From: Omar Polo <op@omarpolo.com>
Subject: Re: fix capabilities sent by gotsh if no refs exist
To: Stefan Sperling <stsp@stsp.name>
Cc: gameoftrees@openbsd.org
Date: Tue, 08 Nov 2022 17:50:40 +0100

On 2022/11/07 21:36:13 +0100, Stefan Sperling <stsp@stsp.name> wrote:
> If the repository contains no references we announce capabilities via
> send_zero_refs(). This function does not yet handle the repo_write case,
> resulting in invalid capabilities being announced to the client.
> 
> In particular, we do not announce the 'report' capability but send reports
> regardless, which results in an "unexpected message from server" error
> being reported by got clone/fetch.
> 
> ok?

sure, ok

you could factor the two if (err) after the outer if and save some
braces.

> diff 593af7bd3baeb8314b7ef9a11fe0559a6ba9557d 5a3cf3b6bde9a6f3b33391a2229d7a6870417361
> commit - 593af7bd3baeb8314b7ef9a11fe0559a6ba9557d
> commit + 5a3cf3b6bde9a6f3b33391a2229d7a6870417361
> blob - 85ee3e8503a054b2d587e80262d305695c1c8449
> blob + b8131d3c9afbbd434818c6c64743b9be8d7edf13
> --- lib/serve.c
> +++ lib/serve.c
> @@ -220,7 +220,7 @@ send_zero_refs(int outfd, int chattygot)
>  }
>  
>  static const struct got_error *
> -send_zero_refs(int outfd, int chattygot)
> +send_zero_refs(int outfd, int client_is_reading, int chattygot)
>  {
>  	const struct got_error *err = NULL;
>  	char buf[GOT_PKT_MAX];
> @@ -237,10 +237,18 @@ send_zero_refs(int outfd, int chattygot)
>  	if (len >= sizeof(buf))
>  		return got_error(GOT_ERR_NO_SPACE);
>  
> -	err = got_gitproto_append_capabilities(&capalen, buf, len,
> -	    sizeof(buf), read_capabilities, nitems(read_capabilities));
> -	if (err)
> -		return err;
> +	if (client_is_reading) {
> +		err = got_gitproto_append_capabilities(&capalen, buf, len,
> +		    sizeof(buf), read_capabilities, nitems(read_capabilities));
> +		if (err)
> +			return err;
> +	} else {
> +		err = got_gitproto_append_capabilities(&capalen, buf, len,
> +		    sizeof(buf), write_capabilities,
> +		    nitems(write_capabilities));
> +		if (err)
> +			return err;
> +	}
>  
>  	return got_pkt_writepkt(outfd, buf, len + capalen, chattygot);
>  }
> @@ -315,7 +323,8 @@ announce_refs(int outfd, struct imsgbuf *ibuf, int cli
>  			nrefs = ireflist.nrefs;
>  			have_nrefs = 1;
>  			if (nrefs == 0)
> -				err = send_zero_refs(outfd, chattygot);
> +				err = send_zero_refs(outfd, client_is_reading,
> +				    chattygot);
>  			break;
>  		case GOTD_IMSG_REF:
>  			if (!have_nrefs || nrefs == 0) {