Merge branch 'mm/diff-renames-default'

The end-user facing Porcelain level commands like "diff" and "log"
now enables the rename detection by default.

* mm/diff-renames-default:
  diff: activate diff.renames by default
  log: introduce init_log_defaults()
  t: add tests for diff.renames (true/false/unset)
  t4001-diff-rename: wrap file creations in a test
  Documentation/diff-config: fix description of diff.renames

Documentation/diff-config.txt

@@ -108,9 +108,13 @@ diff.renameLimit::
 	detection; equivalent to the 'git diff' option '-l'.
 
 diff.renames::
-	Tells Git to detect renames.  If set to any boolean value, it
-	will enable basic rename detection.  If set to "copies" or
-	"copy", it will detect copies, as well.
+	Whether and how Git detects renames.  If set to "false",
+	rename detection is disabled. If set to "true", basic rename
+	detection is enabled.  If set to "copies" or "copy", Git will
+	detect copies, as well.  Defaults to true.  Note that this
+	affects only 'git diff' Porcelain like linkgit:git-diff[1] and
+	linkgit:git-log[1], and not lower level commands such as
+	linkgit:git-diff-files[1].
 
 diff.suppressBlankEmpty::
 	A boolean to inhibit the standard behavior of printing a space

builtin/commit.c

@@ -186,6 +186,7 @@ static void status_init_config(struct wt_status *s, config_fn_t fn)
 	gitmodules_config();
 	git_config(fn, s);
 	determine_whence(s);
+	init_diff_ui_defaults();
 	s->hints = advice_status_hints; /* must come after git_config() */
 }
 

builtin/diff.c

@@ -318,6 +318,7 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 
 	if (!no_index)
 		gitmodules_config();
+	init_diff_ui_defaults();
 	git_config(git_diff_ui_config, NULL);
 
 	init_revisions(&rev, prefix);

builtin/log.c

@@ -100,6 +100,12 @@ static int log_line_range_callback(const struct option *option, const char *arg,
 	return 0;
 }
 
+static void init_log_defaults(void)
+{
+	init_grep_defaults();
+	init_diff_ui_defaults();
+}
+
 static void cmd_log_init_defaults(struct rev_info *rev)
 {
 	if (fmt_pretty)
@@ -416,7 +422,7 @@ int cmd_whatchanged(int argc, const char **argv, const char *prefix)
 	struct rev_info rev;
 	struct setup_revision_opt opt;
 
-	init_grep_defaults();
+	init_log_defaults();
 	git_config(git_log_config, NULL);
 
 	init_revisions(&rev, prefix);
@@ -527,7 +533,7 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 	struct pathspec match_all;
 	int i, count, ret = 0;
 
-	init_grep_defaults();
+	init_log_defaults();
 	git_config(git_log_config, NULL);
 
 	memset(&match_all, 0, sizeof(match_all));
@@ -608,7 +614,7 @@ int cmd_log_reflog(int argc, const char **argv, const char *prefix)
 	struct rev_info rev;
 	struct setup_revision_opt opt;
 
-	init_grep_defaults();
+	init_log_defaults();
 	git_config(git_log_config, NULL);
 
 	init_revisions(&rev, prefix);
@@ -647,7 +653,7 @@ int cmd_log(int argc, const char **argv, const char *prefix)
 	struct rev_info rev;
 	struct setup_revision_opt opt;
 
-	init_grep_defaults();
+	init_log_defaults();
 	git_config(git_log_config, NULL);
 
 	init_revisions(&rev, prefix);
@@ -1280,7 +1286,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	extra_hdr.strdup_strings = 1;
 	extra_to.strdup_strings = 1;
 	extra_cc.strdup_strings = 1;
-	init_grep_defaults();
+	init_log_defaults();
 	git_config(git_format_config, NULL);
 	init_revisions(&rev, prefix);
 	rev.commit_format = CMIT_FMT_EMAIL;

builtin/merge.c

@@ -1187,6 +1187,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	else
 		head_commit = lookup_commit_or_die(head_sha1, "HEAD");
 
+	init_diff_ui_defaults();
 	git_config(git_merge_config, NULL);
 
 	if (branch_mergeoptions)

diff.c

@@ -168,6 +168,11 @@ long parse_algorithm_value(const char *value)
  * never be affected by the setting of diff.renames
  * the user happens to have in the configuration file.
  */
+void init_diff_ui_defaults(void)
+{
+	diff_detect_rename_default = 1;
+}
+
 int git_diff_ui_config(const char *var, const char *value, void *cb)
 {
 	if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {

diff.h

@@ -266,6 +266,7 @@ extern int parse_long_opt(const char *opt, const char **argv,
 			 const char **optarg);
 
 extern int git_diff_basic_config(const char *var, const char *value, void *cb);
+extern void init_diff_ui_defaults(void);
 extern int git_diff_ui_config(const char *var, const char *value, void *cb);
 extern void diff_setup(struct diff_options *);
 extern int diff_opt_parse(struct diff_options *, const char **, int, const char *);

t/t4001-diff-rename.sh

@@ -9,21 +9,84 @@ test_description='Test rename detection in diff engine.
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/diff-lib.sh
 
-echo >path0 'Line 1
-Line 2
-Line 3
-Line 4
-Line 5
-Line 6
-Line 7
-Line 8
-Line 9
-Line 10
-line 11
-Line 12
-Line 13
-Line 14
-Line 15
+test_expect_success 'setup' '
+	cat >path0 <<-\EOF &&
+	Line 1
+	Line 2
+	Line 3
+	Line 4
+	Line 5
+	Line 6
+	Line 7
+	Line 8
+	Line 9
+	Line 10
+	line 11
+	Line 12
+	Line 13
+	Line 14
+	Line 15
+	EOF
+	cat >expected <<-\EOF &&
+	diff --git a/path0 b/path1
+	rename from path0
+	rename to path1
+	--- a/path0
+	+++ b/path1
+	@@ -8,7 +8,7 @@ Line 7
+	 Line 8
+	 Line 9
+	 Line 10
+	-line 11
+	+Line 11
+	 Line 12
+	 Line 13
+	 Line 14
+	EOF
+	cat >no-rename <<-\EOF
+	diff --git a/path0 b/path0
+	deleted file mode 100644
+	index fdbec44..0000000
+	--- a/path0
+	+++ /dev/null
+	@@ -1,15 +0,0 @@
+	-Line 1
+	-Line 2
+	-Line 3
+	-Line 4
+	-Line 5
+	-Line 6
+	-Line 7
+	-Line 8
+	-Line 9
+	-Line 10
+	-line 11
+	-Line 12
+	-Line 13
+	-Line 14
+	-Line 15
+	diff --git a/path1 b/path1
+	new file mode 100644
+	index 0000000..752c50e
+	--- /dev/null
+	+++ b/path1
+	@@ -0,0 +1,15 @@
+	+Line 1
+	+Line 2
+	+Line 3
+	+Line 4
+	+Line 5
+	+Line 6
+	+Line 7
+	+Line 8
+	+Line 9
+	+Line 10
+	+Line 11
+	+Line 12
+	+Line 13
+	+Line 14
+	+Line 15
+	EOF
 '
 
 test_expect_success \
@@ -43,27 +106,27 @@ test_expect_success \
 test_expect_success \
     'git diff-index -p -M after rename and editing.' \
     'git diff-index -p -M $tree >current'
-cat >expected <<\EOF
-diff --git a/path0 b/path1
-rename from path0
-rename to path1
---- a/path0
-+++ b/path1
-@@ -8,7 +8,7 @@ Line 7
- Line 8
- Line 9
- Line 10
--line 11
-+Line 11
- Line 12
- Line 13
- Line 14
-EOF
+
 
 test_expect_success \
     'validate the output.' \
     'compare_diff_patch current expected'
 
+test_expect_success 'test diff.renames=true' '
+	git -c diff.renames=true diff --cached $tree >current &&
+	compare_diff_patch current expected
+'
+
+test_expect_success 'test diff.renames=false' '
+	git -c diff.renames=false diff --cached $tree >current &&
+	compare_diff_patch current no-rename
+'
+
+test_expect_success 'test diff.renames unset' '
+	git diff --cached $tree >current &&
+	compare_diff_patch current expected
+'
+
 test_expect_success 'favour same basenames over different ones' '
 	cp path1 another-path &&
 	git add another-path &&

t/t4013-diff-various.sh

@@ -90,6 +90,8 @@ test_expect_success setup '
 	git commit -m "Rearranged lines in dir/sub" &&
 	git checkout master &&
 
+	git config diff.renames false &&
+
 	git show-branch
 '
 

t/t4014-format-patch.sh

@@ -549,7 +549,7 @@ test_expect_success 'cover-letter inherits diff options' '
 
 	git mv file foo &&
 	git commit -m foo &&
-	git format-patch --cover-letter -1 &&
+	git format-patch --no-renames --cover-letter -1 &&
 	check_patch 0000-cover-letter.patch &&
 	! grep "file => foo .* 0 *\$" 0000-cover-letter.patch &&
 	git format-patch --cover-letter -1 -M &&
@@ -703,7 +703,7 @@ test_expect_success 'options no longer allowed for format-patch' '
 
 test_expect_success 'format-patch --numstat should produce a patch' '
 	git format-patch --numstat --stdout master..side > output &&
-	test 6 = $(grep "^diff --git a/" output | wc -l)'
+	test 5 = $(grep "^diff --git a/" output | wc -l)'
 
 test_expect_success 'format-patch -- <path>' '
 	git format-patch master..side -- file 2>error &&

t/t4047-diff-dirstat.sh

@@ -248,7 +248,8 @@ EOF
 	git rm -r src/move/unchanged &&
 	git rm -r src/move/changed &&
 	git rm -r src/move/rearranged &&
-	git commit -m "changes"
+	git commit -m "changes" &&
+	git config diff.renames false
 '
 
 cat <<EOF >expect_diff_stat

t/t4202-log.sh

@@ -101,8 +101,8 @@ test_expect_success 'oneline' '
 
 test_expect_success 'diff-filter=A' '
 
-	git log --pretty="format:%s" --diff-filter=A HEAD > actual &&
-	git log --pretty="format:%s" --diff-filter A HEAD > actual-separate &&
+	git log --no-renames --pretty="format:%s" --diff-filter=A HEAD > actual &&
+	git log --no-renames --pretty="format:%s" --diff-filter A HEAD > actual-separate &&
 	printf "fifth\nfourth\nthird\ninitial" > expect &&
 	test_cmp expect actual &&
 	test_cmp expect actual-separate
@@ -119,7 +119,7 @@ test_expect_success 'diff-filter=M' '
 
 test_expect_success 'diff-filter=D' '
 
-	actual=$(git log --pretty="format:%s" --diff-filter=D HEAD) &&
+	actual=$(git log --no-renames --pretty="format:%s" --diff-filter=D HEAD) &&
 	expect=$(echo sixth ; echo third) &&
 	verbose test "$actual" = "$expect"
 
@@ -848,7 +848,7 @@ sanitize_output () {
 }
 
 test_expect_success 'log --graph with diff and stats' '
-	git log --graph --pretty=short --stat -p >actual &&
+	git log --no-renames --graph --pretty=short --stat -p >actual &&
 	sanitize_output >actual.sanitized <actual &&
 	test_i18ncmp expect actual.sanitized
 '