Gregory Szorc <gregory.szorc@gmail.com> [Fri, 17 Aug 2018 19:48:52 +0000] rev 39213
dagutil: use revlog.parentrevs() for resolving parent revisions
And remove parents() since it is no longer used.
revlog.parentrevs() is almost the same as parents(). The main
difference is that parentrevs() can return nullrev. dagop.headrevs()
already handles nullrev. We add an inline check for nullrev in the
other call site to account for the difference.
.. api:: parents() removed from dagutil classes
Use parentrevs() on the storage object instead.
Differential Revision: https://phab.mercurial-scm.org/D4328
Gregory Szorc <gregory.szorc@gmail.com> [Fri, 17 Aug 2018 19:45:13 +0000] rev 39212
dagop: extract headsetofconnecteds() from dagutil
The functionality for resolving the set of DAG heads from a
subset simply requires a function to resolve parent revisions.
Let's establish a function in the dagop module to do this, which
seems to be where generic DAG functionality goes these days.
Differential Revision: https://phab.mercurial-scm.org/D4327
Gregory Szorc <gregory.szorc@gmail.com> [Fri, 17 Aug 2018 19:35:24 +0000] rev 39211
setdiscovery: precompute children revisions to avoid quadratic lookup
Moving away from dagutil a few commits ago introduced quadratic
behavior when resolving children revisions during discovery.
This commit introduces a precompute step of the children revisions
to avoid the bad behavior.
I believe the new code should have near identical performance to
what dagutil was doing before. Behavior is still slightly different
because we take into account filtered revisions. But this change was
made when we moved off dagutil.
I added a comment about multiple invocations of this function
redundantly calculating the children revisions. I believe this
potentially undesirable behavior was present when we used dagutil,
as the call to inverse() previously in this function created a new
object and required computing children on every invocation. I thought
we should document the potential for a performance issue rather than
let it go undocumented.
Differential Revision: https://phab.mercurial-scm.org/D4326