Merge branch 'fa/merge-recursive-no-rename'

"git merge-recursive" learned "--no-renames" option to disable its
rename detection logic.

* fa/merge-recursive-no-rename:
  t3034: test deprecated interface
  t3034: test option to disable renames
  t3034: add rename threshold tests
  merge-recursive: find-renames resets threshold
  merge-strategies.txt: fix typo
  merge-recursive: more consistent interface
  merge-recursive: option to disable renames

5 files changed, 337 insertions, 4 deletions

diff --git a/Documentation/merge-strategies.txt b/Documentation/merge-strategies.txt
index 7bbd19b300..2eb92b9327 100644
--- a/Documentation/merge-strategies.txt
+++ b/Documentation/merge-strategies.txt
@@ -81,9 +81,17 @@ no-renormalize;;
 	Disables the `renormalize` option.  This overrides the
 	`merge.renormalize` configuration variable.
 
+no-renames;;
+	Turn off rename detection.
+	See also linkgit:git-diff[1] `--no-renames`.
+
+find-renames[=<n>];;
+	Turn on rename detection, optionally setting the similarity
+	threshold.  This is the default.
+	See also linkgit:git-diff[1] `--find-renames`.
+
 rename-threshold=<n>;;
-	Controls the similarity threshold used for rename detection.
-	See also linkgit:git-diff[1] `-M`.
+	Deprecated synonym for `find-renames=<n>`.
 
 subtree[=<path>];;
 	This option is a more advanced form of 'subtree' strategy, where
diff --git a/merge-recursive.c b/merge-recursive.c
index 8eabde20fb..b880ae50e7 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -482,6 +482,9 @@ static struct string_list *get_renames(struct merge_options *o,
 	struct diff_options opts;
 
 	renames = xcalloc(1, sizeof(struct string_list));
+	if (!o->detect_rename)
+		return renames;
+
 	diff_setup(&opts);
 	DIFF_OPT_SET(&opts, RECURSIVE);
 	DIFF_OPT_CLR(&opts, RENAME_EMPTY);
@@ -2039,6 +2042,7 @@ void init_merge_options(struct merge_options *o)
 	o->diff_rename_limit = -1;
 	o->merge_rename_limit = -1;
 	o->renormalize = 0;
+	o->detect_rename = 1;
 	merge_recursive_config(o);
 	if (getenv("GIT_MERGE_VERBOSITY"))
 		o->verbosity =
@@ -2088,9 +2092,17 @@ int parse_merge_opt(struct merge_options *o, const char *s)
 		o->renormalize = 1;
 	else if (!strcmp(s, "no-renormalize"))
 		o->renormalize = 0;
-	else if (skip_prefix(s, "rename-threshold=", &arg)) {
+	else if (!strcmp(s, "no-renames"))
+		o->detect_rename = 0;
+	else if (!strcmp(s, "find-renames")) {
+		o->detect_rename = 1;
+		o->rename_score = 0;
+	}
+	else if (skip_prefix(s, "find-renames=", &arg) ||
+		 skip_prefix(s, "rename-threshold=", &arg)) {
 		if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
 			return -1;
+		o->detect_rename = 1;
 	}
 	else
 		return -1;
diff --git a/merge-recursive.h b/merge-recursive.h
index 9e090a3470..52f0201f68 100644
--- a/merge-recursive.h
+++ b/merge-recursive.h
@@ -17,6 +17,7 @@ struct merge_options {
 	unsigned renormalize : 1;
 	long xdl_opts;
 	int verbosity;
+	int detect_rename;
 	int diff_rename_limit;
 	int merge_rename_limit;
 	int rename_score;
diff --git a/t/t3032-merge-recursive-options.sh b/t/t3032-merge-recursive-space-options.sh
index 4029c9c8c0..b56180ee4a 100755
--- a/t/t3032-merge-recursive-options.sh
+++ b/t/t3032-merge-recursive-space-options.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-test_description='merge-recursive options
+test_description='merge-recursive space options
 
 * [master] Clarify
  ! [remote] Remove cruft
diff --git a/t/t3034-merge-recursive-rename-options.sh b/t/t3034-merge-recursive-rename-options.sh
new file mode 100755
index 0000000000..b9c4028496
--- /dev/null
+++ b/t/t3034-merge-recursive-rename-options.sh
@@ -0,0 +1,312 @@
+#!/bin/sh
+
+test_description='merge-recursive rename options
+
+Test rename detection by examining rename/delete conflicts.
+
+* (HEAD -> rename) rename
+| * (master) delete
+|/
+* base
+
+git diff --name-status base master
+D	0-old
+D	1-old
+D	2-old
+D	3-old
+
+git diff --name-status -M01 base rename
+R025    0-old   0-new
+R050    1-old   1-new
+R075    2-old   2-new
+R100    3-old   3-new
+
+Actual similarity indices are parsed from diff output. We rely on the fact that
+they are rounded down (see, e.g., Documentation/diff-generate-patch.txt, which
+mentions this in a different context).
+'
+
+. ./test-lib.sh
+
+get_expected_stages () {
+	git checkout rename -- $1-new &&
+	git ls-files --stage $1-new >expected-stages-undetected-$1 &&
+	sed "s/ 0	/ 2	/" <expected-stages-undetected-$1 \
+		>expected-stages-detected-$1 &&
+	git read-tree -u --reset HEAD
+}
+
+rename_detected () {
+	git ls-files --stage $1-old $1-new >stages-actual-$1 &&
+	test_cmp expected-stages-detected-$1 stages-actual-$1
+}
+
+rename_undetected () {
+	git ls-files --stage $1-old $1-new >stages-actual-$1 &&
+	test_cmp expected-stages-undetected-$1 stages-actual-$1
+}
+
+check_common () {
+	git ls-files --stage >stages-actual &&
+	test_line_count = 4 stages-actual
+}
+
+check_threshold_0 () {
+	check_common &&
+	rename_detected 0 &&
+	rename_detected 1 &&
+	rename_detected 2 &&
+	rename_detected 3
+}
+
+check_threshold_1 () {
+	check_common &&
+	rename_undetected 0 &&
+	rename_detected 1 &&
+	rename_detected 2 &&
+	rename_detected 3
+}
+
+check_threshold_2 () {
+	check_common &&
+	rename_undetected 0 &&
+	rename_undetected 1 &&
+	rename_detected 2 &&
+	rename_detected 3
+}
+
+check_exact_renames () {
+	check_common &&
+	rename_undetected 0 &&
+	rename_undetected 1 &&
+	rename_undetected 2 &&
+	rename_detected 3
+}
+
+check_no_renames () {
+	check_common &&
+	rename_undetected 0 &&
+	rename_undetected 1 &&
+	rename_undetected 2 &&
+	rename_undetected 3
+}
+
+test_expect_success 'setup repo' '
+	cat <<-\EOF >3-old &&
+	33a
+	33b
+	33c
+	33d
+	EOF
+	sed s/33/22/ <3-old >2-old &&
+	sed s/33/11/ <3-old >1-old &&
+	sed s/33/00/ <3-old >0-old &&
+	git add [0-3]-old &&
+	git commit -m base &&
+	git rm [0-3]-old &&
+	git commit -m delete &&
+	git checkout -b rename HEAD^ &&
+	cp 3-old 3-new &&
+	sed 1,1s/./x/ <2-old >2-new &&
+	sed 1,2s/./x/ <1-old >1-new &&
+	sed 1,3s/./x/ <0-old >0-new &&
+	git add [0-3]-new &&
+	git rm [0-3]-old &&
+	git commit -m rename &&
+	get_expected_stages 0 &&
+	get_expected_stages 1 &&
+	get_expected_stages 2 &&
+	get_expected_stages 3 &&
+	check_50="false" &&
+	tail="HEAD^ -- HEAD master"
+'
+
+test_expect_success 'setup thresholds' '
+	git diff --name-status -M01 HEAD^ HEAD >diff-output &&
+	test_debug "cat diff-output" &&
+	test_line_count = 4 diff-output &&
+	grep "R[0-9][0-9][0-9]	\([0-3]\)-old	\1-new" diff-output \
+		>grep-output &&
+	test_cmp diff-output grep-output &&
+	th0=$(sed -n "s/R\(...\)	0-old	0-new/\1/p" <diff-output) &&
+	th1=$(sed -n "s/R\(...\)	1-old	1-new/\1/p" <diff-output) &&
+	th2=$(sed -n "s/R\(...\)	2-old	2-new/\1/p" <diff-output) &&
+	th3=$(sed -n "s/R\(...\)	3-old	3-new/\1/p" <diff-output) &&
+	test "$th0" -lt "$th1" &&
+	test "$th1" -lt "$th2" &&
+	test "$th2" -lt "$th3" &&
+	test "$th3" = 100 &&
+	if test 50 -le "$th0"
+	then
+		check_50=check_threshold_0
+	elif test 50 -le "$th1"
+	then
+		check_50=check_threshold_1
+	elif test 50 -le "$th2"
+	then
+		check_50=check_threshold_2
+	fi &&
+	th0="$th0%" &&
+	th1="$th1%" &&
+	th2="$th2%" &&
+	th3="$th3%"
+'
+
+test_expect_success 'assumption for tests: rename detection with diff' '
+	git diff --name-status -M$th0 --diff-filter=R HEAD^ HEAD \
+		>diff-output-0 &&
+	git diff --name-status -M$th1 --diff-filter=R HEAD^ HEAD \
+		>diff-output-1 &&
+	git diff --name-status -M$th2 --diff-filter=R HEAD^ HEAD \
+		>diff-output-2 &&
+	git diff --name-status -M100% --diff-filter=R HEAD^ HEAD \
+		>diff-output-3 &&
+	test_line_count = 4 diff-output-0 &&
+	test_line_count = 3 diff-output-1 &&
+	test_line_count = 2 diff-output-2 &&
+	test_line_count = 1 diff-output-3
+'
+
+test_expect_success 'default similarity threshold is 50%' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive $tail &&
+	$check_50
+'
+
+test_expect_success 'low rename threshold' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive --find-renames=$th0 $tail &&
+	check_threshold_0
+'
+
+test_expect_success 'medium rename threshold' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive --find-renames=$th1 $tail &&
+	check_threshold_1
+'
+
+test_expect_success 'high rename threshold' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive --find-renames=$th2 $tail &&
+	check_threshold_2
+'
+
+test_expect_success 'exact renames only' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive --find-renames=100% $tail &&
+	check_exact_renames
+'
+
+test_expect_success 'rename threshold is truncated' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive --find-renames=200% $tail &&
+	check_exact_renames
+'
+
+test_expect_success 'disabled rename detection' '
+	git read-tree --reset -u HEAD &&
+	git merge-recursive --no-renames $tail &&
+	check_no_renames
+'
+
+test_expect_success 'last wins in --find-renames=<m> --find-renames=<n>' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive \
+		--find-renames=$th0 --find-renames=$th2 $tail &&
+	check_threshold_2
+'
+
+test_expect_success '--find-renames resets threshold' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive \
+		--find-renames=$th0 --find-renames $tail &&
+	$check_50
+'
+
+test_expect_success 'last wins in --no-renames --find-renames' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive --no-renames --find-renames $tail &&
+	$check_50
+'
+
+test_expect_success 'last wins in --find-renames --no-renames' '
+	git read-tree --reset -u HEAD &&
+	git merge-recursive --find-renames --no-renames $tail &&
+	check_no_renames
+'
+
+test_expect_success 'assumption for further tests: trivial merge succeeds' '
+	git read-tree --reset -u HEAD &&
+	git merge-recursive HEAD -- HEAD HEAD &&
+	git diff --quiet --cached &&
+	git merge-recursive --find-renames=$th0 HEAD -- HEAD HEAD &&
+	git diff --quiet --cached &&
+	git merge-recursive --find-renames=$th2 HEAD -- HEAD HEAD &&
+	git diff --quiet --cached &&
+	git merge-recursive --find-renames=100% HEAD -- HEAD HEAD &&
+	git diff --quiet --cached &&
+	git merge-recursive --no-renames HEAD -- HEAD HEAD &&
+	git diff --quiet --cached
+'
+
+test_expect_success '--find-renames rejects negative argument' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive --find-renames=-25 \
+		HEAD -- HEAD HEAD &&
+	git diff --quiet --cached
+'
+
+test_expect_success '--find-renames rejects non-numbers' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive --find-renames=0xf \
+		HEAD -- HEAD HEAD &&
+	git diff --quiet --cached
+'
+
+test_expect_success 'rename-threshold=<n> is a synonym for find-renames=<n>' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive --rename-threshold=$th0 $tail &&
+	check_threshold_0
+'
+
+test_expect_success 'last wins in --no-renames --rename-threshold=<n>' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive --no-renames --rename-threshold=$th0 $tail &&
+	check_threshold_0
+'
+
+test_expect_success 'last wins in --rename-threshold=<n> --no-renames' '
+	git read-tree --reset -u HEAD &&
+	git merge-recursive --rename-threshold=$th0 --no-renames $tail &&
+	check_no_renames
+'
+
+test_expect_success '--rename-threshold=<n> rejects negative argument' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive --rename-threshold=-25 \
+		HEAD -- HEAD HEAD &&
+	git diff --quiet --cached
+'
+
+test_expect_success '--rename-threshold=<n> rejects non-numbers' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive --rename-threshold=0xf \
+		HEAD -- HEAD HEAD &&
+	git diff --quiet --cached
+'
+
+test_expect_success 'last wins in --rename-threshold=<m> --find-renames=<n>' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive \
+		--rename-threshold=$th0 --find-renames=$th2 $tail &&
+	check_threshold_2
+'
+
+test_expect_success 'last wins in --find-renames=<m> --rename-threshold=<n>' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git merge-recursive \
+		--find-renames=$th2 --rename-threshold=$th0 $tail &&
+	check_threshold_0
+'
+
+test_done