/brz/remove-bazaar : contents of bzrlib/commit.py at revision 2790.2.1

: (revision 2790.2.1)

To get this branch, use:

bzr branch
http://gegoxaren.bato24.eu/bzr/brz/remove-bazaar

# Copyright (C) 2005, 2006, 2007 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


# The newly committed revision is going to have a shape corresponding
# to that of the working inventory.  Files that are not in the
# working tree and that were in the predecessor are reported as
# removed --- this can include files that were either removed from the
# inventory or deleted in the working tree.  If they were only
# deleted from disk, they are removed from the working inventory.

# We then consider the remaining entries, which will be in the new
# version.  Directory entries are simply copied across.  File entries
# must be checked to see if a new version of the file should be
# recorded.  For each parent revision inventory, we check to see what
# version of the file was present.  If the file was present in at
# least one tree, and if it was the same version in all the trees,
# then we can just refer to that version.  Otherwise, a new version
# representing the merger of the file versions must be added.

# TODO: Update hashcache before and after - or does the WorkingTree
# look after that?

# TODO: Rather than mashing together the ancestry and storing it back,
# perhaps the weave should have single method which does it all in one
# go, avoiding a lot of redundant work.

# TODO: Perhaps give a warning if one of the revisions marked as
# merged is already in the ancestry, and then don't record it as a
# distinct parent.

# TODO: If the file is newly merged but unchanged from the version it
# merges from, then it should still be reported as newly added
# relative to the basis revision.

# TODO: Change the parameter 'rev_id' to 'revision_id' to be consistent with
# the rest of the code; add a deprecation of the old name.

import os
import re
import sys
import time

from cStringIO import StringIO

from bzrlib import (
    debug,
    errors,
    inventory,
    tree,
    )
from bzrlib.branch import Branch
import bzrlib.config
from bzrlib.errors import (BzrError, PointlessCommit,
                           ConflictsInTree,
                           StrictCommitFailed
                           )
from bzrlib.osutils import (kind_marker, isdir,isfile, is_inside_any, 
                            is_inside_or_parent_of_any,
                            quotefn, sha_file, split_lines)
from bzrlib.testament import Testament
from bzrlib.trace import mutter, note, warning
from bzrlib.xml5 import serializer_v5
from bzrlib.inventory import Inventory, InventoryEntry
from bzrlib import symbol_versioning
from bzrlib.symbol_versioning import (deprecated_passed,
        deprecated_function,
        DEPRECATED_PARAMETER)
from bzrlib.workingtree import WorkingTree
import bzrlib.ui


class NullCommitReporter(object):
    """I report on progress of a commit."""

    def snapshot_change(self, change, path):
        pass

    def completed(self, revno, rev_id):
        pass

    def deleted(self, file_id):
        pass

    def escaped(self, escape_count, message):
        pass

    def missing(self, path):
        pass

    def renamed(self, change, old_path, new_path):
        pass


class ReportCommitToLog(NullCommitReporter):

    def _note(self, format, *args):
        """Output a message.

        Subclasses may choose to override this method.
        """
        note(format, *args)

    def snapshot_change(self, change, path):
        if change == 'unchanged':
            return
        if change == 'added' and path == '':
            return
        self._note("%s %s", change, path)

    def completed(self, revno, rev_id):
        self._note('Committed revision %d.', revno)
    
    def deleted(self, file_id):
        self._note('deleted %s', file_id)

    def escaped(self, escape_count, message):
        self._note("replaced %d control characters in message", escape_count)

    def missing(self, path):
        self._note('missing %s', path)

    def renamed(self, change, old_path, new_path):
        self._note('%s %s => %s', change, old_path, new_path)


class Commit(object):
    """Task of committing a new revision.

    This is a MethodObject: it accumulates state as the commit is
    prepared, and then it is discarded.  It doesn't represent
    historical revisions, just the act of recording a new one.

            missing_ids
            Modified to hold a list of files that have been deleted from
            the working directory; these should be removed from the
            working inventory.
    """
    def __init__(self,
                 reporter=None,
                 config=None):
        if reporter is not None:
            self.reporter = reporter
        else:
            self.reporter = NullCommitReporter()
        self.config = config
        
    def commit(self,
               message=None,
               timestamp=None,
               timezone=None,
               committer=None,
               specific_files=None,
               rev_id=None,
               allow_pointless=True,
               strict=False,
               verbose=False,
               revprops=None,
               working_tree=None,
               local=False,
               reporter=None,
               config=None,
               message_callback=None,
               recursive='down'):
        """Commit working copy as a new revision.

        :param message: the commit message (it or message_callback is required)

        :param timestamp: if not None, seconds-since-epoch for a
            postdated/predated commit.

        :param specific_files: If true, commit only those files.

        :param rev_id: If set, use this as the new revision id.
            Useful for test or import commands that need to tightly
            control what revisions are assigned.  If you duplicate
            a revision id that exists elsewhere it is your own fault.
            If null (default), a time/random revision id is generated.

        :param allow_pointless: If true (default), commit even if nothing
            has changed and no merges are recorded.

        :param strict: If true, don't allow a commit if the working tree
            contains unknown files.

        :param revprops: Properties for new revision
        :param local: Perform a local only commit.
        :param recursive: If set to 'down', commit in any subtrees that have
            pending changes of any sort during this commit.
        """
        mutter('preparing to commit')

        if working_tree is None:
            raise BzrError("working_tree must be passed into commit().")
        else:
            self.work_tree = working_tree
            self.branch = self.work_tree.branch
            if getattr(self.work_tree, 'requires_rich_root', lambda: False)():
                if not self.branch.repository.supports_rich_root():
                    raise errors.RootNotRich()
        if message_callback is None:
            if message is not None:
                if isinstance(message, str):
                    message = message.decode(bzrlib.user_encoding)
                message_callback = lambda x: message
            else:
                raise BzrError("The message or message_callback keyword"
                               " parameter is required for commit().")

        self.bound_branch = None
        self.local = local
        self.master_branch = None
        self.master_locked = False
        self.rev_id = None
        self.specific_files = specific_files
        self.allow_pointless = allow_pointless
        self.recursive = recursive
        self.revprops = revprops
        self.message_callback = message_callback
        self.timestamp = timestamp
        self.timezone = timezone
        self.committer = committer
        self.strict = strict
        self.verbose = verbose

        if reporter is None and self.reporter is None:
            self.reporter = NullCommitReporter()
        elif reporter is not None:
            self.reporter = reporter

        self.work_tree.lock_write()
        self.pb = bzrlib.ui.ui_factory.nested_progress_bar()
        self.basis_tree = self.work_tree.basis_tree()
        self.basis_tree.lock_read()
        try:
            # Cannot commit with conflicts present.
            if len(self.work_tree.conflicts()) > 0:
                raise ConflictsInTree

            # Setup the bound branch variables as needed.
            self._check_bound_branch()

            # Check that the working tree is up to date
            old_revno, new_revno = self._check_out_of_date_tree()

            if self.config is None:
                self.config = self.branch.get_config()

            # If provided, ensure the specified files are versioned
            if specific_files is not None:
                # Note: We don't actually need the IDs here. This routine
                # is being called because it raises PathNotVerisonedError
                # as a side effect of finding the IDs.
                # XXX: Dont we have filter_unversioned to do this more
                # cheaply?
                tree.find_ids_across_trees(specific_files,
                                           [self.basis_tree, self.work_tree])

            # Setup the progress bar. As the number of files that need to be
            # committed in unknown, progress is reported as stages.
            # We keep track of entries separately though and include that
            # information in the progress bar during the relevant stages.
            self.pb_stage_name = ""
            self.pb_stage_count = 0
            self.pb_stage_total = 5
            if self.bound_branch:
                self.pb_stage_total += 1
            self.pb.show_pct = False
            self.pb.show_spinner = False
            self.pb.show_eta = False
            self.pb.show_count = True
            self.pb.show_bar = True

            # After a merge, a selected file commit is not supported.
            # See 'bzr help merge' for an explanation as to why.
            self.basis_inv = self.basis_tree.inventory
            self._gather_parents()
            if len(self.parents) > 1 and self.specific_files:
                raise errors.CannotCommitSelectedFileMerge(self.specific_files)
            
            # Collect the changes
            self._set_progress_stage("Collecting changes",
                    entries_title="Directory")
            self.builder = self.branch.get_commit_builder(self.parents,
                self.config, timestamp, timezone, committer, revprops, rev_id)
            
            try:
                self._update_builder_with_changes()
                self._check_pointless()

                # TODO: Now the new inventory is known, check for conflicts.
                # ADHB 2006-08-08: If this is done, populate_new_inv should not add
                # weave lines, because nothing should be recorded until it is known
                # that commit will succeed.
                self._set_progress_stage("Saving data locally")
                self.builder.finish_inventory()

                # Prompt the user for a commit message if none provided
                message = message_callback(self)
                assert isinstance(message, unicode), type(message)
                self.message = message
                self._escape_commit_message()

                # Add revision data to the local branch
                self.rev_id = self.builder.commit(self.message)

            except:
                self.builder.abort()
                raise

            self._process_pre_hooks(old_revno, new_revno)

            # Upload revision data to the master.
            # this will propagate merged revisions too if needed.
            if self.bound_branch:
                self._set_progress_stage("Uploading data to master branch")
                self.master_branch.repository.fetch(self.branch.repository,
                                                    revision_id=self.rev_id)
                # now the master has the revision data
                # 'commit' to the master first so a timeout here causes the
                # local branch to be out of date
                self.master_branch.set_last_revision_info(new_revno,
                                                          self.rev_id)

            # and now do the commit locally.
            self.branch.set_last_revision_info(new_revno, self.rev_id)

            # Make the working tree up to date with the branch
            self._set_progress_stage("Updating the working tree")
            rev_tree = self.builder.revision_tree()
            self.work_tree.set_parent_trees([(self.rev_id, rev_tree)])
            self.reporter.completed(new_revno, self.rev_id)
            self._process_post_hooks(old_revno, new_revno)
        finally:
            self._cleanup()
        return self.rev_id

    def _any_real_changes(self):
        """Are there real changes between new_inventory and basis?

        For trees without rich roots, inv.root.revision changes every commit.
        But if that is the only change, we want to treat it as though there
        are *no* changes.
        """
        new_entries = self.builder.new_inventory.iter_entries()
        basis_entries = self.basis_inv.iter_entries()
        new_path, new_root_ie = new_entries.next()
        basis_path, basis_root_ie = basis_entries.next()

        # This is a copy of InventoryEntry.__eq__ only leaving out .revision
        def ie_equal_no_revision(this, other):
            return ((this.file_id == other.file_id)
                    and (this.name == other.name)
                    and (this.symlink_target == other.symlink_target)
                    and (this.text_sha1 == other.text_sha1)
                    and (this.text_size == other.text_size)
                    and (this.text_id == other.text_id)
                    and (this.parent_id == other.parent_id)
                    and (this.kind == other.kind)
                    and (this.executable == other.executable)
                    and (this.reference_revision == other.reference_revision)
                    )
        if not ie_equal_no_revision(new_root_ie, basis_root_ie):
            return True

        for new_ie, basis_ie in zip(new_entries, basis_entries):
            if new_ie != basis_ie:
                return True

        # No actual changes present
        return False

    def _check_pointless(self):
        if self.allow_pointless:
            return
        # A merge with no effect on files
        if len(self.parents) > 1:
            return
        # work around the fact that a newly-initted tree does differ from its
        # basis
        if len(self.basis_inv) == 0 and len(self.builder.new_inventory) == 1:
            raise PointlessCommit()
        # Shortcut, if the number of entries changes, then we obviously have
        # a change
        if len(self.builder.new_inventory) != len(self.basis_inv):
            return
        # If length == 1, then we only have the root entry. Which means
        # that there is no real difference (only the root could be different)
        if (len(self.builder.new_inventory) != 1 and self._any_real_changes()):
            return
        raise PointlessCommit()

    def _check_bound_branch(self):
        """Check to see if the local branch is bound.

        If it is bound, then most of the commit will actually be
        done using the remote branch as the target branch.
        Only at the end will the local branch be updated.
        """
        if self.local and not self.branch.get_bound_location():
            raise errors.LocalRequiresBoundBranch()

        if not self.local:
            self.master_branch = self.branch.get_master_branch()

        if not self.master_branch:
            # make this branch the reference branch for out of date checks.
            self.master_branch = self.branch
            return

        # If the master branch is bound, we must fail
        master_bound_location = self.master_branch.get_bound_location()
        if master_bound_location:
            raise errors.CommitToDoubleBoundBranch(self.branch,
                    self.master_branch, master_bound_location)

        # TODO: jam 20051230 We could automatically push local
        #       commits to the remote branch if they would fit.
        #       But for now, just require remote to be identical
        #       to local.
        
        # Make sure the local branch is identical to the master
        master_info = self.master_branch.last_revision_info()
        local_info = self.branch.last_revision_info()
        if local_info != master_info:
            raise errors.BoundBranchOutOfDate(self.branch,
                    self.master_branch)

        # Now things are ready to change the master branch
        # so grab the lock
        self.bound_branch = self.branch
        self.master_branch.lock_write()
        self.master_locked = True

    def _check_out_of_date_tree(self):
        """Check that the working tree is up to date.

        :return: old_revision_number,new_revision_number tuple
        """
        try:
            first_tree_parent = self.work_tree.get_parent_ids()[0]
        except IndexError:
            # if there are no parents, treat our parent as 'None'
            # this is so that we still consider the master branch
            # - in a checkout scenario the tree may have no
            # parents but the branch may do.
            first_tree_parent = bzrlib.revision.NULL_REVISION
        old_revno, master_last = self.master_branch.last_revision_info()
        if master_last != first_tree_parent:
            if master_last != bzrlib.revision.NULL_REVISION:
                raise errors.OutOfDateTree(self.work_tree)
        if self.branch.repository.has_revision(first_tree_parent):
            new_revno = old_revno + 1
        else:
            # ghost parents never appear in revision history.
            new_revno = 1
        return old_revno,new_revno

    def _process_pre_hooks(self, old_revno, new_revno):
        """Process any registered pre commit hooks."""
        self._set_progress_stage("Running pre_commit hooks")
        self._process_hooks("pre_commit", old_revno, new_revno)

    def _process_post_hooks(self, old_revno, new_revno):
        """Process any registered post commit hooks."""
        # Process the post commit hooks, if any
        self._set_progress_stage("Running post_commit hooks")
        # old style commit hooks - should be deprecated ? (obsoleted in
        # 0.15)
        if self.config.post_commit() is not None:
            hooks = self.config.post_commit().split(' ')
            # this would be nicer with twisted.python.reflect.namedAny
            for hook in hooks:
                result = eval(hook + '(branch, rev_id)',
                              {'branch':self.branch,
                               'bzrlib':bzrlib,
                               'rev_id':self.rev_id})
        # process new style post commit hooks
        self._process_hooks("post_commit", old_revno, new_revno)

    def _process_hooks(self, hook_name, old_revno, new_revno):
        if not Branch.hooks[hook_name]:
            return
        
        # new style commit hooks:
        if not self.bound_branch:
            hook_master = self.branch
            hook_local = None
        else:
            hook_master = self.master_branch
            hook_local = self.branch
        # With bound branches, when the master is behind the local branch,
        # the 'old_revno' and old_revid values here are incorrect.
        # XXX: FIXME ^. RBC 20060206
        if self.parents:
            old_revid = self.parents[0]
        else:
            old_revid = bzrlib.revision.NULL_REVISION
        
        if hook_name == "pre_commit":
            future_tree = self.builder.revision_tree()
            tree_delta = future_tree.changes_from(self.basis_tree,
                                             include_root=True)
        
        for hook in Branch.hooks[hook_name]:
            # show the running hook in the progress bar. As hooks may
            # end up doing nothing (e.g. because they are not configured by
            # the user) this is still showing progress, not showing overall
            # actions - its up to each plugin to show a UI if it want's to
            # (such as 'Emailing diff to foo@example.com').
            self.pb_stage_name = "Running %s hooks [%s]" % \
                (hook_name, Branch.hooks.get_hook_name(hook))
            self._emit_progress()
            if 'hooks' in debug.debug_flags:
                mutter("Invoking commit hook: %r", hook)
            if hook_name == "post_commit":
                hook(hook_local, hook_master, old_revno, old_revid, new_revno,
                     self.rev_id)
            elif hook_name == "pre_commit":
                hook(hook_local, hook_master,
                     old_revno, old_revid, new_revno, self.rev_id,
                     tree_delta, future_tree)

    def _cleanup(self):
        """Cleanup any open locks, progress bars etc."""
        cleanups = [self._cleanup_bound_branch,
                    self.basis_tree.unlock,
                    self.work_tree.unlock,
                    self.pb.finished]
        found_exception = None
        for cleanup in cleanups:
            try:
                cleanup()
            # we want every cleanup to run no matter what.
            # so we have a catchall here, but we will raise the
            # last encountered exception up the stack: and
            # typically this will be useful enough.
            except Exception, e:
                found_exception = e
        if found_exception is not None: 
            # don't do a plan raise, because the last exception may have been
            # trashed, e is our sure-to-work exception even though it loses the
            # full traceback. XXX: RBC 20060421 perhaps we could check the
            # exc_info and if its the same one do a plain raise otherwise 
            # 'raise e' as we do now.
            raise e

    def _cleanup_bound_branch(self):
        """Executed at the end of a try/finally to cleanup a bound branch.

        If the branch wasn't bound, this is a no-op.
        If it was, it resents self.branch to the local branch, instead
        of being the master.
        """
        if not self.bound_branch:
            return
        if self.master_locked:
            self.master_branch.unlock()

    def _escape_commit_message(self):
        """Replace xml-incompatible control characters."""
        # FIXME: RBC 20060419 this should be done by the revision
        # serialiser not by commit. Then we can also add an unescaper
        # in the deserializer and start roundtripping revision messages
        # precisely. See repository_implementations/test_repository.py
        
        # Python strings can include characters that can't be
        # represented in well-formed XML; escape characters that
        # aren't listed in the XML specification
        # (http://www.w3.org/TR/REC-xml/#NT-Char).
        self.message, escape_count = re.subn(
            u'[^\x09\x0A\x0D\u0020-\uD7FF\uE000-\uFFFD]+',
            lambda match: match.group(0).encode('unicode_escape'),
            self.message)
        if escape_count:
            self.reporter.escaped(escape_count, self.message)

    def _gather_parents(self):
        """Record the parents of a merge for merge detection."""
        # TODO: Make sure that this list doesn't contain duplicate 
        # entries and the order is preserved when doing this.
        self.parents = self.work_tree.get_parent_ids()
        self.parent_invs = [self.basis_inv]
        for revision in self.parents[1:]:
            if self.branch.repository.has_revision(revision):
                mutter('commit parent revision {%s}', revision)
                inventory = self.branch.repository.get_inventory(revision)
                self.parent_invs.append(inventory)
            else:
                mutter('commit parent ghost revision {%s}', revision)

    def _update_builder_with_changes(self):
        """Update the commit builder with the data about what has changed.
        """
        # Build the revision inventory.
        #
        # This starts by creating a new empty inventory. Depending on
        # which files are selected for commit, and what is present in the
        # current tree, the new inventory is populated. inventory entries 
        # which are candidates for modification have their revision set to
        # None; inventory entries that are carried over untouched have their
        # revision set to their prior value.
        #
        # ESEPARATIONOFCONCERNS: this function is diffing and using the diff
        # results to create a new inventory at the same time, which results
        # in bugs like #46635.  Any reason not to use/enhance Tree.changes_from?
        # ADHB 11-07-2006

        specific_files = self.specific_files
        mutter("Selecting files for commit with filter %s", specific_files)

        # Check and warn about old CommitBuilders
        if not self.builder.record_root_entry:
            symbol_versioning.warn('CommitBuilders should support recording'
                ' the root entry as of bzr 0.10.', DeprecationWarning, 
                stacklevel=1)
            self.builder.new_inventory.add(self.basis_inv.root.copy())

        # Build the new inventory
        self._populate_from_inventory(specific_files)

        # If specific files are selected, then all un-selected files must be
        # recorded in their previous state. For more details, see
        # https://lists.ubuntu.com/archives/bazaar/2007q3/028476.html.
        if specific_files:
            for path, new_ie in self.basis_inv.iter_entries():
                if new_ie.file_id in self.builder.new_inventory:
                    continue
                if is_inside_any(specific_files, path):
                    continue
                ie = new_ie.copy()
                ie.revision = None
                self.builder.record_entry_contents(ie, self.parent_invs, path,
                                                   self.basis_tree)

        # Report what was deleted. We could skip this when no deletes are
        # detected to gain a performance win, but it arguably serves as a
        # 'safety check' by informing the user whenever anything disappears.
        for path, ie in self.basis_inv.iter_entries():
            if ie.file_id not in self.builder.new_inventory:
                self.reporter.deleted(path)

    def _populate_from_inventory(self, specific_files):
        """Populate the CommitBuilder by walking the working tree inventory."""
        if self.strict:
            # raise an exception as soon as we find a single unknown.
            for unknown in self.work_tree.unknowns():
                raise StrictCommitFailed()
               
        deleted_ids = []
        deleted_paths = set()
        work_inv = self.work_tree.inventory
        assert work_inv.root is not None
        entries = work_inv.iter_entries()
        if not self.builder.record_root_entry:
            entries.next()
        for path, existing_ie in entries:
            file_id = existing_ie.file_id
            name = existing_ie.name
            parent_id = existing_ie.parent_id
            kind = existing_ie.kind
            if kind == 'directory':
                self._next_progress_entry()

            # Skip files that have been deleted from the working tree.
            # The deleted files/directories are also recorded so they
            # can be explicitly unversioned later. Note that when a
            # filter of specific files is given, we must only skip/record
            # deleted files matching that filter.
            if is_inside_any(deleted_paths, path):
                continue
            if not specific_files or is_inside_any(specific_files, path):
                if not self.work_tree.has_filename(path):
                    deleted_paths.add(path)
                    self.reporter.missing(path)
                    deleted_ids.append(file_id)
                    continue
            try:
                kind = self.work_tree.kind(file_id)
                # TODO: specific_files filtering before nested tree processing
                if kind == 'tree-reference' and self.recursive == 'down':
                    self._commit_nested_tree(file_id, path)
            except errors.NoSuchFile:
                pass

            # Record an entry for this item
            # Note: I don't particularly want to have the existing_ie
            # parameter but the test suite currently (28-Jun-07) breaks
            # without it thanks to a unicode normalisation issue. :-(
            definitely_changed = kind != existing_ie.kind 
            self._record_entry(path, file_id, specific_files, kind, name,
                parent_id, definitely_changed, existing_ie)

        # Unversion IDs that were found to be deleted
        self.work_tree.unversion(deleted_ids)

    def _commit_nested_tree(self, file_id, path):
        "Commit a nested tree."
        sub_tree = self.work_tree.get_nested_tree(file_id, path)
        # FIXME: be more comprehensive here:
        # this works when both trees are in --trees repository,
        # but when both are bound to a different repository,
        # it fails; a better way of approaching this is to 
        # finally implement the explicit-caches approach design
        # a while back - RBC 20070306.
        if sub_tree.branch.repository.has_same_location(
            self.work_tree.branch.repository):
            sub_tree.branch.repository = \
                self.work_tree.branch.repository
        try:
            sub_tree.commit(message=None, revprops=self.revprops,
                recursive=self.recursive,
                message_callback=self.message_callback,
                timestamp=self.timestamp, timezone=self.timezone,
                committer=self.committer,
                allow_pointless=self.allow_pointless,
                strict=self.strict, verbose=self.verbose,
                local=self.local, reporter=self.reporter)
        except errors.PointlessCommit:
            pass

    def _record_entry(self, path, file_id, specific_files, kind, name,
                      parent_id, definitely_changed, existing_ie=None):
        "Record the new inventory entry for a path if any."
        # mutter('check %s {%s}', path, file_id)
        if (not specific_files or 
            is_inside_or_parent_of_any(specific_files, path)):
                # mutter('%s selected for commit', path)
                if definitely_changed or existing_ie is None:
                    ie = inventory.make_entry(kind, name, parent_id, file_id)
                else:
                    ie = existing_ie.copy()
                    ie.revision = None
        else:
            # mutter('%s not selected for commit', path)
            if self.basis_inv.has_id(file_id):
                ie = self.basis_inv[file_id].copy()
            else:
                # this entry is new and not being committed
                ie = None
        if ie is not None:
            self.builder.record_entry_contents(ie, self.parent_invs, 
                path, self.work_tree)
            self._report_change(ie, path)
        return ie

    def _report_change(self, ie, path):
        """Report a change to the user.

        The change that has occurred is described relative to the basis
        inventory.
        """
        if (self.basis_inv.has_id(ie.file_id)):
            basis_ie = self.basis_inv[ie.file_id]
        else:
            basis_ie = None
        change = ie.describe_change(basis_ie, ie)
        if change in (InventoryEntry.RENAMED, 
            InventoryEntry.MODIFIED_AND_RENAMED):
            old_path = self.basis_inv.id2path(ie.file_id)
            self.reporter.renamed(change, old_path, path)
        else:
            self.reporter.snapshot_change(change, path)

    def _set_progress_stage(self, name, entries_title=None):
        """Set the progress stage and emit an update to the progress bar."""
        self.pb_stage_name = name
        self.pb_stage_count += 1
        self.pb_entries_title = entries_title
        if entries_title is not None:
            self.pb_entries_count = 0
            self.pb_entries_total = '?'
        self._emit_progress()

    def _next_progress_entry(self):
        """Emit an update to the progress bar and increment the entry count."""
        self.pb_entries_count += 1
        self._emit_progress()

    def _emit_progress(self):
        if self.pb_entries_title:
            if self.pb_entries_total == '?':
                text = "%s [%s %d] - Stage" % (self.pb_stage_name,
                    self.pb_entries_title, self.pb_entries_count)
            else:
                text = "%s [%s %d/%s] - Stage" % (self.pb_stage_name,
                    self.pb_entries_title, self.pb_entries_count,
                    str(self.pb_entries_total))
        else:
            text = "%s - Stage" % (self.pb_stage_name)
        self.pb.update(text, self.pb_stage_count, self.pb_stage_total)
