Merge branch 'jk/am-i-resolved-fix'

"git am -i --resolved" segfaulted after trying to see a commit as
if it were a tree, which has been corrected.

* jk/am-i-resolved-fix:
  am: fix --interactive HEAD tree resolution
  am: drop tty requirement for --interactive
  am: read interactive input from stdin
  am: simplify prompt response handling

builtin/am.c

@@ -1339,9 +1339,10 @@ static void write_index_patch(const struct am_state *state)
 	struct rev_info rev_info;
 	FILE *fp;
 
-	if (!get_oid_tree("HEAD", &head))
-		tree = lookup_tree(the_repository, &head);
-	else
+	if (!get_oid("HEAD", &head)) {
+		struct commit *commit = lookup_commit_or_die(&head, "HEAD");
+		tree = get_commit_tree(commit);
+	} else
 		tree = lookup_tree(the_repository,
 				   the_repository->hash_algo->empty_tree);
 
@@ -1643,11 +1644,8 @@ static int do_interactive(struct am_state *state)
 {
 	assert(state->msg);
 
-	if (!isatty(0))
-		die(_("cannot be interactive without stdin connected to a terminal."));
-
 	for (;;) {
-		const char *reply;
+		char reply[64];
 
 		puts(_("Commit Body is:"));
 		puts("--------------------------");
@@ -1659,11 +1657,11 @@ static int do_interactive(struct am_state *state)
 		 * in your translation. The program will only accept English
 		 * input at this point.
 		 */
-		reply = git_prompt(_("Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all: "), PROMPT_ECHO);
+		printf(_("Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all: "));
+		if (!fgets(reply, sizeof(reply), stdin))
+			die("unable to read from stdin; aborting");
 
-		if (!reply) {
-			continue;
-		} else if (*reply == 'y' || *reply == 'Y') {
+		if (*reply == 'y' || *reply == 'Y') {
 			return 0;
 		} else if (*reply == 'a' || *reply == 'A') {
 			state->interactive = 0;
@@ -2334,6 +2332,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 				argv_array_push(&paths, mkpath("%s/%s", prefix, argv[i]));
 		}
 
+		if (state.interactive && !paths.argc)
+			die(_("interactive mode requires patches on the command line"));
+
 		am_setup(&state, patch_format, paths.argv, keep_cr);
 
 		argv_array_clear(&paths);

t/t4257-am-interactive.sh

@@ -0,0 +1,52 @@
+#!/bin/sh
+
+test_description='am --interactive tests'
+. ./test-lib.sh
+
+test_expect_success 'set up patches to apply' '
+	test_commit unrelated &&
+	test_commit no-conflict &&
+	test_commit conflict-patch file patch &&
+	git format-patch --stdout -2 >mbox &&
+
+	git reset --hard unrelated &&
+	test_commit conflict-master file master base
+'
+
+# Sanity check our setup.
+test_expect_success 'applying all patches generates conflict' '
+	test_must_fail git am mbox &&
+	echo resolved >file &&
+	git add -u &&
+	git am --resolved
+'
+
+test_expect_success 'interactive am can apply a single patch' '
+	git reset --hard base &&
+	# apply the first, but not the second
+	test_write_lines y n | git am -i mbox &&
+
+	echo no-conflict >expect &&
+	git log -1 --format=%s >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'interactive am can resolve conflict' '
+	git reset --hard base &&
+	# apply both; the second one will conflict
+	test_write_lines y y | test_must_fail git am -i mbox &&
+	echo resolved >file &&
+	git add -u &&
+	# interactive "--resolved" will ask us if we want to apply the result
+	echo y | git am -i --resolved &&
+
+	echo conflict-patch >expect &&
+	git log -1 --format=%s >actual &&
+	test_cmp expect actual &&
+
+	echo resolved >expect &&
+	git cat-file blob HEAD:file >actual &&
+	test_cmp expect actual
+'
+
+test_done