Merge branch 'jc/cache-unmerge'

* jc/cache-unmerge:
  rerere forget path: forget recorded resolution
  rerere: refactor rerere logic to make it independent from I/O
  rerere: remove silly 1024-byte line limit
  resolve-undo: teach "update-index --unresolve" to use resolve-undo info
  resolve-undo: "checkout -m path" uses resolve-undo information
  resolve-undo: allow plumbing to clear the information
  resolve-undo: basic tests
  resolve-undo: record resolved conflicts in a new index extension section
  builtin-merge.c: use standard active_cache macros

Conflicts:
	builtin-ls-files.c
	builtin-merge.c
	builtin-rerere.c

1 files changed, 143 insertions, 0 deletions

diff --git a/t/t2030-unresolve-info.sh b/t/t2030-unresolve-info.sh
new file mode 100755
index 0000000000..a38bd6df84
--- /dev/null
+++ b/t/t2030-unresolve-info.sh
@@ -0,0 +1,143 @@
+#!/bin/sh
+
+test_description='undoing resolution'
+
+. ./test-lib.sh
+
+check_resolve_undo () {
+	msg=$1
+	shift
+	while case $# in
+	0)	break ;;
+	1|2|3)	die "Bug in check-resolve-undo test" ;;
+	esac
+	do
+		path=$1
+		shift
+		for stage in 1 2 3
+		do
+			sha1=$1
+			shift
+			case "$sha1" in
+			'') continue ;;
+			esac
+			sha1=$(git rev-parse --verify "$sha1")
+			printf "100644 %s %s\t%s\n" $sha1 $stage $path
+		done
+	done >"$msg.expect" &&
+	git ls-files --resolve-undo >"$msg.actual" &&
+	test_cmp "$msg.expect" "$msg.actual"
+}
+
+prime_resolve_undo () {
+	git reset --hard &&
+	git checkout second^0 &&
+	test_tick &&
+	test_must_fail git merge third^0 &&
+	echo merge does not leave anything &&
+	check_resolve_undo empty &&
+	echo different >file &&
+	git add file &&
+	echo resolving records &&
+	check_resolve_undo recorded file initial:file second:file third:file
+}
+
+test_expect_success setup '
+	test_commit initial file first &&
+	git branch side &&
+	git branch another &&
+	test_commit second file second &&
+	git checkout side &&
+	test_commit third file third &&
+	git checkout another &&
+	test_commit fourth file fourth &&
+	git checkout master
+'
+
+test_expect_success 'add records switch clears' '
+	prime_resolve_undo &&
+	test_tick &&
+	git commit -m merged &&
+	echo committing keeps &&
+	check_resolve_undo kept file initial:file second:file third:file &&
+	git checkout second^0 &&
+	echo switching clears &&
+	check_resolve_undo cleared
+'
+
+test_expect_success 'rm records reset clears' '
+	prime_resolve_undo &&
+	test_tick &&
+	git commit -m merged &&
+	echo committing keeps &&
+	check_resolve_undo kept file initial:file second:file third:file &&
+
+	echo merge clears upfront &&
+	test_must_fail git merge fourth^0 &&
+	check_resolve_undo nuked &&
+
+	git rm -f file &&
+	echo resolving records &&
+	check_resolve_undo recorded file initial:file HEAD:file fourth:file &&
+
+	git reset --hard &&
+	echo resetting discards &&
+	check_resolve_undo discarded
+'
+
+test_expect_success 'plumbing clears' '
+	prime_resolve_undo &&
+	test_tick &&
+	git commit -m merged &&
+	echo committing keeps &&
+	check_resolve_undo kept file initial:file second:file third:file &&
+
+	echo plumbing clear &&
+	git update-index --clear-resolve-undo &&
+	check_resolve_undo cleared
+'
+
+test_expect_success 'add records checkout -m undoes' '
+	prime_resolve_undo &&
+	git diff HEAD &&
+	git checkout --conflict=merge file &&
+	echo checkout used the record and removed it &&
+	check_resolve_undo removed &&
+	echo the index and the work tree is unmerged again &&
+	git diff >actual &&
+	grep "^++<<<<<<<" actual
+'
+
+test_expect_success 'unmerge with plumbing' '
+	prime_resolve_undo &&
+	git update-index --unresolve file &&
+	git ls-files -u >actual &&
+	test $(wc -l <actual) = 3
+'
+
+test_expect_success 'rerere and rerere --forget' '
+	mkdir .git/rr-cache &&
+	prime_resolve_undo &&
+	echo record the resolution &&
+	git rerere &&
+	rerere_id=$(cd .git/rr-cache && echo */postimage) &&
+	rerere_id=${rerere_id%/postimage} &&
+	test -f .git/rr-cache/$rerere_id/postimage &&
+	git checkout -m file &&
+	echo resurrect the conflict &&
+	grep "^=======" file &&
+	echo reresolve the conflict &&
+	git rerere &&
+	test "z$(cat file)" = zdifferent &&
+	echo register the resolution again &&
+	git add file &&
+	check_resolve_undo kept file initial:file second:file third:file &&
+	test -z "$(git ls-files -u)" &&
+	git rerere forget file &&
+	! test -f .git/rr-cache/$rerere_id/postimage &&
+	tr "\0" "\n" <.git/MERGE_RR >actual &&
+	echo "$rerere_id	file" >expect &&
+	test_cmp expect actual
+'
+
+test_done