| Message ID | 20190620074050.GA3713@sigill.intra.peff.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drop non-object_id hashing | expand |
Jeff King <peff@peff.net> writes: > The find_commit_name() function passes an object_id.hash as the key of a > hashmap. That ends up in commit_name_neq(), which then feeds it to > oideq(). Which means we should actually be the whole "struct object_id". > > It works anyway because pointers to the two are interchangeable. And > because we're going through a layer of void pointers, the compiler > doesn't notice the type mismatch. Wow. Good eyes. I wouldn't have noticed this (and for the reasons you stated, it is very tricky for any clever compiler to notice it). Impressed. > But it's worth cleaning up (especially since once we switch away from > sha1hash() on the same line, accessing the hash member will look doubly > out of place). Yup. Thanks. > > Signed-off-by: Jeff King <peff@peff.net> > --- > builtin/describe.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/builtin/describe.c b/builtin/describe.c > index 1409cedce2..0a5cde00a2 100644 > --- a/builtin/describe.c > +++ b/builtin/describe.c > @@ -76,7 +76,7 @@ static int commit_name_neq(const void *unused_cmp_data, > > static inline struct commit_name *find_commit_name(const struct object_id *peeled) > { > - return hashmap_get_from_hash(&names, sha1hash(peeled->hash), peeled->hash); > + return hashmap_get_from_hash(&names, sha1hash(peeled->hash), peeled); > } > > static int replace_name(struct commit_name *e,
On Thu, Jun 20, 2019 at 09:32:49AM -0700, Junio C Hamano wrote: > Jeff King <peff@peff.net> writes: > > > The find_commit_name() function passes an object_id.hash as the key of a > > hashmap. That ends up in commit_name_neq(), which then feeds it to > > oideq(). Which means we should actually be the whole "struct object_id". > > > > It works anyway because pointers to the two are interchangeable. And > > because we're going through a layer of void pointers, the compiler > > doesn't notice the type mismatch. > > Wow. Good eyes. I wouldn't have noticed this (and for the reasons > you stated, it is very tricky for any clever compiler to notice it). > > Impressed. It only looks impressive in retrospect. It became very obvious when updating the reference to sha1hash(peeled->hash) in the same line, and then scratching my head about why this one was looking at the hash member. But history rewriting lets me re-order it to make myself look good. Thanks, "rebase -i"! :) -Peff
diff --git a/builtin/describe.c b/builtin/describe.c index 1409cedce2..0a5cde00a2 100644 --- a/builtin/describe.c +++ b/builtin/describe.c @@ -76,7 +76,7 @@ static int commit_name_neq(const void *unused_cmp_data, static inline struct commit_name *find_commit_name(const struct object_id *peeled) { - return hashmap_get_from_hash(&names, sha1hash(peeled->hash), peeled->hash); + return hashmap_get_from_hash(&names, sha1hash(peeled->hash), peeled); } static int replace_name(struct commit_name *e,
The find_commit_name() function passes an object_id.hash as the key of a hashmap. That ends up in commit_name_neq(), which then feeds it to oideq(). Which means we should actually be the whole "struct object_id". It works anyway because pointers to the two are interchangeable. And because we're going through a layer of void pointers, the compiler doesn't notice the type mismatch. But it's worth cleaning up (especially since once we switch away from sha1hash() on the same line, accessing the hash member will look doubly out of place). Signed-off-by: Jeff King <peff@peff.net> --- builtin/describe.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)