parse-options: recognize abbreviated negated option with arg

Giving an argument to an option that doesn't take one causes Git to
report that error specifically:

   $ git rm --dry-run=bogus
   error: option `dry-run' takes no value

The same is true when the option is negated or abbreviated:

   $ git rm --no-dry-run=bogus
   error: option `no-dry-run' takes no value

   $ git rm --dry=bogus
   error: option `dry-run' takes no value

Not so when doing both, though:

   $ git rm --no-dry=bogus
   error: unknown option `no-dry=bogus'
   usage: git rm [-f | --force] [-n] [-r] [--cached] [--ignore-unmatch]

(Rest of the usage message omitted.)

Improve consistency and usefulness of the error message by recognizing
abbreviated negated options even if they have a (most likely bogus)
argument.  With this patch we get:

   $ git rm --no-dry=bogus
   error: option `no-dry-run' takes no value

Signed-off-by: René Scharfe <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: rscharfe

parse-options.c

@@ -391,7 +391,7 @@ static enum parse_opt_result parse_long_opt(
 					ambiguous_option = abbrev_option;
 					ambiguous_flags = abbrev_flags;
 				}
-				if (!(flags & OPT_UNSET) && *arg_end)
+				if (*arg_end)
 					p->opt = arg_end + 1;
 				abbrev_option = options;
 				abbrev_flags = flags ^ opt_flags;
@@ -412,7 +412,8 @@ static enum parse_opt_result parse_long_opt(
 			if (!skip_prefix(arg + 3, long_name, &rest)) {
 				/* abbreviated and negated? */
 				if (allow_abbrev &&
-				    starts_with(long_name, arg + 3))
+				    !strncmp(long_name, arg + 3,
+					     arg_end - arg - 3))
 					goto is_abbreviated;
 				else
 					continue;

t/t0040-parse-options.sh

@@ -210,6 +210,22 @@ test_expect_success 'superfluous value provided: boolean' '
 	test_cmp expect actual
 '
 
+test_expect_success 'superfluous value provided: boolean, abbreviated' '
+	cat >expect <<-\EOF &&
+	error: option `yes'\'' takes no value
+	EOF
+	test_expect_code 129 env GIT_TEST_DISALLOW_ABBREVIATED_OPTIONS=false \
+	test-tool parse-options --ye=hi 2>actual &&
+	test_cmp expect actual &&
+
+	cat >expect <<-\EOF &&
+	error: option `no-yes'\'' takes no value
+	EOF
+	test_expect_code 129 env GIT_TEST_DISALLOW_ABBREVIATED_OPTIONS=false \
+	test-tool parse-options --no-ye=hi 2>actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'superfluous value provided: cmdmode' '
 	cat >expect <<-\EOF &&
 	error: option `mode1'\'' takes no value