In the previous commit, we fixed a segmentation fault when a tree object
could not be written.
However, before the tree object is written, `merge-ort` wants to write
out a blob object (except in cases where the merge results in a blob
that already exists in the database). And this can fail, too, but we
ignore that write failure so far.
Let's pay close attention and error out early if the blob could not be
written. This reduces the error output of t4301.25 ("merge-ort fails
gracefully in a read-only repository") from:
error: insufficient permission for adding an object to repository database ./objects
error: error: Unable to add numbers to database
error: insufficient permission for adding an object to repository database ./objects
error: error: Unable to add greeting to database
error: insufficient permission for adding an object to repository database ./objects
fatal: failure to merge
to:
error: insufficient permission for adding an object to repository database ./objects
error: error: Unable to add numbers to database
fatal: failure to merge
This is _not_ just a cosmetic change: Even though one might assume that
the operation would have failed anyway at the point when the new tree
object is written (and the corresponding tree object _will_ be new if it
contains a blob that is new), but that is not so: As pointed out by
Elijah Newren, when Git has previously been allowed to add loose objects
via `sudo` calls, it is very possible that the blob object cannot be
written (because the corresponding `.git/objects/??/` directory may be
owned by `root`) but the tree object can be written (because the
corresponding objects directory is owned by the current user). This
would result in a corrupt repository because it is missing the blob
object, and with this here patch we prevent that.
Note: This patch adjusts two variable declarations from `unsigned` to
`int` because their purpose is to hold the return value of
`handle_content_merge()`, which is of type `int`. The existing users of
those variables are only interested whether that variable is zero or
non-zero, therefore this type change does not affect the existing code.
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If the blob/tree objects cannot be written, we really need the merge
operations to fail, and not to continue (and then try to access the tree
object which is however still set to `NULL`).
Let's stop ignoring the return value of `write_object_file()` and
`write_tree()` and set `clean = -1` in the error case.
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Further update the help messages given while merging submodules.
* en/submodule-merge-messages-fixes:
merge-ort: provide helpful submodule update message when possible
merge-ort: avoid surprise with new sub_flag variable
merge-ort: remove translator lego in new "submodule conflict suggestion"
submodule merge: update conflict error message
Commit 66b209b86a ("merge-ort: implement CE_SKIP_WORKTREE handling with
conflicted entries", 2021-03-20) added some code for merge-ort to handle
conflicted and skip_worktree entries in general. Included in this was
an ugly hack for dealing with present-despite-skipped entries and a
testcase (t6428.2) specific to that hack, since at that time users could
accidentally get files into that state when using a sparse checkout.
However, with the merging of 82386b4496 ("Merge branch
'en/present-despite-skipped'", 2022-03-09), that class of problems was
addressed globally and in a much cleaner way. As such, the
present-despite-skipped hack in merge-ort is no longer needed and can
simply be removed.
No additional testcase is needed here; t6428.2 was written to test the
necessary functionality and is being kept. The fact that this test
continues to pass despite the code being removed shows that the extra
code is no longer necessary.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In commit 4057523a40 ("submodule merge: update conflict error message",
2022-08-04), a more detailed message was provided when submodules
conflict, in order to help users know how to resolve those conflicts.
There were a couple situations for which a different message would be
more appropriate, but that commit left handling those for future work.
Unfortunately, that commit would check if any submodules were of the
type that it didn't know how to explain, and, if so, would avoid
providing the more detailed explanation even for the submodules it did
know how to explain.
Change this to have the code print the helpful messages for the subset
of submodules it knows how to explain.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit 4057523a40 ("submodule merge: update conflict error message",
2022-08-04) added a sub_flag variable that is used to store a value from
enum conflict_and_info_types, but initializes it with a value of -1 that
does not correspond to any of the conflict_and_info_types. The code may
never set it to a valid value and yet still use it, which can be
surprising when reading over the code at first. Initialize it instead
to the generic CONFLICT_SUBMODULE_FAILED_TO_MERGE value, which is still
distinct from the two values we need to special case.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In commit 4057523a40 ("submodule merge: update conflict error message",
2022-08-04), the new "submodule conflict suggestion" code was
translating 6 different pieces of the new message and then used
carefully crafted logic to allow stitching it back together with special
formatting. Keep the components of the message together as much as
possible, so that:
* we reduce the number of things translators have to translate
* translators have more control over the format of the output
* the code is much easier for developers to understand too
Also, reformat some comments running beyond the 80th column while at it.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Plug memory leaks in the failure code path in the "merge-ort" merge
strategy backend.
* js/ort-clean-up-after-failed-merge:
merge-ort: do leave trace2 region even if checkout fails
merge-ort: clean up after failed merge
When attempting to merge in a superproject with conflicting submodule
pointers that cannot be fast-forwarded or trivially resolved, the merge
fails and Git prints an error message that accurately describes the
failure, but does not provide steps for the user to resolve the error.
Git is left in a conflicted state, which requires the user to:
1. merge submodules or update submodules to an already existing
commit that reflects the merge
2. add submodules changes to the superproject
3. finish merging superproject
These steps are non-obvious for newer submodule users to figure out
based on the error message and neither `git submodule status` nor `git
status` provide any useful pointers.
Update error message to provide steps to resolve submodule merge
conflict. Future work could involve adding an advice flag to the
message. Although the message is long, it also has the id of the
submodule commit that needs to be merged, which could be useful
information for the user.
Additionally, 5 merge failures that resulted in an early return have
been updated to reflect the status of the merge.
1. Null merge base (null o): CONFLICT_SUBMODULE_NULL_MERGE_BASE added
as a new conflict type and will print updated error message.
2. Null merge side a (null a): BUG(). See [1] for discussion
3. Null merge side b (null b): BUG(). See [1] for discussion
4. Submodule not checked out: added NEEDSWORK bit
5. Submodule commits not present: added NEEDSWORK bit
The errors with a NEEDSWORK bit deserve a more detailed explanation of
how to resolve them. See [2] for more context.
[1] https://lore.kernel.org/git/CABPp-BE0qGwUy80dmVszkJQ+tcpfLRW0OZyErymzhZ9+HWY1mw@mail.gmail.com/
[2] https://lore.kernel.org/git/xmqqpmhjjwo9.fsf@gitster.g/
Signed-off-by: Calvin Wan <calvinwan@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 557ac0350d (merge-ort: begin performance work; instrument with
trace2_region_* calls, 2021-01-23), we added Trace2 instrumentation, but
in the error path that returns early, we forgot to tell Trace2 that
we're leaving the region. Let's fix that.
Pointed-out-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 9fefce68dc (merge-ort: basic outline for merge_switch_to_result(),
2020-12-13), we added functionality to lay down the result of a merge on
disk. But we forgot to release the data structures in case
`unpack_trees()` failed to run properly.
This was pointed out by the `linux-leaks` job in our CI runs.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fixes a long-standing corner case bug around directory renames in
the merge-ort strategy.
* en/merge-dual-dir-renames-fix:
merge-ort: fix issue with dual rename and add/add conflict
merge-ort: shuffle the computation and cleanup of potential collisions
merge-ort: make a separate function for freeing struct collisions
merge-ort: small cleanups of check_for_directory_rename
t6423: add tests of dual directory rename plus add/add conflict
There is code in both merge-recursive and merge-ort for avoiding doubly
transitive renames (i.e. one side renames directory A/ -> B/, and the
other side renames directory B/ -> C/), because this combination would
otherwise make a mess for new files added to A/ on the first side and
wondering which directory they end up in -- especially if there were
even more renames such as the first side renaming C/ -> D/. In such
cases, it just turns "off" directory rename detection for the higher
order transitive cases.
The testcases added in t6423 a couple commits ago are slightly different
but similar in principle. They involve a similar case of paired
renaming but instead of A/ -> B/ and B/ -> C/, the second side renames
a leading directory of B/ to C/. And both sides add a new file
somewhere under the directory that the other side will rename. While
the new files added start within different directories and thus could
logically end up within different directories, it is weird for a file
on one side to end up where the other one started and not move along
with it. So, let's just turn off directory rename detection in this
case as well.
Another way to look at this is that if the source name involved in a
directory rename on one side is the target name of a directory rename
operation for a file from the other side, then we avoid the doubly
transitive rename. (More concretely, if a directory rename on side D
wants to rename a file on side E from OLD_NAME -> NEW_NAME, and side D
already had a file named NEW_NAME, and a directory rename on side E
wants to rename side D's NEW_NAME -> NEWER_NAME, then we turn off the
directory rename detection for NEW_NAME to prevent the
NEW_NAME -> NEWER_NAME rename, and instead end up with an add/add
conflict on NEW_NAME.)
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Run compute_collisions() for renames on both sides of history before
any calls to collect_renames(), and do not free the computed collisions
until after both calls to collect_renames(). This is just a code
reorganization at this point that doesn't make sense on its own, but
will permit us to use the computed collision info from both sides
within each call to collect_renames() in a subsequent commit.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit makes no functional changes, it's just some code movement in
preparation for later changes.
Signed-off-by: Elijah Newren <newren@palantir.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
No functional changes, just some preparatory cleanups.
Suggested-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Elijah Newren <newren@palantir.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With the new `detailed` parameter, a new mode can be triggered when
displaying the merge messages: The `detailed` mode prints NUL-delimited
fields of the following form:
<path-count> NUL <path>... NUL <conflict-type> NUL <message>
The `<path-count>` field determines how many `<path>` fields there are.
The intention of this mode is to support server-side operations, where
worktree-less merges can lead to conflicts and depending on the type
and/or path count, the caller might know how to handle said conflict.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is all fine and dandy for a regular Git command that is intended to
be run interactively to produce a bunch of messages upon an error.
However, in `merge-ort`'s case, we want to call the command e.g. in
server-side software, where the actual error messages are not quite as
interesting as machine-readable, immutable terms that describe the exact
nature of any given conflict.
With this patch, the `merge-ort` machinery records the exact type (as
specified via an `enum` value) as well as the involved path(s) together
with the conflict's message.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This allows us once again to get away with less data copying.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To prepare for using the `merge-ort` machinery in server operations, we
cannot simply produce a free-form string that combines a variable-length
list of messages.
Instead, we need to list them one by one. The natural fit for this is a
`string_list`.
We will subsequently add even more information in the `util` attribute
of the string list items.
Based-on-a-patch-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There was one case in merge-ort that would call path_msg() multiple
times for the same logical conflict, and it was in order to give advice
about how to resolve a conflict. This advice does not make as much
sense with remerge-diff, or with merge-tree being invoked by a GitHub
GUI for resolution of messages, and is making it hard to provide
which-logical-conflict-affects-which-paths information in a machine
parseable way to a higher level caller of merge-tree. Let's simply
remove this informational message.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
After a merge, this function allows the user to extract the same
information that would be printed by `ls-files -u`, which means
files with their mode, oid, and stage.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This patch includes no new code; it simply moves a bunch of lines into a
new function. As such, there are no functional changes. This is just a
preparatory step to allow the printed messages to be handled differently
by other callers, such as in `git merge-tree --write-tree`.
(Patch best viewed with
--color-moved --color-moved-ws=allow-indentation-change
to see that it is a simple code movement.)
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Plug the memory leaks from the trickiest API of all, the revision
walker.
* ab/plug-leak-in-revisions: (27 commits)
revisions API: add a TODO for diff_free(&revs->diffopt)
revisions API: have release_revisions() release "topo_walk_info"
revisions API: have release_revisions() release "date_mode"
revisions API: call diff_free(&revs->pruning) in revisions_release()
revisions API: release "reflog_info" in release revisions()
revisions API: clear "boundary_commits" in release_revisions()
revisions API: have release_revisions() release "prune_data"
revisions API: have release_revisions() release "grep_filter"
revisions API: have release_revisions() release "filter"
revisions API: have release_revisions() release "cmdline"
revisions API: have release_revisions() release "mailmap"
revisions API: have release_revisions() release "commits"
revisions API users: use release_revisions() for "prune_data" users
revisions API users: use release_revisions() with UNLEAK()
revisions API users: use release_revisions() in builtin/log.c
revisions API users: use release_revisions() in http-push.c
revisions API users: add "goto cleanup" for release_revisions()
stash: always have the owner of "stash_info" free it
revisions API users: use release_revisions() needing REV_INFO_INIT
revision.[ch]: document and move code declared around "init"
...
Introduce and apply coccinelle rule to discourage an explicit
comparison between a pointer and NULL, and applies the clean-up to
the maintenance track.
* ep/maint-equals-null-cocci:
tree-wide: apply equals-null.cocci
tree-wide: apply equals-null.cocci
contrib/coccinnelle: add equals-null.cocci
Add a release_revisions() to various users of "struct rev_list" in
those straightforward cases where we only need to add the
release_revisions() call to the end of a block, and don't need to
e.g. refactor anything to use a "goto cleanup" pattern.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Count string_list items in size_t, not "unsigned int".
* ab/string-list-count-in-size-t:
string-list API: change "nr" and "alloc" to "size_t"
gettext API users: don't explicitly cast ngettext()'s "n"
Object-file API shuffling.
* ab/object-file-api-updates:
object-file API: pass an enum to read_object_with_reference()
object-file.c: add a literal version of write_object_file_prepare()
object-file API: have hash_object_file() take "enum object_type"
object API: rename hash_object_file_literally() to write_*()
object-file API: split up and simplify check_object_signature()
object API users + docs: check <0, not !0 with check_object_signature()
object API docs: move check_object_signature() docs to cache.h
object API: correct "buf" v.s. "map" mismatch in *.c and *.h
object-file API: have write_object_file() take "enum object_type"
object-file API: add a format_object_header() function
object-file API: return "void", not "int" from hash_object_file()
object-file.c: split up declaration of unrelated variables
Align the level of verbose output from the ort backend during inner
merge to that of the recursive backend.
* en/merge-ort-align-verbosity-with-recursive:
merge-ort: exclude messages from inner merges by default
Change the "nr" and "alloc" members of "struct string_list" to use
"size_t" instead of "nr". On some platforms the size of an "unsigned
int" will be smaller than a "size_t", e.g. a 32 bit unsigned v.s. 64
bit unsigned. As "struct string_list" is a generic API we use in a lot
of places this might cause overflows.
As one example: code in "refs.c" keeps track of the number of refs
with a "size_t", and auxiliary code in builtin/remote.c in
get_ref_states() appends those to a "struct string_list".
While we're at it split the "nr" and "alloc" in string-list.h across
two lines, which is the case for most such struct member
declarations (e.g. in "strbuf.h" and "strvec.h").
Changing e.g. "int i" to "size_t i" in run_and_feed_hook() isn't
strictly necessary, and there are a lot more cases where we'll use a
local "int", "unsigned int" etc. variable derived from the "nr" in the
"struct string_list". But in that case as well as
add_wrapped_shortlog_msg() in builtin/shortlog.c we need to adjust the
printf format referring to "nr" anyway, so let's also change the other
variables referring to it.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
merge-recursive would only report messages from inner merges when the
GIT_MERGE_VERBOSITY was set to 5. Do the same for merge-ort.
Note that somewhat reverts 0d83d8240d ("merge-ort: mark conflict/warning
messages from inner merges as omittable", 2022-02-02) based on two
facts:
* This commit basically removes the showing of messages from inner
merges as well, at least by default. The only difference is that
users can request to get them back by turning up the verbosity.
* Messages from inner merges are specially annotated since 4a3d86e1bb
("merge-ort: make informational messages from recursive merges
clearer", 2022-02-17). The ability to distinguish them from outer
merge comments make them less problematic to include, and easier
for humans to parse.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the write_object_file() function to take an "enum object_type"
instead of a "const char *type". Its callers either passed
{commit,tree,blob,tag}_type and can pass the corresponding OBJ_* type
instead, or were hardcoding strings like "blob".
This avoids the back & forth fragility where the callers of
write_object_file() would have the enum type, and convert it
themselves via type_name(). We do have to now do that conversion
ourselves before calling write_object_file_prepare(), but those
codepaths will be similarly adjusted in subsequent commits.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The struct strmap paths member of merge_options_internal is perhaps the
most central data structure to all of merge-ort. Because all the paths
involved in the merge need to be kept until the merge is complete, this
"paths" data structure traditionally took responsibility for owning all
the allocated paths. When the merge is over, those paths were free()d
as part of free()ing this strmap.
In commit 6697ee01b5 (merge-ort: switch our strmaps over to using
memory pools, 2021-07-30), we changed the allocations for pathnames to
come from a memory pool. That meant the ownership changed slightly;
there were no individual free() calls to make, instead the memory pool
owned all those paths and they were free()d all at once.
Unfortunately unique_path() was written presuming the pre-memory-pool
model, and allocated a path on the heap and left it in the strmap for
later free()ing. Modify it to return a path allocated from the memory
pool instead.
Note that there's one instance -- in record_conflicted_index_entries()
-- where the returned string from unique_path() was only used very
temporarily and thus had been immediately free()'d. This codepath was
associated with an ugly skip-worktree workaround that has since been
better fixed by the in-flight en/present-despite-skipped topic. This
workaround probably makes sense to excise once that topic merges down,
but for now, just remove the immediate free() and allow the returned
string to be free()d when the memory pool is released.
This fixes the following memory leak as reported by valgrind:
==PID== 65 bytes in 1 blocks are definitely lost in loss record 79 of 134
==PID== at 0xADDRESS: malloc
==PID== by 0xADDRESS: realloc
==PID== by 0xADDRESS: xrealloc (wrapper.c:126)
==PID== by 0xADDRESS: strbuf_grow (strbuf.c:98)
==PID== by 0xADDRESS: strbuf_vaddf (strbuf.c:394)
==PID== by 0xADDRESS: strbuf_addf (strbuf.c:335)
==PID== by 0xADDRESS: unique_path (merge-ort.c:733)
==PID== by 0xADDRESS: process_entry (merge-ort.c:3678)
==PID== by 0xADDRESS: process_entries (merge-ort.c:4037)
==PID== by 0xADDRESS: merge_ort_nonrecursive_internal (merge-ort.c:4621)
==PID== by 0xADDRESS: merge_ort_internal (merge-ort.c:4709)
==PID== by 0xADDRESS: merge_incore_recursive (merge-ort.c:4760)
==PID== by 0xADDRESS: merge_ort_recursive (merge-ort-wrappers.c:57)
==PID== by 0xADDRESS: try_merge_strategy (merge.c:753)
Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
detect_and_process_renames() detects renames on both sides of history
and then combines these into a single diff_queue_struct. The combined
diff_queue_struct needs to be able to hold the renames found on either
side, and since it knows the (maximum) size it needs, it pre-emptively
grows the array to the appropriate size:
ALLOC_GROW(combined.queue,
renames->pairs[1].nr + renames->pairs[2].nr,
combined.alloc);
It then collects the items from each side:
collect_renames(opt, &combined, MERGE_SIDE1, ...)
collect_renames(opt, &combined, MERGE_SIDE2, ...)
Note, though, that collect_renames() sometimes determines that some
pairs are unnecessary and does not include them in the combined array.
When it is done, detect_and_process_renames() frees this memory:
if (combined.nr) {
...
free(combined.queue);
}
The problem is that sometimes even when there are pairs, none of them
are necessary. Instead of checking combined.nr, just remove the
if-check; free() knows to skip NULL pointers. This change fixes the
following memory leak, as reported by valgrind:
==PID== 192 bytes in 1 blocks are definitely lost in loss record 107 of 134
==PID== at 0xADDRESS: malloc
==PID== by 0xADDRESS: realloc
==PID== by 0xADDRESS: xrealloc (wrapper.c:126)
==PID== by 0xADDRESS: detect_and_process_renames (merge-ort.c:3134)
==PID== by 0xADDRESS: merge_ort_nonrecursive_internal (merge-ort.c:4610)
==PID== by 0xADDRESS: merge_ort_internal (merge-ort.c:4709)
==PID== by 0xADDRESS: merge_incore_recursive (merge-ort.c:4760)
==PID== by 0xADDRESS: merge_ort_recursive (merge-ort-wrappers.c:57)
==PID== by 0xADDRESS: try_merge_strategy (merge.c:753)
==PID== by 0xADDRESS: cmd_merge (merge.c:1676)
==PID== by 0xADDRESS: run_builtin (git.c:461)
==PID== by 0xADDRESS: handle_builtin (git.c:713)
==PID== by 0xADDRESS: run_argv (git.c:780)
==PID== by 0xADDRESS: cmd_main (git.c:911)
==PID== by 0xADDRESS: main (common-main.c:52)
Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is another simple change with a long explanation...
merge-recursive and merge-ort are both based on the same recursive idea:
if there is more than one merge base, merge the merge bases (which may
require first merging the merge bases of the merges bases, etc.). The
depth of the inner merge is recorded via a variable called "call_depth",
which we'll bring up again later. Naturally, the inner merges
themselves can have conflicts and various messages generated about those
files.
merge-recursive immediately prints to stdout as it goes, at the risk of
printing multiple conflict notices for the same path separated far apart
from each other with many intervenining conflict notices for other paths
between them. And this is true even if there are no inner merges
involved. An example of this was given in [1] and apparently caused
some confusion:
CONFLICT (rename/add): Rename A->B in HEAD. B added in otherbranch
...dozens of conflicts for OTHER paths...
CONFLICT (content): Merge conflicts in B
In contrast, merge-ort collects messages and stores them by path so that
it can print them grouped by path. Thus, the same case handled by
merge-ort would have output of the form:
CONFLICT (rename/add): Rename A->B in HEAD. B added in otherbranch
CONFLICT (content): Merge conflicts in B
...dozens of conflicts for OTHER paths...
This is generally helpful, but does make a separate bug more
problematic. In particular, while merge-recursive might report the
following for a recursive merge:
Auto-merging dir.c
Auto-merging midx.c
CONFLICT (content): Merge conflict in midx.c
Auto-merging diff.c
Auto-merging dir.c
CONFLICT (content): Merge conflict in dir.c
merge-ort would instead report:
Auto-merging diff.c
Auto-merging dir.c
Auto-merging dir.c
CONFLICT (content): Merge conflict in dir.c
Auto-merging midx.c
CONFLICT (content): Merge conflict in midx.c
The fact that messages for the same file are together is probably
helpful in general, but with the indentation missing for the inner
merge it unfortunately serves to confuse. This probably would lead
users to wonder:
* Why is Git reporting that "dir.c" is being merged twice?
* If midx.c has conflicts, why do I not see any when I open up the
file and why are no conflicts shown in the index?
Fix this output confusion by changing the output to clearly
differentiate the messages for outer merges from the ones for inner
merges, changing the above output from merge-ort to:
Auto-merging diff.c
From inner merge: Auto-merging dir.c
Auto-merging dir.c
CONFLICT (content): Merge conflict in dir.c
From inner merge: Auto-merging midx.c
From inner merge: CONFLICT (content): Merge conflict in midx.c
(Note: the number of spaces after the 'From inner merge:' is
2*call_depth).
One other thing to note here, that I didn't notice until typing up this
commit message, is that merge-recursive does not print any messages from
the inner merges by default; the extra verbosity has to be requested.
merge-ort currently has no verbosity controls and always prints these.
We may also want to change that, but for now, just make the output
clearer with these extra markings and indentation.
[1] https://lore.kernel.org/git/CAGyf7-He4in8JWUh9dpAwvoPkQz9hr8nCBpxOxhZEd8+jtqTpg@mail.gmail.com/
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git log --remerge-diff" shows the difference from mechanical merge
result and the result that is actually recorded in a merge commit.
* en/remerge-diff:
diff-merges: avoid history simplifications when diffing merges
merge-ort: mark conflict/warning messages from inner merges as omittable
show, log: include conflict/warning messages in --remerge-diff headers
diff: add ability to insert additional headers for paths
merge-ort: format messages slightly different for use in headers
merge-ort: mark a few more conflict messages as omittable
merge-ort: capture and print ll-merge warnings in our preferred fashion
ll-merge: make callers responsible for showing warnings
log: clean unneeded objects during `log --remerge-diff`
show, log: provide a --remerge-diff capability
The merge-ort misbehaved when merge.renameLimit configuration is
set too low and failed to find all renames.
* en/merge-ort-restart-optim-fix:
merge-ort: avoid assuming all renames detected
A recursive merge involves merging the merge bases of the two branches
being merged. Such an inner merge can itself generate conflict notices.
While such notices may be useful when initially trying to create a
merge, they seem to just be noise when investigating merges later with
--remerge-diff. (Especially when both sides of the outer merge resolved
the conflict the same way leading to no overall conflict.) Remove them.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
When users run
git show --remerge-diff $MERGE_COMMIT
or
git log -p --remerge-diff ...
stdout is not an appropriate location to dump conflict messages, but we
do want to provide them to users. We will include them in the diff
headers instead...but for that to work, we need for any multiline
messages to replace newlines with both a newline and a space. Add a new
flag to signal when we want these messages modified in such a fashion,
and use it in path_msg() to modify these messages this way. Also, allow
a special prefix to be specified for these headers.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
path_msg() has the ability to mark messages as omittable, designed for
remerge-diff where we'll instead be showing conflict messages as diff
headers for a subsequent diff. While all these messages are very useful
when trying to create a merge initially, early use with the
--remerge-diff feature (the only user of this omittable conflict message
capability), suggests that the particular messages marked in this commit
are just noise when trying to see what changes users made to create a
merge commit. Mark them as omittable.
Note that there were already a few messages marked as omittable in
merge-ort when doing a remerge-diff, because the development of
--remerge-diff preceded the upstreaming of merge-ort and I was trying to
ensure merge-ort could handle all the necessary requirements. See
commit c5a6f65527 ("merge-ort: add modify/delete handling and delayed
output processing", 2020-12-03) for the initial details. For some
examples of already-marked-as-omittable messages, see either
"Auto-merging <path>" or some of the submodule update hints. This
commit just adds two more messages that should also be omittable.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of immediately printing ll-merge warnings to stderr, we save
them in our output strbuf. Besides allowing us to move these warnings
to a special file for --remerge-diff, this has two other benefits for
regular merges done by merge-ort:
* The deferral of messages ensures we can print all messages about
any given path together (merge-recursive was known to sometimes
intersperse messages about other paths, particularly when renames
were involved).
* The deferral of messages means we can avoid printing spurious
conflict messages when we just end up aborting due to local user
modifications in the way. (In contrast to merge-recursive.c which
prematurely checks for local modifications in the way via
unpack_trees() and gets the check wrong both in terms of false
positives and false negatives relative to renames, merge-ort does
not perform the local modifications in the way check until the
checkout() step after the full merge has been computed.)
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since some callers may want to send warning messages to somewhere other
than stdout/stderr, stop printing "warning: Cannot merge binary files"
from ll-merge and instead modify the return status of ll_merge() to
indicate when a merge of binary files has occurred. Message printing
probably does not belong in a "low-level merge" anyway.
This commit continues printing the message as-is, just from the callers
instead of within ll_merge(). Future changes will start handling the
message differently in the merge-ort codepath.
There was one special case here: the callers in rerere.c do NOT check
for and print such a message; since those code paths explicitly skip
over binary files, there is no reason to check for a return status of
LL_MERGE_BINARY_CONFLICT or print the related message.
Note that my methodology included first modifying ll_merge() to return
a struct, so that the compiler would catch all the callers for me and
ensure I had modified all of them. After modifying all of them, I then
changed the struct to an enum.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The documentation for merge_incore_recursive(), modelled after
merge_recursive(), notes that
merge_bases will be consumed (emptied) so make a copy if you need it
However, in merge_ort_internal() (which merge_incore_recursive() calls),
it runs
merged_merge_bases = pop_commit(&merge_bases);
...
for (iter = merge_bases; iter; iter = iter->next) {
...
}
In other words, it only consumes the *first* entry of merge_bases, and
the rest it iterates through. If it iterated through all of them, the
caller could be responsible for free'ing the memory. If it consumed all
of them, the current documentation would be correct and the callers
would need to do nothing. The current middle ground makes it impossible
for callers to avoid memory leaks, since any attempt to use the
merge_bases it passes in would result in a use-after-free.
It turns out this part of the code was copied from merge-recursive.c,
which has had the same bug for 15.5 years. However, since we are trying
to keep merge-recursive.c stable as we sunset it, let's just fix the
leak in in merge_ort_internal() by having it actually consume all the
elements of the merge_bases commit_list.
Testing this commit against t6404 (the first testcase specifically
about recursive merges) under valgrind shows that this patch fixes
the following leak:
32 (16 direct, 16 indirect) bytes in 1 blocks are definitely lost \
in loss record 49 of 126
at 0x484086F: malloc (vg_replace_malloc.c:380)
by 0x69FFEB: do_xmalloc (wrapper.c:41)
by 0x6A0073: xmalloc (wrapper.c:62)
by 0x52A72D: commit_list_insert (commit.c:556)
by 0x47EC86: try_merge_strategy (merge.c:751)
by 0x48143B: cmd_merge (merge.c:1679)
by 0x40686E: run_builtin (git.c:464)
by 0x406C51: handle_builtin (git.c:716)
by 0x406E96: run_argv (git.c:783)
by 0x40730A: cmd_main (git.c:914)
by 0x4E7DFA: main (common-main.c:56)
Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In commit 8b09a900a1 ("merge-ort: restart merge with cached renames to
reduce process entry cost", 2021-07-16), we noted that in the merge-ort
steps of
collect_merge_info()
detect_and_process_renames()
process_entries()
that process_entries() was expensive, and we could often make it cheaper
by changing this to
collect_merge_info()
detect_and_process_renames()
<cache all the renames, and restart>
collect_merge_info()
detect_and_process_renames()
process_entries()
because the second collect_merge_info() would be cheaper (we could avoid
traversing into some directories), the second
detect_and_process_renames() would be free since we had already detected
all renames, and then process_entries() has far fewer entries to handle.
However, this was built on the assumption that the first
detect_and_process_renames() actually detected all potential renames.
If someone has merge.renameLimit set to some small value, that
assumption is violated which manifests later with the following message:
$ git -c merge.renameLimit=1 rebase upstream
...
git: merge-ort.c:546: clear_or_reinit_internal_opts: Assertion
`renames->cached_pairs_valid_side == 0' failed.
Turn off this cache-renames-and-restart whenever we cannot detect all
renames, and add a testcase that would have caught this problem.
Reported-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Tested-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
