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 option in standalone diff utilities and can be used
e.g. 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 at the same time.
Apart from adding a new field to struct diff_options, also define a new
flag, XDF_IGNORE_REGEX, for the 'xdl_opts' field of that structure.
This is done because the xpparam_t structure (which is used for passing
around the regular expression supplied to -I) is not zeroed out in all
call stacks involving xdl_diff() and thus only performing a NULL check
on xpp->ignore_regex could result in xdl_mark_ignorable_regex() treating
garbage on the stack as a regular expression. As the 'flags' field of
xpparam_t is initialized in all call stacks involving xdl_diff(), adding
a flag check avoids that problem.
Signed-off-by: Michał Kępień <michal@xxxxxxx>
---
Documentation/diff-options.txt | 3 +++
diff.c | 16 +++++++++++++++
diff.h | 2 ++
xdiff/xdiff.h | 2 ++
xdiff/xdiffi.c | 36 ++++++++++++++++++++++++++++++++++
5 files changed, 59 insertions(+)
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 573fb9bb71..a7ef3f5645 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -687,6 +687,9 @@ endif::git-format-patch[]
--ignore-blank-lines::
Ignore changes whose lines are all blank.
+-I<regex>::
+ Ignore changes whose all lines match <regex>.
+
--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..c9603c941e 100644
--- a/diff.c
+++ b/diff.c
@@ -3587,6 +3587,7 @@ 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.anchors = o->anchors;
xpp.anchors_nr = o->anchors_nr;
xecfg.ctxlen = o->context;
@@ -3716,6 +3717,7 @@ 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.anchors = o->anchors;
xpp.anchors_nr = o->anchors_nr;
xecfg.ctxlen = o->context;
@@ -5203,6 +5205,17 @@ 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;
+
+ BUG_ON_OPT_NEG(unset);
+ options->xdl_opts |= XDF_IGNORE_REGEX;
+ options->ignore_regex = arg;
+ return 0;
+}
+
static int diff_opt_pickaxe_regex(const struct option *opt,
const char *arg, int unset)
{
@@ -5491,6 +5504,9 @@ 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', NULL, 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 3de343270f..0b8871c0c1 100644
--- a/diff.h
+++ b/diff.h
@@ -234,6 +234,8 @@ struct diff_options {
*/
const char *pickaxe;
+ const char *ignore_regex;
+
const char *single_follow;
const char *a_prefix, *b_prefix;
const char *line_prefix;
diff --git a/xdiff/xdiff.h b/xdiff/xdiff.h
index 032e3a9f41..db28055a5e 100644
--- a/xdiff/xdiff.h
+++ b/xdiff/xdiff.h
@@ -40,6 +40,7 @@ extern "C" {
XDF_IGNORE_CR_AT_EOL)
#define XDF_IGNORE_BLANK_LINES (1 << 7)
+#define XDF_IGNORE_REGEX (1 << 8)
#define XDF_PATIENCE_DIFF (1 << 14)
#define XDF_HISTOGRAM_DIFF (1 << 15)
@@ -78,6 +79,7 @@ typedef struct s_mmbuffer {
typedef struct s_xpparam {
unsigned long flags;
+ const char *ignore_regex;
/* See Documentation/diff-options.txt. */
char **anchors;
diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
index bd035139f9..13f7ab95ac 100644
--- a/xdiff/xdiffi.c
+++ b/xdiff/xdiffi.c
@@ -1019,6 +1019,39 @@ static void xdl_mark_ignorable(xdchange_t *xscr, xdfenv_t *xe, long flags)
}
}
+static void
+xdl_mark_ignorable_regex(xdchange_t *xscr, const xdfenv_t *xe,
+ const char *ignore_regex)
+{
+ xdchange_t *xch;
+ regex_t regex;
+
+ if (regcomp(®ex, ignore_regex, REG_EXTENDED | REG_NEWLINE))
+ die("invalid regex: %s", ignore_regex);
+
+ for (xch = xscr; xch; xch = xch->next) {
+ regmatch_t regmatch;
+ xrecord_t **rec;
+ int ignore = 1;
+ long i;
+
+ rec = &xe->xdf1.recs[xch->i1];
+ for (i = 0; i < xch->chg1 && ignore; i++)
+ ignore = !regexec_buf(®ex, rec[i]->ptr, rec[i]->size,
+ 1, ®match, 0);
+
+ rec = &xe->xdf2.recs[xch->i2];
+ for (i = 0; i < xch->chg2 && ignore; i++)
+ ignore = !regexec_buf(®ex, rec[i]->ptr, rec[i]->size,
+ 1, ®match, 0);
+
+ /*
+ * Do not override --ignore-blank-lines.
+ */
+ 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;
@@ -1040,6 +1073,9 @@ int xdl_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
if (xpp->flags & XDF_IGNORE_BLANK_LINES)
xdl_mark_ignorable(xscr, &xe, xpp->flags);
+ if ((xpp->flags & XDF_IGNORE_REGEX) && xpp->ignore_regex)
+ xdl_mark_ignorable_regex(xscr, &xe, xpp->ignore_regex);
+
if (ef(&xe, xscr, ecb, xecfg) < 0) {
xdl_free_script(xscr);
--
2.28.0
