Merge branch 'ks/branch-list-detached-rebase-i'

"git branch --list" during an interrupted "rebase -i" now lets
users distinguish the case where a detached HEAD is being rebased
and a normal branch is being rebased.

* ks/branch-list-detached-rebase-i:
  t3200: verify "branch --list" sanity when rebasing from detached HEAD
  branch --list: print useful info whilst interactive rebasing a detached HEAD

ref-filter.c

@@ -1309,10 +1309,14 @@ char *get_head_description(void)
 	memset(&state, 0, sizeof(state));
 	wt_status_get_state(&state, 1);
 	if (state.rebase_in_progress ||
-	    state.rebase_interactive_in_progress)
-		strbuf_addf(&desc, _("(no branch, rebasing %s)"),
-			    state.branch);
-	else if (state.bisect_in_progress)
+	    state.rebase_interactive_in_progress) {
+		if (state.branch)
+			strbuf_addf(&desc, _("(no branch, rebasing %s)"),
+				    state.branch);
+		else
+			strbuf_addf(&desc, _("(no branch, rebasing detached HEAD %s)"),
+				    state.detached_from);
+	} else if (state.bisect_in_progress)
 		strbuf_addf(&desc, _("(no branch, bisect started on %s)"),
 			    state.branch);
 	else if (state.detached_from) {

t/t3200-branch.sh

@@ -6,6 +6,7 @@
 test_description='git branch assorted tests'
 
 . ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-rebase.sh
 
 test_expect_success 'prepare a trivial repository' '
 	echo Hello >A &&
@@ -1246,6 +1247,29 @@ test_expect_success '--merged is incompatible with --no-merged' '
 	test_must_fail git branch --merged HEAD --no-merged HEAD
 '
 
+test_expect_success '--list during rebase' '
+	test_when_finished "reset_rebase" &&
+	git checkout master &&
+	FAKE_LINES="1 edit 2" &&
+	export FAKE_LINES &&
+	set_fake_editor &&
+	git rebase -i HEAD~2 &&
+	git branch --list >actual &&
+	test_i18ngrep "rebasing master" actual
+'
+
+test_expect_success '--list during rebase from detached HEAD' '
+	test_when_finished "reset_rebase && git checkout master" &&
+	git checkout master^0 &&
+	oid=$(git rev-parse --short HEAD) &&
+	FAKE_LINES="1 edit 2" &&
+	export FAKE_LINES &&
+	set_fake_editor &&
+	git rebase -i HEAD~2 &&
+	git branch --list >actual &&
+	test_i18ngrep "rebasing detached HEAD $oid" actual
+'
+
 test_expect_success 'tracking with unexpected .fetch refspec' '
 	rm -rf a b c d &&
 	git init a &&