diff: add -I<regex> that ignores matching changes

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>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 7987d72b0212e1247ff5ea14b553d4a322c1f5f5..012daf9452d83956d28aef368da7108dfe094d38 100644 (file)
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -681,6 +681,11 @@ 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 d24aaa304780b7105618434d80a76627e588d280..92e247fb83e0f24862ad829e78bd190794db547d 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -3584,6 +3584,8 @@ 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;
@@ -3711,6 +3713,8 @@ 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;
@@ -5174,6 +5178,22 @@ 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)
 {
@@ -5462,6 +5482,9 @@ 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 9443dc1b0039026ba6c32efd3e445fa61a0860f5..976f83e031555546cbebd87e2a797851e7b64af5 100644 (file)
--- 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 43267d6024fb70110634314d664a885ea477053c..585ceedb13a9149c94984b0d4e7ae4e7656b9a15 100755 (executable)
--- 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 '
 
@@ -309,6 +310,7 @@ 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
 
@@ -449,4 +451,43 @@ 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 (file)
index 0000000..929f35a
--- /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 032e3a9f41a2f79eaab78ae36666b8b6218b3899..7a046051468f9e7e804d9eb7f0bd7eeeba6727db 100644 (file)
--- 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 bd035139f954a61b5f3dc30d9fdedfbdb2a7972b..380eb728ed4ea579678195b66b856fb297b892cf 100644 (file)
--- 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) {