Re: [3/4] What's not in 1.5.2 (new topics)
- From
Petr Baudis <pasky@suse.cz>
- Date
- May 18, 2007, 04:50 UTC
- Message-ID
- <20070518045025.GT4489@pasky.or.cz>
- In-Reply-To
- <464CF435.1010405@midwinter.com>
On Fri, May 18, 2007 at 02:32:53AM CEST, Steven Grimm wrote:
Show 19 quoted lines
> For example -- and yes, this is partially a rehash of other people's > ideas -- instead of mapping a subproject path directly to revision@URL, > instead map it to revision@symbolic name. The symbolic name is then > separately mapped to a URL, and it's that symbolic name that can be > locally overridden. The mappings of symbolic names to URLs is > unversioned; the mapping of subprojects to revision@symbolic is > versioned. Local overrides happen at the symbolic->URL mapping. > > So you'd have something like > > version 1: kernel-src/ -> kernel24 > version 2: kernel-src/ -> kernel26 > unversioned: > kernel24 -> git://whatever/2.4 > kernel26 -> git://whatever/2.6 > > And then locally, the override is: > > kernel24 -> git://myhost/2.4
Yes, this would be nice; in one of my first mails in this thread I devoted a non-trivially large writeup to this, then proceeded to remove it since this has a serious problem.
Actually, Git already has a nice mechanism to handle these unversionaed pointers - tags. Just make refs/tags/subproject/kernel24 containing the URL to fetch. It's even easily overridable locally (and not easily overridable remotely...).
The problem is ugly too, though - suddenly, you have created a SINGLE UNIVERSE-WIDE NAMESPACE INSIDE A DISTRIBUTED VCS. And that's not going to work well. I think I don't have to elaborate too much - the aforementioned FreeBSD people will have different ideas about kernels than you, _you_ will have different idea about kernels in few tens of years than now, then if you need to merge or probably even fetch, you will get into big trouble.
Notice that we don't have any such namespace right now (except the D(SHA1) namespace, which is however possible only because it's so huge _and_ the names are assigned automagically in a way that virtually guarantees uniqueness across the whole universe) - tags come closest, but there is nothing that fundamentally breaks when a clash happens inside the namespace - it's just UI thing. But subproject names are etched to the history - once you name it, you just can't get rid of it forever.
-- Petr "Pasky" Baudis Stuff: http://pasky.or.cz/ Ever try. Ever fail. No matter. // Try again. Fail again. Fail better. -- Samuel Beckett