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[PATCH v4 2/2] diff: add -I<regex> that ignores matching changes

From
Michał Kępień <michal@isc.org>
Date
Oct 20, 2020, 06:48 UTC
Message-ID
<20201020064809.14297-3-michal@isc.org>
In-Reply-To
<20201020064809.14297-1-michal@isc.org>

Add a new diff option that enables ignoring changes whose all lines (changed, removed, and added) match a given regular expression. This is similar to the -I/--ignore-matching-lines option in standalone diff utilities and can be used e.g. to ignore changes which only affect code comments or to look for unrelated changes in commits containing a large number of automatically applied modifications (e.g. a tree-wide string replacement). The difference between -G/-S and the new -I option is that the latter filters output on a per-change basis.

Use the 'ignore' field of xdchange_t for marking a change as ignored or not. Since the same field is used by --ignore-blank-lines, identical hunk emitting rules apply for --ignore-blank-lines and -I. These two options can also be used together in the same git invocation (they are complementary to each other).

Rename xdl_mark_ignorable() to xdl_mark_ignorable_lines(), to indicate that it is logically a "sibling" of xdl_mark_ignorable_regex() rather than its "parent".

Signed-off-by: Michał Kępień <michal@isc.org>
---
 Documentation/diff-options.txt             |  5 ++
 diff.c                                     | 23 +++++
 diff.h                                     |  4 +
 t/t4013-diff-various.sh                    | 41 +++++++++
 t/t4013/diff.log_-IA_-IB_-I1_-I2_-p_master | 99 ++++++++++++++++++++++
 xdiff/xdiff.h                              |  4 +
 xdiff/xdiffi.c                             | 47 +++++++++-
 7 files changed, 221 insertions(+), 2 deletions(-)
 create mode 100644 t/t4013/diff.log_-IA_-IB_-I1_-I2_-p_master
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 573fb9bb71..ee52b65e46 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -687,6 +687,11 @@ endif::git-format-patch[]
 --ignore-blank-lines::
 	Ignore changes whose lines are all blank.
 
+-I<regex>::
+--ignore-matching-lines=<regex>::
+	Ignore changes whose all lines match <regex>.  This option may
+	be specified more than once.
+
 --inter-hunk-context=<lines>::
 	Show the context between diff hunks, up to the specified number
 	of lines, thereby fusing hunks that are close to each other.
diff --git a/diff.c b/diff.c
index 2bb2f8f57e..d24f47df99 100644
--- a/diff.c
+++ b/diff.c
@@ -3587,6 +3587,8 @@ static void builtin_diff(const char *name_a,
 		if (header.len && !o->flags.suppress_diff_headers)
 			ecbdata.header = &header;
 		xpp.flags = o->xdl_opts;
+		xpp.ignore_regex = o->ignore_regex;
+		xpp.ignore_regex_nr = o->ignore_regex_nr;
 		xpp.anchors = o->anchors;
 		xpp.anchors_nr = o->anchors_nr;
 		xecfg.ctxlen = o->context;
@@ -3716,6 +3718,8 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
 		memset(&xpp, 0, sizeof(xpp));
 		memset(&xecfg, 0, sizeof(xecfg));
 		xpp.flags = o->xdl_opts;
+		xpp.ignore_regex = o->ignore_regex;
+		xpp.ignore_regex_nr = o->ignore_regex_nr;
 		xpp.anchors = o->anchors;
 		xpp.anchors_nr = o->anchors_nr;
 		xecfg.ctxlen = o->context;
@@ -5203,6 +5207,22 @@ static int diff_opt_patience(const struct option *opt,
 	return 0;
 }
 
+static int diff_opt_ignore_regex(const struct option *opt,
+				 const char *arg, int unset)
+{
+	struct diff_options *options = opt->value;
+	regex_t *regex;
+
+	BUG_ON_OPT_NEG(unset);
+	regex = xmalloc(sizeof(*regex));
+	if (regcomp(regex, arg, REG_EXTENDED | REG_NEWLINE))
+		return error(_("invalid regex given to -I: '%s'"), arg);
+	ALLOC_GROW(options->ignore_regex, options->ignore_regex_nr + 1,
+		   options->ignore_regex_alloc);
+	options->ignore_regex[options->ignore_regex_nr++] = regex;
+	return 0;
+}
+
 static int diff_opt_pickaxe_regex(const struct option *opt,
 				  const char *arg, int unset)
 {
@@ -5491,6 +5511,9 @@ static void prep_parse_options(struct diff_options *options)
 		OPT_BIT_F(0, "ignore-blank-lines", &options->xdl_opts,
 			  N_("ignore changes whose lines are all blank"),
 			  XDF_IGNORE_BLANK_LINES, PARSE_OPT_NONEG),
+		OPT_CALLBACK_F('I', "ignore-matching-lines", options, N_("<regex>"),
+			       N_("ignore changes whose all lines match <regex>"),
+			       0, diff_opt_ignore_regex),
 		OPT_BIT(0, "indent-heuristic", &options->xdl_opts,
 			N_("heuristic to shift diff hunk boundaries for easy reading"),
 			XDF_INDENT_HEURISTIC),
diff --git a/diff.h b/diff.h
index 11de52e9e9..a402227b80 100644
--- a/diff.h
+++ b/diff.h
@@ -234,6 +234,10 @@ struct diff_options {
 	 */
 	const char *pickaxe;
 
+	/* -I<regex> */
+	regex_t **ignore_regex;
+	size_t ignore_regex_nr, ignore_regex_alloc;
+
 	const char *single_follow;
 	const char *a_prefix, *b_prefix;
 	const char *line_prefix;
diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh
index 5c7b0122b4..f72d456d3b 100755
--- a/t/t4013-diff-various.sh
+++ b/t/t4013-diff-various.sh
@@ -6,6 +6,7 @@
 test_description='Various diff formatting options'
 
 . ./test-lib.sh
+. "$TEST_DIRECTORY"/diff-lib.sh
 
 test_expect_success setup '
 
@@ -333,6 +334,7 @@ log -SF master --max-count=2
 log -GF master
 log -GF -p master
 log -GF -p --pickaxe-all master
+log -IA -IB -I1 -I2 -p master
 log --decorate --all
 log --decorate=full --all
 
@@ -473,4 +475,43 @@ test_expect_success 'diff-tree --stdin with log formatting' '
 	test_cmp expect actual
 '
 
+test_expect_success 'diff -I<regex>: setup' '
+	git checkout master &&
+	test_seq 50 >file0 &&
+	git commit -m "Set up -I<regex> test file" file0 &&
+	test_seq 50 | sed -e "s/13/ten and three/" -e "/7\$/d" >file0 &&
+	echo >>file0
+'
+test_expect_success 'diff -I<regex>' '
+	git diff --ignore-blank-lines -I"ten.*e" -I"^[124-9]" >actual &&
+	cat >expect <<-\EOF &&
+	diff --git a/file0 b/file0
+	--- a/file0
+	+++ b/file0
+	@@ -34,7 +31,6 @@
+	 34
+	 35
+	 36
+	-37
+	 38
+	 39
+	 40
+	EOF
+	compare_diff_patch expect actual
+'
+
+test_expect_success 'diff -I<regex> --stat' '
+	git diff --stat --ignore-blank-lines -I"ten.*e" -I"^[124-9]" >actual &&
+	cat >expect <<-\EOF &&
+	 file0 | 1 -
+	 1 file changed, 1 deletion(-)
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'diff -I<regex>: detect malformed regex' '
+	test_expect_code 129 git diff --ignore-matching-lines="^[124-9" 2>error &&
+	test_i18ngrep "invalid regex given to -I: " error
+'
+
 test_done
diff --git a/t/t4013/diff.log_-IA_-IB_-I1_-I2_-p_master b/t/t4013/diff.log_-IA_-IB_-I1_-I2_-p_master
new file mode 100644
index 0000000000..929f35a05b
--- /dev/null
+++ b/t/t4013/diff.log_-IA_-IB_-I1_-I2_-p_master
@@ -0,0 +1,99 @@
+$ git log -IA -IB -I1 -I2 -p master
+commit 59d314ad6f356dd08601a4cd5e530381da3e3c64
+Merge: 9a6d494 c7a2ab9
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:04:00 2006 +0000
+
+    Merge branch 'side'
+
+commit c7a2ab9e8eac7b117442a607d5a9b3950ae34d5a
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:03:00 2006 +0000
+
+    Side
+
+diff --git a/file0 b/file0
+index 01e79c3..f4615da 100644
+--- a/file0
++++ b/file0
+@@ -1,3 +1,6 @@
+ 1
+ 2
+ 3
++A
++B
++C
+diff --git a/file3 b/file3
+new file mode 100644
+index 0000000..7289e35
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+diff --git a/dir/sub b/dir/sub
+index 8422d40..cead32e 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -2,3 +2,5 @@ A
+ B
+ C
+ D
++E
++F
+diff --git a/file1 b/file1
+new file mode 100644
+index 0000000..b1e6722
+--- /dev/null
++++ b/file1
+@@ -0,0 +1,3 @@
++A
++B
++C
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+diff --git a/dir/sub b/dir/sub
+index 35d242b..8422d40 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -1,2 +1,4 @@
+ A
+ B
++C
++D
+diff --git a/file0 b/file0
+index 01e79c3..b414108 100644
+--- a/file0
++++ b/file0
+@@ -1,3 +1,6 @@
+ 1
+ 2
+ 3
++4
++5
++6
+diff --git a/file2 b/file2
+deleted file mode 100644
+index 01e79c3..0000000
+--- a/file2
++++ /dev/null
+@@ -1,3 +0,0 @@
+-1
+-2
+-3
+
+commit 444ac553ac7612cc88969031b02b3767fb8a353a
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:00:00 2006 +0000
+
+    Initial
+$
diff --git a/xdiff/xdiff.h b/xdiff/xdiff.h
index 032e3a9f41..7a04605146 100644
--- a/xdiff/xdiff.h
+++ b/xdiff/xdiff.h
@@ -79,6 +79,10 @@ typedef struct s_mmbuffer {
 typedef struct s_xpparam {
 	unsigned long flags;
 
+	/* -I<regex> */
+	regex_t **ignore_regex;
+	size_t ignore_regex_nr;
+
 	/* See Documentation/diff-options.txt. */
 	char **anchors;
 	size_t anchors_nr;
diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
index bd035139f9..380eb728ed 100644
--- a/xdiff/xdiffi.c
+++ b/xdiff/xdiffi.c
@@ -998,7 +998,7 @@ static int xdl_call_hunk_func(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 	return 0;
 }
 
-static void xdl_mark_ignorable(xdchange_t *xscr, xdfenv_t *xe, long flags)
+static void xdl_mark_ignorable_lines(xdchange_t *xscr, xdfenv_t *xe, long flags)
 {
 	xdchange_t *xch;
 
@@ -1019,6 +1019,46 @@ static void xdl_mark_ignorable(xdchange_t *xscr, xdfenv_t *xe, long flags)
 	}
 }
 
+static int record_matches_regex(xrecord_t *rec, xpparam_t const *xpp) {
+	regmatch_t regmatch;
+	int i;
+
+	for (i = 0; i < xpp->ignore_regex_nr; i++)
+		if (!regexec_buf(xpp->ignore_regex[i], rec->ptr, rec->size, 1,
+				 &regmatch, 0))
+			return 1;
+
+	return 0;
+}
+
+static void xdl_mark_ignorable_regex(xdchange_t *xscr, const xdfenv_t *xe,
+				     xpparam_t const *xpp)
+{
+	xdchange_t *xch;
+
+	for (xch = xscr; xch; xch = xch->next) {
+		xrecord_t **rec;
+		int ignore = 1;
+		long i;
+
+		/*
+		 * Do not override --ignore-blank-lines.
+		 */
+		if (xch->ignore)
+			continue;
+
+		rec = &xe->xdf1.recs[xch->i1];
+		for (i = 0; i < xch->chg1 && ignore; i++)
+			ignore = record_matches_regex(rec[i], xpp);
+
+		rec = &xe->xdf2.recs[xch->i2];
+		for (i = 0; i < xch->chg2 && ignore; i++)
+			ignore = record_matches_regex(rec[i], xpp);
+
+		xch->ignore = ignore;
+	}
+}
+
 int xdl_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
 	     xdemitconf_t const *xecfg, xdemitcb_t *ecb) {
 	xdchange_t *xscr;
@@ -1038,7 +1078,10 @@ int xdl_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
 	}
 	if (xscr) {
 		if (xpp->flags & XDF_IGNORE_BLANK_LINES)
-			xdl_mark_ignorable(xscr, &xe, xpp->flags);
+			xdl_mark_ignorable_lines(xscr, &xe, xpp->flags);
+
+		if (xpp->ignore_regex)
+			xdl_mark_ignorable_regex(xscr, &xe, xpp);
 
 		if (ef(&xe, xscr, ecb, xecfg) < 0) {
 

-- 
2.28.0
Previous: Michał KępieńNext: Ævar Arnfjörð Bjarmason
Message 48 of 57 in “diff: add -I<regex> that ignores matching changes”
  1. 0/2 diff: add -I<regex> that ignores matching changesMichał Kępień, Oct 1, 2020
  2. 2/2 t: add -I<regex> testsMichał Kępień, Oct 1, 2020
  3. 1/2 diff: add -I<regex> that ignores matching changesMichał Kępień, Oct 1, 2020
  4. Junio C HamanoOct 1, 2020
  5. Michał KępieńOct 7, 2020
  6. Junio C HamanoOct 7, 2020
  7. Junio C HamanoOct 1, 2020
  8. 0/3 diff: add -I<regex> that ignores matching changesMichał Kępień, Oct 12, 2020
  9. 1/3 merge-base, xdiff: zero out xpparam_t structuresMichał Kępień, Oct 12, 2020
  10. Johannes SchindelinOct 12, 2020
  11. Junio C HamanoOct 12, 2020
  12. Junio C HamanoOct 12, 2020
  13. Michał KępieńOct 13, 2020
  14. 2/3 diff: add -I<regex> that ignores matching changesMichał Kępień, Oct 12, 2020
  15. Johannes SchindelinOct 12, 2020
  16. Junio C HamanoOct 12, 2020
  17. Johannes SchindelinOct 12, 2020
  18. Junio C HamanoOct 12, 2020
  19. Michał KępieńOct 13, 2020
  20. Junio C HamanoOct 13, 2020
  21. Michał KępieńOct 13, 2020
  22. Johannes SchindelinOct 13, 2020
  23. Junio C HamanoOct 13, 2020
  24. Michał KępieńOct 13, 2020
  25. Junio C HamanoOct 12, 2020
  26. Michał KępieńOct 13, 2020
  27. Junio C HamanoOct 12, 2020
  28. Michał KępieńOct 13, 2020
  29. 3/3 t: add -I<regex> testsMichał Kępień, Oct 12, 2020
  30. Johannes SchindelinOct 12, 2020
  31. Michał KępieńOct 13, 2020
  32. Johannes SchindelinOct 13, 2020
  33. Junio C HamanoOct 13, 2020
  34. Michał KępieńOct 13, 2020
  35. Johannes SchindelinOct 15, 2020
  36. 0/2 diff: add -I<regex> that ignores matching changesMichał Kępień, Oct 15, 2020
  37. 1/2 merge-base, xdiff: zero out xpparam_t structuresMichał Kępień, Oct 15, 2020
  38. 2/2 diff: add -I<regex> that ignores matching changesMichał Kępień, Oct 15, 2020
  39. Phillip WoodOct 16, 2020
  40. Junio C HamanoOct 16, 2020
  41. Michał KępieńOct 19, 2020
  42. Junio C HamanoOct 16, 2020
  43. Michał KępieńOct 19, 2020
  44. Junio C HamanoOct 19, 2020
  45. Johannes SchindelinOct 16, 2020
  46. 0/2 diff: add -I<regex> that ignores matching changesMichał Kępień, Oct 20, 2020
  47. 1/2 merge-base, xdiff: zero out xpparam_t structuresMichał Kępień, Oct 20, 2020
  48. 2/2 diff: add -I<regex> that ignores matching changesMichał Kępień, Oct 20, 2020
  49. 1/2 diff: add an API for deferred freeingÆvar Arnfjörð Bjarmason, Feb 5, 2021
  50. Johannes SchindelinFeb 10, 2021
  51. Ævar Arnfjörð BjarmasonFeb 11, 2021
  52. Johannes SchindelinFeb 11, 2021
  53. Jeff KingFeb 11, 2021
  54. 2/2 diff: plug memory leak from regcomp() on {log,diff} -IÆvar Arnfjörð Bjarmason, Feb 11, 2021
  55. 0/2 diff: add an API for deferred freeingÆvar Arnfjörð Bjarmason, Feb 11, 2021
  56. 1/2 diff: add an API for deferred freeingÆvar Arnfjörð Bjarmason, Feb 11, 2021
  57. 2/2 diff: plug memory leak from regcomp() on {log,diff} -IÆvar Arnfjörð Bjarmason, Feb 5, 2021

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