Merge branch 'js/diff-filter-negation-fix'

"git diff --diff-filter=aR" is now parsed correctly.

* js/diff-filter-negation-fix:
  diff-filter: be more careful when looking for negative bits
  diff.c: move the diff filter bits definitions up a bit
  docs(diff): lose incorrect claim about `diff-files --diff-filter=A`

4 files changed, 60 insertions, 59 deletions

diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 7e27841a95..3674ac48e9 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -628,11 +628,8 @@ ifndef::git-format-patch[]
 Also, these upper-case letters can be downcased to exclude.  E.g.
 `--diff-filter=ad` excludes added and deleted paths.
 +
-Note that not all diffs can feature all types. For instance, diffs
-from the index to the working tree can never have Added entries
-(because the set of paths included in the diff is limited by what is in
-the index).  Similarly, copied and renamed entries cannot appear if
-detection for those types is disabled.
+Note that not all diffs can feature all types. For instance, copied and
+renamed entries cannot appear if detection for those types is disabled.
 
 -S<string>::
 	Look for differences that change the number of occurrences of
diff --git a/diff.c b/diff.c
index 32f0c01236..7d5cfd325e 100644
--- a/diff.c
+++ b/diff.c
@@ -4613,6 +4613,43 @@ void repo_diff_setup(struct repository *r, struct diff_options *options)
 	prep_parse_options(options);
 }
 
+static const char diff_status_letters[] = {
+	DIFF_STATUS_ADDED,
+	DIFF_STATUS_COPIED,
+	DIFF_STATUS_DELETED,
+	DIFF_STATUS_MODIFIED,
+	DIFF_STATUS_RENAMED,
+	DIFF_STATUS_TYPE_CHANGED,
+	DIFF_STATUS_UNKNOWN,
+	DIFF_STATUS_UNMERGED,
+	DIFF_STATUS_FILTER_AON,
+	DIFF_STATUS_FILTER_BROKEN,
+	'\0',
+};
+
+static unsigned int filter_bit['Z' + 1];
+
+static void prepare_filter_bits(void)
+{
+	int i;
+
+	if (!filter_bit[DIFF_STATUS_ADDED]) {
+		for (i = 0; diff_status_letters[i]; i++)
+			filter_bit[(int) diff_status_letters[i]] = (1 << i);
+	}
+}
+
+static unsigned filter_bit_tst(char status, const struct diff_options *opt)
+{
+	return opt->filter & filter_bit[(int) status];
+}
+
+unsigned diff_filter_bit(char status)
+{
+	prepare_filter_bits();
+	return filter_bit[(int) status];
+}
+
 void diff_setup_done(struct diff_options *options)
 {
 	unsigned check_mask = DIFF_FORMAT_NAME |
@@ -4726,6 +4763,12 @@ void diff_setup_done(struct diff_options *options)
 	if (!options->use_color || external_diff())
 		options->color_moved = 0;
 
+	if (options->filter_not) {
+		if (!options->filter)
+			options->filter = ~filter_bit[DIFF_STATUS_FILTER_AON];
+		options->filter &= ~options->filter_not;
+	}
+
 	FREE_AND_NULL(options->parseopts);
 }
 
@@ -4817,43 +4860,6 @@ static int parse_dirstat_opt(struct diff_options *options, const char *params)
 	return 1;
 }
 
-static const char diff_status_letters[] = {
-	DIFF_STATUS_ADDED,
-	DIFF_STATUS_COPIED,
-	DIFF_STATUS_DELETED,
-	DIFF_STATUS_MODIFIED,
-	DIFF_STATUS_RENAMED,
-	DIFF_STATUS_TYPE_CHANGED,
-	DIFF_STATUS_UNKNOWN,
-	DIFF_STATUS_UNMERGED,
-	DIFF_STATUS_FILTER_AON,
-	DIFF_STATUS_FILTER_BROKEN,
-	'\0',
-};
-
-static unsigned int filter_bit['Z' + 1];
-
-static void prepare_filter_bits(void)
-{
-	int i;
-
-	if (!filter_bit[DIFF_STATUS_ADDED]) {
-		for (i = 0; diff_status_letters[i]; i++)
-			filter_bit[(int) diff_status_letters[i]] = (1 << i);
-	}
-}
-
-static unsigned filter_bit_tst(char status, const struct diff_options *opt)
-{
-	return opt->filter & filter_bit[(int) status];
-}
-
-unsigned diff_filter_bit(char status)
-{
-	prepare_filter_bits();
-	return filter_bit[(int) status];
-}
-
 static int diff_opt_diff_filter(const struct option *option,
 				const char *optarg, int unset)
 {
@@ -4863,21 +4869,6 @@ static int diff_opt_diff_filter(const struct option *option,
 	BUG_ON_OPT_NEG(unset);
 	prepare_filter_bits();
 
-	/*
-	 * If there is a negation e.g. 'd' in the input, and we haven't
-	 * initialized the filter field with another --diff-filter, start
-	 * from full set of bits, except for AON.
-	 */
-	if (!opt->filter) {
-		for (i = 0; (optch = optarg[i]) != '\0'; i++) {
-			if (optch < 'a' || 'z' < optch)
-				continue;
-			opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
-			opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
-			break;
-		}
-	}
-
 	for (i = 0; (optch = optarg[i]) != '\0'; i++) {
 		unsigned int bit;
 		int negate;
@@ -4894,7 +4885,7 @@ static int diff_opt_diff_filter(const struct option *option,
 			return error(_("unknown change class '%c' in --diff-filter=%s"),
 				     optarg[i], optarg);
 		if (negate)
-			opt->filter &= ~bit;
+			opt->filter_not |= bit;
 		else
 			opt->filter |= bit;
 	}
diff --git a/diff.h b/diff.h
index ce9e2cf2e4..8ae18e5ab1 100644
--- a/diff.h
+++ b/diff.h
@@ -283,7 +283,7 @@ struct diff_options {
 	struct diff_flags flags;
 
 	/* diff-filter bits */
-	unsigned int filter;
+	unsigned int filter, filter_not;
 
 	int use_color;
 
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index dc884107de..a20d578349 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -142,6 +142,19 @@ test_expect_success 'diff-filter=R' '
 
 '
 
+test_expect_success 'multiple --diff-filter bits' '
+
+	git log -M --pretty="format:%s" --diff-filter=R HEAD >expect &&
+	git log -M --pretty="format:%s" --diff-filter=Ra HEAD >actual &&
+	test_cmp expect actual &&
+	git log -M --pretty="format:%s" --diff-filter=aR HEAD >actual &&
+	test_cmp expect actual &&
+	git log -M --pretty="format:%s" \
+		--diff-filter=a --diff-filter=R HEAD >actual &&
+	test_cmp expect actual
+
+'
+
 test_expect_success 'diff-filter=C' '
 
 	git log -C -C --pretty="format:%s" --diff-filter=C HEAD >actual &&