From: Junio C Hamano <junkio@cox.net>
Date: Tue, 17 May 2005 19:27:03 GMT
Subject: Re: [PATCH 1/2] Introduce git-run-with-user-path helper program.
Message-ID: <7vk6lxfybc.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <20050517190355.GA7136@pasky.ji.cz>

>>>>> "PB" == Petr Baudis <pasky@ucw.cz> writes:

>> +int path_ignored(const char *path)
>> +{
>> +	if (!verify_path(path))
>> +		return 1;
>> +
>> +	/* Put the Porcelain layer ignore logic here.
>> +	 * Return non-zero if path is to be ignored.
>> +	 */
>> +	return 0;
>> +}

PB> I actually think you shouldn't. All the Porcelain layers should
PB> hopefully use the same git toolkit layer, not each one shipping own due
PB> to differences in things like this.

What you said above _is_ exactly my intention.  I phrased that
comment very badly.  It should have said:

    /* We _will_ put the "ignore logic Porcelain layers agree upon"
     * here, once we have a concensus.
     *
     * The code should return non-zero if path is to be ignored.
     */

I did not put any implementation there because I do not think we
have agreed upon anything yet.  This patch is to establish
the framework.  

The second patch is separate, because it is _my_ version of the
ignore logic proposal, to serve as a sample.  Whatever ignore
logic is agreed upon, that _will_ be in the place you pointed
out and there will be no choice.  Everybody _will_ use the
ignore logic.

>> +/****************************************************************/
>> +
>> +/* Path canonicalization part */

PB> And why is this in the library?

Why not?  It is something other programs would eventually find
useful.

Also the second patch, a sample implementation of ignore logic I
proposed, wants to know GIT_PROJECT_TOP to figure out the file
pointed at by GIT_DIR/.git/info/ignore-file.

Also it would not hurt if you are always running from the
project top and give only verify_path() approved paths.  Then
canon_path would become identity function.

git-run-with-user-path is useful both in implementing
porcelain-add if the porcelain's policy is to take filesystem
paths not GIT paths, like this:

    #!/bin/sh
    # porcelain-add
    exec git-run-with-user-path git-update-cache --add -- -- "$@"

Also if the porcelain's policy is to take GIT paths not
filesystem paths, then users can say:

    $ find . ! -type d -print0 |
      xargs -0 git-run-with-user-path cg-add --

You cannot use both for obvious reasons.