[PATCH] revset: introduce feature revset for tracking in-progress work (issue4968)

[Andrew Halberstadt]

On 30/11/15 06:39 PM, Durham Goode wrote:
> On 11/26/15 5:31 PM, Andrew Halberstadt wrote:
>> # HG changeset patch
>> # User Andrew Halberstadt <ahalberstadt at mozilla.com>
>> # Date 1448490626 18000
>> #      Wed Nov 25 17:30:26 2015 -0500
>> # Node ID 3545b0234e4884f57dac44fd4e443deac5b9d673
>> # Parent  61fbf5dc12b23e7a2a30cf04ebd9f096c42a1f61
>> revset: introduce feature revset for tracking in-progress work 
>> (issue4968)
>>
>> The revset "only(<rev>) and not public()" is often used to track wip 
>> features.
>> But this approach is simplistic and doesn't take things like merges,
>> obsolescence and bookmarks into account. This change formalizes a 
>> 'feature()'
>> revset that can turn a set of revision specifications into all the 
>> commits
>> within their associated feature branches.
>>
>> A commit C is in the feature ending at revision R if all of the 
>> following
>> conditions are true:
>>
>> 1. C is R or C is an ancestor of R
>> 2. C is not public
>> 3. C is not a merge commit
>> 4. C is not obsolete
>> 5. no bookmarks exist in [C, R) for C != R
>> 6. all commits in (C, R) are also within R for C != R
>>
> This is awfully specific. What are the use cases that you want to use 
> this revset for?
>
> #3 why exclude merge commits if they met all the other criteria?
> #5 this implies a certain usage of bookmarks (depending on what your 
> use cases for feature() are)

Yeah, timeless is pretty much dead on with my reasoning. You're also 
right about #5, it was designed to be used specifically with an 
extension [1] I wrote for enabling a particular bookmark based workflow. 
I understand if there's a desire to make the definition in core a little 
less strict, e.g by dropping the bookmarks/merge bits. Though for me 
personally, the bookmarks requirement is also the most useful part.

See the README of bookbinder for examples, but I use this regularly for 
log, rebase, graft, incoming/outgoing + all the evolve commands.

[1] https://bitbucket.org/halbersa/bookbinder