diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 76cf05e2ad..17cbfabdde 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -643,8 +643,9 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 				filter &= ~(DO_FLAGS|DO_NOREV);
 				verify = 1;
 				abbrev = DEFAULT_ABBREV;
-				if (arg[7] == '=')
-					abbrev = strtoul(arg + 8, NULL, 10);
+				if (!arg[7])
+					continue;
+				abbrev = strtoul(arg + 8, NULL, 10);
 				if (abbrev < MINIMUM_ABBREV)
 					abbrev = MINIMUM_ABBREV;
 				else if (40 <= abbrev)
diff --git a/diff.c b/diff.c
index c6da383c56..cefc13eb8e 100644
--- a/diff.c
+++ b/diff.c
@@ -3399,7 +3399,7 @@ void diff_setup_done(struct diff_options *options)
 			 */
 			read_cache();
 	}
-	if (options->abbrev <= 0 || 40 < options->abbrev)
+	if (40 < options->abbrev)
 		options->abbrev = 40; /* full */
 
 	/*