Hi Michał
Thanks for working on this, it will be a useful addition. Unfortunately
there's a use-after-free error see below
On 15/10/2020 08:24, Michał Kępień wrote:
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@xxxxxxx>
---
Documentation/diff-options.txt | 5 ++++
diff.c | 28 ++++++++++++++++++++
diff.h | 4 +++
t/t4013-diff-various.sh | 33 ++++++++++++++++++++++++
xdiff/xdiff.h | 4 +++
xdiff/xdiffi.c | 47 ++++++++++++++++++++++++++++++++--
6 files changed, 119 insertions(+), 2 deletions(-)
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..677de23352 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),
@@ -6405,6 +6428,11 @@ void diff_flush(struct diff_options *options)
DIFF_QUEUE_CLEAR(q);
if (options->close_file)
fclose(options->file);
+ for (i = 0; i < options->ignore_regex_nr; i++) {
+ regfree(options->ignore_regex[i]);
+ free(options->ignore_regex[i]);
+ }
+ free(options->ignore_regex);
If I run `git log -p -I foo` then the address sanitizer reports
AddressSanitizer: heap-use-after-free xdiff/xdiffi.c:1027 in
record_matches_regex
after it has printed the diff for the first commit. I think freeing the
regex here is the cause of the problem.
Best Wishes
Phillip
/*
* Report the content-level differences with HAS_CHANGES;
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..efaaee2ef0 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 '
@@ -473,4 +474,36 @@ test_expect_success 'diff-tree --stdin with log formatting' '
test_cmp expect actual
'
+test_expect_success 'diff -I<regex>' '
+ test_seq 50 >I.txt &&
+ sed -e "s/13/ten and three/" -e "/7\$/d" <I.txt >J.txt &&
+ echo >>J.txt &&
+
+ test_expect_code 1 git diff --no-index --ignore-blank-lines -I"ten.*e" -I"^[124-9]" I.txt J.txt >actual &&
+ cat >expect <<-\EOF &&
+ diff --git a/I.txt b/J.txt
+ --- a/I.txt
+ +++ b/J.txt
+ @@ -34,7 +31,6 @@
+ 34
+ 35
+ 36
+ -37
+ 38
+ 39
+ 40
+ EOF
+ compare_diff_patch expect actual &&
+
+ test_expect_code 1 git diff --stat --no-index --ignore-blank-lines -I"ten.*e" -I"^[124-9]" I.txt J.txt >actual &&
+ cat >expect <<-\EOF &&
+ I.txt => J.txt | 1 -
+ 1 file changed, 1 deletion(-)
+ EOF
+ test_cmp expect actual &&
+
+ test_expect_code 129 git diff --no-index --ignore-matching-lines="^[124-9]" --ignore-matching-lines="^[124-9" I.txt J.txt >output 2>&1 &&
+ test_i18ngrep "invalid regex given to -I: " output
+'
+
test_done
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,
+ ®match, 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) {
