Merge branch 'rs/parse-options-with-keep-unknown-abbrev-fix' into maint-2.43

"git diff --no-rename A B" did not disable rename detection but did
not trigger an error from the command line parser.

* rs/parse-options-with-keep-unknown-abbrev-fix:
  parse-options: simplify positivation handling
  parse-options: fully disable option abbreviation with PARSE_OPT_KEEP_UNKNOWN

parse-options.c

@@ -357,6 +357,7 @@ static enum parse_opt_result parse_long_opt(
 	const char *arg_end = strchrnul(arg, '=');
 	const struct option *abbrev_option = NULL, *ambiguous_option = NULL;
 	enum opt_parsed abbrev_flags = OPT_LONG, ambiguous_flags = OPT_LONG;
+	int allow_abbrev = !(p->flags & PARSE_OPT_KEEP_UNKNOWN_OPT);
 
 	for (; options->type != OPTION_END; options++) {
 		const char *rest, *long_name = options->long_name;
@@ -367,12 +368,16 @@ static enum parse_opt_result parse_long_opt(
 		if (!long_name)
 			continue;
 
-again:
+		if (!starts_with(arg, "no-") &&
+		    !(options->flags & PARSE_OPT_NONEG) &&
+		    skip_prefix(long_name, "no-", &long_name))
+			opt_flags |= OPT_UNSET;
+
 		if (!skip_prefix(arg, long_name, &rest))
 			rest = NULL;
 		if (!rest) {
 			/* abbreviated? */
-			if (!(p->flags & PARSE_OPT_KEEP_UNKNOWN_OPT) &&
+			if (allow_abbrev &&
 			    !strncmp(long_name, arg, arg_end - arg)) {
 is_abbreviated:
 				if (abbrev_option &&
@@ -396,22 +401,18 @@ is_abbreviated:
 			if (options->flags & PARSE_OPT_NONEG)
 				continue;
 			/* negated and abbreviated very much? */
-			if (starts_with("no-", arg)) {
+			if (allow_abbrev && starts_with("no-", arg)) {
 				flags |= OPT_UNSET;
 				goto is_abbreviated;
 			}
 			/* negated? */
-			if (!starts_with(arg, "no-")) {
-				if (skip_prefix(long_name, "no-", &long_name)) {
-					opt_flags |= OPT_UNSET;
-					goto again;
-				}
+			if (!starts_with(arg, "no-"))
 				continue;
-			}
 			flags |= OPT_UNSET;
 			if (!skip_prefix(arg + 3, long_name, &rest)) {
 				/* abbreviated and negated? */
-				if (starts_with(long_name, arg + 3))
+				if (allow_abbrev &&
+				    starts_with(long_name, arg + 3))
 					goto is_abbreviated;
 				else
 					continue;

t/t4013-diff-various.sh

@@ -663,4 +663,10 @@ test_expect_success 'diff --default-prefix overrides diff.mnemonicprefix' '
 	check_prefix actual a/file0 b/file0
 '
 
+test_expect_success 'diff --no-renames cannot be abbreviated' '
+	test_expect_code 129 git diff --no-rename >actual 2>error &&
+	test_must_be_empty actual &&
+	grep "invalid option: --no-rename" error
+'
+
 test_done