'git subtree split' can incorrectly skip a merge even when both parents
act on the subtree, provided the merge results in a tree identical to
one of the parents. Fix by copying the merge if at least one parent is
non-identical, and the non-identical parent is not an ancestor of the
identical parent.
Also, add a test case which checks that a descendant remains a
descendent on the subtree in this case.
Signed-off-by: Dave Ware <davidw@xxxxxxxxxxxxxxxxxxxx>
---
Notes:
Many thanks to Eric Sunshine and Junio Hamano for adivce on this patch
Also many thanks to David A. Greene for help with subtree test style
Changes since v6
- I forgot the notes when I sumbitted v6. (I have now set notes.rewriteRef,
so hopefully this wont happen again).
- Fixed some missing && in my test rewrite.
Changes since v5
- Rewrote test case to use subtree test repo and commit creation methods
- Added comments on what the test does and which bits are checked
- Added comments to test on related bugs which aren't fixed yet
Changes since v4
- Minor spelling and style fixes to test case
Changes since v3:
- Improvements to commit message
- Removed incorrect use of --boundary on rev-list
- Changed use of rev-list to use --count
Changes since v2:
- Minor improvements to commit message
- Changed space indentation to tab indentation in test case
- Changed use of rev-list for obtaining commit id to use rev-parse instead
Changes since v1:
- Minor improvements to commit message
- Added sign off
- Moved test case from own file into t7900-subtree.sh
- Added subshell to test around 'cd'
- Moved record of commit for cherry-pick to variable instead of dumping into file
[v6]: http://thread.gmane.org/gmane.comp.version-control.git/282065/focus=284095
[v5]: http://thread.gmane.org/gmane.comp.version-control.git/282065/focus=282197
[v4]: http://thread.gmane.org/gmane.comp.version-control.git/282065/focus=282182
[v3]: http://thread.gmane.org/gmane.comp.version-control.git/282065/focus=282176
[v2]: http://thread.gmane.org/gmane.comp.version-control.git/282065/focus=282121
[v1]: http://thread.gmane.org/gmane.comp.version-control.git/282065
contrib/subtree/git-subtree.sh | 12 ++++++--
contrib/subtree/t/t7900-subtree.sh | 60 ++++++++++++++++++++++++++++++++++++++
2 files changed, 70 insertions(+), 2 deletions(-)
diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh
index edf36f8..5c83727 100755
--- a/contrib/subtree/git-subtree.sh
+++ b/contrib/subtree/git-subtree.sh
@@ -479,8 +479,16 @@ copy_or_skip()
p="$p -p $parent"
fi
done
-
- if [ -n "$identical" ]; then
+
+ copycommit=
+ if [ -n "$identical" ] && [ -n "$nonidentical" ]; then
+ extras=$(git rev-list --count $identical..$nonidentical)
+ if [ "$extras" -ne 0 ]; then
+ # we need to preserve history along the other branch
+ copycommit=1
+ fi
+ fi
+ if [ -n "$identical" ] && [ -z "$copycommit" ]; then
echo $identical
else
copy_commit $rev $tree "$p" || exit $?
diff --git a/contrib/subtree/t/t7900-subtree.sh b/contrib/subtree/t/t7900-subtree.sh
index 751aee3..3bf96a9 100755
--- a/contrib/subtree/t/t7900-subtree.sh
+++ b/contrib/subtree/t/t7900-subtree.sh
@@ -1014,4 +1014,64 @@ test_expect_success 'push split to subproj' '
)
'
+#
+# This test covers 2 cases in subtree split copy_or_skip code
+# 1) Merges where one parent is a superset of the changes of the other
+# parent regarding changes to the subtree, in this case the merge
+# commit should be copied
+# 2) Merges where only one parent operate on the subtree, and the merge
+# commit should be skipped
+#
+# (1) is checked by ensuring subtree_tip is a descendent of subtree_branch
+# (2) should have a check added (not_a_subtree_change shouldn't be present
+# on the produced subtree)
+#
+# Other related cases which are not tested (or currently handled correctly)
+# - Case (1) where there are more than 2 parents, it will sometimes correctly copy
+# the merge, and sometimes not
+# - Merge commit where both parents have same tree as the merge, currently
+# will always be skipped, even if they reached that state via different
+# set of commits.
+#
+
+next_test
+test_expect_success 'subtree descendant check' '
+ subtree_test_create_repo "$subtree_test_count" &&
+ test_create_commit "$subtree_test_count" folder_subtree/a &&
+ (
+ cd "$subtree_test_count" &&
+ git branch branch
+ ) &&
+ test_create_commit "$subtree_test_count" folder_subtree/0 &&
+ test_create_commit "$subtree_test_count" folder_subtree/b &&
+ cherry=$(cd "$subtree_test_count"; git rev-parse HEAD) &&
+ (
+ cd "$subtree_test_count" &&
+ git checkout branch
+ ) &&
+ test_create_commit "$subtree_test_count" commit_on_branch &&
+ (
+ cd "$subtree_test_count" &&
+ git cherry-pick $cherry &&
+ git checkout master &&
+ git merge -m "merge should be kept on subtree" branch &&
+ git branch no_subtree_work_branch
+ ) &&
+ test_create_commit "$subtree_test_count" folder_subtree/d &&
+ (
+ cd "$subtree_test_count" &&
+ git checkout no_subtree_work_branch
+ ) &&
+ test_create_commit "$subtree_test_count" not_a_subtree_change &&
+ (
+ cd "$subtree_test_count" &&
+ git checkout master &&
+ git merge -m "merge should be skipped on subtree" no_subtree_work_branch &&
+
+ git subtree split --prefix folder_subtree/ --branch subtree_tip master &&
+ git subtree split --prefix folder_subtree/ --branch subtree_branch branch &&
+ check_equal $(git rev-list --count subtree_tip..subtree_branch) 0
+ )
+'
+
test_done
--
1.9.1
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