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26404 Commits

Author SHA1 Message Date
Junio C Hamano
4a5a8008fd Merge branch 'jc/submodule-sync-no-auto-vivify' into maint
* jc/submodule-sync-no-auto-vivify:
  submodule add: always initialize .git/config entry
  submodule sync: do not auto-vivify uninteresting submodule
2011-08-16 11:41:26 -07:00
Junio C Hamano
a35d78c0f4 Merge branch 'jc/zlib-wrap' into maint
* jc/zlib-wrap:
  zlib: allow feeding more than 4GB in one go
  zlib: zlib can only process 4GB at a time
  zlib: wrap deflateBound() too
  zlib: wrap deflate side of the API
  zlib: wrap inflateInit2 used to accept only for gzip format
  zlib: wrap remaining calls to direct inflate/inflateEnd
  zlib wrapper: refactor error message formatter
2011-08-16 11:23:26 -07:00
Junio C Hamano
184cb4d689 Merge branch 'fk/relink-upon-ldflags-update' into maint
* fk/relink-upon-ldflags-update:
  Makefile: Track changes to LDFLAGS and relink when necessary
2011-08-16 11:23:26 -07:00
Junio C Hamano
d5c756e99e Merge branch 'bc/submodule-foreach-stdin-fix-1.7.4' into maint
* bc/submodule-foreach-stdin-fix-1.7.4:
  git-submodule.sh: preserve stdin for the command spawned by foreach
  t/t7407: demonstrate that the command called by 'submodule foreach' loses stdin
2011-08-16 11:23:26 -07:00
Junio C Hamano
824f4a9389 Merge branch 'aw/rebase-i-p' into maint
* aw/rebase-i-p:
  rebase -i -p: include non-first-parent commits in todo list
2011-08-16 11:23:25 -07:00
Junio C Hamano
f253376dcb Merge branch 'jc/diff-index-quick-exit-early' into maint
* jc/diff-index-quick-exit-early:
  diff-index --quiet: learn the "stop feeding the backend early" logic

Conflicts:
	unpack-trees.h
2011-08-16 11:23:25 -07:00
Junio C Hamano
e10e476fb1 Merge branch 'jk/combine-diff-binary-etc' into maint
* jk/combine-diff-binary-etc:
  combine-diff: respect textconv attributes
  refactor get_textconv to not require diff_filespec
  combine-diff: handle binary files as binary
  combine-diff: calculate mode_differs earlier
  combine-diff: split header printing into its own function
2011-08-16 11:23:24 -07:00
Jeff King
2a6f08ac1f am: refresh the index at start and --resolved
If a file is unchanged but stat-dirty, we may erroneously
fail to apply patches, thinking that they conflict with a
dirty working tree.

This patch adds a call to "update-index --refresh". It comes
as late as possible, so that we don't bother with it for
thinks like "git rebase --abort", or when mbox-splitting
fails. However, it does come before we actually start
applying patches, meaning we will only call it once when we
start applying patches (or any time we return to "am" after
having resolved conflicts), and not once per patch.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-16 11:15:41 -07:00
Jonathan Nieder
127f045222 revert: plug memory leak in "cherry-pick root commit" codepath
The empty tree passed as common ancestor to merge_trees() when
cherry-picking a parentless commit is allocated on the heap and never
freed.  Leaking such a small one-time allocation is not a very big
problem, but now that "git cherry-pick" can cherry-pick multiple
commits it can start to add up.

Avoid the leak by storing the fake tree exactly once in the BSS
section (i.e., use a static).  While at it, let's add a test to make
sure cherry-picking multiple parentless commits continues to work.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-16 10:51:34 -07:00
Michael Haggerty
d68e1c183c Unroll the loop over passes
The passes no longer share much code, and the unrolled code is easier
to understand.

Use a new index variable instead of num_attr for the second loop, as
we are no longer counting attributes but rather indexing through them.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 15:02:01 -07:00
Michael Haggerty
e0a5f9aaae Change while loop into for loop
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 15:02:00 -07:00
Michael Haggerty
85c4a0d048 Determine the start of the states outside of the pass loop
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 15:02:00 -07:00
Michael Haggerty
d175129857 Change parse_attr() to take a pointer to struct attr_state
parse_attr() only needs access to the attr_state to which it should
store its results, not to the whole match_attr structure.  This change
also removes the need for it to know num_attr.  Change its signature
accordingly and add a comment.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 15:01:59 -07:00
Michael Haggerty
4c7517c9cc Increment num_attr in parse_attr_line(), not parse_attr()
num_attr is incremented iff parse_attr() returns non-NULL.  So do the
counting in parse_attr_line() instead of within parse_attr().  This
allows an integer rather than a pointer to an integer to be passed to
parse_attr().

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 15:01:58 -07:00
Michael Haggerty
ba845b7550 Document struct match_attr
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 15:01:58 -07:00
Michael Haggerty
86ab7f0cca Add a file comment
Consolidate here a few general comments plus links to other
documentation.  Delete a comment with an out-of-date description of
the .gitattributes file format.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 15:01:57 -07:00
Dmitry Ivankov
8fb3ad76b1 fast-import: prevent producing bad delta
To produce deltas for tree objects fast-import tracks two versions
of tree's entries - base and current one. Base version stands both
for a delta base of this tree, and for a entry inside a delta base
of a parent tree. So care should be taken to keep it in sync.

tree_content_set cuts away a whole subtree and replaces it with a
new one (or NULL for lazy load of a tree with known sha1). It
keeps a base sha1 for this subtree (needed for parent tree). And
here is the problem, 'subtree' tree root doesn't have the implied
base version entries.

Adjusting the subtree to include them would mean a deep rewrite of
subtree. Invalidating the subtree base version would mean recursive
invalidation of parents' base versions. So just mark this tree as
do-not-delta me. Abuse setuid bit for this purpose.

tree_content_replace is the same as tree_content_set except that is
is used to replace the root, so just clearing base sha1 here (instead
of setting the bit) is fine.

[di: log message]

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Dmitry Ivankov <divanorama@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:40:01 -07:00
Dmitry Ivankov
9a0edb79f2 fast-import: add a test for tree delta base corruption
fast-import is able to write imported tree objects in delta format.
It holds a tree structure in memory where each tree entry may have
a delta base sha1 assigned. When delta base data is needed it is
reconstructed from this in-memory structure. Though sometimes the
delta base data doesn't match the delta base sha1 so wrong or even
corrupt pack is produced.

Add a small test that produces a corrupt pack. It uses just tree
copy and file modification commands aside from the very basic commit
and blob commands.

Signed-off-by: Dmitry Ivankov <divanorama@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:40:00 -07:00
Elijah Newren
f701aae077 merge-recursive: Don't re-sort a list whose order we depend upon
In record_df_conflict_files() we would resort the entries list using
df_name_compare to get a convenient ordering.  Unfortunately, this broke
assumptions of the get_renames() code (via string_list_lookup() calls)
which needed the list to be in the standard ordering.  When those lookups
would fail, duplicate stage_data entries could be inserted, causing the
process_renames and process_entry code to fail (in particular, a path that
that process_renames had marked as processed would still be processed
anyway in process_entry due to the duplicate entry).

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:27:48 -07:00
Elijah Newren
6d63070cac merge-recursive: Fix virtual merge base for rename/rename(1to2)/add-dest
Earlier in this series, the patch "merge-recursive: add handling for
rename/rename/add-dest/add-dest" added code to handle the rename on each
side of history also being involved in a rename/add conflict, but only
did so in the non-recursive case.  Add code for the recursive case,
ensuring that the "added" files are not simply deleted.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:40 -07:00
Elijah Newren
b630b81470 t6036: criss-cross + rename/rename(1to2)/add-dest + simple modify
This is another testcase trying to exercise the virtual merge base
creation in the rename/rename(1to2) code.  A testcase is added that we
should be able to merge cleanly, but which requires a virtual merge base
to be created that correctly handles rename/add-dest conflicts within the
rename/rename(1to2) testcase handling.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:40 -07:00
Elijah Newren
35a74abff3 merge-recursive: Avoid unnecessary file rewrites
Often times, a potential conflict at a path is resolved by merge-recursive
by using the content that was already present at that location.  In such
cases, we do not want to overwrite the content that is already present, as
that could trigger unnecessary recompilations.  One of the patches earlier
in this series ("merge-recursive: When we detect we can skip an update,
actually skip it") fixed the cases that involved content merges, but there
were a few other cases as well.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:40 -07:00
Elijah Newren
3e333a6146 t6022: Additional tests checking for unnecessary updates of files
I stumbled across a case, this one not involving a content merge, where
git currently rewrites a file unnecessarily.  A quick audit uncovered two
additional situations (also not involving content merges) with the same
problem.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:40 -07:00
Elijah Newren
f53d39778c merge-recursive: Fix spurious 'refusing to lose untracked file...' messages
Calling update_stages() before update_file() can sometimes result in git
thinking the file being updated is untracked (whenever update_stages
moves it to stage 3).  Reverse the call order, and add a big comment to
update_stages to hopefully prevent others from making the same mistake.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:40 -07:00
Elijah Newren
3f680ff0cf t6022: Add testcase for spurious "refusing to lose untracked" messages
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:39 -07:00
Jeff King
814f7d902b t3030: fix accidental success in symlink rename
In this test, we have merge two branches. On one branch, we
renamed "a" to "e". On the other, we renamed "a" to "e" and
then added a symlink pointing at "a" pointing to "e".

The results for the test indicate that the merge should
succeed, but also that "a" should no longer exist. Since
both sides renamed "a" to the same destination, we will end
up comparing those destinations for content.

But what about what's left? One side (the rename only),
replaced "a" with nothing. The other side replaced it with a
symlink. The common base must also be nothing, because any
"a" before this was meaningless (it was totally unrelated
content that ended up getting renamed).

The only sensible resolution is to keep the symlink. The
rename-only side didn't touch the content versus the common
base, and the other side added content. The 3-way merge
dictates that we take the side with a change.

And this gives the overall merge an intuitive result.  One
side made one change (a rename), and the other side made two
changes: an identical rename, and an addition (that just
happened to be at the same spot). The end result should
contain both changes.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:39 -07:00
Elijah Newren
3672c97148 merge-recursive: Fix working copy handling for rename/rename/add/add
If either side of a rename/rename(1to2) conflict is itself also involved
in a rename/add-dest conflict, then we need to make sure both the rename
and the added file appear in the working copy.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:39 -07:00
Elijah Newren
1ac91b32b5 merge-recursive: add handling for rename/rename/add-dest/add-dest
Each side of the rename in rename/rename(1to2) could potentially also be
involved in a rename/add conflict.  Ensure stages for such conflicts are
also recorded.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:39 -07:00
Elijah Newren
e03acb8bc1 merge-recursive: Have conflict_rename_delete reuse modify/delete code
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:39 -07:00
Elijah Newren
b70332520d merge-recursive: Make modify/delete handling code reusable
modify/delete and rename/delete share a lot of similarities; we'd like all
the criss-cross and D/F conflict handling specializations to be shared
between the two.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:39 -07:00
Elijah Newren
434b8525e7 merge-recursive: Consider modifications in rename/rename(2to1) conflicts
Our previous conflict resolution for renaming two different files to the
same name ignored the fact that each of those files may have modifications
from both sides of history to consider.  We need to do a three-way merge
for each of those files, and then handle the conflict of both sets of
merged contents trying to be recorded with the same name.

It is important to note that this changes our strategy in the recursive
case.  After doing a three-way content merge of each of the files
involved, we still are faced with the fact that we are trying to put both
of the results (including conflict markers) into the same path.  We could
do another two-way merge, but I think that becomes confusing.  Also,
taking a hint from the modify/delete and rename/delete cases we handled
earlier, a more useful "common ground" would be to keep the three-way
content merge but record it with the original filename.  The renames can
still be detected, we just allow it to be done in the o->call_depth=0
case.  This seems to result in simpler & easier to understand merge
conflicts as well, as evidenced by some of the changes needed in our
testsuite in t6036.  (However, it should be noted that this change will
cause problems those renames also occur along with a file being added
whose name matches the source of the rename.  Since git currently cannot
detect rename/add-source situations, though, this codepath is not
currently used for those cases anyway.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:39 -07:00
Elijah Newren
dac4741554 merge-recursive: Create function for merging with branchname:file markers
We want to be able to reuse the code to do a three-way file content merge
and have the conflict markers use both branchname and filename.  Split it
out into a separate function.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:38 -07:00
Elijah Newren
232c635f7e merge-recursive: Record more data needed for merging with dual renames
When two different files are renamed to one, we need to be able to do
three-way merges for both of those files.  To do that, we need to record
the sha1sum of the (possibly modified) file on the unrenamed side.  Modify
setup_rename_conflict_info() to take this extra information and record it
when the rename_type is RENAME_TWO_FILES_TO_ONE.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:38 -07:00
Elijah Newren
461f504117 merge-recursive: Defer rename/rename(2to1) handling until process_entry
This puts the code for the different types of double rename conflicts
closer together (fewer lines of other code separating the two paths) and
increases similarity between how they are handled.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:38 -07:00
Elijah Newren
a99b7f2256 merge-recursive: Small cleanups for conflict_rename_rename_1to2
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:38 -07:00
Elijah Newren
c52ff85d97 merge-recursive: Fix rename/rename(1to2) resolution for virtual merge base
When renaming one file to two files, we really should be doing a content
merge.  Also, in the recursive case, undoing the renames and recording the
merged file in the index with the source of the rename (while deleting
both destinations) allows the renames to be re-detected in the
non-recursive merge and will result in fewer spurious conflicts.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:38 -07:00
Elijah Newren
6bdaead1e5 merge-recursive: Introduce a merge_file convenience function
merge_file previously required diff_filespec arguments, but all callers
only had sha1s and modes.  Rename merge_file to merge_file_1 and introduce
a new merge_file convenience function which takes the sha1s and modes and
creates the temporary diff_filespec variables needed to call merge_file_1.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:38 -07:00
Elijah Newren
ec61d14963 merge-recursive: Fix modify/delete resolution in the recursive case
When o->call_depth>0 and we have conflicts, we try to find "middle ground"
when creating the virtual merge base.  In the case of content conflicts,
this can be done by doing a three-way content merge and using the result.
In all parts where the three-way content merge is clean, it is the correct
middle ground, and in parts where it conflicts there is no middle ground
but the conflict markers provide a good compromise since they are unlikely
to accidentally match any further changes.

In the case of a modify/delete conflict, we cannot do the same thing.
Accepting either endpoint as the resolution for the virtual merge base
runs the risk that when handling the non-recursive case we will silently
accept one person's resolution over another without flagging a conflict.
In this case, the closest "middle ground" we have is actually the merge
base of the candidate merge bases.  (We could alternatively attempt a
three way content merge using an empty file in place of the deleted file,
but that seems to be more work than necessary.)

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:38 -07:00
Elijah Newren
5b448b8530 merge-recursive: When we detect we can skip an update, actually skip it
In 882fd11 (merge-recursive: Delay content merging for renames 2010-09-20),
there was code that checked for whether we could skip updating a file in
the working directory, based on whether the merged version matched the
current working copy.  Due to the desire to handle directory/file conflicts
that were resolvable, that commit deferred content merging by first
updating the index with the unmerged entries and then moving the actual
merging (along with the skip-the-content-update check) to another function
that ran later in the merge process.  As part moving the content merging
code, a bug was introduced such that although the message about skipping
the update would be printed (whenever GIT_MERGE_VERBOSITY was sufficiently
high), the file would be unconditionally updated in the working copy
anyway.

When we detect that the file does not need to be updated in the working
copy, update the index appropriately and then return early before updating
the working copy.

Note that there was a similar change in b2c8c0a (merge-recursive: When we
detect we can skip an update, actually skip it 2011-02-28), but it was
reverted by 6db4105 (Revert "Merge branch 'en/merge-recursive'"
2011-05-19) since it did not fix both of the relevant types of unnecessary
update breakages and, worse, it made use of some band-aids that caused
other problems.  The reason this change works is due to the changes earlier
in this series to (a) record_df_conflict_files instead of just unlinking
them early, (b) allowing make_room_for_path() to remove D/F entries,
(c) the splitting of update_stages_and_entry() to have its functionality
called at different points, and (d) making the pathnames of the files
involved in the merge available to merge_content().

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:37 -07:00
Elijah Newren
3c217c077a merge-recursive: Provide more info in conflict markers with file renames
Whenever there are merge conflicts in file contents, we would mark the
different sides of the conflict with the two branches being merged.
However, when there is a rename involved as well, the branchname is not
sufficient to specify where the conflicting content came from.  In such
cases, mark the two sides of the conflict with branchname:filename rather
than just branchname.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:37 -07:00
Elijah Newren
4f66dade81 merge-recursive: Cleanup and consolidation of rename_conflict_info
The consolidation of process_entry() and process_df_entry() allows us to
consolidate more code paths concerning rename conflicts, and to do
a few additional related cleanups.  It also means we are using
rename_df_conflict_info in some cases where there is no D/F conflict;
rename it to rename_conflict_info.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:37 -07:00
Elijah Newren
edd2faf52e merge-recursive: Consolidate process_entry() and process_df_entry()
The whole point of adding process_df_entry() was to ensure that files of
D/F conflicts were processed after paths under the corresponding
directory.  However, given that the entries are in sorted order, all we
need to do is iterate through them in reverse order to achieve the same
effect.  That lets us remove some duplicated code, and lets us keep
track of one less thing as we read the code ("do we need to make sure
this is processed before process_df_entry() or do we need to defer it
until then?").

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:37 -07:00
Elijah Newren
51931bf08e merge-recursive: Improve handling of rename target vs. directory addition
When dealing with file merging and renames and D/F conflicts and possible
criss-cross merges (how's that for a corner case?), we did not do a
thorough job ensuring the index and working directory had the correct
contents.   Fix the logic in merge_content() to handle this.  Also,
correct some erroneous tests in t6022 that were expecting the wrong number
of unmerged index entries.  These changes fix one of the tests in t6042
(and almost fix another one from t6042 as well).

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:37 -07:00
Elijah Newren
7769a75e96 merge-recursive: Add comments about handling rename/add-source cases
There are a couple of places where changes are needed to for situations
involving rename/add-source issues.  Add comments about the needed changes
(and existing bugs) until git has been enabled to detect such cases.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:37 -07:00
Elijah Newren
0a6b87126e merge-recursive: Make dead code for rename/rename(2to1) conflicts undead
The code for rename_rename_2to1 conflicts (two files both being renamed to
the same filename) was dead since the rename/add path was always being
independently triggered for each of the renames instead.  Further,
reviving the dead code showed that it was inherently buggy and would
always segfault -- among a few other bugs.

Move the else-if branch for the rename/rename block before the rename/add
block to make sure it is checked first, and fix up the rename/rename(2to1)
code segments to make it handle most cases.  Work is still needed to
handle higher dimensional corner cases such as rename/rename/modify/modify
issues.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:37 -07:00
Elijah Newren
531357a4cc merge-recursive: Fix deletion of untracked file in rename/delete conflicts
In the recursive case (o->call_depth > 0), we do not modify the working
directory.  However, when o->call_depth==0, file renames can mean we need
to delete the old filename from the working copy.  Since there have been
lots of changes and mistakes here, let's go through the details.  Let's
start with a simple explanation of what we are trying to achieve:

  Original goal: If a file is renamed on the side of history being merged
  into head, the filename serving as the source of that rename needs to be
  removed from the working directory.

The path to getting the above statement implemented in merge-recursive took
several steps.  The relevant bits of code may be instructive to keep in
mind for the explanation, especially since an English-only description
involves double negatives that are hard to follow.  These bits of code are:
  int remove_file(..., const char *path, int no_wd)
  {
    ...
    int update_working_directory = !o->call_depth && !no_wd;
and
  remove_file(o, 1, ren1_src, <expression>);
Where the choice for <expression> has morphed over time:

65ac6e9 (merge-recursive: adjust to loosened "working file clobbered"
check 2006-10-27), introduced the "no_wd" parameter to remove_file() and
used "1" for <expression>.  This meant ren1_src was never deleted, leaving
it around in the working copy.

In 8371234 (Remove uncontested renamed files during merge. 2006-12-13),
<expression> was changed to "index_only" (where index_only ==
!!o->call_depth; see b7fa51da).   This was equivalent to using "0" for
<expression> (due to the early logic in remove_file), and is orthogonal to
the condition we actually want to check at this point; it resulted in the
source file being removed except when index_only was false.  This was
problematic because the file could have been renamed on the side of history
including head, in which case ren1_src could correspond to an untracked
file that should not be deleted.

In 183d797 (Keep untracked files not involved in a merge. 2007-02-04),
<expression> was changed to "index_only || stage == 3".  While this gives
correct behavior, the "index_only ||" portion of <expression> is
unnecessary and makes the code slightly harder to follow.

There were also two further changes to this expression, though without
any change in behavior.  First in b7fa51d (merge-recursive: get rid of the
index_only global variable 2008-09-02), it was changed to "o->call_depth
|| stage == 3".  (index_only == !!o->call_depth).  Later, in 41d70bd6
(merge-recursive: Small code clarification -- variable name and comments),
this was changed to "o->call_depth || renamed_stage == 2" (where stage was
renamed to other_stage and renamed_stage == other_stage ^ 1).

So we ended with <expression> being "o->call_depth || renamed_stage == 2".
But the "o->call_depth ||" piece was unnecessary.  We can remove it,
leaving us with <expression> being "renamed_stage == 2".  This doesn't
change behavior at all, but it makes the code clearer.  Which is good,
because it's about to get uglier.

  Corrected goal: If a file is renamed on the side of history being merged
  into head, the filename serving as the source of that rename needs to be
  removed from the working directory *IF* that file is tracked in head AND
  the file tracked in head is related to the original file.

Note that the only difference between the original goal and the corrected
goal is the two extra conditions added at the end.  The first condition is
relevant in a rename/delete conflict.  If the file was deleted on the
HEAD side of the merge and an untracked file of the same name was added to
the working copy, then without that extra condition the untracked file
will be erroneously deleted.  This changes <expression> to "renamed_stage
== 2 || !was_tracked(ren1_src)".

The second additional condition is relevant in two cases.

The first case the second condition can occur is when a file is deleted
and a completely different file is added with the same name.  To my
knowledge, merge-recursive has no mechanism for detecting deleted-and-
replaced-by-different-file cases, so I am simply punting on this
possibility.

The second case for the second condition to occur is when there is a
rename/rename/add-source conflict.  That is, when the original file was
renamed on both sides of history AND the original filename is being
re-used by some unrelated (but tracked) content.  This case also presents
some additional difficulties for us since we cannot currently detect these
rename/rename/add-source conflicts; as long as the rename detection logic
"optimizes" by ignoring filenames that are present at both ends of the
diff, these conflicts will go unnoticed.  However, rename/rename conflicts
are handled by an entirely separate codepath not being discussed here, so
this case is not relevant for the line of code under consideration.

In summary:
  Change <expression> from "o->call_depth || renamed_stage == 2" to
  "renamed_stage == 2 || !was_tracked(ren1_src)", in order to remove
  unnecessary code and avoid deleting untracked files.

96 lines of explanation in the changelog to describe a one-line fix...

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:36 -07:00
Elijah Newren
b8ddf16424 merge-recursive: Split update_stages_and_entry; only update stages at end
Instead of having the process_renames logic update the stages in the index
for the rename destination, have the index updated after process_entry or
process_df_entry.  This will also allow us to have process_entry determine
whether a file was tracked and existed in the working copy before the
merge started.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:36 -07:00
Elijah Newren
ed0148a520 merge-recursive: Allow make_room_for_path() to remove D/F entries
If there were several files conflicting below a directory corresponding
to a D/F conflict, and the file of that D/F conflict is in the way, we
want it to be removed.  Since files of D/F conflicts are handled last,
they can be reinstated later and possibly with a new unique name.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:36 -07:00
Johannes Sixt
86d4b528d8 string-list: Add API to remove an item from an unsorted list
Teach the string-list API how to remove an entry in O(1) runtime by
moving the last entry to the vacated spot. As such, the routine works
only for unsorted lists.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:35 -07:00
Elijah Newren
aacb82de3f merge-recursive: Split was_tracked() out of would_lose_untracked()
Checking whether a filename was part of stage 0 or stage 2 is code that we
would like to be able to call from a few other places without also
lstat()-ing the file to see if it exists in the working copy.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-14 14:19:35 -07:00