Commit graph

7 commits

Author SHA1 Message Date
Elijah Newren 67360b75c6 diff: fix filtering of merge commits under --remerge-diff
Commit 95433eeed9 ("diff: add ability to insert additional headers for
paths", 2022-02-02) introduced the possibility of additional headers.
Because there could be conflicts with no content differences (e.g. a
modify/delete conflict resolved in favor of taking the modified file
as-is), that commit also modified the diff_queue_is_empty() and
diff_flush_patch() logic to ensure these headers were included even if
there was no associated content diff.

However, the added logic was a bit inconsistent between these two
functions.  diff_queue_is_empty() overlooked the fact that the
additional headers strmap could be non-NULL and empty, which would cause
it to display commits that should have been filtered out.

Fix the diff_queue_is_empty() logic to also account for
additional_path_headers being empty.

Reported-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-09-02 09:22:25 -07:00
Elijah Newren 71a146dc70 diff: fix filtering of additional headers under --remerge-diff
Commit 95433eeed9 ("diff: add ability to insert additional headers for
paths", 2022-02-02) introduced the possibility of additional headers.
Because there could be conflicts with no content differences (e.g. a
modify/delete conflict resolved in favor of taking the modified file
as-is), that commit also modified the diff_queue_is_empty() and
diff_flush_patch() logic to ensure these headers were included even if
there was no associated content diff.

However, when the pickaxe is active, we really only want the remerge
conflict headers to be shown when there is an associated content diff.
Adjust the logic in these two functions accordingly.

This also removes the TEST_PASSES_SANITIZE_LEAK=true declaration from
t4069, as there is apparently some kind of memory leak with the pickaxe
code.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-09-02 09:22:25 -07:00
Elijah Newren 9b08091cb7 diff: have submodule_format logic avoid additional diff headers
Commit 95433eeed9 ("diff: add ability to insert additional headers for
paths", 2022-02-02) introduced the possibility of additional headers,
created in create_filepairs_for_header_only_notifications().  These are
represented by inserting additional pairs in diff_queued_diff which
always have a mode of 0 and a null_oid.  When these were added, one
code path was noted to assume that at least one of the diff_filespecs
in the pair were valid, and that codepath was corrected.

The submodule_format handling is another codepath with the same issue;
it would operate on these additional headers and attempt to display them
as submodule changes.  Prevent that by explicitly checking for "phoney"
filepairs (i.e. filepairs with both modes being 0).

Reported-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-09-02 09:22:25 -07:00
Ævar Arnfjörð Bjarmason 055e57b7b2 log: fix a memory leak in "git show <revision>..."
Fix a memory leak in code added in 5d7eeee2ac (git-show: grok blobs,
trees and tags, too, 2006-12-14). As we iterate over a "<revision>..."
command-line and encounter ad OBJ_COMMIT we want to use our "struct
rev_info", but with a "pending" array of one element: the one commit
we're showing in the loop.

To do this 5d7eeee2ac saved away a pointer to rev.pending.objects and
rev.pending.nr for its iteration. We'd then clobber those (and alloc)
when we needed to show an OBJ_COMMIT.

We'd therefore leak the "rev.pending" we started out with, and only
free the new "rev.pending" in the "OBJ_COMMIT" case arm as
prepare_revision_walk() would draw it down.

Let's fix this memory leak. Now when we encounter an OBJ_COMMIT we
save away the "rev.pending" before clearing it. We then add a single
commit to it, which our indirect invocation of prepare_revision_walk()
will remove. After that we restore the "rev.pending".

Our "rev.pending" will then get free'd by the release_revisions()
added in f6bfea0ad0 (revisions API users: use release_revisions() in
builtin/log.c, 2022-04-13)

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-03 10:16:28 -07:00
Elijah Newren 0dec322d31 diff-merges: avoid history simplifications when diffing merges
Doing diffs for merges are special; they should typically avoid history
simplification.  For example, with

    git log --diff-merges=first-parent -- path

the default history simplification would remove merge commits from
consideration if the file "path" matched the second parent.  That is
counter to what the user wants when looking for first-parent diffs.
Similar comments can be made for --diff-merges=separate (which diffs
against both parents) and --diff-merges=remerge (which diffs against a
remerge of the merge commit).

However, history simplification still makes sense if not doing diffing
merges, and it also makes sense for the combined and dense-combined
forms of diffing merges (because both of those are defined to only show
a diff when the merge result at the relevant paths differs from *both*
parents).

So, for separate, first-parent, and remerge styles of diff-merges, turn
off history simplification.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-02 10:02:28 -08:00
Elijah Newren 20323d104e show, log: include conflict/warning messages in --remerge-diff headers
Conflicts such as modify/delete, rename/rename, or file/directory are
not representable via content conflict markers, and the normal output
messages notifying users about these were dropped with --remerge-diff.
While we don't want these messages randomly shown before the commit
and diff headers, we do want them to still be shown; include them as
part of the diff headers instead.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-02 10:02:28 -08:00
Elijah Newren db757e8b8d show, log: provide a --remerge-diff capability
When this option is specified, we remerge all (two parent) merge commits
and diff the actual merge commit to the automatically created version,
in order to show how users removed conflict markers, resolved the
different conflict versions, and potentially added new changes outside
of conflict regions in order to resolve semantic merge problems (or,
possibly, just to hide other random changes).

This capability works by creating a temporary object directory and
marking it as the primary object store.  This makes it so that any blobs
or trees created during the automatic merge are easily removable
afterwards by just deleting all objects from the temporary object
directory.

There are a few ways that this implementation is suboptimal:
  * `log --remerge-diff` becomes slow, because the temporary object
    directory can fill with many loose objects while running
  * the log output can be muddied with misplaced "warning: cannot merge
    binary files" messages, since ll-merge.c unconditionally writes those
    messages to stderr while running instead of allowing callers to
    manage them.
  * important conflict and warning messages are simply dropped; thus for
    conflicts like modify/delete or rename/rename or file/directory which
    are not representable with content conflict markers, there may be no
    way for a user of --remerge-diff to know that there had been a
    conflict which was resolved (and which possibly motivated other
    changes in the merge commit).
  * when fixing the previous issue, note that some unimportant conflict
    and warning messages might start being included.  We should instead
    make sure these remain dropped.
Subsequent commits will address these issues.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-02 10:02:27 -08:00