Re: [PATCH 2/2] read-cache: fix an -Wmaybe-uninitialized warning

> For the purposes of this discussion, the ce_write_entry() function has
> three code blocks of interest, that look like so:
> 
>         /* block #1 */
>         if (ce->ce_flags & CE_STRIP_NAME) {
>                 saved_namelen = ce_namelen(ce);
>                 ce->ce_namelen = 0;
>         }
> 
>         /* block #2 */
>         /*
> 	 * several code blocks that contain, among others, calls
>          * to copy_cache_entry_to_ondisk(ondisk, ce);
>          */
> 
>         /* block #3 */
>         if (ce->ce_flags & CE_STRIP_NAME) {
>                 ce->ce_namelen = saved_namelen;
>                 ce->ce_flags &= ~CE_STRIP_NAME;
>         }
> 
> The warning implies that gcc thinks it is possible that the first
> block is not entered, the calls to copy_cache_entry_to_ondisk()
> could toggle the CE_STRIP_NAME flag on, thereby entering block #3
> with saved_namelen unset. However, the copy_cache_entry_to_ondisk()
> function does not write to ce->ce_flags (it only reads). gcc could
> easily determine this, since that function is local to this file,
> but it obviously doesn't.

> In order to suppress this warning, we make it clear to the reader
> (human and compiler), that block #3 will only be entered when the
> first block has been entered, by introducing a new 'stripped_name'
> boolean variable. We also take the opportunity to change the type
> of 'saved_namelen' to 'unsigned int' to match ce->ce_namelen.

> diff --git a/read-cache.c b/read-cache.c
> index 2eb81a66b..49607ddcd 100644
> --- a/read-cache.c
> +++ b/read-cache.c
> @@ -2104,13 +2104,15 @@ static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce,
>  			  struct strbuf *previous_name, struct ondisk_cache_entry *ondisk)
>  {
>  	int size;
> -	int saved_namelen = saved_namelen; /* compiler workaround */
>  	int result;
> +	unsigned int saved_namelen;
> +	int stripped_name = 0;