Hi Paul,

On Fri, 31 Aug 2018, Paul-Sebastian Ungureanu wrote:

Maybe `q->queue[i]->one->path` would be okay, too? Dunno.

+		strbuf_addch(data, 0);

Neat trick. However, I had to study the code to see that the output of
this function will be fed to `update-index -z` to see why the NUL is
appended here. Maybe add a code comment here?

If you follow my suggestion to replace this magic `2` by a symbol that
describes the meaning "include all", then this line would need to be
changed, too.

+		setup_standard_excludes(&dir);
+
+	seen = xcalloc(ps.nr, 1);
+
+	max_len = fill_directory(&dir, the_repository->index, &ps);
+	for (i = 0; i < dir.nr; i++) {
+		struct dir_entry *ent = dir.entries[i];
+		if (!dir_path_match(&the_index, ent, &ps, max_len, seen)) {
+			free(ent);
+			continue;
+		}
+		strbuf_addf(out, "%s%c", ent->name, '\0');
+		free(ent);

This is a *very* minor nit pick... I would have written it this way
instead:

		if (dir_path_match(&the_index, ent, &ps, max_len, seen)) {
			strbuf_addstr(out, ent->name);
			/* NUL-terminate: will be fed to update-index -z */
			strbuf_addch(out, 0);
		}
		free(ent);

Just an idea...

+	}
+
+	free(dir.entries);
+	free(dir.ignored);
+	clear_directory(&dir);
+	free(seen);
+	return out->len;
+}

If you introduce a local variable `found` and increase it whenever a match
was found, then you could also handle `out == NULL` by skipping the
`strbuf_*()` calls, which would come in handin in the `check_changes()`
function that does not actually want to use the output.

+
+/*
+ * The return value of `check_changes()` can be:
+ *
+ * < 0 if there was an error
+ * = 0 if there are no changes.
+ * > 0 if there are changes.
+ */
+static int check_changes(struct pathspec ps, int include_untracked)
+{
+	int result;
+	int ret = 0;
+	struct rev_info rev;
+	struct object_id dummy;
+	struct strbuf out = STRBUF_INIT;
+
+	init_revisions(&rev, NULL);
+	rev.prune_data = ps;
+
+	rev.diffopt.flags.quick = 1;
+	rev.diffopt.flags.ignore_submodules = 1;
+	rev.abbrev = 0;
+
+	/* No initial commit. */
+	if (get_oid("HEAD", &dummy))
+		return -1;
+
+	add_head_to_pending(&rev);
+	diff_setup_done(&rev.diffopt);
+
+	if (read_cache() < 0)
+		return 1;
+	result = run_diff_index(&rev, 1);
+	if (diff_result_code(&rev.diffopt, result))
+		return 1;
+
+	object_array_clear(&rev.pending);
+	result = run_diff_files(&rev, 0);
+	if (diff_result_code(&rev.diffopt, result))
+		return 1;

These lines look familiar... Maybe call has_unstaged_changes() and
has_uncommitted_changes() here? (I have to admit that I have no idea what
those functions do with unborn branches.)

+
+	if (include_untracked && get_untracked_files(ps, include_untracked,
+						     &out)) {
+		strbuf_release(&out);
+		return 1;
+	}
+
+	strbuf_release(&out);
+	return 0;
+}
+
+static int save_untracked_files(struct stash_info *info, struct strbuf *msg,
+				struct strbuf *in)
+{
+	int ret = 0;
+	struct strbuf untracked_msg = STRBUF_INIT;
+	struct strbuf out = STRBUF_INIT;
+	struct child_process cp_upd_index = CHILD_PROCESS_INIT;
+	struct child_process cp_write_tree = CHILD_PROCESS_INIT;
+
+	cp_upd_index.git_cmd = 1;
+	argv_array_pushl(&cp_upd_index.args, "update-index", "-z", "--add",
+			 "--remove", "--stdin", NULL);
+	argv_array_pushf(&cp_upd_index.env_array, "GIT_INDEX_FILE=%s",
+			 stash_index_path.buf);
+
+	strbuf_addf(&untracked_msg, "untracked files on %s\n", msg->buf);
+	if (pipe_command(&cp_upd_index, in->buf, in->len, NULL, 0, NULL, 0)) {
+		ret = -1;
+		goto done;
+	}
+
+	cp_write_tree.git_cmd = 1;
+	argv_array_push(&cp_write_tree.args, "write-tree");
+	argv_array_pushf(&cp_write_tree.env_array, "GIT_INDEX_FILE=%s",
+			 stash_index_path.buf);
+	if (pipe_command(&cp_write_tree, NULL, 0, &out, 0,NULL, 0)) {
+		ret = -1;
+		goto done;
+	}
+	get_oid_hex(out.buf, &info->u_tree);
+
+	if (commit_tree(untracked_msg.buf, untracked_msg.len,
+			&info->u_tree, NULL, &info->u_commit, NULL, NULL)) {
+		ret = -1;
+		goto done;
+	}
+
+done:
+	strbuf_release(&untracked_msg);
+	strbuf_release(&out);
+	remove_path(stash_index_path.buf);
+	return ret;
+}
+
+static struct strbuf patch = STRBUF_INIT;

As far as I can see, this variable should be local to `stash_patch` (and
released at the end).

[Coming back after reading the shell script code and realizing that it
wrote the $TMP-patch file that is then used in `push_stash`]

Ah! So the output of `stash_patch()` is not just a return value indicating
success, but it also wants to return the patch. How about passing this in
via a parameter after `struct pathspec ps`, say, `struct strbuf
*out_patch`?

+
+static int stash_patch(struct stash_info *info, struct pathspec ps)
+{
+	int i;
+	int ret = 0;
+	struct strbuf out = STRBUF_INIT;
+	struct child_process cp_read_tree = CHILD_PROCESS_INIT;
+	struct child_process cp_add_i = CHILD_PROCESS_INIT;
+	struct child_process cp_write_tree = CHILD_PROCESS_INIT;
+	struct child_process cp_diff_tree = CHILD_PROCESS_INIT;
+
+	remove_path(stash_index_path.buf);
+
+	cp_read_tree.git_cmd = 1;
+	argv_array_pushl(&cp_read_tree.args, "read-tree", "HEAD", NULL);
+	argv_array_pushf(&cp_read_tree.env_array, "GIT_INDEX_FILE=%s",
+			 stash_index_path.buf);
+	if (run_command(&cp_read_tree)) {
+		ret = -1;
+		goto done;
+	}
+

Maybe insert the comment "find out what the user wants" here?

+	cp_add_i.git_cmd = 1;
+	argv_array_pushl(&cp_add_i.args, "add--interactive", "--patch=stash",
+			"--", NULL);
+	for (i = 0; i < ps.nr; ++i)
+		argv_array_push(&cp_add_i.args, ps.items[i].match);

I guess you could use `add_ps_items_to_argv_array(&cp_add_i.args, &ps)` here.

+	argv_array_pushf(&cp_add_i.env_array, "GIT_INDEX_FILE=%s",
+			 stash_index_path.buf);
+	if (run_command(&cp_add_i)) {
+		ret = -1;
+		goto done;
+	}
+

Maybe insert the comment "state of the working tree" here?

+	cp_write_tree.git_cmd = 1;
+	argv_array_push(&cp_write_tree.args, "write-tree");
+	argv_array_pushf(&cp_write_tree.env_array, "GIT_INDEX_FILE=%s",
+			 stash_index_path.buf);
+	if (pipe_command(&cp_write_tree, NULL, 0, &out, 0,NULL, 0)) {
+		ret = -1;
+		goto done;
+	}
+
+	get_oid_hex(out.buf, &info->w_tree);
+
+	cp_diff_tree.git_cmd = 1;
+	argv_array_pushl(&cp_diff_tree.args, "diff-tree", "-p", "HEAD",
+			 oid_to_hex(&info->w_tree), "--", NULL);
+	if (pipe_command(&cp_diff_tree, NULL, 0, &patch, 0, NULL, 0)) {
+		ret = -1;
+		goto done;
+	}
+
+	if (!patch.len) {
+		fprintf_ln(stderr, _("No changes selected"));
+		ret = 1;
+	}
+
+done:
+	strbuf_release(&out);
+	remove_path(stash_index_path.buf);
+	return ret;
+}
+
+static int stash_working_tree(struct stash_info *info, struct pathspec ps)
+{
+	int ret = 0;
+	struct child_process cp_upd_index = CHILD_PROCESS_INIT;
+	struct child_process cp_write_tree = CHILD_PROCESS_INIT;
+	struct strbuf out = STRBUF_INIT;
+	struct strbuf diff_output = STRBUF_INIT;
+	struct rev_info rev;
+
+	set_alternate_index_output(stash_index_path.buf);
+	if (reset_tree(&info->i_tree, 0, 0)) {

So this is the `git read-tree --index-output="$TMPindex" -m $i_tree` call.

At first, I thought that one of the zeros meant that the `merge` flag
would be turned off, but that is always turned on. Okay. (I guess
positional parameters make this a bit less readable, not your fault, but
C's.)

+		ret = -1;
+		goto done;
+	}
+	set_alternate_index_output(NULL);

Side note (i.e. rant): I wish this was more thread-safe. Granted, right
now it does not make sense to reset_tree() in parallel. But Stefan Beller
is working on being able to reset_tree() submodules, in which case
running reset_tree() in parallel will make a ton of sense.

+
+	git_config(git_diff_basic_config, NULL);

Is this not called in as part of `git_config(git_default_config, NULL);`
in cmd_stash() already?

*clicketyclick*

I guess not. But then, maybe it would make sense to run with
`git_diff_basic_config` from the get go, to avoid having to run
`git_config()` twice.

+	init_revisions(&rev, NULL);
+	rev.prune_data = ps;
+	rev.diffopt.output_format = DIFF_FORMAT_CALLBACK;
+	rev.diffopt.format_callback = add_diff_to_buf;
+	rev.diffopt.format_callback_data = &diff_output;
+
+	if (read_cache_preload(&rev.diffopt.pathspec) < 0) {
+		ret = -1;
+		goto done;
+	}
+
+	add_pending_object(&rev, parse_object(the_repository, &info->b_commit), "");
+	if (run_diff_index(&rev, 0)) {
+		ret = -1;
+		goto done;
+	}
+
+	cp_upd_index.git_cmd = 1;
+	argv_array_pushl(&cp_upd_index.args, "update-index", "-z", "--add",
+			 "--remove", "--stdin", NULL);
+	argv_array_pushf(&cp_upd_index.env_array, "GIT_INDEX_FILE=%s",
+			 stash_index_path.buf);
+
+	if (pipe_command(&cp_upd_index, diff_output.buf, diff_output.len,
+			 NULL, 0, NULL, 0)) {
+		ret = -1;
+		goto done;
+	}
+
+	cp_write_tree.git_cmd = 1;
+	argv_array_push(&cp_write_tree.args, "write-tree");
+	argv_array_pushf(&cp_write_tree.env_array, "GIT_INDEX_FILE=%s",
+			 stash_index_path.buf);
+	if (pipe_command(&cp_write_tree, NULL, 0, &out, 0,NULL, 0)) {
+		ret = -1;
+		goto done;
+	}
+
+	get_oid_hex(out.buf, &info->w_tree);
+
+done:
+	UNLEAK(rev);
+	strbuf_release(&out);
+	object_array_clear(&rev.pending);
+	strbuf_release(&diff_output);
+	remove_path(stash_index_path.buf);
+	return ret;
+}
+
+static int do_create_stash(struct pathspec ps, const char **stash_msg,

As the `stash_msg` will receive an allocated buffer that will need to be
released by the caller, this should be a `char **stash_msg` (no `const`).

+			   int include_untracked, int patch_mode,
+			   struct stash_info *info)
+{
+	int untracked_commit_option = 0;
+	int ret = 0;
+	int flags;
+	const char *head_short_sha1 = NULL;
+	const char *branch_ref = NULL;
+	const char *branch_name = "(no branch)";
+	struct commit *head_commit = NULL;
+	struct commit_list *parents = NULL;
+	struct strbuf msg = STRBUF_INIT;
+	struct strbuf commit_tree_label = STRBUF_INIT;
+	struct strbuf out = STRBUF_INIT;
+	struct strbuf stash_msg_buf = STRBUF_INIT;
+
+	read_cache_preload(NULL);
+	refresh_cache(REFRESH_QUIET);
+
+	if (!check_changes(ps, include_untracked)) {
+		ret = 1;
+		*stash_msg = NULL;
+		goto done;
+	}
+
+	if (get_oid("HEAD", &info->b_commit)) {
+		fprintf_ln(stderr, _("You do not have the initial commit yet"));
+		ret = -1;
+		*stash_msg = NULL;

Oh, so we actually do not even have to handle an unborn branch if we move
the `check_changes()` call after this block?

+		goto done;
+	} else {
+		head_commit = lookup_commit(the_repository, &info->b_commit);
+	}
+
+	branch_ref = resolve_ref_unsafe("HEAD", 0, NULL, &flags);
+	if (flags & REF_ISSYMREF)
+		branch_name = strrchr(branch_ref, '/') + 1;
+	head_short_sha1 = find_unique_abbrev(&head_commit->object.oid,
+					     DEFAULT_ABBREV);
+	strbuf_addf(&msg, "%s: %s ", branch_name, head_short_sha1);
+	pp_commit_easy(CMIT_FMT_ONELINE, head_commit, &msg);
+
+	strbuf_addf(&commit_tree_label, "index on %s\n", msg.buf);
+	commit_list_insert(head_commit, &parents);
+	if (write_cache_as_tree(&info->i_tree, 0, NULL) ||
+	    commit_tree(commit_tree_label.buf, commit_tree_label.len,
+			&info->i_tree, parents, &info->i_commit, NULL, NULL)) {
+		fprintf_ln(stderr, _("Cannot save the current index state"));
+		ret = -1;
+		*stash_msg = NULL;
+		goto done;
+	}
+
+	if (include_untracked && get_untracked_files(ps, include_untracked,
+						     &out)) {
+		if (save_untracked_files(info, &msg, &out)) {
+			fprintf_ln(stderr, _("Cannot save the untracked files"));
+			ret = -1;
+			*stash_msg = NULL;
+			goto done;
+		}
+		untracked_commit_option = 1;
+	}
+	if (patch_mode) {
+		ret = stash_patch(info, ps);
+		*stash_msg = NULL;
+		if (ret < 0) {
+			fprintf_ln(stderr, _("Cannot save the current worktree state"));
+			goto done;
+		} else if (ret > 0) {
+			goto done;
+		}
+	} else {
+		if (stash_working_tree(info, ps)) {
+			fprintf_ln(stderr, _("Cannot save the current worktree state"));
+			ret = -1;
+			*stash_msg = NULL;
+			goto done;
+		}
+	}
+
+	if (!*stash_msg || !strlen(*stash_msg))
+		strbuf_addf(&stash_msg_buf, "WIP on %s", msg.buf);
+	else
+		strbuf_addf(&stash_msg_buf, "On %s: %s", branch_name,
+			    *stash_msg);
+	*stash_msg = strbuf_detach(&stash_msg_buf, NULL);
+
+	/*
+	 * `parents` will be empty after calling `commit_tree()`, so there is
+	 * no need to call `free_commit_list()`

If it is empty, why do we need to set it to `NULL` explicitly?

+	 */
+	parents = NULL;
+	if (untracked_commit_option)
+		commit_list_insert(lookup_commit(the_repository, &info->u_commit), &parents);
+	commit_list_insert(lookup_commit(the_repository, &info->i_commit), &parents);
+	commit_list_insert(head_commit, &parents);
+
+	if (commit_tree(*stash_msg, strlen(*stash_msg), &info->w_tree,
+			parents, &info->w_commit, NULL, NULL)) {
+		fprintf_ln(stderr, _("Cannot record working tree state"));
+		ret = -1;
+		goto done;
+	}
+
+done:
+	strbuf_release(&commit_tree_label);
+	strbuf_release(&msg);
+	strbuf_release(&out);
+	strbuf_release(&stash_msg_buf);
+	return ret;
+}
+
+static int create_stash(int argc, const char **argv, const char *prefix)
+{
+	int include_untracked = 0;
+	int ret = 0;
+	const char *stash_msg = NULL;

As we are taking custody of the buffer here, `stash_msg` should be of type
`char *`, i.e. no `const`.

The rest of the patch looks good to me.

Phew! What a patch! This took quite a while to review, so I am taking a
break with this patch series here, and hope to continue in a few hours
from now.

Thanks,
Dscho