git/patch-ids.c, branch v2.14.3

patch-ids.c: use hashmap correctly

2017-06-30T20:11:54Z

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 Signed-off-by: Junio C Hamano

hashmap.h: compare function has access to a data field

2017-06-30T19:49:28Z

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 Signed-off-by: Junio C Hamano

diff-tree: convert diff_tree_sha1 to struct object_id

2017-06-05T02:23:58Z

Signed-off-by: Brandon Williams Signed-off-by: Junio C Hamano

tree-diff: convert diff_root_tree_sha1 to struct object_id

2017-06-02T00:36:30Z

Signed-off-by: Brandon Williams Signed-off-by: Junio C Hamano

diff: convert diff_flush_patch_id to struct object_id

2017-06-02T00:36:07Z

Signed-off-by: Brandon Williams Signed-off-by: Junio C Hamano

patch-ids: convert to struct object_id

2017-06-02T00:36:07Z

Signed-off-by: Brandon Williams Signed-off-by: Junio C Hamano

add_commit_patch_id(): avoid allocating memory unnecessarily

2017-05-08T03:18:19Z

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 Signed-off-by: Junio C Hamano

Convert GIT_SHA1_RAWSZ used for allocation to GIT_MAX_RAWSZ

2017-03-27T05:08:21Z

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 Signed-off-by: Junio C Hamano

patch-ids: refuse to compute patch-id for merge commit

2016-09-12T20:45:01Z

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 Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

patch-ids: turn off rename detection

2016-09-09T21:13:53Z

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 Signed-off-by: Junio C Hamano