Merge branch 'rr/die-on-missing-upstream' into maint

When a reflog notation is used for implicit "current branch", we did
not say which branch, and worse said "branch ''".

* rr/die-on-missing-upstream:
  sha1_name: fix error message for @{<N>}, @{<date>}
  sha1_name: fix error message for @{u}

sha1_name.c

@@ -517,12 +517,21 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 		}
 		if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 				&co_time, &co_tz, &co_cnt)) {
+			if (!len) {
+				if (!prefixcmp(real_ref, "refs/heads/")) {
+					str = real_ref + 11;
+					len = strlen(real_ref + 11);
+				} else {
+					/* detached HEAD */
+					str = "HEAD";
+					len = 4;
+				}
+			}
 			if (at_time)
 				warning("Log for '%.*s' only goes "
 					"back to %s.", len, str,
 					show_date(co_time, co_tz, DATE_RFC2822));
 			else {
-				free(real_ref);
 				die("Log for '%.*s' only has %d entries.",
 				    len, str, co_cnt);
 			}
@@ -1033,14 +1042,15 @@ int interpret_branch_name(const char *name, struct strbuf *buf)
 	 * points to something different than a branch.
 	 */
 	if (!upstream)
-		return error(_("HEAD does not point to a branch"));
+		die(_("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'"),
+			die(_("No such branch: '%s'"), cp);
+		if (!upstream->merge) {
+			die(_("No upstream configured for branch '%s'"),
 				upstream->name);
-		return error(
+		}
+		die(
 			_("Upstream branch '%s' not stored as a remote-tracking branch"),
 			upstream->merge[0]->src);
 	}

t/t1507-rev-parse-upstream.sh

@@ -129,8 +129,7 @@ test_expect_success 'branch@{u} works when tracking a local branch' '
 
 test_expect_success 'branch@{u} error message when no upstream' '
 	cat >expect <<-EOF &&
-	error: No upstream configured for branch ${sq}non-tracking${sq}
-	fatal: Needed a single revision
+	fatal: No upstream configured for branch ${sq}non-tracking${sq}
 	EOF
 	error_message non-tracking@{u} 2>actual &&
 	test_i18ncmp expect actual
@@ -138,8 +137,7 @@ test_expect_success 'branch@{u} error message when no upstream' '
 
 test_expect_success '@{u} error message when no upstream' '
 	cat >expect <<-EOF &&
-	error: No upstream configured for branch ${sq}master${sq}
-	fatal: Needed a single revision
+	fatal: No upstream configured for branch ${sq}master${sq}
 	EOF
 	test_must_fail git rev-parse --verify @{u} 2>actual &&
 	test_i18ncmp expect actual
@@ -147,8 +145,7 @@ test_expect_success '@{u} error message when no upstream' '
 
 test_expect_success 'branch@{u} error message with misspelt branch' '
 	cat >expect <<-EOF &&
-	error: No such branch: ${sq}no-such-branch${sq}
-	fatal: Needed a single revision
+	fatal: No such branch: ${sq}no-such-branch${sq}
 	EOF
 	error_message no-such-branch@{u} 2>actual &&
 	test_i18ncmp expect actual
@@ -156,8 +153,7 @@ test_expect_success 'branch@{u} error message with misspelt branch' '
 
 test_expect_success '@{u} error message when not on a branch' '
 	cat >expect <<-EOF &&
-	error: HEAD does not point to a branch
-	fatal: Needed a single revision
+	fatal: HEAD does not point to a branch
 	EOF
 	git checkout HEAD^0 &&
 	test_must_fail git rev-parse --verify @{u} 2>actual &&
@@ -166,8 +162,7 @@ test_expect_success '@{u} error message when not on a branch' '
 
 test_expect_success 'branch@{u} error message if upstream branch not fetched' '
 	cat >expect <<-EOF &&
-	error: Upstream branch ${sq}refs/heads/side${sq} not stored as a remote-tracking branch
-	fatal: Needed a single revision
+	fatal: Upstream branch ${sq}refs/heads/side${sq} not stored as a remote-tracking branch
 	EOF
 	error_message bad-upstream@{u} 2>actual &&
 	test_i18ncmp expect actual