Re: [PATCH] find_pack_entry(): do not keep packed_git pointer locally

> Commit f7c22cc (always start looking up objects in the last used pack
> first - 2007-05-30) introduces a static packed_git* pointer as an
> optimization.  The kept pointer however may become invalid if
> free_pack_by_name() happens to free that particular pack.
>
> Current code base does not access packs after calling
> free_pack_by_name() so it should not be a problem. Anyway, move the
> pointer out so that free_pack_by_name() can reset it to avoid running
> into troubles in future.
>
> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> ---

> diff --git a/sha1_file.c b/sha1_file.c
> index 88f2151..4ecc953 100644
> --- a/sha1_file.c
> +++ b/sha1_file.c
> @@ -54,6 +54,8 @@ static struct cached_object empty_tree = {
>  	0
>  };
>  
> +static struct packed_git *find_pack_entry_last_found = (void *)1;
> +
>  static struct cached_object *find_cached_object(const unsigned char *sha1)
>  {
>  	int i;
> @@ -720,6 +722,8 @@ void free_pack_by_name(const char *pack_name)
>  			close_pack_index(p);
>  			free(p->bad_object_sha1);
>  			*pp = p->next;
> +			if (find_pack_entry_last_found == p)
> +				find_pack_entry_last_found = (void*)1;
>  			free(p);
>  			return;
>  		}
> @@ -2012,14 +2016,13 @@ int is_pack_valid(struct packed_git *p)
>  
>  static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
>  {
> -	static struct packed_git *last_found = (void *)1;
>  	struct packed_git *p;
>  	off_t offset;
>  
>  	prepare_packed_git();
>  	if (!packed_git)
>  		return 0;
> -	p = (last_found == (void *)1) ? packed_git : last_found;
> +	p = (find_pack_entry_last_found == (void *)1) ? packed_git : find_pack_entry_last_found;
>  
>  	do {
>  		if (p->num_bad_objects) {
> @@ -2046,16 +2049,16 @@ static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
>  			e->offset = offset;
>  			e->p = p;
>  			hashcpy(e->sha1, sha1);
> -			last_found = p;
> +			find_pack_entry_last_found = p;
>  			return 1;
>  		}
>  
>  		next:
> -		if (p == last_found)
> +		if (p == find_pack_entry_last_found)
>  			p = packed_git;
>  		else
>  			p = p->next;
> -		if (p == last_found)
> +		if (p == find_pack_entry_last_found)
>  			p = p->next;
>  	} while (p);
>  	return 0;