git checkout: do not allow switching to a tree-ish that is not a commit

diff --git a/builtin-rev-parse.c b/builtin-rev-parse.c
index a7860ed75ac4a7b1895bfe088e34a39b24448f57..9aa049ec170b0125fddde29adda3c720c8a7b8ee 100644 (file)
--- a/builtin-rev-parse.c
+++ b/builtin-rev-parse.c
@@ -241,6 +241,36 @@ static int try_difference(const char *arg)
        return 0;
 }
 
+static int try_parent_shorthands(const char *arg)
+{
+       char *dotdot;
+       unsigned char sha1[20];
+       struct commit *commit;
+       struct commit_list *parents;
+       int parents_only;
+
+       if ((dotdot = strstr(arg, "^!")))
+               parents_only = 0;
+       else if ((dotdot = strstr(arg, "^@")))
+               parents_only = 1;
+
+       if (!dotdot || dotdot[2])
+               return 0;
+
+       *dotdot = 0;
+       if (get_sha1(arg, sha1))
+               return 0;
+
+       if (!parents_only)
+               show_rev(NORMAL, sha1, arg);
+       commit = lookup_commit_reference(sha1);
+       for (parents = commit->parents; parents; parents = parents->next)
+               show_rev(parents_only ? NORMAL : REVERSED,
+                               parents->item->object.sha1, arg);
+
+       return 1;
+}
+
 static int parseopt_dump(const struct option *o, const char *arg, int unset)
 {
        struct strbuf *parsed = o->value;
@@ -268,7 +298,7 @@ static int cmd_parseopt(int argc, const char **argv, const char *prefix)
 {
        static int keep_dashdash = 0;
        static char const * const parseopt_usage[] = {
-               "git-rev-parse --parseopt [options] -- [<args>...]",
+               "git rev-parse --parseopt [options] -- [<args>...]",
                NULL
        };
        static struct option parseopt_opts[] = {
@@ -573,6 +603,8 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
                /* Not a flag argument */
                if (try_difference(arg))
                        continue;
+               if (try_parent_shorthands(arg))
+                       continue;
                name = arg;
                type = NORMAL;
                if (*arg == '^') {