Subject: Re: [PATCH 2/2] fast-export: refactor get_tags_and_duplicates()

From: Junio C Hamano <[email-masked]>
Date: Tue, 03 Sep 2013 12:44:57 -0700

Felipe Contreras <[email-masked]> writes:

> Split into a separate helper function get_commit() so that the part that
> finds the relevant commit, and the part that does something with it
> (handle tag object, etc.) are in different places.
>
> No functional changes.

Actually, the old code used to use commit unchecked if e->item->type
said it is OBJ_COMMIT but e->item was somehow NULL.  The new code
checks this case and skips with a warning(), which I think is an
improvement, if not a bugfix (it only makes it easier to diagnose a
bug in the code that populates rev_cmdline_entry).

Thanks; will queue.

> Signed-off-by: Felipe Contreras <[email-masked]>
> ---
>  builtin/fast-export.c | 68 ++++++++++++++++++++++++++++-----------------------
>  1 file changed, 38 insertions(+), 30 deletions(-)
>
> diff --git a/builtin/fast-export.c b/builtin/fast-export.c
> index 957392c..03e1090 100644
> --- a/builtin/fast-export.c
> +++ b/builtin/fast-export.c
> @@ -485,9 +485,32 @@ static void handle_tag(const char *name, struct tag *tag)
>  	       (int)message_size, (int)message_size, message ? message : "");
>  }
>  
> +static struct commit *get_commit(struct rev_cmdline_entry *e, char *full_name)
> +{
> +	switch (e->item->type) {
> +	case OBJ_COMMIT:
> +		return (struct commit *)e->item;
> +	case OBJ_TAG: {
> +		struct tag *tag = (struct tag *)e->item;
> +
> +		/* handle nested tags */
> +		while (tag && tag->object.type == OBJ_TAG) {
> +			parse_object(tag->object.sha1);
> +			string_list_append(&extra_refs, full_name)->util = tag;
> +			tag = (struct tag *)tag->tagged;
> +		}
> +		if (!tag)
> +			die("Tag %s points nowhere?", e->name);
> +		return (struct commit *)tag;
> +		break;
> +	}
> +	default:
> +		return NULL;
> +	}
> +}
> +
>  static void get_tags_and_duplicates(struct rev_cmdline_info *info)
>  {
> -	struct tag *tag;
>  	int i;
>  
>  	for (i = 0; i < info->nr; i++) {
> @@ -502,41 +525,26 @@ static void get_tags_and_duplicates(struct rev_cmdline_info *info)
>  		if (dwim_ref(e->name, strlen(e->name), sha1, &full_name) != 1)
>  			continue;
>  
> -		switch (e->item->type) {
> -		case OBJ_COMMIT:
> -			commit = (struct commit *)e->item;
> -			break;
> -		case OBJ_TAG:
> -			tag = (struct tag *)e->item;
> -
> -			/* handle nested tags */
> -			while (tag && tag->object.type == OBJ_TAG) {
> -				parse_object(tag->object.sha1);
> -				string_list_append(&extra_refs, full_name)->util = tag;
> -				tag = (struct tag *)tag->tagged;
> -			}
> -			if (!tag)
> -				die ("Tag %s points nowhere?", e->name);
> -			switch(tag->object.type) {
> -			case OBJ_COMMIT:
> -				commit = (struct commit *)tag;
> -				break;
> -			case OBJ_BLOB:
> -				export_blob(tag->object.sha1);
> -				continue;
> -			default: /* OBJ_TAG (nested tags) is already handled */
> -				warning("Tag points to object of unexpected type %s, skipping.",
> -					typename(tag->object.type));
> -				continue;
> -			}
> -			break;
> -		default:
> +		commit = get_commit(e, full_name);
> +		if (!commit) {
>  			warning("%s: Unexpected object of type %s, skipping.",
>  				e->name,
>  				typename(e->item->type));
>  			continue;
>  		}
>  
> +		switch(commit->object.type) {
> +		case OBJ_COMMIT:
> +			break;
> +		case OBJ_BLOB:
> +			export_blob(commit->object.sha1);
> +			continue;
> +		default: /* OBJ_TAG (nested tags) is already handled */
> +			warning("Tag points to object of unexpected type %s, skipping.",
> +				typename(commit->object.type));
> +			continue;
> +		}
> +
>  		/*
>  		 * This ref will not be updated through a commit, lets make
>  		 * sure it gets properly updated eventually.