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[PATCHv4 17/17] diff.c: color moved lines differently

From
Stefan Beller <sbeller@google.com>
Date
May 23, 2017, 02:40 UTC
Message-ID
<20170523024048.16879-18-sbeller@google.com>
In-Reply-To
<20170523024048.16879-1-sbeller@google.com>

When a patch consists mostly of moving blocks of code around, it can be quite tedious to ensure that the blocks are moved verbatim, and not undesirably modified in the move. To that end, color blocks that are moved within the same patch differently. For example (OM, del, add, and NM are different colors):

    [OM]  -void sensitive_stuff(void)
    [OM]  -{
    [OM]  -        if (!is_authorized_user())
    [OM]  -                die("unauthorized");
    [OM]  -        sensitive_stuff(spanning,
    [OM]  -                        multiple,
    [OM]  -                        lines);
    [OM]  -}
           void another_function()
           {
    [del] -        printf("foo");
    [add] +        printf("bar");
           }
    [NM]  +void sensitive_stuff(void)
    [NM]  +{
    [NM]  +        if (!is_authorized_user())
    [NM]  +                die("unauthorized");
    [NM]  +        sensitive_stuff(spanning,
    [NM]  +                        multiple,
    [NM]  +                        lines);
    [NM]  +}

Adjacent blocks are colored differently. For example, in this potentially malicious patch, the swapping of blocks can be spotted:

    [OM]  -void sensitive_stuff(void)
    [OM]  -{
    [OMA] -        if (!is_authorized_user())
    [OMA] -                die("unauthorized");
    [OM]  -        sensitive_stuff(spanning,
    [OM]  -                        multiple,
    [OM]  -                        lines);
    [OMA] -}
           void another_function()
           {
    [del] -        printf("foo");
    [add] +        printf("bar");
           }
    [NM]  +void sensitive_stuff(void)
    [NM]  +{
    [NMA] +        sensitive_stuff(spanning,
    [NMA] +                        multiple,
    [NMA] +                        lines);
    [NM]  +        if (!is_authorized_user())
    [NM]  +                die("unauthorized");
    [NMA] +}

If the moved code is larger, it is easier to hide some permutation in the code, which is why the alternative coloring is really needed.

As the reviewers attention should be brought to the places, where the difference is introduced to the moved code, we cannot just have one new color for all of moved code.

First I implemented an alternative design, which would show a moved hunk in one color, and its boundaries in another color. This idea was error prone as it inspected each line and its neighboring lines to determine if the line was (a) moved and (b) if was deep inside a hunk by having matching neighboring lines. This is unreliable as the we can construct hunks which have equal neighbors that just exceed the number of lines inspected. (Think of 'AXYZBXYZCXYZD..' with each letter as a line, that is permutated to AXYZCXYZBXYZD..').

Instead this provides a dynamic programming greedy algorithm that finds the largest moved hunk and then switches color to the alternative color for the next hunk. By doing this any permutation is recognized and displayed. That implies that there is no dedicated boundary or inside-hunk color, but instead we'll have just two colors alternating for hunks.

It would be a bit more UX friendly if the two corresponding hunks (of added and deleted lines) for one move would get the same color id. (Both get "regular moved" or "alternative moved"). This problem is deferred to a later patch for now.

A note on the options '--submodule=diff' and '--color-words/--word-diff': In the conversion to use emit_line in the prior patches both submodules as well as word diff output carefully chose to call emit_line with sign=0. All output with sign=0 is ignored for move detection purposes in this patch, such that no weird looking output will be generated for these cases. This leads to another thought: We could pass on '--color-moved' to submodules such that they color up moved lines for themselves. If we'd do so only line moves within a repository boundary are marked up.

Helped-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
# Conflicts:
#	diff.c
---
 Documentation/config.txt   |  14 ++-
 diff.c                     | 275 +++++++++++++++++++++++++++++++++++++++++++--
 diff.h                     |   9 +-
 t/t4015-diff-whitespace.sh | 267 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 552 insertions(+), 13 deletions(-)
diff --git a/Documentation/config.txt b/Documentation/config.txt
index 475e874d51..902d017c3b 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1051,14 +1051,24 @@ This does not affect linkgit:git-format-patch[1] or the
 'git-diff-{asterisk}' plumbing commands.  Can be overridden on the
 command line with the `--color[=<when>]` option.
 
+color.moved::
+	A boolean value, whether a diff should color moved lines
+	differently. The moved lines are searched for in the diff only.
+	Duplicated lines from somewhere in the project that are not
+	part of the diff are not colored as moved.
+	Defaults to false.
+
 color.diff.<slot>::
 	Use customized color for diff colorization.  `<slot>` specifies
 	which part of the patch to use the specified color, and is one
 	of `context` (context text - `plain` is a historical synonym),
 	`meta` (metainformation), `frag`
 	(hunk header), 'func' (function in hunk header), `old` (removed lines),
-	`new` (added lines), `commit` (commit headers), or `whitespace`
-	(highlighting whitespace errors).
+	`new` (added lines), `commit` (commit headers), `whitespace`
+	(highlighting whitespace errors), `oldMoved` (removed lines that
+	reappear), `newMoved` (added lines that were removed elsewhere),
+	`oldMovedAlternative` and `newMovedAlternative` (as a fallback to
+	cover adjacent blocks of moved code)
 
 color.decorate.<slot>::
 	Use customized color for 'git log --decorate' output.  `<slot>` is one
diff --git a/diff.c b/diff.c
index c0b8afa38f..23e70d348e 100644
--- a/diff.c
+++ b/diff.c
@@ -31,6 +31,7 @@ static int diff_indent_heuristic; /* experimental */
 static int diff_rename_limit_default = 400;
 static int diff_suppress_blank_empty;
 static int diff_use_color_default = -1;
+static int diff_color_moved_default;
 static int diff_context_default = 3;
 static int diff_interhunk_context_default;
 static const char *diff_word_regex_cfg;
@@ -55,6 +56,10 @@ static char diff_colors[][COLOR_MAXLEN] = {
 	GIT_COLOR_YELLOW,	/* COMMIT */
 	GIT_COLOR_BG_RED,	/* WHITESPACE */
 	GIT_COLOR_NORMAL,	/* FUNCINFO */
+	GIT_COLOR_BOLD_RED,	/* OLD_MOVED_A */
+	GIT_COLOR_BG_RED,	/* OLD_MOVED_B */
+	GIT_COLOR_BOLD_GREEN,	/* NEW_MOVED_A */
+	GIT_COLOR_BG_GREEN,	/* NEW_MOVED_B */
 };
 
 static NORETURN void die_want_option(const char *option_name)
@@ -80,6 +85,14 @@ static int parse_diff_color_slot(const char *var)
 		return DIFF_WHITESPACE;
 	if (!strcasecmp(var, "func"))
 		return DIFF_FUNCINFO;
+	if (!strcasecmp(var, "oldmoved"))
+		return DIFF_FILE_OLD_MOVED;
+	if (!strcasecmp(var, "oldmovedalternative"))
+		return DIFF_FILE_OLD_MOVED_ALT;
+	if (!strcasecmp(var, "newmoved"))
+		return DIFF_FILE_NEW_MOVED;
+	if (!strcasecmp(var, "newmovedalternative"))
+		return DIFF_FILE_NEW_MOVED_ALT;
 	return -1;
 }
 
@@ -234,6 +247,10 @@ int git_diff_ui_config(const char *var, const char *value, void *cb)
 		diff_use_color_default = git_config_colorbool(var, value);
 		return 0;
 	}
+	if (!strcmp(var, "color.moved")) {
+		diff_color_moved_default = git_config_bool(var, value);
+		return 0;
+	}
 	if (!strcmp(var, "diff.context")) {
 		diff_context_default = git_config_int(var, value);
 		if (diff_context_default < 0)
@@ -354,6 +371,88 @@ int git_diff_basic_config(const char *var, const char *value, void *cb)
 	return git_default_config(var, value, cb);
 }
 
+struct moved_entry {
+	struct hashmap_entry ent;
+	const struct diff_line *line;
+	struct moved_entry *next_line;
+};
+
+static void get_ws_cleaned_string(const struct diff_line *l,
+				  struct strbuf *out)
+{
+	int i;
+	for (i = 0; i < l->len; i++) {
+		if (isspace(l->line[i]))
+			continue;
+		strbuf_addch(out, l->line[i]);
+	}
+}
+
+static int diff_line_cmp_no_ws(const struct diff_line *a,
+					 const struct diff_line *b,
+					 const void *keydata)
+{
+	int ret;
+	struct strbuf sba = STRBUF_INIT;
+	struct strbuf sbb = STRBUF_INIT;
+
+	get_ws_cleaned_string(a, &sba);
+	get_ws_cleaned_string(b, &sbb);
+	ret = sba.len != sbb.len || strncmp(sba.buf, sbb.buf, sba.len);
+
+	strbuf_release(&sba);
+	strbuf_release(&sbb);
+	return ret;
+}
+
+static int diff_line_cmp(const struct diff_line *a,
+				   const struct diff_line *b,
+				   const void *keydata)
+{
+	return a->len != b->len || strncmp(a->line, b->line, a->len);
+}
+
+static int moved_entry_cmp(const struct moved_entry *a,
+			   const struct moved_entry *b,
+			   const void *keydata)
+{
+	return diff_line_cmp(a->line, b->line, keydata);
+}
+
+static int moved_entry_cmp_no_ws(const struct moved_entry *a,
+				 const struct moved_entry *b,
+				 const void *keydata)
+{
+	return diff_line_cmp_no_ws(a->line, b->line, keydata);
+}
+
+static unsigned get_line_hash(struct diff_line *line, unsigned ignore_ws)
+{
+	static struct strbuf sb = STRBUF_INIT;
+
+	if (ignore_ws) {
+		strbuf_reset(&sb);
+		get_ws_cleaned_string(line, &sb);
+		return memhash(sb.buf, sb.len);
+	} else {
+		return memhash(line->line, line->len);
+	}
+}
+
+static struct moved_entry *prepare_entry(struct diff_options *o,
+					 int line_no)
+{
+	struct moved_entry *ret = xmalloc(sizeof(*ret));
+	unsigned ignore_ws = DIFF_XDL_TST(o, IGNORE_WHITESPACE);
+	struct diff_line *l = &o->line_buffer[line_no];
+
+	ret->ent.hash = get_line_hash(l, ignore_ws);
+	ret->line = l;
+	ret->next_line = NULL;
+
+	return ret;
+}
+
 static char *quote_two(const char *one, const char *two)
 {
 	int need_one = quote_c_style(one, NULL, NULL, 1);
@@ -516,6 +615,141 @@ static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 	ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 }
 
+static void add_lines_to_move_detection(struct diff_options *o,
+					struct hashmap *add_lines,
+					struct hashmap *del_lines)
+{
+	struct moved_entry *prev_line = NULL;
+
+	int n;
+	for (n = 0; n < o->line_buffer_nr; n++) {
+		int sign = 0;
+		struct hashmap *hm;
+		struct moved_entry *key;
+
+		switch (o->line_buffer[n].sign) {
+		case '+':
+			sign = '+';
+			hm = add_lines;
+			break;
+		case '-':
+			sign = '-';
+			hm = del_lines;
+			break;
+		case ' ':
+		default:
+			prev_line = NULL;
+			continue;
+		}
+
+		key = prepare_entry(o, n);
+		if (prev_line &&
+		    prev_line->line->sign == sign)
+			prev_line->next_line = key;
+
+		hashmap_add(hm, key);
+		prev_line = key;
+	}
+}
+
+static void mark_color_as_moved(struct diff_options *o,
+				struct hashmap *add_lines,
+				struct hashmap *del_lines)
+{
+	struct moved_entry **pmb = NULL; /* potentially moved blocks */
+	int pmb_nr = 0, pmb_alloc = 0;
+	int use_alt_color = 0;
+	int n;
+
+	for (n = 0; n < o->line_buffer_nr; n++) {
+		struct hashmap *hm = NULL;
+		struct moved_entry *key;
+		struct moved_entry *match = NULL;
+		struct diff_line *l = &o->line_buffer[n];
+		int i, lp, rp;
+
+		switch (l->sign) {
+		case '+':
+			hm = del_lines;
+			break;
+		case '-':
+			hm = add_lines;
+			break;
+		default:
+			use_alt_color = 0;
+			pmb_nr = 0; /* no running sets */
+			continue;
+		}
+
+		/* Check for any match to color it as a move. */
+		key = prepare_entry(o, n);
+		match = hashmap_get(hm, key, o);
+		free(key);
+		if (!match)
+			continue;
+
+		/* Check any potential block runs, advance each or nullify */
+		for (i = 0; i < pmb_nr; i++) {
+			struct moved_entry *p = pmb[i];
+			struct moved_entry *pnext = (p && p->next_line) ?
+					p->next_line : NULL;
+			if (pnext &&
+			    !diff_line_cmp(pnext->line, l, o)) {
+				pmb[i] = p->next_line;
+			} else {
+				pmb[i] = NULL;
+			}
+		}
+
+		/* Shrink the set to the remaining runs */
+		for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
+			while (lp < pmb_nr && pmb[lp])
+				lp++;
+			/* lp points at the first NULL now */
+
+			while (rp > -1 && !pmb[rp])
+				rp--;
+			/* rp points at the last non-NULL */
+
+			if (lp < pmb_nr && rp > -1 && lp < rp) {
+				pmb[lp] = pmb[rp];
+				pmb[rp] = NULL;
+				rp--;
+				lp++;
+			}
+		}
+
+		if (rp > -1) {
+			/* Remember the number of running sets */
+			pmb_nr = rp + 1;
+		} else {
+			/* Toggle color */
+			use_alt_color = (use_alt_color + 1) % 2;
+
+			/* Build up a new set */
+			pmb_nr = 0;
+			for (; match; match = hashmap_get_next(hm, match)) {
+				ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
+				pmb[pmb_nr++] = match;
+			}
+		}
+
+		switch (l->sign) {
+		case '+':
+			l->set = diff_get_color_opt(o,
+				DIFF_FILE_NEW_MOVED + use_alt_color);
+			break;
+		case '-':
+			l->set = diff_get_color_opt(o,
+				DIFF_FILE_OLD_MOVED + use_alt_color);
+			break;
+		default:
+			die("BUG: we should have continued earlier?");
+		}
+	}
+	free(pmb);
+}
+
 static void emit_diff_line(struct diff_options *o,
 				     struct diff_line *e)
 {
@@ -3518,6 +3752,8 @@ void diff_setup(struct diff_options *options)
 	options->line_buffer = NULL;
 	options->line_buffer_nr = 0;
 	options->line_buffer_alloc = 0;
+
+	options->color_moved = diff_color_moved_default;
 }
 
 void diff_setup_done(struct diff_options *options)
@@ -3627,6 +3863,9 @@ void diff_setup_done(struct diff_options *options)
 
 	if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
 		die(_("--follow requires exactly one pathspec"));
+
+	if (!options->use_color || external_diff())
+		options->color_moved = 0;
 }
 
 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
@@ -4051,6 +4290,10 @@ int diff_opt_parse(struct diff_options *options,
 	}
 	else if (!strcmp(arg, "--no-color"))
 		options->use_color = 0;
+	else if (!strcmp(arg, "--color-moved"))
+		options->color_moved = 1;
+	else if (!strcmp(arg, "--no-color-moved"))
+		options->color_moved = 0;
 	else if (!strcmp(arg, "--color-words")) {
 		options->use_color = 1;
 		options->word_diff = DIFF_WORDS_COLOR;
@@ -4856,16 +5099,9 @@ static void diff_flush_patch_all_file_pairs(struct diff_options *o)
 {
 	int i;
 	struct diff_queue_struct *q = &diff_queued_diff;
-	/*
-	 * For testing purposes we want to make sure the diff machinery
-	 * works completely with the buffer. If there is anything emitted
-	 * outside the emit_diff_line, then the order is screwed
-	 * up and the tests will fail.
-	 *
-	 * TODO (later in this series):
-	 * We'll unset this flag in a later patch.
-	 */
-	o->use_buffer = 1;
+
+	if (o->color_moved)
+		o->use_buffer = 1;
 
 	for (i = 0; i < q->nr; i++) {
 		struct diff_filepair *p = q->queue[i];
@@ -4874,6 +5110,24 @@ static void diff_flush_patch_all_file_pairs(struct diff_options *o)
 	}
 
 	if (o->use_buffer) {
+		if (o->color_moved) {
+			struct hashmap add_lines, del_lines;
+			unsigned ignore_ws = DIFF_XDL_TST(o, IGNORE_WHITESPACE);
+
+			hashmap_init(&del_lines, ignore_ws ?
+				(hashmap_cmp_fn)moved_entry_cmp_no_ws :
+				(hashmap_cmp_fn)moved_entry_cmp, 0);
+			hashmap_init(&add_lines, ignore_ws ?
+				(hashmap_cmp_fn)moved_entry_cmp_no_ws :
+				(hashmap_cmp_fn)moved_entry_cmp, 0);
+
+			add_lines_to_move_detection(o, &add_lines, &del_lines);
+			mark_color_as_moved(o, &add_lines, &del_lines);
+
+			hashmap_free(&add_lines, 0);
+			hashmap_free(&del_lines, 0);
+		}
+
 		for (i = 0; i < o->line_buffer_nr; i++)
 			emit_diff_line(o, &o->line_buffer[i]);
 
@@ -4962,6 +5216,7 @@ void diff_flush(struct diff_options *options)
 		if (!options->file)
 			die_errno("Could not open /dev/null");
 		options->close_file = 1;
+		options->color_moved = 0;
 		for (i = 0; i < q->nr; i++) {
 			struct diff_filepair *p = q->queue[i];
 			if (check_pair_status(p))
diff --git a/diff.h b/diff.h
index fad1258556..445259ebf7 100644
--- a/diff.h
+++ b/diff.h
@@ -7,6 +7,7 @@
 #include "tree-walk.h"
 #include "pathspec.h"
 #include "object.h"
+#include "hashmap.h"
 
 struct rev_info;
 struct diff_options;
@@ -228,6 +229,8 @@ struct diff_options {
 
 	struct diff_line *line_buffer;
 	int line_buffer_nr, line_buffer_alloc;
+
+	int color_moved;
 };
 
 /* Emit [line_prefix] [set] line [reset] */
@@ -243,7 +246,11 @@ enum color_diff {
 	DIFF_FILE_NEW = 5,
 	DIFF_COMMIT = 6,
 	DIFF_WHITESPACE = 7,
-	DIFF_FUNCINFO = 8
+	DIFF_FUNCINFO = 8,
+	DIFF_FILE_OLD_MOVED = 9,
+	DIFF_FILE_OLD_MOVED_ALT = 10,
+	DIFF_FILE_NEW_MOVED = 11,
+	DIFF_FILE_NEW_MOVED_ALT = 12
 };
 const char *diff_get_color(int diff_use_color, enum color_diff ix);
 #define diff_get_color_opt(o, ix) \
diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index 289806d0c7..0e92bf94bf 100755
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -972,4 +972,271 @@ test_expect_success 'option overrides diff.wsErrorHighlight' '
 
 '
 
+test_expect_success 'detect moved code, complete file' '
+	git reset --hard &&
+	cat <<-\EOF >test.c &&
+	#include<stdio.h>
+	main()
+	{
+	printf("Hello World");
+	}
+	EOF
+	git add test.c &&
+	git commit -m "add main function" &&
+	git mv test.c main.c &&
+	git diff HEAD --color-moved --no-renames | test_decode_color >actual &&
+	cat >expected <<-\EOF &&
+	<BOLD>diff --git a/main.c b/main.c<RESET>
+	<BOLD>new file mode 100644<RESET>
+	<BOLD>index 0000000..a986c57<RESET>
+	<BOLD>--- /dev/null<RESET>
+	<BOLD>+++ b/main.c<RESET>
+	<CYAN>@@ -0,0 +1,5 @@<RESET>
+	<BGREEN>+<RESET><BGREEN>#include<stdio.h><RESET>
+	<BGREEN>+<RESET><BGREEN>main()<RESET>
+	<BGREEN>+<RESET><BGREEN>{<RESET>
+	<BGREEN>+<RESET><BGREEN>printf("Hello World");<RESET>
+	<BGREEN>+<RESET><BGREEN>}<RESET>
+	<BOLD>diff --git a/test.c b/test.c<RESET>
+	<BOLD>deleted file mode 100644<RESET>
+	<BOLD>index a986c57..0000000<RESET>
+	<BOLD>--- a/test.c<RESET>
+	<BOLD>+++ /dev/null<RESET>
+	<CYAN>@@ -1,5 +0,0 @@<RESET>
+	<BRED>-#include<stdio.h><RESET>
+	<BRED>-main()<RESET>
+	<BRED>-{<RESET>
+	<BRED>-printf("Hello World");<RESET>
+	<BRED>-}<RESET>
+	EOF
+
+	test_cmp expected actual
+'
+
+test_expect_success 'detect moved code, inside file' '
+	git reset --hard &&
+	cat <<-\EOF >main.c &&
+		#include<stdio.h>
+		int stuff()
+		{
+			printf("Hello ");
+			printf("World\n");
+		}
+
+		int secure_foo(struct user *u)
+		{
+			if (!u->is_allowed_foo)
+				return;
+			foo(u);
+		}
+
+		int main()
+		{
+			foo();
+		}
+	EOF
+	cat <<-\EOF >test.c &&
+		#include<stdio.h>
+		int bar()
+		{
+			printf("Hello World, but different\n");
+		}
+
+		int another_function()
+		{
+			bar();
+		}
+	EOF
+	git add main.c test.c &&
+	git commit -m "add main and test file" &&
+	cat <<-\EOF >main.c &&
+		#include<stdio.h>
+		int stuff()
+		{
+			printf("Hello ");
+			printf("World\n");
+		}
+
+		int main()
+		{
+			foo();
+		}
+	EOF
+	cat <<-\EOF >test.c &&
+		#include<stdio.h>
+		int bar()
+		{
+			printf("Hello World, but different\n");
+		}
+
+		int secure_foo(struct user *u)
+		{
+			if (!u->is_allowed_foo)
+				return;
+			foo(u);
+		}
+
+		int another_function()
+		{
+			bar();
+		}
+	EOF
+	git diff HEAD --no-renames --color-moved| test_decode_color >actual &&
+	cat <<-\EOF >expected &&
+	<BOLD>diff --git a/main.c b/main.c<RESET>
+	<BOLD>index 27a619c..7cf9336 100644<RESET>
+	<BOLD>--- a/main.c<RESET>
+	<BOLD>+++ b/main.c<RESET>
+	<CYAN>@@ -5,13 +5,6 @@<RESET> <RESET>printf("Hello ");<RESET>
+	 printf("World\n");<RESET>
+	 }<RESET>
+	 <RESET>
+	<BRED>-int secure_foo(struct user *u)<RESET>
+	<BRED>-{<RESET>
+	<BRED>-if (!u->is_allowed_foo)<RESET>
+	<BRED>-return;<RESET>
+	<BRED>-foo(u);<RESET>
+	<BRED>-}<RESET>
+	<BRED>-<RESET>
+	 int main()<RESET>
+	 {<RESET>
+	 foo();<RESET>
+	<BOLD>diff --git a/test.c b/test.c<RESET>
+	<BOLD>index 1dc1d85..e34eb69 100644<RESET>
+	<BOLD>--- a/test.c<RESET>
+	<BOLD>+++ b/test.c<RESET>
+	<CYAN>@@ -4,6 +4,13 @@<RESET> <RESET>int bar()<RESET>
+	 printf("Hello World, but different\n");<RESET>
+	 }<RESET>
+	 <RESET>
+	<BGREEN>+<RESET><BGREEN>int secure_foo(struct user *u)<RESET>
+	<BGREEN>+<RESET><BGREEN>{<RESET>
+	<BGREEN>+<RESET><BGREEN>if (!u->is_allowed_foo)<RESET>
+	<BGREEN>+<RESET><BGREEN>return;<RESET>
+	<BGREEN>+<RESET><BGREEN>foo(u);<RESET>
+	<BGREEN>+<RESET><BGREEN>}<RESET>
+	<BGREEN>+<RESET>
+	 int another_function()<RESET>
+	 {<RESET>
+	 bar();<RESET>
+	EOF
+
+	test_cmp expected actual
+'
+
+test_expect_success 'detect permutations inside moved code' '
+	# reusing the move example from last test:
+	cat <<-\EOF >main.c &&
+		#include<stdio.h>
+		int stuff()
+		{
+			printf("Hello ");
+			printf("World\n");
+		}
+
+		int main()
+		{
+			foo();
+		}
+	EOF
+	cat <<-\EOF >test.c &&
+		#include<stdio.h>
+		int bar()
+		{
+			printf("Hello World, but different\n");
+		}
+
+		int secure_foo(struct user *u)
+		{
+			foo(u);
+			if (!u->is_allowed_foo)
+				return;
+		}
+
+		int another_function()
+		{
+			bar();
+		}
+	EOF
+	git diff HEAD --no-renames --color-moved| test_decode_color >actual &&
+	cat <<-\EOF >expected &&
+	<BOLD>diff --git a/main.c b/main.c<RESET>
+	<BOLD>index 27a619c..7cf9336 100644<RESET>
+	<BOLD>--- a/main.c<RESET>
+	<BOLD>+++ b/main.c<RESET>
+	<CYAN>@@ -5,13 +5,6 @@<RESET> <RESET>printf("Hello ");<RESET>
+	 printf("World\n");<RESET>
+	 }<RESET>
+	 <RESET>
+	<BRED>-int secure_foo(struct user *u)<RESET>
+	<BRED>-{<RESET>
+	<BOLD;RED>-if (!u->is_allowed_foo)<RESET>
+	<BOLD;RED>-return;<RESET>
+	<BRED>-foo(u);<RESET>
+	<BOLD;RED>-}<RESET>
+	<BOLD;RED>-<RESET>
+	 int main()<RESET>
+	 {<RESET>
+	 foo();<RESET>
+	<BOLD>diff --git a/test.c b/test.c<RESET>
+	<BOLD>index 1dc1d85..2bedec9 100644<RESET>
+	<BOLD>--- a/test.c<RESET>
+	<BOLD>+++ b/test.c<RESET>
+	<CYAN>@@ -4,6 +4,13 @@<RESET> <RESET>int bar()<RESET>
+	 printf("Hello World, but different\n");<RESET>
+	 }<RESET>
+	 <RESET>
+	<BGREEN>+<RESET><BGREEN>int secure_foo(struct user *u)<RESET>
+	<BGREEN>+<RESET><BGREEN>{<RESET>
+	<BOLD;GREEN>+<RESET><BOLD;GREEN>foo(u);<RESET>
+	<BGREEN>+<RESET><BGREEN>if (!u->is_allowed_foo)<RESET>
+	<BGREEN>+<RESET><BGREEN>return;<RESET>
+	<BOLD;GREEN>+<RESET><BOLD;GREEN>}<RESET>
+	<BOLD;GREEN>+<RESET>
+	 int another_function()<RESET>
+	 {<RESET>
+	 bar();<RESET>
+	EOF
+
+	test_cmp expected actual
+'
+
+test_expect_success 'move detection does not mess up colored words' '
+	cat <<-\EOF >text.txt &&
+	Lorem Ipsum is simply dummy text of the printing and typesetting industry.
+	EOF
+	git add text.txt &&
+	git commit -a -m "clean state" &&
+	cat <<-\EOF >text.txt &&
+	simply Lorem Ipsum dummy is text of the typesetting and printing industry.
+	EOF
+	git diff --color-moved --word-diff >actual &&
+	git diff --word-diff >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'move detection with submodules' '
+	test_create_repo bananas &&
+	echo ripe >bananas/recipe &&
+	git -C bananas add recipe &&
+	test_commit fruit &&
+	test_commit -C bananas recipe &&
+	git submodule add ./bananas &&
+	git add bananas &&
+	git commit -a -m "bananas are like a heavy library?" &&
+	echo foul >bananas/recipe &&
+	echo ripe >fruit.t &&
+
+	git diff --submodule=diff --color-moved >actual &&
+
+	# no move detection as the moved line is across repository boundaries.
+	test_decode_color <actual >decoded_actual &&
+	! grep BGREEN decoded_actual &&
+	! grep BRED decoded_actual &&
+
+	# nor did we mess with it another way
+	git diff --submodule=diff | test_decode_color >expect &&
+	test_cmp expect decoded_actual
+'
+
 test_done
-- 
2.13.0.18.g7d86cc8ba0
Previous: Stefan BellerNext: Stefan Beller
Message 125 of 128 in “Diff machine: highlight moved lines.”
  1. 00/19 Diff machine: highlight moved lines.Stefan Beller, May 14, 2017
  2. 01/19 diff: readability fixStefan Beller, May 14, 2017
  3. 02/19 diff: move line ending check into emit_hunk_headerStefan Beller, May 14, 2017
  4. Junio C HamanoMay 15, 2017
  5. Stefan BellerMay 15, 2017
  6. 06/19 diff: add emit_line_fmtStefan Beller, May 14, 2017
  7. Brandon WilliamsMay 15, 2017
  8. 03/19 diff.c: drop 'nofirst' from emit_line_0Stefan Beller, May 14, 2017
  9. Jonathan TanMay 15, 2017
  10. Stefan BellerMay 15, 2017
  11. Jonathan TanMay 16, 2017
  12. Brandon WilliamsMay 15, 2017
  13. Stefan BellerMay 15, 2017
  14. Brandon WilliamsMay 15, 2017
  15. 08/19 diff.c: convert builtin_diff to use emit_line_*Stefan Beller, May 14, 2017
  16. Jonathan TanMay 15, 2017
  17. 10/19 diff.c: convert emit_rewrite_lines to use emit_line_*Stefan Beller, May 14, 2017
  18. Jonathan TanMay 15, 2017
  19. Stefan BellerMay 15, 2017
  20. 07/19 diff.c: convert fn_out_consume to use emit_line_*Stefan Beller, May 14, 2017
  21. Junio C HamanoMay 16, 2017
  22. Junio C HamanoMay 16, 2017
  23. Stefan BellerMay 16, 2017
  24. 11/19 submodule.c: convert show_submodule_summary to use emit_line_fmtStefan Beller, May 14, 2017
  25. 17/19 diff.c: factor out emit_line_ws for coloring whitespacesStefan Beller, May 14, 2017
  26. 14/19 diff.c: convert word diffing to use emit_line_*Stefan Beller, May 14, 2017
  27. Jonathan TanMay 15, 2017
  28. Stefan BellerMay 15, 2017
  29. 18/19 diff: buffer all output if asked toStefan Beller, May 14, 2017
  30. Jeff KingMay 14, 2017
  31. Stefan BellerMay 14, 2017
  32. Jonathan TanMay 16, 2017
  33. Stefan BellerMay 16, 2017
  34. 19/19 diff.c: color moved lines differentlyStefan Beller, May 14, 2017
  35. Brandon WilliamsMay 15, 2017
  36. Jonathan TanMay 16, 2017
  37. Jeff KingMay 16, 2017
  38. 12/19 diff.c: convert emit_binary_diff_body to use emit_line_*Stefan Beller, May 14, 2017
  39. 16/19 diff.c: convert diff_summary to use emit_line_*Stefan Beller, May 14, 2017
  40. 13/19 diff.c: convert show_stats to use emit_line_*Stefan Beller, May 14, 2017
  41. 09/19 diff.c: convert emit_rewrite_diff to use emit_line_*Stefan Beller, May 14, 2017
  42. 15/19 diff.c: convert diff_flush to use emit_line_*Stefan Beller, May 14, 2017
  43. Jonathan TanMay 15, 2017
  44. Stefan BellerMay 15, 2017
  45. 04/19 diff.c: factor out diff_flush_patch_all_file_pairsStefan Beller, May 14, 2017
  46. 05/19 diff.c: emit_line_0 can handle no color settingStefan Beller, May 14, 2017
  47. Jonathan TanMay 15, 2017
  48. Stefan BellerMay 15, 2017
  49. Junio C HamanoMay 15, 2017
  50. Stefan BellerMay 15, 2017
  51. 00/20 Diff machine: highlight moved lines.Stefan Beller, May 17, 2017
  52. 01/20 diff: readability fixStefan Beller, May 17, 2017
  53. 02/20 diff: move line ending check into emit_hunk_headerStefan Beller, May 17, 2017
  54. 03/20 diff.c: factor out diff_flush_patch_all_file_pairsStefan Beller, May 17, 2017
  55. 04/20 diff.c: teach emit_line_0 to accept sign parameterStefan Beller, May 17, 2017
  56. 07/20 diff.c: inline emit_line_0 into emit_lineStefan Beller, May 17, 2017
  57. 11/20 diff.c: convert emit_rewrite_lines to use emit_line_*Stefan Beller, May 17, 2017
  58. Junio C HamanoMay 17, 2017
  59. Stefan BellerMay 17, 2017
  60. Junio C HamanoMay 18, 2017
  61. 14/20 diff.c: convert show_stats to use emit_line_*Stefan Beller, May 17, 2017
  62. 06/20 diff.c: emit_line_0 takes parameter whether to output line prefixStefan Beller, May 17, 2017
  63. 08/20 diff.c: convert fn_out_consume to use emit_lineStefan Beller, May 17, 2017
  64. 17/20 diff.c: convert diff_summary to use emit_line_*Stefan Beller, May 17, 2017
  65. 16/20 diff.c: convert diff_flush to use emit_line_*Stefan Beller, May 17, 2017
  66. 20/20 diff.c: color moved lines differentlyStefan Beller, May 17, 2017
  67. 12/20 submodule.c: convert show_submodule_summary to use emit_line_fmtStefan Beller, May 17, 2017
  68. Junio C HamanoMay 17, 2017
  69. Stefan BellerMay 17, 2017
  70. Junio C HamanoMay 18, 2017
  71. Stefan BellerMay 18, 2017
  72. Junio C HamanoMay 20, 2017
  73. Stefan BellerMay 20, 2017
  74. 18/20 diff.c: emit_line includes whitespace highlightingStefan Beller, May 17, 2017
  75. 05/20 diff.c: emit_line_0 can handle no color settingStefan Beller, May 17, 2017
  76. 19/20 diff: buffer all output if asked toStefan Beller, May 17, 2017
  77. 13/20 diff.c: convert emit_binary_diff_body to use emit_line_*Stefan Beller, May 17, 2017
  78. 15/20 diff.c: convert word diffing to use emit_line_*Stefan Beller, May 17, 2017
  79. 09/20 diff.c: convert builtin_diff to use emit_line_*Stefan Beller, May 17, 2017
  80. 10/20 diff.c: convert emit_rewrite_diff to use emit_line_*Stefan Beller, May 17, 2017
  81. 00/20 Diff machine: highlight moved lines.Stefan Beller, May 18, 2017
  82. 01/20 diff: readability fixStefan Beller, May 18, 2017
  83. 03/20 diff.c: factor out diff_flush_patch_all_file_pairsStefan Beller, May 18, 2017
  84. 02/20 diff: move line ending check into emit_hunk_headerStefan Beller, May 18, 2017
  85. 11/20 diff.c: convert emit_rewrite_lines to use emit_line_*Stefan Beller, May 18, 2017
  86. 09/20 diff.c: convert builtin_diff to use emit_line_*Stefan Beller, May 18, 2017
  87. 10/20 diff.c: convert emit_rewrite_diff to use emit_line_*Stefan Beller, May 18, 2017
  88. 13/20 diff.c: convert emit_binary_diff_body to use emit_line_*Stefan Beller, May 18, 2017
  89. 12/20 submodule.c: convert show_submodule_summary to use emit_line_fmtStefan Beller, May 18, 2017
  90. 17/20 diff.c: convert diff_summary to use emit_line_*Stefan Beller, May 18, 2017
  91. 20/20 diff.c: color moved lines differentlyStefan Beller, May 18, 2017
  92. Jonathan TanMay 19, 2017
  93. Stefan BellerMay 19, 2017
  94. Jonathan TanMay 19, 2017
  95. 19/20 diff: buffer all output if asked toStefan Beller, May 18, 2017
  96. 18/20 diff.c: emit_line includes whitespace highlightingStefan Beller, May 18, 2017
  97. 15/20 diff.c: convert word diffing to use emit_line_*Stefan Beller, May 18, 2017
  98. 16/20 diff.c: convert diff_flush to use emit_line_*Stefan Beller, May 18, 2017
  99. 08/20 diff.c: convert fn_out_consume to use emit_lineStefan Beller, May 18, 2017
  100. 14/20 diff.c: convert show_stats to use emit_line_*Stefan Beller, May 18, 2017
  101. 07/20 diff.c: inline emit_line_0 into emit_lineStefan Beller, May 18, 2017
  102. 06/20 diff.c: emit_line_0 takes parameter whether to output line prefixStefan Beller, May 18, 2017
  103. 05/20 diff.c: emit_line_0 can handle no color settingStefan Beller, May 18, 2017
  104. 04/20 diff.c: teach emit_line_0 to accept sign parameterStefan Beller, May 18, 2017
  105. Jonathan TanMay 18, 2017
  106. Stefan BellerMay 22, 2017
  107. 00/17 Diff machine: highlight moved lines.Stefan Beller, May 23, 2017
  108. 01/17 diff: readability fixStefan Beller, May 23, 2017
  109. 02/17 diff: move line ending check into emit_hunk_headerStefan Beller, May 23, 2017
  110. 05/17 diff.c: convert fn_out_consume to use emit_lineStefan Beller, May 23, 2017
  111. 06/17 diff.c: convert builtin_diff to use emit_line_*Stefan Beller, May 23, 2017
  112. 07/17 diff.c: convert emit_rewrite_diff to use emit_line_*Stefan Beller, May 23, 2017
  113. 08/17 diff.c: convert emit_rewrite_lines to use emit_line_*Stefan Beller, May 23, 2017
  114. 09/17 submodule.c: convert show_submodule_summary to use emit_line_fmtStefan Beller, May 23, 2017
  115. Junio C HamanoMay 23, 2017
  116. Stefan BellerMay 23, 2017
  117. 11/17 diff.c: convert show_stats to use emit_line_*Stefan Beller, May 23, 2017
  118. 10/17 diff.c: convert emit_binary_diff_body to use emit_line_*Stefan Beller, May 23, 2017
  119. 16/17 diff: buffer all output if asked toStefan Beller, May 23, 2017
  120. 14/17 diff.c: convert diff_summary to use emit_line_*Stefan Beller, May 23, 2017
  121. 15/17 diff.c: emit_line includes whitespace highlightingStefan Beller, May 23, 2017
  122. 13/17 diff.c: convert diff_flush to use emit_line_*Stefan Beller, May 23, 2017
  123. 12/17 diff.c: convert word diffing to use emit_line_*Stefan Beller, May 23, 2017
  124. 04/17 diff: introduce more flexible emit functionStefan Beller, May 23, 2017
  125. 17/17 diff.c: color moved lines differentlyStefan Beller, May 23, 2017
  126. 03/17 diff.c: factor out diff_flush_patch_all_file_pairsStefan Beller, May 23, 2017
  127. Jacob KellerMay 27, 2017
  128. Stefan BellerMay 30, 2017

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