Re: [PATCH v3] fetch-pack: always allow fetching of literal SHA1s

[Jonathan Nieder <jrnieder@gmail.com>]

Hi,

Jonathan Tan wrote:

> fetch-pack, when fetching a literal SHA-1 from a server that is not
> configured with uploadpack.allowtipsha1inwant (or similar), always
> returns an error message of the form "Server does not allow request for
> unadvertised object %s". However, it is sometimes the case that such
> object is advertised. This situation would occur, for example, if a user
> or a script was provided a SHA-1 instead of a branch or tag name for
> fetching, and wanted to invoke "git fetch" or "git fetch-pack" using
> that SHA-1.

Yay, thanks again.

[...]
> --- a/fetch-pack.c
> +++ b/fetch-pack.c
> @@ -598,6 +598,7 @@ static void filter_refs(struct fetch_pack_args *args,
>  {
>  	struct ref *newlist = NULL;
>  	struct ref **newtail = &newlist;
> +	struct ref *unmatched = NULL;
>  	struct ref *ref, *next;
>  	int i;
>  
> @@ -631,13 +632,15 @@ static void filter_refs(struct fetch_pack_args *args,
>  			ref->next = NULL;
>  			newtail = &ref->next;
>  		} else {
> -			free(ref);
> +			ref->next = unmatched;
> +			unmatched = ref;

Interesting.  Makes sense.

[...]
>  	/* Append unmatched requests to the list */
>  	for (i = 0; i < nr_sought; i++) {
>  		unsigned char sha1[20];
> +		int can_append = 0;

Can this be simplified by factoring out a function?  I.e. something
like

	if ((... ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1)
	    || find_oid_among_refs(unmatched, oid)
	    || find_oid_among_refs(newlist, oid)) {
		ref->match_status = REF_MATCHED;
		...
	} else {
		ref->match_status = REF_UNADVERTISED_NOT_ALLOWED;
	}

[...]
> @@ -657,6 +679,11 @@ static void filter_refs(struct fetch_pack_args *args,
>  		}
>  	}
>  	*refs = newlist;
> +
> +	for (ref = unmatched; ref; ref = next) {
> +		next = ref->next;
> +		free(ref);
> +	}
>  }

optional nit: keeping the "*refs =" line as the last line of the
function would make it easier to see the contract at a glance.  (That
said, a doc comment at the top would make it even clearer.)

> --- a/t/t5500-fetch-pack.sh
> +++ b/t/t5500-fetch-pack.sh
> @@ -547,6 +547,41 @@ test_expect_success 'fetch-pack can fetch a raw sha1' '

Yay, thanks much for these.

[...]
> +test_expect_success 'fetch-pack can fetch a raw sha1 overlapping a named ref' '

Ha, you read my mind. :)

Except for the search-ref-list-for-oid function needing to be factored out,
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

Thanks.