t4012: Break up pipe into serial redirections

diff --git a/sha1_name.c b/sha1_name.c
index aff224b2a0cbc955b05eb67119bf5b15d05e2d64..5d81ea0564c8d90b417eb8ec5ed8c32baa2c3ea3 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -856,10 +856,22 @@ int interpret_branch_name(const char *name, struct strbuf *buf)
        len = cp + tmp_len - name;
        cp = xstrndup(name, cp - name);
        upstream = branch_get(*cp ? cp : NULL);
-       if (!upstream
-           || !upstream->merge
-           || !upstream->merge[0]->dst)
-               return error("No upstream branch found for '%s'", cp);
+       /*
+        * Upstream can be NULL only if cp refers to HEAD and HEAD
+        * points to something different than a branch.
+        */
+       if (!upstream)
+               return error(_("HEAD does not point to a branch"));
+       if (!upstream->merge || !upstream->merge[0]->dst) {
+               if (!ref_exists(upstream->refname))
+                       return error(_("No such branch: '%s'"), cp);
+               if (!upstream->merge)
+                       return error(_("No upstream configured for branch '%s'"),
+                                    upstream->name);
+               return error(
+                       _("Upstream branch '%s' not stored as a remote-tracking branch"),
+                       upstream->merge[0]->src);
+       }
        free(cp);
        cp = shorten_unambiguous_ref(upstream->merge[0]->dst, 0);
        strbuf_reset(buf);