Subject: Re: [RFC PATCH] fast-export, fast-import: Let tags specify an internal name

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Wed, 21 Apr 2021 10:03:57 +0200

On Tue, Apr 20 2021, Luke Shumaker wrote:

> -static void handle_tag(const char *name, struct tag *tag)
> +static void handle_tag(const char *refname, struct tag *tag)
>  {
>  	unsigned long size;
>  	enum object_type type;
>  	char *buf;
> -	const char *tagger, *tagger_end, *message;
> +	const char *refbasename;
> +	const char *tagname, *tagname_end, *tagger, *tagger_end, *message;

Let's put the new "*tagname, *tagname_end" on its own line, the current
convention is to not conflate unrelated variable declarations on the
same line (as e.g. the existing "message" and "tagger" does.

>  	size_t message_size = 0;
>  	struct object *tagged;
>  	int tagged_mark;
> @@ -800,6 +801,11 @@ static void handle_tag(const char *name, struct tag *tag)
>  		message += 2;
>  		message_size = strlen(message);
>  	}
> +	tagname = memmem(buf, message ? message - buf : size, "\ntag ", 5);
> +	if (!tagname)
> +		die("malformed tag %s", oid_to_hex(&tag->object.oid));
> +	tagname += 5;
> +	tagname_end = strchrnul(tagname, '\n');

So it's no longer possible to export a reporitory with a missing "tag"
entry in a tag? Maybe OK, but we have an escape hatch for it with fsck,
we don't need one here?

In any case a test for it would be good to have.

> @@ -884,14 +890,19 @@ static void handle_tag(const char *name, struct tag *tag)
>  
>  	if (tagged->type == OBJ_TAG) {
>  		printf("reset %s\nfrom %s\n\n",
> -		       name, oid_to_hex(&null_oid));
> +		       refname, oid_to_hex(&null_oid));
>  	}
> -	skip_prefix(name, "refs/tags/", &name);
> -	printf("tag %s\n", name);
> +	refbasename = refname;
> +	skip_prefix(refbasename, "refs/tags/", &refbasename);
> +	printf("tag %s\n", refbasename);
>  	if (mark_tags) {
>  		mark_next_object(&tag->object);
>  		printf("mark :%"PRIu32"\n", last_idnum);
>  	}
> +	if ((size_t)(tagname_end - tagname) != strlen(refbasename) ||

Would be more readable IMO to have a temporary variable for that
"tagname_end - tagname", then just cast that and use it here.

> +	    strncmp(tagname, refbasename, (size_t)(tagname_end - tagname)))

and here.

> @@ -2803,6 +2803,13 @@ static void parse_new_tag(const char *arg)
>  	read_next_command();
>  	parse_mark();
>  
> +	/* name ... */
> +	if (skip_prefix(command_buf.buf, "name ", &v)) {
> +		name = strdupa(v);
> +		read_next_command();
> +	} else
> +		name = NULL;
> +

Skip this whole (stylistically incorrect, should have {}) and just
initialize it to NULL when you declare the variable?