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[PATCH v4 6/9] diff.c: add a blocks mode for moved code detection

From
Stefan Beller <sbeller@google.com>
Date
Jun 29, 2018, 00:19 UTC
Message-ID
<20180629001958.85143-7-sbeller@google.com>
In-Reply-To
<20180629001958.85143-1-sbeller@google.com>

The new "blocks" mode provides a middle ground between plain and zebra. It is as intuitive (few colors) as plain, but still has the requirement for a minimum of lines/characters to count a block as moved.

Suggested-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
 (https://public-inbox.org/git/87o9j0uljo.fsf@evledraar.gmail.com/)
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/diff-options.txt |  8 ++++--
 diff.c                         |  6 +++--
 diff.h                         |  5 ++--
 t/t4015-diff-whitespace.sh     | 49 ++++++++++++++++++++++++++++++++--
 4 files changed, 60 insertions(+), 8 deletions(-)
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index e3a44f03cdc..ba56169de31 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -276,10 +276,14 @@ plain::
 	that are added somewhere else in the diff. This mode picks up any
 	moved line, but it is not very useful in a review to determine
 	if a block of code was moved without permutation.
-zebra::
+blocks::
 	Blocks of moved text of at least 20 alphanumeric characters
 	are detected greedily. The detected blocks are
-	painted using either the 'color.diff.{old,new}Moved' color or
+	painted using either the 'color.diff.{old,new}Moved' color.
+	Adjacent blocks cannot be told apart.
+zebra::
+	Blocks of moved text are detected as in 'blocks' mode. The blocks
+	are painted using either the 'color.diff.{old,new}Moved' color or
 	'color.diff.{old,new}MovedAlternative'. The change between
 	the two colors indicates that a new block was detected.
 dimmed_zebra::
diff --git a/diff.c b/diff.c
index d1bae900cdc..95c51c0b7df 100644
--- a/diff.c
+++ b/diff.c
@@ -271,6 +271,8 @@ static int parse_color_moved(const char *arg)
 		return COLOR_MOVED_NO;
 	else if (!strcmp(arg, "plain"))
 		return COLOR_MOVED_PLAIN;
+	else if (!strcmp(arg, "blocks"))
+		return COLOR_MOVED_BLOCKS;
 	else if (!strcmp(arg, "zebra"))
 		return COLOR_MOVED_ZEBRA;
 	else if (!strcmp(arg, "default"))
@@ -278,7 +280,7 @@ static int parse_color_moved(const char *arg)
 	else if (!strcmp(arg, "dimmed_zebra"))
 		return COLOR_MOVED_ZEBRA_DIM;
 	else
-		return error(_("color moved setting must be one of 'no', 'default', 'zebra', 'dimmed_zebra', 'plain'"));
+		return error(_("color moved setting must be one of 'no', 'default', 'blocks', 'zebra', 'dimmed_zebra', 'plain'"));
 }
 
 int git_diff_ui_config(const char *var, const char *value, void *cb)
@@ -903,7 +905,7 @@ static void mark_color_as_moved(struct diff_options *o,
 
 		block_length++;
 
-		if (flipped_block)
+		if (flipped_block && o->color_moved != COLOR_MOVED_BLOCKS)
 			l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
 	}
 	adjust_last_block(o, n, block_length);
diff --git a/diff.h b/diff.h
index d29560f822c..7bd4f182c33 100644
--- a/diff.h
+++ b/diff.h
@@ -208,8 +208,9 @@ struct diff_options {
 	enum {
 		COLOR_MOVED_NO = 0,
 		COLOR_MOVED_PLAIN = 1,
-		COLOR_MOVED_ZEBRA = 2,
-		COLOR_MOVED_ZEBRA_DIM = 3,
+		COLOR_MOVED_BLOCKS = 2,
+		COLOR_MOVED_ZEBRA = 3,
+		COLOR_MOVED_ZEBRA_DIM = 4,
 	} color_moved;
 	#define COLOR_MOVED_DEFAULT COLOR_MOVED_ZEBRA
 	#define COLOR_MOVED_MIN_ALNUM_COUNT 20
diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index ddbc3901385..e54529f026d 100755
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -1223,7 +1223,7 @@ test_expect_success 'plain moved code, inside file' '
 	test_cmp expected actual
 '
 
-test_expect_success 'detect permutations inside moved code -- dimmed_zebra' '
+test_expect_success 'detect blocks of moved code' '
 	git reset --hard &&
 	cat <<-\EOF >lines.txt &&
 		long line 1
@@ -1271,6 +1271,50 @@ test_expect_success 'detect permutations inside moved code -- dimmed_zebra' '
 	test_config color.diff.newMovedDimmed "normal cyan" &&
 	test_config color.diff.oldMovedAlternativeDimmed "normal blue" &&
 	test_config color.diff.newMovedAlternativeDimmed "normal yellow" &&
+	git diff HEAD --no-renames --color-moved=blocks --color >actual.raw &&
+	grep -v "index" actual.raw | test_decode_color >actual &&
+	cat <<-\EOF >expected &&
+	<BOLD>diff --git a/lines.txt b/lines.txt<RESET>
+	<BOLD>--- a/lines.txt<RESET>
+	<BOLD>+++ b/lines.txt<RESET>
+	<CYAN>@@ -1,16 +1,16 @@<RESET>
+	<MAGENTA>-long line 1<RESET>
+	<MAGENTA>-long line 2<RESET>
+	<MAGENTA>-long line 3<RESET>
+	 line 4<RESET>
+	 line 5<RESET>
+	 line 6<RESET>
+	 line 7<RESET>
+	 line 8<RESET>
+	 line 9<RESET>
+	<CYAN>+<RESET><CYAN>long line 1<RESET>
+	<CYAN>+<RESET><CYAN>long line 2<RESET>
+	<CYAN>+<RESET><CYAN>long line 3<RESET>
+	<CYAN>+<RESET><CYAN>long line 14<RESET>
+	<CYAN>+<RESET><CYAN>long line 15<RESET>
+	<CYAN>+<RESET><CYAN>long line 16<RESET>
+	 line 10<RESET>
+	 line 11<RESET>
+	 line 12<RESET>
+	 line 13<RESET>
+	<MAGENTA>-long line 14<RESET>
+	<MAGENTA>-long line 15<RESET>
+	<MAGENTA>-long line 16<RESET>
+	EOF
+	test_cmp expected actual
+
+'
+
+test_expect_success 'detect permutations inside moved code -- dimmed_zebra' '
+	# reuse setup from test before!
+	test_config color.diff.oldMoved "magenta" &&
+	test_config color.diff.newMoved "cyan" &&
+	test_config color.diff.oldMovedAlternative "blue" &&
+	test_config color.diff.newMovedAlternative "yellow" &&
+	test_config color.diff.oldMovedDimmed "normal magenta" &&
+	test_config color.diff.newMovedDimmed "normal cyan" &&
+	test_config color.diff.oldMovedAlternativeDimmed "normal blue" &&
+	test_config color.diff.newMovedAlternativeDimmed "normal yellow" &&
 	git diff HEAD --no-renames --color-moved=dimmed_zebra --color >actual.raw &&
 	grep -v "index" actual.raw | test_decode_color >actual &&
 	cat <<-\EOF >expected &&
@@ -1669,7 +1713,8 @@ test_expect_success '--color-moved treats adjacent blocks as separate for MIN_AL
 	7charsA
 	EOF
 
-	git diff HEAD --color-moved=zebra --color --no-renames | grep -v "index" | test_decode_color >actual &&
+	git diff HEAD --color-moved=zebra --color --no-renames >actual.raw &&
+	grep -v "index" actual.raw | test_decode_color >actual &&
 	cat >expected <<-\EOF &&
 	<BOLD>diff --git a/bar b/bar<RESET>
 	<BOLD>--- a/bar<RESET>

-- 
2.18.0.399.gad0ab374a1-goog
Previous: Stefan BellerNext: Brandon Williams
Message 17 of 25 in “Moved code detection: ignore space on uniform indentation”
  1. 0/8 Moved code detection: ignore space on uniform indentationStefan Beller, Jun 22, 2018
  2. 1/8 xdiff/xdiff.h: remove unused flagsStefan Beller, Jun 22, 2018
  3. 2/8 xdiff/xdiffi.c: remove unneeded function declarationsStefan Beller, Jun 22, 2018
  4. 4/8 diff.c: adjust hash function signature to match hashmap expectationStefan Beller, Jun 22, 2018
  5. 5/8 diff.c: add a blocks mode for moved code detectionStefan Beller, Jun 22, 2018
  6. 3/8 diff.c: do not pass diff options as keydata to hashmapStefan Beller, Jun 22, 2018
  7. 6/8 diff.c: decouple white space treatment from move detection algorithmStefan Beller, Jun 22, 2018
  8. 7/8 diff.c: factor advance_or_nullify out of mark_color_as_movedStefan Beller, Jun 22, 2018
  9. 8/8 diff.c: add white space mode to move detection that allows indent changesStefan Beller, Jun 22, 2018
  10. SZEDER GáborJun 23, 2018
  11. Junio C HamanoJun 22, 2018
  12. 0/9 Moved code detection: ignore space on uniform indentationStefan Beller, Jun 29, 2018
  13. 1/9 xdiff/xdiff.h: remove unused flagsStefan Beller, Jun 29, 2018
  14. 2/9 xdiff/xdiffi.c: remove unneeded function declarationsStefan Beller, Jun 29, 2018
  15. 4/9 diff.c: do not pass diff options as keydata to hashmapStefan Beller, Jun 29, 2018
  16. 5/9 diff.c: adjust hash function signature to match hashmap expectationStefan Beller, Jun 29, 2018
  17. 6/9 diff.c: add a blocks mode for moved code detectionStefan Beller, Jun 29, 2018
  18. Brandon WilliamsJul 2, 2018
  19. 7/9 diff.c: decouple white space treatment from move detection algorithmStefan Beller, Jun 29, 2018
  20. Brandon WilliamsJul 2, 2018
  21. 3/9 t4015: avoid git as a pipe inputStefan Beller, Jun 29, 2018
  22. 8/9 diff.c: factor advance_or_nullify out of mark_color_as_movedStefan Beller, Jun 29, 2018
  23. 9/9 diff.c: add white space mode to move detection that allows indent changesStefan Beller, Jun 29, 2018
  24. Brandon WilliamsJul 2, 2018
  25. Stefan BellerJul 2, 2018

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