At GitHub, a few repositories were triggering errors of the form:
git: merge-ort.c:3037: process_renames: Assertion `newinfo && !newinfo->merged.clean' failed.
Aborted (core dumped)
While these may look similar to both
a562d90a350d (merge-ort: fix failing merges in special corner case,
2025-11-03)
and
f6ecb603ff8a (merge-ort: fix directory rename on top of source of other
rename/delete, 2025-08-06)
the cause is different and in this case the problem is not an
over-conservative assertion, but a bug before the assertion where we did
not update all relevant state appropriately.
It sadly took me a really long time to figure out how to get a simple
reproducer for this one. It doesn't really have that many moving parts,
but there are multiple pieces of background information needed to
understand it.
First of all, when we have two files added at the same path, merge-ort
does a two-way merge of those files. If we have two directories added
at the same path, we basically do the same thing (taking the union of
files, and two-way merging files with the same name). But two-way
merging requires components of the same type. We can't merge the
contents of a regular file with a directory, or with a symlink, or with
a submodule. Nor can any of those other types be merged with each
other, e.g. merging a submodule with a directory is a bad idea. When
two paths have the same name but their types do not match, merge-ort is
forced to move one of them to an alternate filename (using the
unique_path() function).
Second, if two commits being merged have more than one merge-base,
merge-ort will merge the merge-bases to create a virtual merge-base, and
use that as the base commit.
Third, one of the really important optimizations in merge-ort is trivial
tree-level resolution (roughly meaning merging trees without recursing
into them). This optimization has some nuance to it that is important
to the current bug, and to understand it, it helps to first look at the
high-level overview of how merge-ort runs; there are basically three
high-level functions that the work is divided between:
collect_merge_info() - walks the top-level trees getting individual
paths of interest
detect_renames() - detect renames between paths in order to match up
paths for three-way merging
process_entries() - does a few things of interest:
* three-way merging of files,
* other special handling (e.g. adjusting paths with conflicting
types to avoid path collisions)
* as it finishes handling all the files within a subdirectory,
writes out a new tree object for that directory
If it were not for renames, we could just always do tree-level merging
whenever the tree on at least one side was unmodified. Unfortunately,
we need to recurse into trees to determine whether there are renames.
However, we can also do tree-level merging so long as there aren't any
*relevant* renames (another merge-ort optimization), which we can
determine without recursing into trees.
We would also be able to do tree-level merging if we somehow apriori
knew what renames existed, by only recursing into the trees which we
could otherwise trivially merge if they contained files involved in
renames. That might not seem useful, because we need to find out the
renames and we have to recurse into trees to do so, but when you find
out that the process_entries() step is more computationally expensive
than the collect_merge_info() step, it yields an interesting strategy:
* run collect_merge_info()
* run detect_renames()
* cache the renames()
* restart -- rerun collect_merge_info(), using the cached renames to
only recurse into the needed trees
* we already have the renames cached so no need to re-detect
* run process_entries() on the reduced list of paths
which was implemented back in 7bee6c100431 (merge-ort: avoid recursing
into directories when we don't need to, 2021-07-16) Crucially, this
restarting only occurs if the number of paths we could skip recursing
into exceeds the number we still need to recurse into by some safety
factor (wanted_factor in handle_deferred_entries()); forgetting this
fact is a great way to repeatedly fail to create a minimal testcase for
several days and go down alternate wrong paths).
Now, I earlier summarized this optimization as "merging trees without
recursing into them", but this optimization does not require that all
three sides of history has a directory at a given path. So long as the
tree on one side matches the tree in the base version, we can decide to
resolve in favor of whatever the other side of history has at that path
-- be it a directory, a file, a submodule, or a symlink. Unfortunately,
the code in question didn't fully realize this, and was written assuming
the base version and both sides would have a directory at the given
path, as can be seen by the "ci->filemask == 0" comment in
resolve_trivial_directory_merge() that was added as part of 7bee6c100431
(merge-ort: avoid recursing into directories when we don't need to,
2021-07-16). A few additional lines of code are needed to handle cases
where we have something other than a directory on the other side of
history.
But, knowing that resolve_trivial_directory_merge() doesn't have
sufficient state updating logic doesn't show us how to trigger a bug
without combining with the other bits of information we provided above.
Here's a relevant testcase:
* branches A & B
* commit A1: adds "folder" as a directory with files tracked under it
* commit B1: adds "folder" as a submodule
* commit A2: merges B1 into A1, keeping "folder" as a directory
(and in fact, with no changes to "folder" since A1), discarding the
submodule
* commit B2: merges A1 into B1, keeping "folder" as a submodule
(and in fact, with no changes to "folder" since B1), discarding the
directory
Here, if we try to merge A2 & B2, the logic proceeds as follows:
* we have multiple merge-bases: A1 & B1. So we have to merge those
to get a virtual merge base.
* due to "folder" as a directory and "folder" as a submodule, the
path collision logic triggers and renames "folder" as a submodule
to "folder~Temporary merge branch 2" so we can keep it alongside
"folder" as a directory.
* we now have a virtual merge base (containing both "folder"
directory and a "folder~Temporary merge branch 2" submodule) and
can now do the outer merge
* in the first step of the outer merge, we attempt to defer recursing
into folder/ as a directory, but find we need to for rename
detection.
* in rename detection, we note that "folder~Temporary merge branch 2"
has the same hash as "folder" as a submodule in B2, which means we
have an exact rename.
* after rename detection, we discover no path in folder/ is needed
for renames, and so we can cache renames and restart.
* after restarting, we avoid recursing into "folder/" and realize we
can resolve it trivially since it hasn't been modified. The
resolution removes "folder/", leaving us only "folder" as a
submodule from commit B2.
* After this point, we should have a rename/delete conflict on
"folder~Temporary merge branch 2" -> "folder", but our marking of
the merge of "folder" as clean broke our ability to handle that and
in fact triggers an assertion in process_renames().
When there was a df_conflict (directory/"file" conflict, where "file"
could be submodule or regular file or symlink), ensure
resolve_trivial_directory_merge() handles it properly. In particular:
* do not pre-emptively mark the path as cleanly merged if the
remaining path is a file; allow it to be processed in
process_entries() later to determine if it was clean
* clear the parts of dirmask or filemask corresponding to the matching
sides of history, since we are resolving those away
* clear the df_conflict bit afterwards; since we cleared away the two
matching sides and only have one side left, that one side can't
have a directory/file conflict with itself.
Also add the above minimal testcase showcasing this bug to t6422, **with
a sufficient number of paths under the folder/ directory to actually
trigger it**. (I wish I could have all those days back from all the
wrong paths I went down due to not having enough files under that
directory...)
I know this commit has a very high ratio of lines in the commit message
to lines of comments, and a relatively high ratio of comments to actual
code, but given how long it took me to track down, on the off chance
that we ever need to further modify this logic, I wanted it thoroughly
documented for future me and for whatever other poor soul might end up
needing to read this commit message.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "seq" tool has a "-f" option to produce printf-style formatted
lines. Let's teach our test_seq helper the same trick. This lets us get
rid of some shell loops in test snippets (which are particularly verbose
in our test suite because we have to "|| return 1" to keep the &&-chain
going).
This converts a few call-sites I found by grepping around the test
suite. A few notes on these:
- In "seq", the format specifier is a "%g" float. Since test_seq only
supports integers, I've kept the more natural "%d" (which is what
these call sites were using already).
- Like "seq", test_seq automatically adds a newline to the specified
format. This is what all callers are doing already except for t0021,
but there we do not care about the exact format. We are just trying
to printf a large number of bytes to a file. It's not worth
complicating other callers or adding an option to avoid the newline
in that caller.
- Most conversions are just replacing a shell loop (which does get rid
of an extra fork, since $() requires a subshell). In t0612 we can
replace an awk invocation, which I think makes the end result more
readable, as there's less quoting.
- In t7422 we can replace one loop, but sadly we have to leave the
loop directly above it. This is because that earlier loop wants to
include the seq value twice in the output, which test_seq does not
support (nor does regular seq). If you run:
test_seq -f "foo-%d %d" 10
the second "%d" will always be the empty string. You might naively
think that test_seq could add some extra arguments, like:
# 3 ought to be enough for anyone...
printf "$fmt\n" "$i "$i" $i"
but that just triggers printf to format multiple lines, one per
extra set of arguments.
So we'd have to actually parse the format string, figure out how
many "%" placeholders are there, and then feed it that many
instances of the sequence number. The complexity isn't worth it.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Both of these existed to allow us to reuse all the merge-related tests
in the testsuite while easily flipping between the 'recursive' and the
'ort' backends. Now that we have removed merge-recursive and remapped
'recursive' to mean 'ort', we don't need this scaffolding anymore.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that the default value for TEST_PASSES_SANITIZE_LEAK is `true` there
is no longer a need to have that variable declared in all of our tests.
Drop it.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
They are equivalents and the former still exists, so as long as the
only change this commit makes are to rewrite test_i18ngrep to
test_grep, there won't be any new bug, even if there still are
callers of test_i18ngrep remaining in the tree, or when merged to
other topics that add new uses of test_i18ngrep.
This patch was produced more or less with
git grep -l -e 'test_i18ngrep ' 't/t[0-9][0-9][0-9][0-9]-*.sh' |
xargs perl -p -i -e 's/test_i18ngrep /test_grep /'
and a good way to sanity check the result yourself is to run the
above in a checkout of c4603c1c (test framework: further deprecate
test_i18ngrep, 2023-10-31) and compare the resulting working tree
contents with the result of applying this patch to the same commit.
You'll see that test_i18ngrep in a few t/lib-*.sh files corrected,
in addition to the manual reproduction.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In commit [1] tests in t6422-merge-rename-corner-cases.sh were
refactored to not run setup steps separately. This included replacing
all tests like
test_expect_success "setup ..." '
<code of setup>
'
with corresponding Shell functions
test_setup_... () {
<code of setup>
}
During this replacement first and last lines of one of such tests got
left commented out in code. Drop these lines to avoid confusion.
[1] da1e295e00 (t604[236]: do not run setup in separate tests, 2019-10-22)
Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert the merge-specific tests (those in the t64xx range) over to
using 'git init' instead of 'test_create_repo'.
Reviewed-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix a memory leak where "cat-file" will leak the "path" member. See
e5fba602e59 (textconv: support for cat_file, 2010-06-15) for the code
that introduced the offending get_oid_with_context() call (called
get_sha1_with_context() at the time).
As a result we can mark several tests as passing with SANITIZE=leak
using "TEST_PASSES_SANITIZE_LEAK=true".
As noted in dc944b65f1d (get_sha1_with_context: dynamically allocate
oc->path, 2017-05-19) callers must free the "path" member. That same
commit added the relevant free() to this function, but we weren't
catching cases where we'd return early.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This trick was performed via
$ (cd t &&
sed -i -e 's/master/main/g' -e 's/MASTER/MAIN/g' \
-e 's/Master/Main/g' -- t6[4-9]*.sh)
This allows us to define `GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main`
for those tests.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We are in the process of renaming the default branch name to `main`,
which is two characters shorter than `master`. Therefore, some lines
need to be adjusted in t6416, t6422 and t6427 that want to align text
involving the default branch name.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In addition to the manual adjustment to let the `linux-gcc` CI job run
the test suite with `master` and then with `main`, this patch makes sure
that GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME is set in all test scripts
that currently rely on the initial branch name being `master by default.
To determine which test scripts to mark up, the first step was to
force-set the default branch name to `master` in
- all test scripts that contain the keyword `master`,
- t4211, which expects `t/t4211/history.export` with a hard-coded ref to
initialize the default branch,
- t5560 because it sources `t/t556x_common` which uses `master`,
- t8002 and t8012 because both source `t/annotate-tests.sh` which also
uses `master`)
This trick was performed by this command:
$ sed -i '/^ *\. \.\/\(test-lib\|lib-\(bash\|cvs\|git-svn\)\|gitweb-lib\)\.sh$/i\
GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=master\
export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME\
' $(git grep -l master t/t[0-9]*.sh) \
t/t4211*.sh t/t5560*.sh t/t8002*.sh t/t8012*.sh
After that, careful, manual inspection revealed that some of the test
scripts containing the needle `master` do not actually rely on a
specific default branch name: either they mention `master` only in a
comment, or they initialize that branch specificially, or they do not
actually refer to the current default branch. Therefore, the
aforementioned modification was undone in those test scripts thusly:
$ git checkout HEAD -- \
t/t0027-auto-crlf.sh t/t0060-path-utils.sh \
t/t1011-read-tree-sparse-checkout.sh \
t/t1305-config-include.sh t/t1309-early-config.sh \
t/t1402-check-ref-format.sh t/t1450-fsck.sh \
t/t2024-checkout-dwim.sh \
t/t2106-update-index-assume-unchanged.sh \
t/t3040-subprojects-basic.sh t/t3301-notes.sh \
t/t3308-notes-merge.sh t/t3423-rebase-reword.sh \
t/t3436-rebase-more-options.sh \
t/t4015-diff-whitespace.sh t/t4257-am-interactive.sh \
t/t5323-pack-redundant.sh t/t5401-update-hooks.sh \
t/t5511-refspec.sh t/t5526-fetch-submodules.sh \
t/t5529-push-errors.sh t/t5530-upload-pack-error.sh \
t/t5548-push-porcelain.sh \
t/t5552-skipping-fetch-negotiator.sh \
t/t5572-pull-submodule.sh t/t5608-clone-2gb.sh \
t/t5614-clone-submodules-shallow.sh \
t/t7508-status.sh t/t7606-merge-custom.sh \
t/t9302-fast-import-unpack-limit.sh
We excluded one set of test scripts in these commands, though: the range
of `git p4` tests. The reason? `git p4` stores the (foreign) remote
branch in the branch called `p4/master`, which is obviously not the
default branch. Manual analysis revealed that only five of these tests
actually require a specific default branch name to pass; They were
modified thusly:
$ sed -i '/^ *\. \.\/lib-git-p4\.sh$/i\
GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=master\
export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME\
' t/t980[0167]*.sh t/t9811*.sh
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
merge-recursive.c is built on the idea of running unpack_trees() and
then "doing minor touch-ups" to get the result. Unfortunately,
unpack_trees() was run in an update-as-it-goes mode, leading
merge-recursive.c to follow suit and end up with an immediate evaluation
and fix-it-up-as-you-go design. Some things like directory/file
conflicts are not well representable in the index data structure, and
required special extra code to handle. But then when it was discovered
that rename/delete conflicts could also be involved in directory/file
conflicts, the special directory/file conflict handling code had to be
copied to the rename/delete codepath. ...and then it had to be copied
for modify/delete, and for rename/rename(1to2) conflicts, ...and yet it
still missed some. Further, when it was discovered that there were also
file/submodule conflicts and submodule/directory conflicts, we needed to
copy the special submodule handling code to all the special cases
throughout the codebase.
And then it was discovered that our handling of directory/file conflicts
was suboptimal because it would create untracked files to store the
contents of the conflicting file, which would not be cleaned up if
someone were to run a 'git merge --abort' or 'git rebase --abort'. It
was also difficult or scary to try to add or remove the index entries
corresponding to these files given the directory/file conflict in the
index. But changing merge-recursive.c to handle these correctly was a
royal pain because there were so many sites in the code with similar but
not identical code for handling directory/file/submodule conflicts that
would all need to be updated.
I have worked hard to push all directory/file/submodule conflict
handling in merge-ort through a single codepath, and avoid creating
untracked files for storing tracked content (it does record things at
alternate paths, but makes sure they have higher-order stages in the
index).
Since updating merge-recursive is too much work and we don't want to
destabilize it, instead update the testsuite to have different
expectations for relevant directory/file/submodule conflict tests.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are a number of tests that the "recursive" backend does not handle
correctly but which the redesign in "ort" will. Add a new helper in
lib-merge.sh for selecting a different test expectation based on the
setting of GIT_TEST_MERGE_ALGORITHM, and use it in various testcases to
document which ones we expect to fail under recursive but pass under
ort.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Much like the last commit accepted 'add/add' and 'rename/add'
interchangably, we also want to do the same for 'add/add' and
'rename/rename'. This also allows us to avoid the ambiguity in meaning
with 'rename/rename' (is it two separate files renamed to the same
location, or one file renamed on both sides but differently)?
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
merge-recursive treats an add/add conflict where one of the adds came
from a rename as a separate 'rename/add' type of conflict. However, if
there is not content conflict after the content merge(s), then the file
is not considered to be conflicted. That suggests the conflict type is
really just add/add. Other merge engines might choose to print messages
to the console that just refer to these as add/add conflicts; accept
both types of output.
Note: it could help to notify users if the three-way content merge of
the rename had content conflicts, because when we then go to two-way
merge THAT with the conflicting add we can get nested conflict markers.
merge-recursive, unfortunately, doesn't do that, but other merge engines
could.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This test had multiple issues causing it to fail for the wrong
reason(s):
* rename/rename(1to2) conflicts have always left the original source
path present in the working directory and index (at stage 1). Thus,
the triple rename/rename(1to2) should result in 9 unstaged files,
not 6.
* It messed up the three-way content merge for checking the results of
merging for one of the renames, accidentally turning it into a
two-way merge.
* It got the contents of the base files it was using to compare
against wrong, due to an off-by-one error, and overwrite-redirection
('>') instead of append-redirection ('>>').
* It used slightly too-long conflict markers
* It didn't include filenames in the conflict marker hunks (granted,
that was a shortcoming of the merge-recursive backend for rename/add
and rename/rename(2to1) conflicts, but since it's
test_expect_failure anyway we might as well make it expect our
preferred behavior rather than some compromise that we can't yet
reach anyway).
Fix these issues so that a merge backend which correctly handles these
kinds of nested conflicts will pass the test.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Apparently I don't know how to count untracked files, and since the
tests in question were marked as test_expect_failure, no one ever
noticed it until now. Correct the count, as these tests clearly create
three untracked files ('out', 'err', and 'file_count').
(I believe this problem arose because earlier incarnations counted lines
via a pipe to 'wc -l'. Reviewers asked that it be replaced by writing
the output to a file and using test_line_count, but when the temporary
output was added to a separate file, the count of untracked files should
have increased.)
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The tests for the merge machinery are spread over several places.
Collect them into t64xx for simplicity. Some notes:
t60[234]*.sh:
Merge tests started in t602*, overgrew bisect and remote tracking
tests in t6030, t6040, and t6041, and nearly overtook replace tests
in t6050. This made picking out relevant tests that I wanted to run
in a tighter loop slightly more annoying for years.
t303*.sh:
These started out as tests for the 'merge-recursive' toplevel command,
but did not restrict to that and had lots of overlap with the
underlying merge machinery.
t7405, t7613:
submodule-specific merge logic started out in submodule.c but was
moved to merge-recursive.c in commit 18cfc08866 ("submodule.c: move
submodule merging to merge-recursive.c", 2018-05-15). Since these
tests are about the logic found in the merge machinery, moving these
tests to be with the merge tests makes sense.
t7607, t7609:
Having tests spread all over the place makes it more likely that
additional tests related to a certain piece of logic grow in all those
other places. Much like t303*.sh, these two tests were about the
underlying merge machinery rather than outer levels.
Tests that were NOT moved:
t76[01]*.sh:
Other than the four tests mentioned above, the remaining tests in
t76[01]*.sh are related to non-recursive merge strategies, parameter
parsing, and other stuff associated with the highlevel builtin/merge.c
rather than the recursive merge machinery.
t3[45]*.sh:
The rebase testcases in t34*.sh also test the merge logic pretty
heavily; sometimes changes I make only trigger failures in the rebase
tests. The rebase tests are already nicely coupled together, though,
and I didn't want to mess that up. Similar comments apply for the
cherry-pick tests in t35*.sh.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
