copies._forwardcopies: use set operations to find missing files
This is a performance win for a number of reasons:
- We don't iterate over contexts, which avoids a completely unnecessary sorted
call + the O(number of files) abstraction cost of doing that.
- We don't check membership in a context, which avoids another
O(number of files) abstraction cost.
- We iterate over the manifests in C instead of Python.
For a large repo with 170,000 files, this improves perfpathcopies from 0.34
seconds to 0.07. Anything that uses pathcopies, such as rebase or diff --git
between two revisions, benefits.
$ cat >> $HGRCPATH <<EOF
> [extensions]
> graphlog=
> rebase=
>
> [alias]
> tglog = log -G --template "{rev}: '{desc}' {branches}\n"
> EOF
$ hg init repo
$ cd repo
$ echo A > a
$ echo >> a
$ hg ci -Am A
adding a
$ echo B > a
$ echo >> a
$ hg ci -m B
$ echo C > a
$ echo >> a
$ hg ci -m C
$ hg up -q -C 0
$ echo D >> a
$ hg ci -Am AD
created new head
$ hg tglog
@ 3: 'AD'
|
| o 2: 'C'
| |
| o 1: 'B'
|/
o 0: 'A'
$ hg rebase -s 1 -d 3
merging a
merging a
saved backup bundle to $TESTTMP/repo/.hg/strip-backup/*-backup.hg (glob)
$ hg tglog
@ 3: 'C'
|
o 2: 'B'
|
o 1: 'AD'
|
o 0: 'A'
$ cd ..