Patrick Steinhardt <ps@xxxxxx> writes:
> I have two smallish comments, but neither of them really have to be
> addressed. Overall I very much agree with this iteration and think that
> it's the right way to go.
I've locally done the following locally but it probably does not
need to be resent to the list before merging down to 'next'.
1: b23a93597c ! 1: d3b2ff75fd setup: add an escape hatch for "no more default hash algorithm" change
@@ Commit message
default object hash, 2024-05-07), to keep end-user systems still
broken when we have gap in our test coverage but yet give them an
escape hatch to set the GIT_TEST_DEFAULT_HASH_ALGO environment
- variable to "sha1" in order to revert to the previous behaviour.
+ variable to "sha1" in order to revert to the previous behaviour, in
+ case we haven't done a thorough job in fixing the fallout from
+ c8aed5e8. After we build confidence, we should remove the escape
+ hatch support, but we are not there yet after only fixing three
+ commands (hash-object, apply, and patch-id) in this series.
Due to the way the end-user facing GIT_DEFAULT_HASH environment
variable is used in our test suite, we unfortunately cannot reuse it
2: 6a20370944 = 2: abece6e970 t1517: test commands that are designed to be run outside repository
3: fa258c5d47 = 3: 4a1c95931f builtin/patch-id: fix uninitialized hash function
4: 164d340cbe = 4: 8d058b8024 builtin/hash-object: fix uninitialized hash function
5: bd0246eb51 ! 5: 4674ab682d apply: fix uninitialized hash function
@@ Commit message
Make sure we explicitly fall back to SHA-1 algorithm for backward
compatibility.
+ It is of dubious value to make this configurable to other hash
+ algorithms, as the code does not use the_hash_algo for hashing
+ purposes when working outside a repository (which is how
+ the_hash_algo is left to NULL)---it is only used to learn the max
+ length of the hash when parsing the object names on the "index"
+ line, but failing to parse the "index" line is not a hard failure,
+ and the program does not support operations like applying binary
+ patches and --3way fallback that requires object access outside a
+ repository.
+
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
## builtin/apply.c ##
@@ builtin/apply.c: int cmd_apply(int argc, const char **argv, const char *prefix)
if (init_apply_state(&state, the_repository, prefix))
exit(128);
++ /*
++ * We could to redo the "apply.c" machinery to make this
++ * arbitrary fallback unnecessary, but it is dubious that it
++ * is worth the effort.
++ * cf. https://lore.kernel.org/git/xmqqcypfcmn4.fsf@gitster.g/
++ */
+ if (!the_hash_algo)
+ repo_set_hash_algo(the_repository, GIT_HASH_SHA1);
+
