From 243e0614e0f8783599b20106b50eee56d0a17332 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Date: Mon, 5 Nov 2007 13:15:21 +0000
Subject: [PATCH] parse-options: abbreviation engine fix.

When an option could be an ambiguous abbreviation of two options, the code
used to error out.  Even if an exact match would have occured later.

Test and original patch by Pierre Habouzit.

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 parse-options.c          | 33 +++++++++++++++++++++------------
 t/t0040-parse-options.sh | 13 +++++++++++++
 test-parse-options.c     |  1 +
 3 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/parse-options.c b/parse-options.c
index cc09c98ec3..15b32f741b 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -119,8 +119,8 @@ static int parse_long_opt(struct optparse_t *p, const char *arg,
                           const struct option *options)
 {
 	const char *arg_end = strchr(arg, '=');
-	const struct option *abbrev_option = NULL;
-	int abbrev_flags = 0;
+	const struct option *abbrev_option = NULL, *ambiguous_option = NULL;
+	int abbrev_flags = 0, ambiguous_flags = 0;
 
 	if (!arg_end)
 		arg_end = arg + strlen(arg);
@@ -137,16 +137,16 @@ static int parse_long_opt(struct optparse_t *p, const char *arg,
 			/* abbreviated? */
 			if (!strncmp(options->long_name, arg, arg_end - arg)) {
 is_abbreviated:
-				if (abbrev_option)
-					return error("Ambiguous option: %s "
-						"(could be --%s%s or --%s%s)",
-						arg,
-						(flags & OPT_UNSET) ?
-							"no-" : "",
-						options->long_name,
-						(abbrev_flags & OPT_UNSET) ?
-							"no-" : "",
-						abbrev_option->long_name);
+				if (abbrev_option) {
+					/*
+					 * If this is abbreviated, it is
+					 * ambiguous. So when there is no
+					 * exact match later, we need to
+					 * error out.
+					 */
+					ambiguous_option = abbrev_option;
+					ambiguous_flags = abbrev_flags;
+				}
 				if (!(flags & OPT_UNSET) && *arg_end)
 					p->opt = arg_end + 1;
 				abbrev_option = options;
@@ -176,6 +176,15 @@ is_abbreviated:
 		}
 		return get_value(p, options, flags);
 	}
+
+	if (ambiguous_option)
+		return error("Ambiguous option: %s "
+			"(could be --%s%s or --%s%s)",
+			arg,
+			(ambiguous_flags & OPT_UNSET) ?  "no-" : "",
+			ambiguous_option->long_name,
+			(abbrev_flags & OPT_UNSET) ?  "no-" : "",
+			abbrev_option->long_name);
 	if (abbrev_option)
 		return get_value(p, abbrev_option, abbrev_flags);
 	return error("unknown option `%s'", arg);
diff --git a/t/t0040-parse-options.sh b/t/t0040-parse-options.sh
index ae49424aa0..462fdf262f 100755
--- a/t/t0040-parse-options.sh
+++ b/t/t0040-parse-options.sh
@@ -18,6 +18,7 @@ string options
     -s, --string <string>
                           get a string
     --string2 <str>       get another string
+    --st <st>             get another string (pervert ordering)
 
 EOF
 
@@ -90,4 +91,16 @@ test_expect_failure 'ambiguously abbreviated option' '
         test $? != 129
 '
 
+cat > expect << EOF
+boolean: 0
+integer: 0
+string: 123
+EOF
+
+test_expect_success 'non ambiguous option (after two options it abbreviates)' '
+	test-parse-options --st 123 > output 2> output.err &&
+	test ! -s output.err &&
+	git diff expect output
+'
+
 test_done
diff --git a/test-parse-options.c b/test-parse-options.c
index 277cfe4d6d..4d3e2ec39e 100644
--- a/test-parse-options.c
+++ b/test-parse-options.c
@@ -18,6 +18,7 @@ int main(int argc, const char **argv)
 		OPT_GROUP("string options"),
 		OPT_STRING('s', "string", &string, "string", "get a string"),
 		OPT_STRING(0, "string2", &string, "str", "get another string"),
+		OPT_STRING(0, "st", &string, "st", "get another string (pervert ordering)"),
 		OPT_END(),
 	};
 	int i;