Add and apply a semantic patch for converting code that open-codes
CALLOC_ARRAY to use it instead. It shortens the code and infers the
element size automatically.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This fixes a bug introduced in dfb7a1b4d0 (patch-ids: stop using a
hand-rolled hashmap implementation, 2016-07-29) in which
git rev-list --cherry-pick A...B
will fail to suppress commits reachable from A even if a commit with
matching patch-id appears in B.
Around the time of that commit, the algorithm for "--cherry-pick" looked
something like this:
0. Traverse all of the commits, marking them as being on the left or
right side of the symmetric difference.
1. Iterate over the left-hand commits, inserting a patch-id struct for
each into a hashmap, and pointing commit->util to the patch-id
struct.
2. Iterate over the right-hand commits, checking which are present in
the hashmap. If so, we exclude the commit from the output _and_ we
mark the patch-id as "seen".
3. Iterate again over the left-hand commits, checking whether
commit->util->seen is set; if so, exclude them from the output.
At the end, we'll have eliminated commits from both sides that have a
matching patch-id on the other side. But there's a subtle assumption
here: for any given patch-id, we must have exactly one struct
representing it. If two commits from A both have the same patch-id and
we allow duplicates in the hashmap, then we run into a problem:
a. In step 1, we insert two patch-id structs into the hashmap.
b. In step 2, our lookups will find only one of these structs, so only
one "seen" flag is marked.
c. In step 3, one of the commits in A will have its commit->util->seen
set, but the other will not. We'll erroneously output the latter.
Prior to dfb7a1b4d0, our hashmap did not allow duplicates. Afterwards,
it used hashmap_add(), which explicitly does allow duplicates.
At that point, the solution would have been easy: when we are about to
add a duplicate, skip doing so and return the existing entry which
matches. But it gets more complicated.
In 683f17ec44 (patch-ids: replace the seen indicator with a commit
pointer, 2016-07-29), our step 3 goes away entirely. Instead, in step 2,
when the right-hand side finds a matching patch_id from the left-hand
side, we can directly mark the left-hand patch_id->commit to be omitted.
Solving that would be easy, too; there's a one-to-many relationship of
patch-ids to commits, so we just need to keep a list.
But there's more. Commit b3dfeebb92 (rebase: avoid computing unnecessary
patch IDs, 2016-07-29) built on that by lazily computing the full
patch-ids. So we don't even know when adding to the hashmap whether two
commits truly have the same id. We'd have to tentatively assign them a
list, and then possibly split them apart (possibly into N new structs)
at the moment we compute the real patch-ids. This could work, but it's
complicated and error-prone.
Instead, let's accept that we may store duplicates, and teach the lookup
side to be more clever. Rather than asking for a single matching
patch-id, it will need to iterate over all matching patch-ids. This does
mean examining every entry in a single hash bucket, but the worst-case
for a hash lookup was already doing that.
We'll keep the hashmap details out of the caller by providing a simple
iteration interface. We can retain the simple has_commit_patch_id()
interface for the other callers, but we'll simplify its return value
into an integer, rather than returning the patch_id struct. That way
they won't be tempted to look at the "commit" field of the return value
without iterating.
Reported-by: Arnaud Morin <arnaud.morin@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change all remnants of "sha1" in hash-lookup.c and .h and rename them to
reflect that we're not just able to handle SHA-1 these days.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
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>
`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>
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 "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>
There are no callers left of sha1hash() that do not simply pass the
"hash" member of a "struct object_id". Let's get rid of the outdated
sha1-specific function and provide one that operates on the whole struct
(even though the technique, taking the first few bytes of the hash, will
remain the same).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We weren't flushing the context each time we processed a hunk in the
patch-id generation code in diff.c, but we were doing that when we
generated "stable" patch-ids with the 'patch-id' tool. Let's port that
similar logic over from patch-id.c into diff.c so we can get the same
hash when we're generating patch-ids for 'format-patch --base=' types of
command invocations.
Cc: Xiaolong Ye <xiaolong.ye@intel.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A new variant repo_diff_setup() is added that takes 'struct repository *'
and diff_setup() becomes a thin macro around it that is protected by
NO_THE_REPOSITORY_COMPATIBILITY_MACROS, similar to NO_THE_INDEX_....
The plan is these macros will always be defined for all library files
and the macros are only accessible in builtin/
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The comparison functions used for hashmaps don't care about
strict ordering; they only want to compare entries for
equality. Let's use the oideq() function instead, which can
potentially be better optimized. Note that unlike the
previous patches mass-converting calls like "!oidcmp()",
this patch could actually provide an improvement even with
the current implementation. Those comparison functions are
passed around as function pointers, so at compile-time the
compiler cannot realize that the caller (which is in another
file completely) will treat the return value as a boolean.
Note that this does change the return values in quite a
subtle way (it's still an int, but now the sign bit is
irrelevant for ordering). Because of their funny
hashmap-specific signature, it's unlikely that any of these
static functions would be reused for more generic ordering.
But to be double-sure, let's stop using "cmp" in their
names.
Calling them "eq" doesn't quite work either, because the
hashmap convention is actually _inverted_. "0" means "same",
and non-zero means "different". So I've called them "neq" by
convention here.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove the `DIFF_OPT_SET` macro and instead set the flags directly.
This conversion is done using the following semantic patch:
@@
expression E;
identifier fld;
@@
- DIFF_OPT_SET(&E, fld)
+ E.flags.fld = 1
@@
type T;
T *ptr;
identifier fld;
@@
- DIFF_OPT_SET(ptr, fld)
+ ptr->flags.fld = 1
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As alluded to in the previous patch, the code in patch-ids.c is
using the hashmaps API wrong.
Luckily we do not have a bug, as all hashmap functionality that we use
here (hashmap_get) passes through the keydata. If hashmap_get_next were
to be used, a bug would occur as that passes NULL for the key_data.
So instead use the hashmap API correctly and provide the caller required
data in the compare function via the first argument that always gets
passed and was setup via the hashmap_init function.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When using the hashmap a common need is to have access to caller provided
data in the compare function. A couple of times we abuse the keydata field
to pass in the data needed. This happens for example in patch-ids.c.
This patch changes the function signature of the compare function
to have one more void pointer available. The pointer given for each
invocation of the compare function must be defined in the init function
of the hashmap and is just passed through.
Documentation of this new feature is deferred to a later patch.
This is a rather mechanical conversion, just adding the new pass-through
parameter. However while at it improve the naming of the fields of all
compare functions used by hashmaps by ensuring unused parameters are
prefixed with 'unused_' and naming the parameters what they are (instead
of 'unused' make it 'unused_keydata').
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It would appear that we allocate (and forget to release) memory if the
patch ID is not even defined.
Reported by the Coverity tool.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since we will likely be introducing a new hash function at some point,
and that hash function might be longer than 20 bytes, use the constant
GIT_MAX_RAWSZ, which is designed to be suitable for allocations, instead
of GIT_SHA1_RAWSZ. This will ease the transition down the line by
distinguishing between places where we need to allocate memory suitable
for the largest hash from those where we need to handle the current
hash.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The patch-id code which powers "log --cherry-pick" doesn't
look at whether each commit is a merge or not. It just feeds
the commit's first parent to the diff, and ignores any
additional parents.
In theory, this might be useful if you wanted to find
equivalence between, say, a merge commit and a squash-merge
that does the same thing. But it also promotes a false
equivalence between distinct merges. For example, every
"merge -s ours" would look identical to an empty commit
(which is true in a sense, but presumably there was a value
in merging in the discarded history). Since patch-ids are
meant for throwing away duplicates, we should err on the
side of _not_ matching such merges.
Moreover, we may spend a lot of extra time computing these
merge diffs. In the case that inspired this patch, a "git
format-patch --cherry-pick" dropped from over 3 minutes to
less than 3 seconds.
This seems pretty drastic, but is easily explained. The
command was invoked by a "git rebase" of an older topic
branch; there had been tens of thousands of commits on the
upstream branch in the meantime. In addition, this project
used a topic-branch workflow with occasional "back-merges"
from "master" to each topic (to resolve conflicts on the
topics rather than in the merge commits). So there were not
only extra merges, but the diffs for these back-merges were
generally quite large (because they represented _everything_
that had been merged to master since the topic branched).
This patch treats a merge fed to commit_patch_id() or
add_commit_patch_id() as an error, and a lookup for such a
merge via has_commit_patch_id() will always return NULL.
An earlier version of the patch tried to distinguish between
"error" and "patch id for merges not defined", but that
becomes unnecessarily complicated. The only callers are:
1. revision traversals which want to do --cherry-pick;
they call add_commit_patch_id(), but do not care if it
fails. They only want to add what we can, look it up
later with has_commit_patch_id(), and err on the side
of not-matching.
2. format-patch --base, which calls commit_patch_id().
This _does_ notice errors, but should never feed a
merge in the first place (and if it were to do so
accidentally, then this patch is a strict improvement;
we notice the bug rather than generating a bogus
patch-id).
So in both cases, this does the right thing.
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The patch-id code may be running inside another porcelain
like "git log" or "git format-patch", and therefore may have
set diff_detect_rename_default, either via the diff-ui
config, or by default since 5404c11 (diff: activate
diff.renames by default, 2016-02-25). This is the case even
if a command is run with `--no-renames`, as that is applied
only to the diff-options used by the command itself.
Rename detection doesn't help the patch-id results. It
_may_ actually hurt, as minor differences in the files that
would be overlooked by patch-id's canonicalization might
result in different renames (though I'd doubt that it ever
comes up in practice).
But mostly it is just a waste of CPU to compute these
renames.
Note that this does have one user-visible impact: the
prerequisite patches listed by "format-patch --base". There
may be some confusion between different versions of git as
older ones will enable renames, but newer ones will not.
However, this was already a problem, as people with
different settings for the "diff.renames" config would get
different results. After this patch, everyone should get the
same results, regardless of their config.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `rebase` family of Git commands avoid applying patches that were
already integrated upstream. They do that by using the revision walking
option that computes the patch IDs of the two sides of the rebase
(local-only patches vs upstream-only ones) and skipping those local
patches whose patch ID matches one of the upstream ones.
In many cases, this causes unnecessary churn, as already the set of
paths touched by a given commit would suffice to determine that an
upstream patch has no local equivalent.
This hurts performance in particular when there are a lot of upstream
patches, and/or large ones.
Therefore, let's introduce the concept of a "diff-header-only" patch ID,
compare those first, and only evaluate the "full" patch ID lazily.
Please note that in contrast to the "full" patch IDs, those
"diff-header-only" patch IDs are prone to collide with one another, as
adjacent commits frequently touch the very same files. Hence we now
have to be careful to allow multiple hash entries with the same hash.
We accomplish that by using the hashmap_add() function that does not even
test for hash collisions. This also allows us to evaluate the full patch ID
lazily, i.e. only when we found commits with matching diff-header-only
patch IDs.
We add a performance test that demonstrates ~1-6% improvement. In
practice this will depend on various factors such as how many upstream
changes and how big those changes are along with whether file system
caches are cold or warm. As Git's test suite has no way of catching
performance regressions, we also add a regression test that verifies
that the full patch ID computation is skipped when the diff-header-only
computation suffices.
Signed-off-by: Kevin Willford <kcwillford@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This will allow a diff patch id to be created using only the header data
so that the contents of the file will not have to be loaded.
Signed-off-by: Kevin Willford <kcwillford@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The cherry_pick_list was looping through the original side checking the
seen indicator and setting the cherry_flag on the commit. If we save
off the commit in the patch_id we can set the cherry_flag on the correct
commit when running through the other side when a patch_id match is found.
Signed-off-by: Kevin Willford <kcwillford@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This change will use the hashmap from the hashmap.h to keep track of the
patch_ids that have been encountered instead of using an internal
implementation. This simplifies the implementation of the patch ids.
Signed-off-by: Kevin Willford <kcwillford@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make commit_patch_id() available to other builtins.
Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert all instances of get_object_hash to use an appropriate reference
to the hash member of the oid member of struct object. This provides no
functional change, as it is essentially a macro substitution.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
Convert most instances where the sha1 member of struct object is
dereferenced to use get_object_hash. Most instances that are passed to
functions that have versions taking struct object_id, such as
get_sha1_hex/get_oid_hex, or instances that can be trivially converted
to use struct object_id instead, are not converted.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
diff_setup_done() has historically returned an error code, but lost
the last nonzero return in 943d5b7 (allow diff.renamelimit to be set
regardless of -M/-C, 2006-08-09). The callers were in a pretty
confused state: some actually checked for the return code, and some
did not.
Let it return void, and patch all callers to take this into account.
This conveniently also gets rid of a handful of different(!) error
messages that could never be triggered anyway.
Note that the function can still die().
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
instead of the specific one from which the new one has been copied.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
reverse_diff was a bit-value in disguise, it's merged in the flags now.
Signed-off-by: Pierre Habouzit <madcoder@debian.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This implements the patch-id computation and recording library,
patch-ids.c, and rewrites the get_patch_ids() function used in
cherry and format-patch to use it, so that they do not pollute
the object namespace. Earlier code threw non-objects into the
in-core object database, and hoped for not getting bitten by
SHA-1 collisions. While it may be practically Ok, it still was
an ugly hack.
Signed-off-by: Junio C Hamano <junkio@cox.net>
René Scharfe