With a rename/rename(1to2) conflict, we attempt to do a three-way merge
of the file contents, so that the correct contents can be placed in the
working tree at both paths. If the file is a binary, however, no
content merging is possible and we should just use the original version
of the file at each of the paths.
Reported-by: Chunlin Zhang <zhangchunlin@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are a variety of situations where a filter process can make use of
some additional metadata. For example, some people find the ident
filter too limiting and would like to include the commit or the branch
in their smudged files. This information isn't available during
checkout as HEAD hasn't been updated at that point, and it wouldn't be
available in archives either.
Let's add a way to pass this metadata down to the filter. We pass the
blob we're operating on, the treeish (preferring the commit over the
tree if one exists), and the ref we're operating on. Note that we won't
pass this information in all cases, such as when renormalizing or when
we're performing diffs, since it doesn't make sense in those cases.
The data we currently get from the filter process looks like the
following:
command=smudge
pathname=git.c
0000
With this change, we'll get data more like this:
command=smudge
pathname=git.c
refname=refs/tags/v2.25.1
treeish=c522f061d551c9bb8684a7c3859b2ece4499b56b
blob=7be7ad34bd053884ec48923706e70c81719a8660
0000
There are a couple things to note about this approach. For operations
like checkout, treeish will always be a commit, since we cannot check
out individual trees, but for other operations, like archive, we can end
up operating on only a particular tree, so we'll provide only a tree as
the treeish. Similar comments apply for refname, since there are a
variety of cases in which we won't have a ref.
This commit wires up the code to print this information, but doesn't
pass any of it at this point. In a future commit, we'll have various
code paths pass the actual useful data down.
Signed-off-by: brian m. carlson <bk2204@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Handling of conflicting renames in merge-recursive have further
been made consistent with how existing codepaths try to mimic what
is done to add/add conflicts.
* en/merge-path-collision:
merge-recursive: apply collision handling unification to recursive case
The merge-recursive machinery failed to refresh the cache entry for
a merge result in a couple of places, resulting in an unnecessary
merge failure, which has been fixed.
* en/t3433-rebase-stat-dirty-failure:
merge-recursive: fix the refresh logic in update_file_flags
t3433: new rebase testcase documenting a stat-dirty-like failure
In the en/merge-path-collision topic (see commit ac193e0e0a, "Merge
branch 'en/merge-path-collision'", 2019-01-04), all the "file collision"
conflict types were modified for consistency. In particular,
rename/add, rename/rename(2to1) and each rename/add piece of a
rename/rename(1to2)/add[/add] conflict were made to behave like add/add
conflicts have always been handled.
However, this consistency was not enforced when opt->priv->call_depth >
0 for rename/rename conflicts. Update rename/rename(1to2) and
rename/rename(2to1) conflicts in the recursive case to also be
consistent. As an added bonus, this simplifies the code considerably.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If we need to delete a higher stage entry in the index to place the file
at stage 0, then we'll lose that file's stat information. In such
situations we may still be able to detect that the file on disk is the
version we want (as noted by our comment in the code:
/* do not overwrite file if already present */
), but we do still need to update the mtime since we are creating a new
cache_entry for that file. Update the logic used to determine whether
we refresh a file's mtime.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The flip_stage() helper uses a bit-flipping xor to switch between "2"
and "3". While clever, this relies on a property of those two numbers
that is mostly coincidence. Let's write it as a subtraction; that's more
clear and would extend to other numbers if somebody copies the logic.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The merge-recursive code uses stage number constants like this:
add = &ci->ren1->dst_entry->stages[2 ^ 1];
...
add = &ci->ren2->dst_entry->stages[3 ^ 1];
The xor has the effect of flipping the "1" bit, so that "2 ^ 1" becomes
"3" and "3 ^ 1" becomes "2", which correspond to the "ours" and "theirs"
stages respectively.
Unfortunately, clang-10 and up issue a warning for this code:
merge-recursive.c:1759:40: error: result of '2 ^ 1' is 3; did you mean '1 << 1' (2)? [-Werror,-Wxor-used-as-pow]
add = &ci->ren1->dst_entry->stages[2 ^ 1];
~~^~~
1 << 1
merge-recursive.c:1759:40: note: replace expression with '0x2 ^ 1' to silence this warning
We could silence it by using 0x2, as the compiler mentions. Or by just
using the constants "2" and "3" directly. But after digging into it, I
do think this bit-flip is telling us something. If we just wrote:
add = &ci->ren2->dst_entry->stages[2];
for the second one, you might think that "ren2" and "2" correspond. But
they don't. The logic is: ren2 is theirs, which is stage 3, but we
are interested in the opposite side's stage, so flip it to 2.
So let's keep the bit-flipping, but let's also put it behind a named
function, which will make its purpose a bit clearer. This also has the
side effect of suppressing the warning (and an optimizing compiler
should be able to easily turn it into a constant as before).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Back when merge-recursive was first introduced in commit 6d297f8137
(Status update on merge-recursive in C, 2006-07-08), it created a
sha_eq() function. This function pre-dated the introduction of
hashcmp() to cache.h by about a month, but was switched over to using
hashcmp() as part of commit 9047ebbc22 (Split out merge_recursive() to
merge-recursive.c, 2008-08-12). In commit b4da9d62f9 (merge-recursive:
convert leaf functions to use struct object_id, 2016-06-24), sha_eq() was
renamed to oid_eq() and its hashcmp() call was switched to oideq().
oid_eq() is basically just a wrapper around oideq() that has some extra
checks to protect against NULL arguments or to allow short-circuiting if
one of the arguments is NULL. I don't know if any caller ever tried to
call with NULL arguments, but certainly none do now which means the
extra checks serve no purpose. (Also, if these checks were genuinely
useful, then they probably should be added to the main oideq() so all
callers could benefit from them.)
Reduce the cognitive overhead of having both oid_eq() and oideq(), by
getting rid of merge-recursive's special oid_eq() wrapper.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When all files from some subdirectory were renamed to the root
directory, the directory rename heuristics would fail to detect that
as a rename/merge of the subdirectory to the root directory, which has
been corrected.
* en/merge-recursive-directory-rename-fixes:
t604[236]: do not run setup in separate tests
merge-recursive: fix merging a subdirectory into the root directory
merge-recursive: clean up get_renamed_dir_portion()
We allow renaming all entries in e.g. a directory named z/ into a
directory named y/ to be detected as a z/ -> y/ rename, so that if the
other side of history adds any files to the directory z/ in the mean
time, we can provide the hint that they should be moved to y/.
There is no reason to not allow 'y/' to be the root directory, but the
code did not handle that case correctly. Add a testcase and the
necessary special checks to support this case.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Dscho noted a few things making this function hard to follow.
Restructure it a bit and add comments to make it easier to follow. The
restructurings include:
* There was a special case if-check at the end of the function
checking whether someone just renamed a file within its original
directory, meaning that there could be no directory rename involved.
That check was slightly convoluted; it could be done in a more
straightforward fashion earlier in the function, and can be done
more cheaply too (no call to strncmp).
* The conditions for advancing end_of_old and end_of_new before
calling strchr were both confusing and unnecessary. If either
points at a '/', then they need to be advanced in order to find the
next '/'. If either doesn't point at a '/', then advancing them one
char before calling strchr() doesn't hurt. So, just rip out the
if conditions and advance both before calling strchr().
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The merge-recursive machiery is one of the most complex parts of
the system that accumulated cruft over time. This large series
cleans up the implementation quite a bit.
* en/merge-recursive-cleanup: (26 commits)
merge-recursive: fix the fix to the diff3 common ancestor label
merge-recursive: fix the diff3 common ancestor label for virtual commits
merge-recursive: alphabetize include list
merge-recursive: add sanity checks for relevant merge_options
merge-recursive: rename MERGE_RECURSIVE_* to MERGE_VARIANT_*
merge-recursive: split internal fields into a separate struct
merge-recursive: avoid losing output and leaking memory holding that output
merge-recursive: comment and reorder the merge_options fields
merge-recursive: consolidate unnecessary fields in merge_options
merge-recursive: move some definitions around to clean up the header
merge-recursive: rename merge_options argument to opt in header
merge-recursive: rename 'mrtree' to 'result_tree', for clarity
merge-recursive: use common name for ancestors/common/base_list
merge-recursive: fix some overly long lines
cache-tree: share code between functions writing an index as a tree
merge-recursive: don't force external callers to do our logging
merge-recursive: remove useless parameter in merge_trees()
merge-recursive: exit early if index != head
Ensure index matches head before invoking merge machinery, round N
merge-recursive: remove another implicit dependency on the_repository
...
In commit 8e4ec337 ("merge-recursive: fix the diff3 common ancestor
label for virtual commits", 2019-10-01), which was a fix to commit
743474cbfa ("merge-recursive: provide a better label for diff3
common ancestor", 2019-08-17), the label for the common ancestor was
changed from always being
"merged common ancestors"
to instead be based on the number of merge bases and whether the merge
base was a real commit or a virtual one:
>=2: "merged common ancestors"
1, via merge_recursive_generic: "constructed merge base"
1, otherwise: <abbreviated commit hash>
0: "<empty tree>"
The handling for "constructed merge base" worked by allowing
opt->ancestor to be set in merge_recursive_generic(), so we paid
attention to the setting of that variable in merge_recursive_internal().
Now, for the outer merge, the code flow was simply the following:
ancestor_name = "merged merge bases"
loop over merge_bases: merge_recursive_internal()
The first merge base not needing recursion would determine its own
ancestor_name however necessary and thus run
ancestor_name = $SOMETHING
empty loop over merge_bases...
opt->ancestor = ancestor_name
merge_trees_internal()
Now, the next set of merge_bases that would need to be merged after this
particular merge had completed would note that opt->ancestor has been
set to something (to a local ancestor_name variable that has since been
popped off the stack), and thus it would run:
... else if (opt->ancestor) {
ancestor_name = opt->ancestor; /* OOPS! */
loop over merge_bases: merge_recursive_internal()
opt->ancestor = ancestor_name
merge_trees_internal()
This resulted in garbage strings being printed for the virtual merge
bases, which was visible in git.git by just merging commit b744c3af07
into commit 6d8cb22a4f. There are two ways to fix this: set
opt->ancestor to NULL after using it to avoid re-use, or add a
!opt->priv->call_depth check to the if block for using a pre-defined
opt->ancestor. Apply both fixes.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since these macros already take a `keyvar' pointer of a known type,
we can rely on OFFSETOF_VAR to get the correct offset without
relying on non-portable `__typeof__' and `offsetof'.
Argument order is also rearranged, so `keyvar' and `member' are
sequential as they are used as: `keyvar->member'
Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While we cannot rely on a `__typeof__' operator being portable
to use with `offsetof'; we can calculate the pointer offset
using an existing pointer and the address of a member using
pointer arithmetic for compilers without `__typeof__'.
This allows us to simplify usage of hashmap iterator macros
by not having to specify a type when a pointer of that type
is already given.
In the future, list iterator macros (e.g. list_for_each_entry)
may also be implemented using OFFSETOF_VAR to save hackers the
trouble of using container_of/list_entry macros and without
relying on non-portable `__typeof__'.
v3: use `__typeof__' to avoid clang warnings
Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
`hashmap_free_entries' behaves like `container_of' and passes
the offset of the hashmap_entry struct to the internal
`hashmap_free_' function, allowing the function to free any
struct pointer regardless of where the hashmap_entry field
is located.
`hashmap_free' no longer takes any arguments aside from
the hashmap itself.
Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Inspired by list_for_each_entry in the Linux kernel.
Once again, these are somewhat compromised usability-wise
by compilers lacking __typeof__ support.
Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Another step in eliminating the requirement of hashmap_entry
being the first member of a struct.
Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update callers to use hashmap_get_entry, hashmap_get_entry_from_hash
or container_of as appropriate.
This is another step towards eliminating the requirement of
hashmap_entry being the first field in a struct.
Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is less error-prone than "void *" as the compiler now
detects invalid types being passed.
Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is less error-prone than "const void *" as the compiler
now detects invalid types being passed.
Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is less error-prone than "const void *" as the compiler
now detects invalid types being passed.
Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is less error-prone than "void *" as the compiler now
detects invalid types being passed.
Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
C compilers do type checking to make life easier for us. So
rely on that and update all hashmap_entry_init callers to take
"struct hashmap_entry *" to avoid future bugs while improving
safety and readability.
Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In commit 743474cbfa ("merge-recursive: provide a better label for
diff3 common ancestor", 2019-08-17), the label for the common ancestor
was changed from always being
"merged common ancestors"
to instead be based on the number of merge bases:
>=2: "merged common ancestors"
1: <abbreviated commit hash>
0: "<empty tree>"
Unfortunately, this did not take into account that when we have a single
merge base, that merge base could be fake or constructed. In such
cases, this resulted in a label of "00000000". Of course, the previous
label of "merged common ancestors" was also misleading for this case.
Since we have an API that is explicitly about creating fake merge base
commits in merge_recursive_generic(), we should provide a better label
when using that API with one merge base. So, when
merge_recursive_generic() is called with one merge base, set the label
to:
"constructed merge base"
Note that callers of merge_recursive_generic() include the builtin
commands git-am (in combination with git apply --build-fake-ancestor),
git-merge-recursive, and git-stash.
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When the working tree has:
- bar (directory)
- bar/file (file)
- foo (symlink to .)
(note that lstat() for "foo/bar" would tell us that it is a directory)
and the user merges a commit that deletes the foo symlink and instead
contains:
- bar (directory, as above)
- bar/file (file, as above)
- foo (directory)
- foo/bar (file)
the merge should happen without requiring user intervention. However,
this does not happen.
This is because dir_in_way(), when checking the working tree, thinks
that "foo/bar" is a directory. But a symlink should be treated much the
same as a file: since dir_in_way() is only checking to see if there is a
directory in the way, we don't want symlinks in leading paths to
sometimes cause dir_in_way() to return true.
Teach dir_in_way() to also check for symlinks in leading paths before
reporting whether a directory is in the way.
Helped-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Other than cache.h which needs to appear first, and merge-recursive.h
which I want to be second so that we are more likely to notice if
merge-recursive.h has any missing includes, the rest of the list is
long and easier to look through if it's alphabetical.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are lots of options that callers can set, yet most have a limited
range of valid values, some options are meant for output (e.g.
opt->obuf, which is expected to start empty), and callers are expected
to not set opt->priv. Add several sanity checks to ensure callers
provide sane values.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
I want to implement the same outward facing API as found within
merge-recursive.h in a different merge strategy. However, that makes
names like MERGE_RECURSIVE_{NORMAL,OURS,THEIRS} look a little funny;
rename to MERGE_VARIANT_{NORMAL,OURS,THEIRS}.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
merge_options has several internal fields that should not be set or read
by external callers. This just complicates the API. Move them into an
opaque merge_options_internal struct that is defined only in
merge-recursive.c and keep these out of merge-recursive.h.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If opt->buffer_output is less than 2, then merge_trees(),
merge_recursive(), and merge_recursive_generic() are all supposed to
flush the opt->obuf output buffer to stdout and release any memory it
holds. merge_trees() did not do this. Move the logic that handles this
for merge_recursive_internal() to merge_finalize() so that all three
methods handle this requirement.
Note that this bug didn't cause any problems currently, because there
are only two callers of merge_trees() right now (a git grep for
'merge_trees(' is misleading because builtin/merge-tree.c also defines a
'merge_tree' function that is unrelated), and only one of those is
called with buffer_output less than 2 (builtin/checkout.c), but it set
opt->verbosity to 0, for which there is only currently one non-error
message that would be shown: "Already up to date!". However, that one
message can only occur when the merge is utterly trivial (the merge base
tree exactly matches the merge tree), and builtin/checkout.c already
attempts a trivial merge via unpack_trees() before falling back to
merge_trees().
Also, if opt->buffer_output is 2, then the caller is responsible to
handle showing any output in opt->obuf and for free'ing it. This
requirement might be easy to overlook, so add a comment to
merge-recursive.h pointing it out. (There are currently two callers
that set buffer_output to 2, both in sequencer.c, and both of which
handle this correctly.)
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The merge_options struct had lots of fields, making it a little
imposing, but the options naturally fall into multiple different groups.
Grouping similar options and adding a comment or two makes it easier to
read, easier for new folks to figure out which options are related, and
thus easier for them to find the options they need.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We provided users with the ability to state whether they wanted rename
detection, and to put a limit on how much CPU would be spent. Both of
these fields had multiple configuration parameters for setting them,
with one being a fallback and the other being an override. However,
instead of implementing the logic for how to combine the multiple
source locations into the appropriate setting at config loading time,
we loaded and tracked both values and then made the code combine them
every time it wanted to check the overall value. This had a few
minor drawbacks:
* it seems more complicated than necessary
* it runs the risk of people using the independent settings in the
future and breaking the intent of how the options are used
together
* it makes merge_options more complicated than necessary for other
potential users of the API
Fix these problems by moving the logic for combining the pairs of
options into a single value; make it apply at time-of-config-loading
instead of each-time-of-use.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
No substantive code changes (view this with diff --color-moved), but
a few small code cleanups:
* Move structs and an inline function only used by merge-recursive.c
into merge-recursive.c
* Re-order function declarations to be more logical
* Add or fix some explanatory comments
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is not at all clear what 'mr' was supposed to stand for, at least not
to me. Pick a clearer name for this variable.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
merge_trees(), merge_recursive(), and merge_recursive_generic() in
their function headers used four different names for the merge base or
list of merge bases they were passed:
* 'common'
* 'ancestors'
* 'ca'
* 'base_list'
They were able to refer to it four different ways instead of only three
by using a different name in the signature for the .c file than the .h
file. Change all of these to 'merge_base' or 'merge_bases'.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
No substantive code change, just add some line breaks to fix lines that
have grown in length due to various refactorings. Most remaining lines
of excessive length in merge-recursive include error messages and it's
not clear that splitting those improves things.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
write_tree_from_memory() appeared to be a merge-recursive special that
basically duplicated write_index_as_tree(). The two have a different
signature, but the bigger difference was just that write_index_as_tree()
would always unconditionally read the index off of disk instead of
working on the current in-memory index. So:
* split out common code into write_index_as_tree_internal()
* rename write_tree_from_memory() to write_inmemory_index_as_tree(),
make it call write_index_as_tree_internal(), and move it to
cache-tree.c
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Alternatively, you can view this as "make the merge functions behave
more similarly." merge-recursive has three different entry points:
merge_trees(), merge_recursive(), and merge_recursive_generic(). Two of
these would call diff_warn_rename_limit(), but merge_trees() didn't.
This lead to callers of merge_trees() needing to manually call
diff_warn_rename_limit() themselves. Move this to the new
merge_finalize() function to make sure that all three entry points run
this function.
Note that there are two external callers of merge_trees(), one in
sequencer.c and one in builtin/checkout.c. The one in sequencer.c is
cleaned up by this patch and just transfers where the call to
diff_warn_rename_limit() is made; the one in builtin/checkout.c is for
switching to a different commit and in the very rare case where the
warning might be triggered, it would probably be helpful to include
(e.g. if someone is modifying a file that has been renamed in moving to
the other commit, but there are so many renames between the commits that
the limit kicks in and none are detected, it may help to have an
explanation about why they got a delete/modify conflict instead of a
proper content merge in a renamed file).
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
merge_trees() took a results parameter that would only be written when
opt->call_depth was positive, which is never the case now that
merge_trees_internal() has been split from merge_trees(). Remove the
misleading and unused parameter from merge_trees().
While at it, add some comments explaining how the output of
merge_trees() and merge_recursive() differ.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We had a rule to enforce that the index matches head, but it was found
at the beginning of merge_trees() and would only trigger when
opt->call_depth was 0. Since merge_recursive() doesn't call
merge_trees() until after returning from recursing, this meant that the
check wasn't triggered by merge_recursive() until it had first finished
all the intermediate merges to create virtual merge bases. That is a
potentially huge amount of computation (and writing of intermediate
merge results into the .git/objects directory) before it errors out and
says, in effect, "Sorry, I can't do any merging because you have some
local changes that would be overwritten."
Further, not enforcing this requirement earlier allowed other bugs (such
as an unintentional unconditional dropping and reloading of the index in
merge_recursive() even when no recursion was necessary), to mask bugs in
other callers (which were fixed in the commit prior to this one).
Make sure we do the index == head check at the beginning of the merge,
and error out immediately if it fails. While we're at it, fix a small
leak in the show-the-error codepath.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit d7cf3a96e9 ("merge-recursive.c: remove implicit dependency on
the_repository", 2019-01-12) and follow-ups like commit 34e7771bc6
("Use the right 'struct repository' instead of the_repository",
2019-06-27), removed most implicit uses of the_repository. Convert
calls to get_commit_tree() to instead use repo_get_commit_tree() to get
rid of another.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There is a 'free_buf' label to which all but one of the error paths in
update_file_flags() jump; that error case involves a NULL buf and is
thus not a memory leak. However, make that error case execute the same
deallocation code anyway so that if anyone adds any additional memory
allocations or deallocations, then all error paths correctly deallocate
resources.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Improve code readability by introducing an enum to replace the
not-quite-boolean values taken on by detect_directory_renames.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In commit 7ca56aa076 ("merge-recursive: add a label for ancestor",
2010-03-20), a label was added for the '||||||' line to make it have
the more informative heading '|||||| merged common ancestors', with
the statement:
It would be nicer to use a more informative label. Perhaps someone
will provide one some day.
This chosen label was perfectly reasonable when recursiveness kicks in,
i.e. when there are multiple merge bases. (I can't think of a better
label in such cases.) But it is actually somewhat misleading when there
is a unique merge base or no merge base. Change this based on the
number of merge bases:
>=2: "merged common ancestors"
1: <abbreviated commit hash>
0: "<empty tree>"
Tests have also been added to check that we get the right ancestor name
for each of the three cases.
Also, since merge_recursive() and merge_trees() have polar opposite
pre-conditions for opt->ancestor, document merge_recursive()'s
pre-condition with an assertion. (An assertion was added to
merge_trees() already a few commits ago.) The differences in
pre-conditions stem from two factors: (1) merge_trees() does not recurse
and thus does not have multiple sub-merges to worry about -- each of
which would require a different value for opt->ancestor, (2)
merge_trees() is only passed trees rather than commits and thus cannot
internally guess as good of a label. Thus, while external callers of
merge_trees() are required to provide a non-NULL opt->ancestor,
merge_recursive() expects to set this value itself.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We always want our conflict hunks to be labelled so that users can know
where each came from. The previous commit fixed the one caller in the
codebase which was not setting opt->ancestor (and thus not providing a
label for the "merge base" conflict hunk in diff3-style conflict
markers); add an assertion to prevent future codepaths from also
overlooking this requirement.
Enforcing this requirement also allows us to simplify the code for
labelling the conflict hunks by no longer checking if the ancestor label
is NULL.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In commit 8daec1df03 ("merge-recursive: switch from (oid,mode) pairs
to a diff_filespec", 2019-04-05), an assertion on a->path && b->path
was added for code readability to document that these both needed to be
non-NULL at this point in the code. However, the subsequent lines also
read o->path, so it should be included in the assert.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
