Merge branch 'dl/merge-autostash'

"git merge" learns the "--autostash" option.

* dl/merge-autostash: (22 commits)
  pull: pass --autostash to merge
  t5520: make test_pull_autostash() accept expect_parent_num
  merge: teach --autostash option
  sequencer: implement apply_autostash_oid()
  sequencer: implement save_autostash()
  sequencer: unlink autostash in apply_autostash()
  sequencer: extract perform_autostash() from rebase
  rebase: generify create_autostash()
  rebase: extract create_autostash()
  reset: extract reset_head() from rebase
  rebase: generify reset_head()
  rebase: use apply_autostash() from sequencer.c
  sequencer: rename stash_sha1 to stash_oid
  sequencer: make apply_autostash() accept a path
  rebase: use read_oneliner()
  sequencer: make read_oneliner() extern
  sequencer: configurably warn on non-existent files
  sequencer: make read_oneliner() accept flags
  sequencer: make file exists check more efficient
  sequencer: stop leaking buf
  ...

1 files changed, 129 insertions, 47 deletions

diff --git a/sequencer.c b/sequencer.c
index f30bb73c70..9d1b3e7d4f 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -32,6 +32,7 @@
 #include "alias.h"
 #include "commit-reach.h"
 #include "rebase-interactive.h"
+#include "reset.h"
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
@@ -419,25 +420,15 @@ static int write_message(const void *buf, size_t len, const char *filename,
 	return 0;
 }
 
-/*
- * Reads a file that was presumably written by a shell script, i.e. with an
- * end-of-line marker that needs to be stripped.
- *
- * Note that only the last end-of-line marker is stripped, consistent with the
- * behavior of "$(cat path)" in a shell script.
- *
- * Returns 1 if the file was read, 0 if it could not be read or does not exist.
- */
-static int read_oneliner(struct strbuf *buf,
-	const char *path, int skip_if_empty)
+int read_oneliner(struct strbuf *buf,
+	const char *path, unsigned flags)
 {
 	int orig_len = buf->len;
 
-	if (!file_exists(path))
-		return 0;
-
 	if (strbuf_read_file(buf, path, 0) < 0) {
-		warning_errno(_("could not read '%s'"), path);
+		if ((flags & READ_ONELINER_WARN_MISSING) ||
+		    (errno != ENOENT && errno != ENOTDIR))
+			warning_errno(_("could not read '%s'"), path);
 		return 0;
 	}
 
@@ -447,7 +438,7 @@ static int read_oneliner(struct strbuf *buf,
 		buf->buf[buf->len] = '\0';
 	}
 
-	if (skip_if_empty && buf->len == orig_len)
+	if ((flags & READ_ONELINER_SKIP_IF_EMPTY) && buf->len == orig_len)
 		return 0;
 
 	return 1;
@@ -2504,8 +2495,10 @@ static int read_populate_opts(struct replay_opts *opts)
 {
 	if (is_rebase_i(opts)) {
 		struct strbuf buf = STRBUF_INIT;
+		int ret = 0;
 
-		if (read_oneliner(&buf, rebase_path_gpg_sign_opt(), 1)) {
+		if (read_oneliner(&buf, rebase_path_gpg_sign_opt(),
+				  READ_ONELINER_SKIP_IF_EMPTY)) {
 			if (!starts_with(buf.buf, "-S"))
 				strbuf_reset(&buf);
 			else {
@@ -2515,7 +2508,8 @@ static int read_populate_opts(struct replay_opts *opts)
 			strbuf_reset(&buf);
 		}
 
-		if (read_oneliner(&buf, rebase_path_allow_rerere_autoupdate(), 1)) {
+		if (read_oneliner(&buf, rebase_path_allow_rerere_autoupdate(),
+				  READ_ONELINER_SKIP_IF_EMPTY)) {
 			if (!strcmp(buf.buf, "--rerere-autoupdate"))
 				opts->allow_rerere_auto = RERERE_AUTOUPDATE;
 			else if (!strcmp(buf.buf, "--no-rerere-autoupdate"))
@@ -2544,10 +2538,11 @@ static int read_populate_opts(struct replay_opts *opts)
 			opts->keep_redundant_commits = 1;
 
 		read_strategy_opts(opts, &buf);
-		strbuf_release(&buf);
+		strbuf_reset(&buf);
 
 		if (read_oneliner(&opts->current_fixups,
-				  rebase_path_current_fixups(), 1)) {
+				  rebase_path_current_fixups(),
+				  READ_ONELINER_SKIP_IF_EMPTY)) {
 			const char *p = opts->current_fixups.buf;
 			opts->current_fixup_count = 1;
 			while ((p = strchr(p, '\n'))) {
@@ -2557,12 +2552,16 @@ static int read_populate_opts(struct replay_opts *opts)
 		}
 
 		if (read_oneliner(&buf, rebase_path_squash_onto(), 0)) {
-			if (get_oid_hex(buf.buf, &opts->squash_onto) < 0)
-				return error(_("unusable squash-onto"));
+			if (get_oid_hex(buf.buf, &opts->squash_onto) < 0) {
+				ret = error(_("unusable squash-onto"));
+				goto done_rebase_i;
+			}
 			opts->have_squash_onto = 1;
 		}
 
-		return 0;
+done_rebase_i:
+		strbuf_release(&buf);
+		return ret;
 	}
 
 	if (!file_exists(git_path_opts_file()))
@@ -3677,25 +3676,71 @@ static enum todo_command peek_command(struct todo_list *todo_list, int offset)
 	return -1;
 }
 
-static int apply_autostash(struct replay_opts *opts)
+void create_autostash(struct repository *r, const char *path,
+		      const char *default_reflog_action)
+{
+	struct strbuf buf = STRBUF_INIT;
+	struct lock_file lock_file = LOCK_INIT;
+	int fd;
+
+	fd = repo_hold_locked_index(r, &lock_file, 0);
+	refresh_index(r->index, REFRESH_QUIET, NULL, NULL, NULL);
+	if (0 <= fd)
+		repo_update_index_if_able(r, &lock_file);
+	rollback_lock_file(&lock_file);
+
+	if (has_unstaged_changes(r, 1) ||
+	    has_uncommitted_changes(r, 1)) {
+		struct child_process stash = CHILD_PROCESS_INIT;
+		struct object_id oid;
+
+		argv_array_pushl(&stash.args,
+				 "stash", "create", "autostash", NULL);
+		stash.git_cmd = 1;
+		stash.no_stdin = 1;
+		strbuf_reset(&buf);
+		if (capture_command(&stash, &buf, GIT_MAX_HEXSZ))
+			die(_("Cannot autostash"));
+		strbuf_trim_trailing_newline(&buf);
+		if (get_oid(buf.buf, &oid))
+			die(_("Unexpected stash response: '%s'"),
+			    buf.buf);
+		strbuf_reset(&buf);
+		strbuf_add_unique_abbrev(&buf, &oid, DEFAULT_ABBREV);
+
+		if (safe_create_leading_directories_const(path))
+			die(_("Could not create directory for '%s'"),
+			    path);
+		write_file(path, "%s", oid_to_hex(&oid));
+		printf(_("Created autostash: %s\n"), buf.buf);
+		if (reset_head(r, NULL, "reset --hard",
+			       NULL, RESET_HEAD_HARD, NULL, NULL,
+			       default_reflog_action) < 0)
+			die(_("could not reset --hard"));
+
+		if (discard_index(r->index) < 0 ||
+			repo_read_index(r) < 0)
+			die(_("could not read index"));
+	}
+	strbuf_release(&buf);
+}
+
+static int apply_save_autostash_oid(const char *stash_oid, int attempt_apply)
 {
-	struct strbuf stash_sha1 = STRBUF_INIT;
 	struct child_process child = CHILD_PROCESS_INIT;
 	int ret = 0;
 
-	if (!read_oneliner(&stash_sha1, rebase_path_autostash(), 1)) {
-		strbuf_release(&stash_sha1);
-		return 0;
+	if (attempt_apply) {
+		child.git_cmd = 1;
+		child.no_stdout = 1;
+		child.no_stderr = 1;
+		argv_array_push(&child.args, "stash");
+		argv_array_push(&child.args, "apply");
+		argv_array_push(&child.args, stash_oid);
+		ret = run_command(&child);
 	}
-	strbuf_trim(&stash_sha1);
 
-	child.git_cmd = 1;
-	child.no_stdout = 1;
-	child.no_stderr = 1;
-	argv_array_push(&child.args, "stash");
-	argv_array_push(&child.args, "apply");
-	argv_array_push(&child.args, stash_sha1.buf);
-	if (!run_command(&child))
+	if (attempt_apply && !ret)
 		fprintf(stderr, _("Applied autostash.\n"));
 	else {
 		struct child_process store = CHILD_PROCESS_INIT;
@@ -3706,21 +3751,57 @@ static int apply_autostash(struct replay_opts *opts)
 		argv_array_push(&store.args, "-m");
 		argv_array_push(&store.args, "autostash");
 		argv_array_push(&store.args, "-q");
-		argv_array_push(&store.args, stash_sha1.buf);
+		argv_array_push(&store.args, stash_oid);
 		if (run_command(&store))
-			ret = error(_("cannot store %s"), stash_sha1.buf);
+			ret = error(_("cannot store %s"), stash_oid);
 		else
 			fprintf(stderr,
-				_("Applying autostash resulted in conflicts.\n"
+				_("%s\n"
 				  "Your changes are safe in the stash.\n"
 				  "You can run \"git stash pop\" or"
-				  " \"git stash drop\" at any time.\n"));
+				  " \"git stash drop\" at any time.\n"),
+				attempt_apply ?
+				_("Applying autostash resulted in conflicts.") :
+				_("Autostash exists; creating a new stash entry."));
 	}
 
-	strbuf_release(&stash_sha1);
 	return ret;
 }
 
+static int apply_save_autostash(const char *path, int attempt_apply)
+{
+	struct strbuf stash_oid = STRBUF_INIT;
+	int ret = 0;
+
+	if (!read_oneliner(&stash_oid, path,
+			   READ_ONELINER_SKIP_IF_EMPTY)) {
+		strbuf_release(&stash_oid);
+		return 0;
+	}
+	strbuf_trim(&stash_oid);
+
+	ret = apply_save_autostash_oid(stash_oid.buf, attempt_apply);
+
+	unlink(path);
+	strbuf_release(&stash_oid);
+	return ret;
+}
+
+int save_autostash(const char *path)
+{
+	return apply_save_autostash(path, 0);
+}
+
+int apply_autostash(const char *path)
+{
+	return apply_save_autostash(path, 1);
+}
+
+int apply_autostash_oid(const char *stash_oid)
+{
+	return apply_save_autostash_oid(stash_oid, 1);
+}
+
 static const char *reflog_message(struct replay_opts *opts,
 	const char *sub_action, const char *fmt, ...)
 {
@@ -3776,7 +3857,7 @@ static int checkout_onto(struct repository *r, struct replay_opts *opts,
 		return error(_("%s: not a valid OID"), orig_head);
 
 	if (run_git_checkout(r, opts, oid_to_hex(onto), action)) {
-		apply_autostash(opts);
+		apply_autostash(rebase_path_autostash());
 		sequencer_remove_state(opts);
 		return error(_("could not detach HEAD"));
 	}
@@ -4095,7 +4176,7 @@ cleanup_head_ref:
 				run_command(&hook);
 			}
 		}
-		apply_autostash(opts);
+		apply_autostash(rebase_path_autostash());
 
 		if (!opts->quiet) {
 			if (!opts->verbose)
@@ -4313,7 +4394,8 @@ int sequencer_continue(struct repository *r, struct replay_opts *opts)
 		struct strbuf buf = STRBUF_INIT;
 		struct object_id oid;
 
-		if (read_oneliner(&buf, rebase_path_stopped_sha(), 1) &&
+		if (read_oneliner(&buf, rebase_path_stopped_sha(),
+				  READ_ONELINER_SKIP_IF_EMPTY) &&
 		    !get_oid_committish(buf.buf, &oid))
 			record_in_rewritten(&oid, peek_command(&todo_list, 0));
 		strbuf_release(&buf);
@@ -5118,7 +5200,7 @@ int complete_action(struct repository *r, struct replay_opts *opts, unsigned fla
 		todo_list_add_exec_commands(todo_list, commands);
 
 	if (count_commands(todo_list) == 0) {
-		apply_autostash(opts);
+		apply_autostash(rebase_path_autostash());
 		sequencer_remove_state(opts);
 
 		return error(_("nothing to do"));
@@ -5129,12 +5211,12 @@ int complete_action(struct repository *r, struct replay_opts *opts, unsigned fla
 	if (res == -1)
 		return -1;
 	else if (res == -2) {
-		apply_autostash(opts);
+		apply_autostash(rebase_path_autostash());
 		sequencer_remove_state(opts);
 
 		return -1;
 	} else if (res == -3) {
-		apply_autostash(opts);
+		apply_autostash(rebase_path_autostash());
 		sequencer_remove_state(opts);
 		todo_list_release(&new_todo);