[PATCH/RFC 3/4] Handle arg as revision first, then option.

[Kenny Lee Sin Cheong <kenny.lee28@gmail.com>]

Check the argument as a revision at first. If it fails, then tries to
check it as an option, and finally as a pathspec.

Returns -1 when we have an ambiguous revision range, such as
"master..next", to allow the argument to get checked as an option before
calling die() from verify_non_filename(). This is because we are
allowing "-" to be given in a revision range, but making the revision
check first. Otherwise, an ambiguous argument that starts with
"-" (let's say an option) would die even though its normal behaviour is
to silently return. Instead we check for ambiguity in a revision after
making sure that the argument cannot be parsed as an option.

This problem is discussed in:
http://article.gmane.org/gmane.comp.version-control.git/265672

Signed-off-by: Kenny Lee Sin Cheong <kenny.lee28@gmail.com>
---
 revision.c  | 61 +++++++++++++++++++++++++++++++++----------------------------
 sha1_name.c |  2 +-
 2 files changed, 34 insertions(+), 29 deletions(-)

diff --git a/revision.c b/revision.c
index 570945a..1ea290f 100644
--- a/revision.c
+++ b/revision.c
@@ -1516,7 +1516,10 @@ int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsi
 
 			if (!cant_be_filename) {
 				*dotdot = '.';
-				verify_non_filename(revs->prefix, arg);
+				if (is_inside_work_tree() && !is_inside_git_dir() &&
+				    check_filename(revs->prefix, arg)) {
+					return -1;
+				}
 			}
 
 			a_obj = parse_object(from_sha1);
@@ -2198,40 +2201,39 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 	read_from_stdin = 0;
 	for (left = i = 1; i < argc; i++) {
 		const char *arg = argv[i];
-		if (arg[0] == '-' && arg[1] && !starts_with(arg + 1, "..")) {
-			int opts;
-
-			opts = handle_revision_pseudo_opt(submodule,
-						revs, argc - i, argv + i,
-						&flags);
-			if (opts > 0) {
-				i += opts - 1;
-				continue;
-			}
+		if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
+			if (arg[0] == '-' && arg[1] && !starts_with(arg + 1, "..")) {
+				int opts;
+
+				opts = handle_revision_pseudo_opt(submodule,
+								  revs, argc - i, argv + i,
+								  &flags);
+				if (opts > 0) {
+					i += opts - 1;
+					continue;
+				}
 
-			if (!strcmp(arg, "--stdin")) {
-				if (revs->disable_stdin) {
-					argv[left++] = arg;
+				if (!strcmp(arg, "--stdin")) {
+					if (revs->disable_stdin) {
+						argv[left++] = arg;
+						continue;
+					}
+					if (read_from_stdin++)
+						die("--stdin given twice?");
+					read_revisions_from_stdin(revs, &prune_data);
 					continue;
 				}
-				if (read_from_stdin++)
-					die("--stdin given twice?");
-				read_revisions_from_stdin(revs, &prune_data);
-				continue;
-			}
 
-			opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
-			if (opts > 0) {
-				i += opts - 1;
+				opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
+				if (opts > 0) {
+					i += opts - 1;
+					continue;
+				}
+				if (opts < 0)
+					exit(128);
 				continue;
 			}
-			if (opts < 0)
-				exit(128);
-			continue;
-		}
-
 
-		if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
 			int j;
 			if (seen_dashdash || *arg == '^')
 				die("bad revision '%s'", arg);
@@ -2249,6 +2251,9 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 			break;
 		}
 		else
+			/* Make sure that a filename doesn't get interpreted as a revision */
+			if (!seen_dashdash)
+				verify_non_filename(revs->prefix, arg);
 			got_rev_arg = 1;
 	}
 
diff --git a/sha1_name.c b/sha1_name.c
index 7a621ba..b99b1dc 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -483,7 +483,7 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1,
 				break;
 			}
 		}
-	} else if (len == 1 && str[0] == '-') {
+	} else if (len == 1 && str[0] == '-' && !str[1]) {
 		nth_prior = 1;
 	}
 
-- 
2.3.3.203.g8ffb468.dirty