Denton Liu <liu.denton@xxxxxxxxx> writes:
> +void diff_get_merge_base(const struct rev_info *revs, struct object_id *mb)
> +{
> + int i;
> + struct commit *mb_child[2] = {0};
> + struct commit_list *merge_bases;
> +
> + for (i = 0; i < revs->pending.nr; i++) {
> + struct object *obj = revs->pending.objects[i].item;
> + if (obj->flags)
> + die(_("--merge-base does not work with ranges"));
> + if (obj->type != OBJ_COMMIT)
> + die(_("--merge-base only works with commits"));
> + }
This is the first use of die() in this file, that is designed to
keep a set of reusable library functions so that the caller(s) can
do their own die(). They may want to become
return error(_(...));
The same comment applies to all die()s the patch adds.
> + /*
> + * This check must go after the for loop above because A...B
> + * ranges produce three pending commits, resulting in a
> + * misleading error message.
> + */
Should "git diff --merge-base A...B" be forbidden, or does it just
ask the same thing twice and is not a die-worthy offence?
> + if (revs->pending.nr > ARRAY_SIZE(mb_child))
> + die(_("--merge-base does not work with more than two commits"));
Compare with hardcoded '2' in the condition. The requirement for
mb_child[] is that it can hold at least 2 (changes in the future may
find it convenient if its size gets increased to 3 to hold NULL sentinel
to signal end-of-list, for example). Comparison with ARRAY_SIZE() may
be appropriate in different situations but not here where the code knows
it wants to reject more than two no matter how big mb_child[] is.
> + for (i = 0; i < revs->pending.nr; i++)
> + mb_child[i] = lookup_commit_reference(the_repository, &revs->pending.objects[i].item->oid);
> + if (revs->pending.nr < ARRAY_SIZE(mb_child)) {
> + struct object_id oid;
> +
> + if (revs->pending.nr != 1)
> + BUG("unexpected revs->pending.nr: %d", revs->pending.nr);
This is an obviously impossible condition as we will not take more
than 2.
> + if (get_oid("HEAD", &oid))
> + die(_("unable to get HEAD"));
> + mb_child[1] = lookup_commit_reference(the_repository, &oid);
> + }
> +
> + merge_bases = repo_get_merge_bases(the_repository, mb_child[0], mb_child[1]);
> + if (!merge_bases)
> + die(_("no merge base found"));
> + if (merge_bases->next)
> + die(_("multiple merge bases found"));
> +
> + oidcpy(mb, &merge_bases->item->object.oid);
> +
> + free_commit_list(merge_bases);
> +}
OK.
> int run_diff_index(struct rev_info *revs, unsigned int option)
> {
> struct object_array_entry *ent;
> diff --git a/diff.h b/diff.h
> index 0cc874f2d5..ae2bb7001a 100644
> --- a/diff.h
> +++ b/diff.h
> @@ -580,6 +580,8 @@ void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc);
> */
> const char *diff_aligned_abbrev(const struct object_id *sha1, int);
>
> +void diff_get_merge_base(const struct rev_info *revs, struct object_id *mb);
Without an actual caller, we cannot judge if this interface is
designed right, but we'll see soon in the next steps ;-)
Looking good so far.
Thanks.
> +
> /* do not report anything on removed paths */
> #define DIFF_SILENT_ON_REMOVED 01
> /* report racily-clean paths as modified */
