From: Johannes Löthberg <johannes@kyriasis.com>
Date: Mon, 15 Jun 2015 20:59:56 GMT
Subject: Re: [PATCH v4] receive-pack: Create a HEAD ref for ref namespace
Message-ID: <20150615205956.GA15571@leeloo.kyriasis.com>
In-Reply-To: <xmqqlhfk7l6l.fsf@gitster.dls.corp.google.com>

On 15/06, Junio C Hamano wrote:
>Johannes Löthberg <johannes@kyriasis.com> writes:
>>  	else {
>> +		namespace = get_git_namespace();
>> +		if (strcmp(namespace, "refs/namespaces/")) {
>> +			strbuf_addf(&namespaced_head_buf, "%s%s", namespace, "HEAD");
>> +			namespaced_head_path = strbuf_detach(&namespaced_head_buf, NULL);
>> +
>> +			create_symref(namespaced_head_path, namespaced_name, NULL);
>
>In a normal environment without any namespace, get_git_namespace()
>will return an empty string, which is not "refs/namespaces/", so we
>create a symref HEAD (that is .git/HEAD) that points at whatever
>name the command is about.  And this is done every time any ref is
>updated, flipping the HEAD to point at whatever was pushed the last,
>isn't it?
>
>Why is this a good change?  I am puzzled...
>

This creates a HEAD symref in the namespace itself, since there's no 
other place that creates it. It could probably be done better, but I'm 
not very familiar with the Git codebase.

>> +		}
>> +
>>  		struct strbuf err = STRBUF_INIT;
>
>This adds decl-after-stmt.
>
>Going back to the proposed log message...
>
>> Each ref namespace have their own separate branches, tags, and HEAD, so
>> when pushing to a namespace we need to make sure that there exists a
>> HEAD ref for the namespace, otherwise you will not be able to check out
>> the repo after cloning from a namespace
>
>What this paragraph describes is entirely correct, I think.  But I
>do not think receive-pack is the "we" in that paragraph.
>
>When setting up a "namespace" a and b, shouldn't you be doing
>essentially
>
>	r=refs/namespaces/
>	for ns in a b
>        do
>		git symbolic-ref $r$ns/HEAD $r$ns/refs/heads/master
>	done
>
>or something, which is an equivalent to what "git init" does to a
>normal repository?
>

The only way to set up a namespace is by pushing to it.

-- 
Sincerely,
  Johannes Löthberg
  PGP Key ID: 0x50FB9B273A9D0BB5
  https://theos.kyriasis.com/~kyrias/