git notes merge: Manual conflict resolution, part 1/2

Conflicts (that are to be resolved manually) are written into a special-
purpose working tree, located at .git/NOTES_MERGE_WORKTREE. Within this
directory, conflicting notes entries are stored (with conflict markers
produced by ll_merge()) using the SHA1 of the annotated object. The
.git/NOTES_MERGE_WORKTREE directory will only contain the _conflicting_
note entries. The non-conflicting note entries (aka. the partial merge
result) are stored in 'local_tree', and the SHA1 of the resulting commit
is written to 'result_sha1'. The return value from notes_merge() is -1.

The user is told to edit the files within the .git/NOTES_MERGE_WORKTREE
directory in order to resolve the conflicts.

The patch also contains documentation and testcases for the correct setup
of .git/NOTES_MERGE_WORKTREE.

The next part will recombine the partial notes merge result with the
resolved conflicts in .git/NOTES_MERGE_WORKTREE to produce the complete
merge result.

This patch has been improved by the following contributions:
- Jonathan Nieder: Use trace_printf(...) instead of OUTPUT(o, 5, ...)

Thanks-to: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 292 insertions, 0 deletions

diff --git a/t/t3310-notes-merge-manual-resolve.sh b/t/t3310-notes-merge-manual-resolve.sh
new file mode 100755
index 0000000000..eadb6b7df6
--- /dev/null
+++ b/t/t3310-notes-merge-manual-resolve.sh
@@ -0,0 +1,292 @@
+#!/bin/sh
+#
+# Copyright (c) 2010 Johan Herland
+#
+
+test_description='Test notes merging with manual conflict resolution'
+
+. ./test-lib.sh
+
+# Set up a notes merge scenario with different kinds of conflicts
+test_expect_success 'setup commits' '
+	test_commit 1st &&
+	test_commit 2nd &&
+	test_commit 3rd &&
+	test_commit 4th &&
+	test_commit 5th
+'
+
+commit_sha1=$(git rev-parse 1st^{commit})
+commit_sha2=$(git rev-parse 2nd^{commit})
+commit_sha3=$(git rev-parse 3rd^{commit})
+commit_sha4=$(git rev-parse 4th^{commit})
+commit_sha5=$(git rev-parse 5th^{commit})
+
+verify_notes () {
+	notes_ref="$1"
+	git -c core.notesRef="refs/notes/$notes_ref" notes |
+		sort >"output_notes_$notes_ref" &&
+	test_cmp "expect_notes_$notes_ref" "output_notes_$notes_ref" &&
+	git -c core.notesRef="refs/notes/$notes_ref" log --format="%H %s%n%N" \
+		>"output_log_$notes_ref" &&
+	test_cmp "expect_log_$notes_ref" "output_log_$notes_ref"
+}
+
+cat <<EOF | sort >expect_notes_x
+6e8e3febca3c2bb896704335cc4d0c34cb2f8715 $commit_sha4
+e5388c10860456ee60673025345fe2e153eb8cf8 $commit_sha3
+ceefa674873670e7ecd131814d909723cce2b669 $commit_sha2
+EOF
+
+cat >expect_log_x <<EOF
+$commit_sha5 5th
+
+$commit_sha4 4th
+x notes on 4th commit
+
+$commit_sha3 3rd
+x notes on 3rd commit
+
+$commit_sha2 2nd
+x notes on 2nd commit
+
+$commit_sha1 1st
+
+EOF
+
+test_expect_success 'setup merge base (x)' '
+	git config core.notesRef refs/notes/x &&
+	git notes add -m "x notes on 2nd commit" 2nd &&
+	git notes add -m "x notes on 3rd commit" 3rd &&
+	git notes add -m "x notes on 4th commit" 4th &&
+	verify_notes x
+'
+
+cat <<EOF | sort >expect_notes_y
+e2bfd06a37dd2031684a59a6e2b033e212239c78 $commit_sha4
+5772f42408c0dd6f097a7ca2d24de0e78d1c46b1 $commit_sha3
+b0a6021ec006d07e80e9b20ec9b444cbd9d560d3 $commit_sha1
+EOF
+
+cat >expect_log_y <<EOF
+$commit_sha5 5th
+
+$commit_sha4 4th
+y notes on 4th commit
+
+$commit_sha3 3rd
+y notes on 3rd commit
+
+$commit_sha2 2nd
+
+$commit_sha1 1st
+y notes on 1st commit
+
+EOF
+
+test_expect_success 'setup local branch (y)' '
+	git update-ref refs/notes/y refs/notes/x &&
+	git config core.notesRef refs/notes/y &&
+	git notes add -f -m "y notes on 1st commit" 1st &&
+	git notes remove 2nd &&
+	git notes add -f -m "y notes on 3rd commit" 3rd &&
+	git notes add -f -m "y notes on 4th commit" 4th &&
+	verify_notes y
+'
+
+cat <<EOF | sort >expect_notes_z
+cff59c793c20bb49a4e01bc06fb06bad642e0d54 $commit_sha4
+283b48219aee9a4105f6cab337e789065c82c2b9 $commit_sha2
+0a81da8956346e19bcb27a906f04af327e03e31b $commit_sha1
+EOF
+
+cat >expect_log_z <<EOF
+$commit_sha5 5th
+
+$commit_sha4 4th
+z notes on 4th commit
+
+$commit_sha3 3rd
+
+$commit_sha2 2nd
+z notes on 2nd commit
+
+$commit_sha1 1st
+z notes on 1st commit
+
+EOF
+
+test_expect_success 'setup remote branch (z)' '
+	git update-ref refs/notes/z refs/notes/x &&
+	git config core.notesRef refs/notes/z &&
+	git notes add -f -m "z notes on 1st commit" 1st &&
+	git notes add -f -m "z notes on 2nd commit" 2nd &&
+	git notes remove 3rd &&
+	git notes add -f -m "z notes on 4th commit" 4th &&
+	verify_notes z
+'
+
+# At this point, before merging z into y, we have the following status:
+#
+# commit | base/x  | local/y | remote/z | diff from x to y/z
+# -------|---------|---------|----------|---------------------------
+# 1st    | [none]  | b0a6021 | 0a81da8  | added     / added (diff)
+# 2nd    | ceefa67 | [none]  | 283b482  | removed   / changed
+# 3rd    | e5388c1 | 5772f42 | [none]   | changed   / removed
+# 4th    | 6e8e3fe | e2bfd06 | cff59c7  | changed   / changed (diff)
+# 5th    | [none]  | [none]  | [none]   | [none]
+
+cat <<EOF | sort >expect_conflicts
+$commit_sha1
+$commit_sha2
+$commit_sha3
+$commit_sha4
+EOF
+
+cat >expect_conflict_$commit_sha1 <<EOF
+<<<<<<< refs/notes/m
+y notes on 1st commit
+=======
+z notes on 1st commit
+>>>>>>> refs/notes/z
+EOF
+
+cat >expect_conflict_$commit_sha2 <<EOF
+z notes on 2nd commit
+EOF
+
+cat >expect_conflict_$commit_sha3 <<EOF
+y notes on 3rd commit
+EOF
+
+cat >expect_conflict_$commit_sha4 <<EOF
+<<<<<<< refs/notes/m
+y notes on 4th commit
+=======
+z notes on 4th commit
+>>>>>>> refs/notes/z
+EOF
+
+cp expect_notes_y expect_notes_m
+cp expect_log_y expect_log_m
+
+git rev-parse refs/notes/y > pre_merge_y
+
+test_expect_success 'merge z into m (== y) with default ("manual") resolver => Conflicting 3-way merge' '
+	git update-ref refs/notes/m refs/notes/y &&
+	git config core.notesRef refs/notes/m &&
+	test_must_fail git notes merge z >output &&
+	# Output should point to where to resolve conflicts
+	grep -q "\\.git/NOTES_MERGE_WORKTREE" output &&
+	# Inspect merge conflicts
+	ls .git/NOTES_MERGE_WORKTREE >output_conflicts &&
+	test_cmp expect_conflicts output_conflicts &&
+	( for f in $(cat expect_conflicts); do
+		test_cmp "expect_conflict_$f" ".git/NOTES_MERGE_WORKTREE/$f" ||
+		exit 1
+	done ) &&
+	# Verify that current notes tree (pre-merge) has not changed (m == y)
+	verify_notes y &&
+	verify_notes m &&
+	test "$(git rev-parse refs/notes/m)" = "$(cat pre_merge_y)"
+'
+
+cat <<EOF | sort >expect_notes_z
+00494adecf2d9635a02fa431308d67993f853968 $commit_sha4
+283b48219aee9a4105f6cab337e789065c82c2b9 $commit_sha2
+0a81da8956346e19bcb27a906f04af327e03e31b $commit_sha1
+EOF
+
+cat >expect_log_z <<EOF
+$commit_sha5 5th
+
+$commit_sha4 4th
+z notes on 4th commit
+
+More z notes on 4th commit
+
+$commit_sha3 3rd
+
+$commit_sha2 2nd
+z notes on 2nd commit
+
+$commit_sha1 1st
+z notes on 1st commit
+
+EOF
+
+test_expect_success 'change notes in z' '
+	git notes --ref z append -m "More z notes on 4th commit" 4th &&
+	verify_notes z
+'
+
+test_expect_success 'cannot do merge w/conflicts when previous merge is unfinished' '
+	test -d .git/NOTES_MERGE_WORKTREE &&
+	test_must_fail git notes merge z >output 2>&1 &&
+	# Output should indicate what is wrong
+	grep -q "\\.git/NOTES_MERGE_\\* exists" output
+'
+
+# Setup non-conflicting merge between x and new notes ref w
+
+cat <<EOF | sort >expect_notes_w
+ceefa674873670e7ecd131814d909723cce2b669 $commit_sha2
+f75d1df88cbfe4258d49852f26cfc83f2ad4494b $commit_sha1
+EOF
+
+cat >expect_log_w <<EOF
+$commit_sha5 5th
+
+$commit_sha4 4th
+
+$commit_sha3 3rd
+
+$commit_sha2 2nd
+x notes on 2nd commit
+
+$commit_sha1 1st
+w notes on 1st commit
+
+EOF
+
+test_expect_success 'setup unrelated notes ref (w)' '
+	git config core.notesRef refs/notes/w &&
+	git notes add -m "w notes on 1st commit" 1st &&
+	git notes add -m "x notes on 2nd commit" 2nd &&
+	verify_notes w
+'
+
+cat <<EOF | sort >expect_notes_w
+6e8e3febca3c2bb896704335cc4d0c34cb2f8715 $commit_sha4
+e5388c10860456ee60673025345fe2e153eb8cf8 $commit_sha3
+ceefa674873670e7ecd131814d909723cce2b669 $commit_sha2
+f75d1df88cbfe4258d49852f26cfc83f2ad4494b $commit_sha1
+EOF
+
+cat >expect_log_w <<EOF
+$commit_sha5 5th
+
+$commit_sha4 4th
+x notes on 4th commit
+
+$commit_sha3 3rd
+x notes on 3rd commit
+
+$commit_sha2 2nd
+x notes on 2nd commit
+
+$commit_sha1 1st
+w notes on 1st commit
+
+EOF
+
+test_expect_success 'can do merge without conflicts even if previous merge is unfinished (x => w)' '
+	test -d .git/NOTES_MERGE_WORKTREE &&
+	git notes merge x &&
+	verify_notes w &&
+	# Verify that other notes refs has not changed (x and y)
+	verify_notes x &&
+	verify_notes y
+'
+
+test_done