Arbash Meinel, #158333)

   * Mark .bzr directories as "hidden" on Windows.

     (Alexander Belchenko, #71147)

   * ``merge --uncommitted`` can now operate on a single file.

     (Aaron Bentley, Lukáš Lalinský, #136890)

   * Obsolete packs are now cleaned up by pack and autopack operations.

     (Robert Collins, #153789)

   * Operations pulling data from a smart server where the underlying

     repositories are not both annotated/both unannotated will now work.

     (Robert Collins, #165304).

   * Reconcile now shows progress bars. (Robert Collins, #159351)

   * ``RemoteBranch`` was not initializing ``self._revision_id_to_revno_map``

     properly. (John Arbash Meinel, #162486)

   * Removing an already-removed file reports the file does not exist. (Daniel

     Watkins, #152811)

   * Rename on Windows is able to change filename case.

     (Alexander Belchenko, #77740)

   * Return error instead of a traceback for ``bzr log -r0``.

     (Kent Gibson, #133751)

   * Return error instead of a traceback when bzr is unable to create

     symlink on some platforms (e.g. on Windows).

     (Alexander Belchenko, workaround for #81689)

   * Revert doesn't crash when restoring a single file from a deleted

     directory. (Aaron Bentley)

   * Stderr output via logging mechanism now goes through encoded wrapper

     and no more uses utf-8, but terminal encoding instead. So all unicode

     strings now should be readable in non-utf-8 terminal.

     (Alexander Belchenko, #54173)

   * The error message when ``move --after`` should be used makes how to do so

     clearer. (Daniel Watkins, #85237)

   * Unicode-safe output from ``bzr info``. The output will be encoded

     using the terminal encoding and unrepresentable characters will be

     replaced by '?'. (Lukáš Lalinský, #151844)

   * Working trees are no longer created when pushing into a local no-trees

     repo. (Daniel Watkins, #50582)

   * Upgrade util/configobj to version 4.4.0.

     (Vincent Ladeuil, #151208).

   * Wrap medusa ftp test server as an FTPServer feature.

     (Vincent Ladeuil, #157752)

  API BREAKS:

   * ``osutils.backup_file`` is deprecated. Actually it's not used in bzrlib

     during very long time. (Alexander Belchenko)

   * The return value of

     ``VersionedFile.iter_lines_added_or_present_in_versions`` has been

     changed. Previously it was an iterator of lines, now it is an iterator of

     (line, version_id) tuples. This change has been made to aid reconcile and

     fetch operations. (Robert Collins)

   * ``bzrlib.repository.get_versioned_file_checker`` is now private.

     (Robert Collins)

   * The Repository format registry default has been removed; it was previously

     obsoleted by the bzrdir format default, which implies a default repository

     format.

     (Martin Pool)

  INTERNALS:

   * Added ``ContainerSerialiser`` and ``ContainerPushParser`` to

     ``bzrlib.pack``.  These classes provide more convenient APIs for generating

     and parsing containers from streams rather than from files.  (Andrew

     Bennetts)

   * New module ``lru_cache`` providing a cache for use by tasks that need

     semi-random access to large amounts of data. (John A Meinel)

   * InventoryEntry.diff is now deprecated.  Please use diff.DiffTree instead.

  TESTING:

bzr 0.92 2007-11-05

-------------------

  CHANGES:

  * New uninstaller on Win32.  (Alexander Belchenko)

bzr 0.92rc1 2007-10-29

----------------------

  NOTES WHEN UPGRADING:

  CHANGES:

   * ``bzr`` now returns exit code 4 if an internal error occurred, and 

     3 if a normal error occurred.  (Martin Pool)

   * ``pull``, ``merge`` and ``push`` will no longer silently correct some

     repository index errors that occured as a result of the Weave disk format.

     Instead the ``reconcile`` command needs to be run to correct those

     problems if they exist (and it has been able to fix most such problems

     since bzr 0.8). Some new problems have been identified during this release

     and you should run ``bzr check`` once on every repository to see if you

     need to reconcile. If you cannot ``pull`` or ``merge`` from a remote

     repository due to mismatched parent errors - a symptom of index errors -

     you should simply take a full copy of that remote repository to a clean

     directory outside any local repositories, then run reconcile on it, and

     finally pull from it locally. (And naturally email the repositories owner

     to ask them to upgrade and run reconcile).

     (Robert Collins)

  FEATURES:

   * New ``knitpack-experimental`` repository format. This is interoperable with

     the ``dirstate-tags`` format but uses a smarter storage design that greatly

     speeds up many operations, both local and remote. This new format can be

     used as an option to the ``init``, ``init-repository`` and ``upgrade``

     commands. See http://doc.bazaar-vcs.org/0.92/developers/knitpack.html

     for further details. (Robert Collins)

   * For users of bzr-svn (and those testing the prototype subtree support) that

     wish to try packs, a new ``knitpack-subtree-experimental`` format has also

     been added. This is interoperable with the ``dirstate-subtrees`` format.

     (Robert Collins)

   * New ``reconfigure`` command. (Aaron Bentley)

   * New ``revert --forget-merges`` command, which removes the record of a pending 

     merge without affecting the working tree contents.  (Martin Pool)

   * New ``bzr_remote_path`` configuration variable allows finer control of

     remote bzr locations than BZR_REMOTE_PATH environment variable.

     (Aaron Bentley)

   * New ``launchpad-login`` command to tell Bazaar your Launchpad

     user ID.  This can then be used by other functions of the

     Launchpad plugin. (James Henstridge)

  PERFORMANCE:

   * Commit in quiet mode is now slightly faster as the information to

     output is no longer calculated. (Ian Clatworthy)

   * Commit no longer checks for new text keys during insertion when the

     revision id was deterministically unique. (Robert Collins)

   * Committing a change which is not a merge and does not change the number of

     files in the tree is faster by utilising the data about whether files are

     changed to determine if the tree is unchanged rather than recalculating

     it at the end of the commit process. (Robert Collins)

   * Inventory serialisation no longer double-sha's the content.

     (Robert Collins)

   * Knit text reconstruction now avoids making copies of the lines list for