Antw: Re: bug deleting "unmerged" branch (2.12.3)

> "Ulrich Windl" <Ulrich.Windl@rz.uni-regensburg.de> writes:
> 
>> I think if more than one branches are pointing to the same commit,
>> one should be allowed to delete all but the last one without
>> warning. Do you agree?
> 
> That comes from a viewpoint that the only purpose "branch -d" exists
> in addition to "branch -D" is to protect objects from "gc".  Those
> who added the safety feature may have shared that view originally,
> but it turns out that it protects another important thing you are
> forgetting.
> 
> Imagine that two topics, 'topicA' and 'topicB', were independently
> forked from 'master', and then later we wanted to add a feature that
> depends on these two topics.  Since the 'feature' forked, there may
> have been other developments, and we ended up in this topology:
> 
>     ---o---o---o---o---o---M
>         \   \          
>          \   o---A---o---F
>           \         /  
>            o---o---o---o---B
> 
> where A, B and F are the tips of 'topicA', 'topicB' and 'feature'
> branches right now [*1*].
> 
> Now imagine we are on 'master' and just made 'topicB' graduate.  We
> would have this topology.
> 
>     ---o---o---o---o---o---o---M
>         \   \                 /
>          \   o---A---o---F   /
>           \         /       /
>            o---o---o---o---B
> 
> While we do have 'topicA' and 'feature' branches still in flight,
> we are done with 'topicB'.  Even though the tip of 'topicA' is
> reachable from the tip of 'feature', the fact that the branch points
> at 'A' is still relevant.  If we lose that information right now,
> we'd have to go find it when we (1) want to further enhance the
> topic by checking out and building on 'topicA', and (2) want to
> finally get 'topicA' graduate to 'master'.
> 
> Because removal of a topic (in this case 'topicB') is often done
> after a merge of that topic is made into an integration branch,
> "branch -d" that protects branches that are yet to be merged to the
> current branch catches you if you said "branch -d topic{A,B}" (or
> other equivalent forms, most likely you'd have a script that spits
> out list of branches and feed it to "xargs branch -d").
> 
> So, no, I do not agree.

> 
> 
> [Footnotes]
> 
> *1* Since the 'feature' started developing, there were a few commits
>     added to 'topicB' but because the feature does not depend on
>     these enhancements to that topic, B is ahead of the commit that
>     was originally merged with the tip of 'topicA' to form the
>     'feature' branch.