Benno EversWhen searching the commit graph for tag candidates, `git-describe` will stop as soon as there is only one active branch left and it already found an annotated tag as a candidate.
This works well as long as all branches eventually connect back to a common root, but if the tags are found across branches with no common ancestor
B
o----.
\
o-----o---o----x
Ait can happen that the search on one branch terminates prematurely because a tag was found on another, independent branch. This scenario isn't quite as obscure as it sounds, since cloning with a limited depth often introduces many independent "dead ends" into the commit graph.
The help text of `git-describe` states pretty clearly that when describing a commit D, the number appended to the emitted tag X should correspond to the number of commits found by `git log X..D`.
Thus, this commit modifies the stopping condition to only abort the search when only one branch is left to search *and* all current best candidates are descendants from that branch.
Signed-off-by: Benno Evers <benno@bmevers.de> --- We originally found this issue in one of our internal CI jobs, which relied on `git-describe` to assign filenames to the generated artifacts. --- builtin/describe.c | 22 +++++++++++++++---- t/t6120-describe.sh | 53 ++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 70 insertions(+), 5 deletions(-)
Show changes to 2 files +70 −5
builtin/describe.c, t/t6120-describe.sh
diff --git a/builtin/describe.c b/builtin/describe.c index b6df81d8d0..420f4c6401 100644 --- a/builtin/describe.c +++ b/builtin/describe.c @@ -376,11 +376,25 @@ static void describe_commit(struct object_id *oid, struct strbuf *dst) if (!(c->object.flags & t->flag_within)) t->depth++; } + /* Stop if last remaining path already covered by best candidate(s) */ if (annotated_cnt && !list) { - if (debug) - fprintf(stderr, _("finished search at %s\n"), - oid_to_hex(&c->object.oid)); - break; + int best_depth = INT_MAX; + unsigned best_within = 0; + for (cur_match = 0; cur_match < match_cnt; cur_match++) { + struct possible_tag *t = &all_matches[cur_match]; + if (t->depth < best_depth) { + best_depth = t->depth; + best_within = t->flag_within; + } else if (t->depth == best_depth) { + best_within |= t->flag_within; + } + } + if ((c->object.flags & best_within) == best_within) { + if (debug) + fprintf(stderr, _("finished search at %s\n"), + oid_to_hex(&c->object.oid)); + break; + } } while (parents) { struct commit *p = parents->item; diff --git a/t/t6120-describe.sh b/t/t6120-describe.sh index 09c50f3f04..d8cc08258e 100755 --- a/t/t6120-describe.sh +++ b/t/t6120-describe.sh @@ -479,4 +479,55 @@ test_expect_success 'name-rev covers all conditions while looking at parents' ' ) ' -test_done +# B +# o +# \ +# o-----o---o----x +# A +# +test_expect_success 'describe commits with disjoint bases' ' + git init disjoint1 && + ( + cd disjoint1 && + + echo o >> file && git add file && git commit -m o && + echo A >> file && git add file && git commit -m A && + git tag A -a -m A && + echo o >> file && git add file && git commit -m o && + + git checkout --orphan branch && rm file && + echo B > file2 && git add file2 && git commit -m B && + git tag B -a -m B && + git merge --no-ff --allow-unrelated-histories master -m x && + + check_describe "A-3-*" HEAD + ) +' + +# B +# o---o---o------------. +# \ +# o---o---x +# A +# +test_expect_success 'describe commits with disjoint bases 2' ' + git init disjoint2 && + ( + cd disjoint2 && + + echo A >> file && git add file && GIT_COMMITTER_DATE="2020-01-01 18:00" git commit -m A && + git tag A -a -m A && + echo o >> file && git add file && GIT_COMMITTER_DATE="2020-01-01 18:01" git commit -m o && + + git checkout --orphan branch && + echo o >> file2 && git add file2 && GIT_COMMITTER_DATE="2020-01-01 15:00" git commit -m o && + echo o >> file2 && git add file2 && GIT_COMMITTER_DATE="2020-01-01 15:01" git commit -m o && + echo B >> file2 && git add file2 && GIT_COMMITTER_DATE="2020-01-01 15:02" git commit -m B && + git tag B -a -m B && + git merge --no-ff --allow-unrelated-histories master -m x && + + check_describe "B-3-*" HEAD + ) +' + +test_done \ No newline at end of file
-- 2.20.1
