tactical <a5158017@xxxxxxxxx> writes:
> Konstantin Khomoutov wrote:
>
>>>>> From what I read, detached heads are subject to garbage collection.
>>>>
>>>> No, HEAD is protected against garbage collecting. To be sure you
>>>> should name a branch when switching branches, though reflog would
>>>> protect you for 30 days (by default) even if you don't do that.
>>>
>>> So Git doesn't really support anonymous branching as part of a normal
>>> workflow.
>>
>> I perceive a certain logical fallacy here: you cannot switch between
>> anything anonymous because to switch, you should somehow identify
>> something to switch to--a name in whatever sense we put into this word.
>
> In Mercurial, you can just update to a particular changeset (and you
> identify that changeset by repository-local revision number or globally
> unique ID) and then commit again. The point is that there's no need to
> give a label to a head in Mercurial (although you can if you want to, using
> Mercurial bookmarks, which are basically the same as what Git uses).
>
> Here's an example of anonymous branching:
>
> c:\test>hg init
>
> c:\test>echo test>foo
>
> c:\test>hg commit --addremove -m initial
> adding foo
>
> c:\test>echo first>>foo
>
> c:\test>hg commit -m first
>
> c:\test>hg log
> changeset: 1:3e895ec28d6c
> tag: tip
> user: tactical
> date: Mon Sep 26 01:39:46 2011 +0100
> summary: first
>
> changeset: 0:b51644bb3450
> user: tactical
> date: Mon Sep 26 01:39:40 2011 +0100
> summary: initial
>
> c:\test>hg update 0
> 1 files updated, 0 files merged, 0 files removed, 0 files unresolved
>
> c:\test>echo second>>foo
>
> c:\test>hg commit -m second
> created new head
>
> c:\test>hg glog
> @ changeset: 2:35c82a7e7de1
> | tag: tip
> | parent: 0:b51644bb3450
> | user: tactical
> | date: Mon Sep 26 01:40:10 2011 +0100
> | summary: second
> |
> | o changeset: 1:3e895ec28d6c
> |/ user: tactical
> | date: Mon Sep 26 01:39:46 2011 +0100
> | summary: first
> |
> o changeset: 0:b51644bb3450
> user: tactical
> date: Mon Sep 26 01:39:40 2011 +0100
> summary: initial
>
> I now have two anonymous branches, and these will never be garbage
> collected. I can easily update to either branch with "hg update 1" or "hg
> update 2" (or "hg update 0" again, if i want to create yet another
> anonymous branch).
In my opinion the need to examine either log ('hg glog') or heads
('hg heads'?) to see how to switch to anonymous branch is a PITA
that far outweights the need to name branches (to give a temporary,
local-only branch name) in Git.
Nb. by using "detached HEAD" for anonymous branch I meant the
following:
$ git checkout --detach
$ ...
$ <work on detached head>
worth saving?
Y. $ git branch -b t foo/temp
$ git checkout <other branch>
N. $ git checkout <other branch>
> > The branch names is just a way to not mess with
> > SHA-1 names of commits (and to have references to those commits to keep
> > them out of consideration for garbage collection).
> > Hence the idea to demand support for anonymous branches in Git's model
> > is just unfounded.
>
> I think it's simply a weakness of Git. There are zero problems with
> anonymous branching in Mercurial, and it's a very powerful and simple
> system.
IMVVVHO it is just remains of bad initial design decision of Mercurial
about representing branches ;-PPPPPPP
Only now Mercurial has something (transferable bookmarks) which
approaches flexibility and usability of Git branches. It took them
how long... and even then there is a [supposedly] user-friendly but
flexibility-reducing notion that branch (bookmark) names are global.
Not that Git didn't and doesn't have its share of bad design decisions
(like autimatically committing a merge).
--
Jakub Narębski
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