Summary:
Previously `absorb` does not care too much about copies or renames and
assumesa file path only exists in every changeset of `stack[k:len(stack)]`,
but does not exist in any of `stack[0:k]`. If this assumption is not true,
absorb will likely crash.
This patch implements copy or rename handling correctly. After this patch,
renames happens to a single file is tracked correctly. Copies are ignored
by default. For the "double move" case, like:
hg cp a a1
hg cp a a2
hg rm a
We only follow the first path (sorted alphabetically). In this case, changes
to "a1" could affect the content of "a" in a previous changeset, while changes
to "a2" couldn't.
Test Plan: Added a new test
Reviewers: durham, #sourcecontrol, rmcelroy
Reviewed By: rmcelroy
Subscribers: mjpieters
Differential Revision: https://phabricator.intern.facebook.com/D3941438
Signature: t1:3941438:1475166850:97461174619d469750146e25f6bff16dae19bd3d
