Re: [GSoC] [PATCH v2 1/2] submodule--helper: introduce add-clone subcommand

[Atharva Raykar <raykar.ath@gmail.com>]

On 08-Jun-2021, at 18:02, Đoàn Trần Công Danh <congdanhqx@gmail.com> wrote:
> 
>> [...]
>> +static char *get_next_line(char *const begin, const char *const end)
>> +{
>> +	char *pos = begin;
>> +	while (pos != end && *pos++ != '\n');
>> +	return pos;
>> +}
> 
> On my first glance, this function looks like a reinvention of strchr(3).
> Except that, this function also has a second parameter for "end".
> Maybe it has a specical use-case?
> 
>> +
>> +static void show_fetch_remotes(FILE *output, const char *sm_name, const char *git_dir_path)
>> +{
>> +	struct child_process cp_remote = CHILD_PROCESS_INIT;
>> +	struct strbuf sb_remote_out = STRBUF_INIT;
>> +
>> +	cp_remote.git_cmd = 1;
>> +	strvec_pushf(&cp_remote.env_array,
>> +		     "GIT_DIR=%s", git_dir_path);
>> +	strvec_push(&cp_remote.env_array, "GIT_WORK_TREE=.");
>> +	strvec_pushl(&cp_remote.args, "remote", "-v", NULL);
>> +	if (!capture_command(&cp_remote, &sb_remote_out, 0)) {
>> +		char *line;
>> +		char *begin = sb_remote_out.buf;
>> +		char *end = sb_remote_out.buf + sb_remote_out.len;
>> +		while (begin != end && (line = get_next_line(begin, end))) {
> 
> And this is the only use-case.  Because you also want to check if you
> reached the last token or not.  I guess you really meant to write:
> 
> 	while ((line = strchr(begin, '\n')) != NULL) {
> 
> Anyway, I would name the "line" variable as "nextline"
> 
>> +			int namelen = 0, urllen = 0, taillen = 0;
>> +			char *name = parse_token(&begin, line, &namelen);
>> +			char *url = parse_token(&begin, line, &urllen);
>> +			char *tail = parse_token(&begin, line, &taillen);
>> +			if (!memcmp(tail, "(fetch)", 7))
>> +				fprintf(output, "  %.*s\t%.*s\n",
>> +					namelen, name, urllen, url);
> 
> I think this whole block is better replaced with strip_suffix_mem and
> fprintf.
> 
> Overral I would replace the block inside capture_command with:
> 
> -----8<-----
> 	char *nextline;
> 	char *line = sb_remote_out.buf;
> 	while ((nextline = strchr(line, '\n')) != NULL) {
> 		size_t len = nextline - line;
> 		if (strip_suffix_mem(line, &len, "(fetch)"))
> 			fprintf(output, "  %.*s\n", (int)len, line);
> 		line = nextline + 1;
> 	}
> ---->8-----
> 
> And get rid of parse_token and get_next_line functions.

That looks much simpler. Thanks!

I realised that all the token parsing I do is not really necessary.
What I really want to do is "If this line ends with '(fetch)',
print it, but without the '(fetch)'", and I think your version
captures that succinctly.

>> +		}
>> +	}
>> +
>> +	strbuf_release(&sb_remote_out);
>> +}
>> +
>> +static int add_submodule(const struct add_data *add_data)
>> +{
>> +	char *submod_gitdir_path;
>> +	/* perhaps the path already exists and is already a git repo, else clone it */
>> +	if (is_directory(add_data->sm_path)) {
>> +		submod_gitdir_path = xstrfmt("%s/.git", add_data->sm_path);
>> +		if (is_directory(submod_gitdir_path) || file_exists(submod_gitdir_path))
>> +			printf(_("Adding existing path at '%s' to index\n"),
>> +			       add_data->sm_path);
>> +		else
>> +			die(_("'%s' already exists and is not a valid git repo"),
>> +			    add_data->sm_path);
>> +		free(submod_gitdir_path);
>> +	} else {
>> +		struct strvec clone_args = STRVEC_INIT;
>> +		struct child_process cp = CHILD_PROCESS_INIT;
>> +		submod_gitdir_path = xstrfmt(".git/modules/%s", add_data->sm_name);
>> +
>> +		if (is_directory(submod_gitdir_path)) {
>> +			if (!add_data->force) {
>> +				error(_("A git directory for '%s' is found "
>> +					"locally with remote(s):"), add_data->sm_name);
> 
> We don't capitalise first character of error message.
> IOW, downcase "A git".

Got it.

> Well, it's bug-for-bug with shell implementation, so it doesn't matter much, anyway.

While it is meant to be a faithful implementation, I think this
is a good opportunity to make minor style fixes.

>> +				show_fetch_remotes(stderr, add_data->sm_name,
>> +						   submod_gitdir_path);
>> +				fprintf(stderr,
>> +					_("If you want to reuse this local git "
>> +					  "directory instead of cloning again from\n"
>> +					  "  %s\n"
>> +					  "use the '--force' option. If the local git "
>> +					  "directory is not the correct repo\n"
>> +					  "or if you are unsure what this means, choose "
>> +					  "another name with the '--name' option.\n"),
>> +					add_data->realrepo);
> 
> Is there any reason we can't use "error" here?

The message in its entirety looks like this:

error: A git directory for 'test' is found locally with remote(s):
  origin	git@github.com:tfidfwastaken/abc.git
If you want to reuse this local git directory instead of cloning again from
  git@github.com:tfidfwastaken/test.git
use the '--force' option. If the local git directory is not the correct repo
or if you are unsure what this means, choose another name with the '--name' option.

Since the 'error:' is already there in the first line, having it
prepended before 'If you want to reuse...' felt redundant to me.

Besides, it's more of an informational message about what a user
can do next, rather than a message that signifies an error.

If there is a preferred convention or label for such messages,
I can use that. The shell version did not have any such thing though.

>> [...]
>> +	struct option options[] = {
>> +		OPT_STRING('b', "branch", &add_data.branch,
>> +			   N_("branch"),
>> +			   N_("branch of repository to checkout on cloning")),
>> +		OPT_STRING(0, "prefix", &add_data.prefix,
>> +			   N_("path"),
>> +			   N_("alternative anchor for relative paths")),
>> +		OPT_STRING(0, "path", &add_data.sm_path,
>> +			   N_("path"),
>> +			   N_("where the new submodule will be cloned to")),
>> +		OPT_STRING(0, "name", &add_data.sm_name,
>> +			   N_("string"),
>> +			   N_("name of the new submodule")),
>> +		OPT_STRING(0, "url", &add_data.realrepo,
>> +			   N_("string"),
>> +			   N_("url where to clone the submodule from")),
>> +		OPT_STRING(0, "reference", &add_data.reference_path,
>> +			   N_("repo"),
>> +			   N_("reference repository")),
>> +		OPT_BOOL(0, "dissociate", &dissociate,
>> +			 N_("use --reference only while cloning")),
>> +		OPT_INTEGER(0, "depth", &add_data.depth,
>> +			    N_("depth for shallow clones")),
>> +		OPT_BOOL(0, "progress", &progress,
>> +			 N_("force cloning progress")),
>> +		OPT_BOOL('f', "force", &force,
>> +			 N_("allow adding an otherwise ignored submodule path")),
> 
> We have OPT__FORCE, too.

Will switch over to that.

>> +		OPT__QUIET(&quiet, "Suppress output for cloning a submodule"),
> 
> And, please downcase "Suppress".

OK.

>> +		OPT_END()
>> +	};
>> +
>> +	const char *const usage[] = {
>> +		N_("git submodule--helper add-clone [--prefix=<path>] [--quiet] [--force] "
>> +		   "[--reference <repository>] [--depth <depth>] [-b|--branch <branch>]"
>> +		   "[--progress] [--dissociate] --url <url> --path <path> --name <name>"),
> 
> I think it's too crowded here, I guess it's better to write:
> 
> 	N_("git submodule--helper add-clone [<options>...] --url <url> --path <path> --name <name>"),

OK. It shouldn't be an issue to shorten it, because this is not
user-facing, and is only ever used within 'cmd_add()'.

>> +		NULL
>> +	};
>> +
>> +	argc = parse_options(argc, argv, prefix, options, usage, 0);
> 
> From above usage, I think url, path, name is required, should we have a check for them, here?

We could. The reason why I was not too rigorous about this is
because I plan to eliminate the shell interface for this helper
eventually and call add-clone from within C, in the next few
patches.

But this is a small ask, and I can just add a quick check just
to be extra safe, so I'll do it.

>> +
>> +	add_data.progress = !!progress;
>> +	add_data.dissociate = !!dissociate;
>> +	add_data.force = !!force;
>> +	add_data.quiet = !!quiet;
>> +
>> +	if (add_submodule(&add_data))
>> +		return 1;
>> +
>> +	return 0;
>> +}
>> +
>> #define SUPPORT_SUPER_PREFIX (1<<0)
>> 
>> struct cmd_struct {
>> @@ -2757,6 +2955,7 @@ static struct cmd_struct commands[] = {
>> 	{"list", module_list, 0},
>> 	{"name", module_name, 0},
>> 	{"clone", module_clone, 0},
>> +	{"add-clone", add_clone, 0},
>> 	{"update-module-mode", module_update_module_mode, 0},
>> 	{"update-clone", update_clone, 0},
>> 	{"ensure-core-worktree", ensure_core_worktree, 0},
>> diff --git a/git-submodule.sh b/git-submodule.sh
>> index 4678378424..f71e1e5495 100755
>> --- a/git-submodule.sh
>> +++ b/git-submodule.sh
>> @@ -241,43 +241,7 @@ cmd_add()
>> 		die "$(eval_gettext "'$sm_name' is not a valid submodule name")"
>> 	fi
>> 
>> -	# perhaps the path exists and is already a git repo, else clone it
>> -	if test -e "$sm_path"
>> -	then
>> -		if test -d "$sm_path"/.git || test -f "$sm_path"/.git
>> -		then
>> -			eval_gettextln "Adding existing repo at '\$sm_path' to the index"
>> -		else
>> -			die "$(eval_gettext "'\$sm_path' already exists and is not a valid git repo")"
>> -		fi
>> -
>> -	else
>> -		if test -d ".git/modules/$sm_name"
>> -		then
>> -			if test -z "$force"
>> -			then
>> -				eval_gettextln >&2 "A git directory for '\$sm_name' is found locally with remote(s):"
>> -				GIT_DIR=".git/modules/$sm_name" GIT_WORK_TREE=. git remote -v | grep '(fetch)' | sed -e s,^,"  ", -e s,' (fetch)',, >&2
>> -				die "$(eval_gettextln "\
>> -If you want to reuse this local git directory instead of cloning again from
>> -  \$realrepo
>> -use the '--force' option. If the local git directory is not the correct repo
>> -or you are unsure what this means choose another name with the '--name' option.")"
>> -			else
>> -				eval_gettextln "Reactivating local git directory for submodule '\$sm_name'."
>> -			fi
>> -		fi
>> -		git submodule--helper clone ${GIT_QUIET:+--quiet} ${progress:+"--progress"} --prefix "$wt_prefix" --path "$sm_path" --name "$sm_name" --url "$realrepo" ${reference:+"$reference"} ${dissociate:+"--dissociate"} ${depth:+"$depth"} || exit
>> -		(
>> -			sanitize_submodule_env
>> -			cd "$sm_path" &&
>> -			# ash fails to wordsplit ${branch:+-b "$branch"...}
>> -			case "$branch" in
>> -			'') git checkout -f -q ;;
>> -			?*) git checkout -f -q -B "$branch" "origin/$branch" ;;
>> -			esac
>> -		) || die "$(eval_gettext "Unable to checkout submodule '\$sm_path'")"
>> -	fi
>> +	git submodule--helper add-clone ${GIT_QUIET:+--quiet} ${force:+"--force"} ${progress:+"--progress"} ${branch:+--branch "$branch"} --prefix "$wt_prefix" --path "$sm_path" --name "$sm_name" --url "$realrepo" ${reference:+"$reference"} ${dissociate:+"--dissociate"} ${depth:+"$depth"} || exit
>> 	git config submodule."$sm_name".url "$realrepo"
>> 
>> 	git add --no-warn-embedded-repo $force "$sm_path" ||
>> -- 
>> 2.31.1
>> 
> 
> -- 
> Danh

Thanks for the comments!