Commit Graph

669 Commits

Author SHA1 Message Date
Elijah Newren
6da1a25814 hashmap: provide deallocation function names
hashmap_free(), hashmap_free_entries(), and hashmap_free_() have existed
for a while, but aren't necessarily the clearest names, especially with
hashmap_partial_clear() being added to the mix and lazy-initialization
now being supported.  Peff suggested we adopt the following names[1]:

  - hashmap_clear() - remove all entries and de-allocate any
    hashmap-specific data, but be ready for reuse

  - hashmap_clear_and_free() - ditto, but free the entries themselves

  - hashmap_partial_clear() - remove all entries but don't deallocate
    table

  - hashmap_partial_clear_and_free() - ditto, but free the entries

This patch provides the new names and converts all existing callers over
to the new naming scheme.

[1] https://lore.kernel.org/git/20201030125059.GA3277724@coredump.intra.peff.net/

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-02 12:15:50 -08:00
Junio C Hamano
4339259d5f Merge branch 'en/eol-attrs-gotchas'
All "mergy" operations that internally use the merge-recursive
machinery should honor the merge.renormalize configuration, but
many of them didn't.

* en/eol-attrs-gotchas:
  checkout: support renormalization with checkout -m <paths>
  merge: make merge.renormalize work for all uses of merge machinery
  t6038: remove problematic test
  t6038: make tests fail for the right reason
2020-08-10 10:24:02 -07:00
Elijah Newren
8d552258f4 merge: make merge.renormalize work for all uses of merge machinery
The 'merge' command is not the only one that does merges; other commands
like checkout -m or rebase do as well.  Unfortunately, the only area of
the code that checked for the "merge.renormalize" config setting was in
builtin/merge.c, meaning it could only affect merges performed by the
"merge" command.  Move the handling of this config setting to
merge_recursive_config() so that other commands can benefit from it as
well.  Fixes a few tests in t6038.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-03 11:48:15 -07:00
Elijah Newren
56e743426b merge-recursive: fix unclear and outright wrong comments
Commits 7c0a6c8e47 ("merge-recursive: move some definitions around to
clean up the header", 2019-08-17), and b4db8a2b76 ("merge-recursive:
remove useless parameter in merge_trees()", 2019-08-17) added some
useful documentation to the functions, but had a few places where the
new comments were unclear or even misleading.  Fix those comments.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-02 11:03:57 -07:00
Elijah Newren
95983da6b4 merge-recursive: fix rename/rename(1to2) for working tree with a binary
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>
2020-05-14 12:14:19 -07:00
brian m. carlson
ab90ecae99 convert: permit passing additional metadata to filter processes
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>
2020-03-16 11:37:02 -07:00
Junio C Hamano
d1075adfdf Merge branch 'en/merge-path-collision'
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
2020-03-09 11:21:20 -07:00
Junio C Hamano
48d5f25ddd Merge branch 'en/t3433-rebase-stat-dirty-failure'
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
2020-03-02 15:07:19 -08:00
Elijah Newren
802050400a merge-recursive: apply collision handling unification to recursive case
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>
2020-02-27 10:59:59 -08:00
Elijah Newren
fb1c18fc46 merge-recursive: fix the refresh logic in update_file_flags
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>
2020-02-19 10:13:31 -08:00
Junio C Hamano
4c616c2ba1 merge-recursive: use subtraction to flip stage
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>
2020-01-27 11:17:41 -08:00
Jeff King
ee798742bd merge-recursive: silence -Wxor-used-as-pow warning
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>
2020-01-27 11:15:35 -08:00
Junio C Hamano
f25f04edca Merge branch 'en/merge-recursive-oid-eq-simplify'
Code cleanup.

* en/merge-recursive-oid-eq-simplify:
  merge-recursive: remove unnecessary oid_eq function
2020-01-06 14:17:51 -08:00
Elijah Newren
763a59e71c merge-recursive: remove unnecessary oid_eq function
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>
2020-01-02 10:35:24 -08:00
Junio C Hamano
d9800351d3 Merge branch 'en/merge-recursive-directory-rename-fixes'
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()
2019-11-10 18:02:13 +09:00
Elijah Newren
49b8133a9e merge-recursive: fix merging a subdirectory into the root directory
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>
2019-10-23 11:32:49 +09:00
Elijah Newren
d3eebaad5e merge-recursive: clean up get_renamed_dir_portion()
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>
2019-10-23 11:32:48 +09:00
Junio C Hamano
5efabc7ed9 Merge branch 'ew/hashmap'
Code clean-up of the hashmap API, both users and implementation.

* ew/hashmap:
  hashmap_entry: remove first member requirement from docs
  hashmap: remove type arg from hashmap_{get,put,remove}_entry
  OFFSETOF_VAR macro to simplify hashmap iterators
  hashmap: introduce hashmap_free_entries
  hashmap: hashmap_{put,remove} return hashmap_entry *
  hashmap: use *_entry APIs for iteration
  hashmap_cmp_fn takes hashmap_entry params
  hashmap_get{,_from_hash} return "struct hashmap_entry *"
  hashmap: use *_entry APIs to wrap container_of
  hashmap_get_next returns "struct hashmap_entry *"
  introduce container_of macro
  hashmap_put takes "struct hashmap_entry *"
  hashmap_remove takes "const struct hashmap_entry *"
  hashmap_get takes "const struct hashmap_entry *"
  hashmap_add takes "struct hashmap_entry *"
  hashmap_get_next takes "const struct hashmap_entry *"
  hashmap_entry_init takes "struct hashmap_entry *"
  packfile: use hashmap_entry in delta_base_cache_entry
  coccicheck: detect hashmap_entry.hash assignment
  diff: use hashmap_entry_init on moved_entry.ent
2019-10-15 13:48:02 +09:00
Junio C Hamano
280bd44551 Merge branch 'en/merge-recursive-cleanup'
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
  ...
2019-10-15 13:47:59 +09:00
Elijah Newren
b657047719 merge-recursive: fix the fix to the diff3 common ancestor label
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>
2019-10-08 11:36:27 +09:00
Eric Wong
404ab78e39 hashmap: remove type arg from hashmap_{get,put,remove}_entry
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>
2019-10-07 10:20:12 +09:00
Eric Wong
23dee69f53 OFFSETOF_VAR macro to simplify hashmap iterators
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>
2019-10-07 10:20:11 +09:00
Eric Wong
c8e424c9c9 hashmap: introduce hashmap_free_entries
`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>
2019-10-07 10:20:11 +09:00
Eric Wong
87571c3f71 hashmap: use *_entry APIs for iteration
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>
2019-10-07 10:20:11 +09:00
Eric Wong
939af16eac hashmap_cmp_fn takes hashmap_entry params
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>
2019-10-07 10:20:11 +09:00
Eric Wong
f23a465132 hashmap_get{,_from_hash} return "struct hashmap_entry *"
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>
2019-10-07 10:20:11 +09:00
Eric Wong
26b455f21e hashmap_put takes "struct hashmap_entry *"
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>
2019-10-07 10:20:10 +09:00
Eric Wong
28ee794128 hashmap_remove takes "const struct hashmap_entry *"
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>
2019-10-07 10:20:10 +09:00
Eric Wong
b6c5241606 hashmap_get takes "const struct hashmap_entry *"
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>
2019-10-07 10:20:10 +09:00
Eric Wong
b94e5c1df6 hashmap_add takes "struct hashmap_entry *"
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>
2019-10-07 10:20:10 +09:00
Eric Wong
d22245a2e3 hashmap_entry_init takes "struct hashmap_entry *"
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>
2019-10-07 10:20:09 +09:00
Elijah Newren
8e4ec3376e merge-recursive: fix the diff3 common ancestor label for virtual commits
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>
2019-10-02 14:59:29 +09:00
Jonathan Tan
83e3ad3b12 merge-recursive: symlink's descendants not in way
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>
2019-09-20 10:15:57 -07:00
Elijah Newren
4615a8cb5b merge-recursive: alphabetize include list
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>
2019-08-19 10:08:04 -07:00
Elijah Newren
45ef16f77a merge-recursive: add sanity checks for relevant merge_options
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>
2019-08-19 10:08:04 -07:00
Elijah Newren
f3081dae01 merge-recursive: rename MERGE_RECURSIVE_* to MERGE_VARIANT_*
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>
2019-08-19 10:08:04 -07:00
Elijah Newren
5bf7e5779e merge-recursive: split internal fields into a separate struct
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>
2019-08-19 10:08:04 -07:00
Elijah Newren
e95e481f9e merge-recursive: avoid losing output and leaking memory holding that output
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>
2019-08-19 10:08:04 -07:00
Elijah Newren
a779fb829b merge-recursive: comment and reorder the merge_options fields
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>
2019-08-19 10:08:04 -07:00
Elijah Newren
8599ab4574 merge-recursive: consolidate unnecessary fields in merge_options
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>
2019-08-19 10:08:04 -07:00
Elijah Newren
7c0a6c8e47 merge-recursive: move some definitions around to clean up the header
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>
2019-08-19 10:08:04 -07:00
Elijah Newren
bab56877e0 merge-recursive: rename 'mrtree' to 'result_tree', for clarity
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>
2019-08-19 10:08:04 -07:00
Elijah Newren
ff1bfa2cd5 merge-recursive: use common name for ancestors/common/base_list
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>
2019-08-19 10:08:03 -07:00
Elijah Newren
4d7101e25c merge-recursive: fix some overly long lines
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>
2019-08-19 10:08:03 -07:00
Elijah Newren
724dd767b2 cache-tree: share code between functions writing an index as a tree
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>
2019-08-19 10:08:03 -07:00
Elijah Newren
345480d1ed merge-recursive: don't force external callers to do our logging
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>
2019-08-19 10:08:03 -07:00
Elijah Newren
b4db8a2b76 merge-recursive: remove useless parameter in merge_trees()
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>
2019-08-19 10:08:03 -07:00
Elijah Newren
98a1d3d888 merge-recursive: exit early if index != head
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>
2019-08-19 10:08:03 -07:00
Elijah Newren
10f751c06b merge-recursive: remove another implicit dependency on the_repository
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>
2019-08-19 10:08:03 -07:00
Elijah Newren
f836bf3937 merge-recursive: future-proof update_file_flags() against memory leaks
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>
2019-08-19 10:08:03 -07:00