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authorBenno Evers <benno@bmevers.de>2020-02-26 17:48:53 (GMT)
committerJunio C Hamano <gitster@pobox.com>2020-02-26 20:14:12 (GMT)
commit30b1c7ad9d64695a65c23f922e6ffd2fd35660da (patch)
tree513f58dfd862fd8198ccf6fdccfffde83db897b2 /t
parent2d2118b814c11f509e1aa76cb07110f7231668dc (diff)
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describe: don't abort too early when searching tags
When 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 A it 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. For repositories with a single root, this condition is always true: When the search is reduced to a single active branch, the current commit must be an ancestor of *all* tag candidates. This means that in the common case, this change will have no negative performance impact since the same number of commits as before will be traversed. Signed-off-by: Benno Evers <benno@bmevers.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 't')
-rwxr-xr-xt/t6120-describe.sh51
1 files changed, 51 insertions, 0 deletions
diff --git a/t/t6120-describe.sh b/t/t6120-describe.sh
index 09c50f3..34502e3 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' '
)
'
+# 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