Re: [PATCH 1/5] connect: split git:// setup into a separate function

From: Junio C Hamano <gitster@pobox.com>
Date: Oct 24, 2017, 01:44 UTC
Message-ID: <xmqqpo9d9v5y.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20171023231703.f457jp43dh7fddpv@aiede.mtv.corp.google.com>

Jonathan Nieder <jrnieder@gmail.com> writes:

Show 10 quoted lines

> The git_connect function is growing long.  Split the
> PROTO_GIT-specific portion to a separate function to make it easier to
> read.
>
> No functional change intended.
>
> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
> Reviewed-by: Stefan Beller <sbeller@google.com>
> ---
> As before, except with sbeller's Reviewed-by.

I found this quite nice, except for one thing.

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> +/*
> + * Open a connection using Git's native protocol.
> + *
> + * The caller is responsible for freeing hostandport, but this function may
> + * modify it (for example, to truncate it to remove the port part).
> + */
> +static struct child_process *git_connect_git(int fd[2], char *hostandport,
> +					     const char *path, const char *prog,
> +					     int flags)
> +{
> +	struct child_process *conn = &no_fork;
> +	struct strbuf request = STRBUF_INIT;

As this one decides what "conn" to return, including the fallback &no_fork instance,...

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> +	...
> +	return conn;
> +}
> +
>  /*
>   * This returns a dummy child_process if the transport protocol does not
>   * need fork(2), or a struct child_process object if it does.  Once done,
> @@ -881,50 +939,7 @@ struct child_process *git_connect(int fd[2], const char *url,

Each of the if/elseif/ cascade, one of which calls the new helper, now makes an explicit assignment to "conn" declared in git_connect().

Which means the defaulting of git_connect::conn to &no_fork is now unneeded. One of the things that made the original cascade a bit harder to follow than necessary, aside from the physical length of the PROTO_GIT part, was that the case where conn remains to point at no_fork looked very special and it was buried in that long PROTO_GIT part. Now the main source of that issue is fixed, it would make it clear to leave conn uninitialized (or initialize to NULL---but leaving it uninitialized would make the intention of the code more clear, I would think, that each of the if/elseif/ cascade must assign to it).

Show 9 quoted lines

>  		printf("Diag: path=%s\n", path ? path : "NULL");
>  		conn = NULL;
>  	} else if (protocol == PROTO_GIT) {
> -		struct strbuf request = STRBUF_INIT;
> -...
> +		conn = git_connect_git(fd, hostandport, path, prog, flags);
>  	} else {
>  		struct strbuf cmd = STRBUF_INIT;
>  		const char *const *var;