context: extend efficient manifest filtering to when all paths are files
On a repository with over 250,000 files and 700,000 commits, this improves
cases like
hg status --rev <rev> -- <file> # rev is not .
from 2.1 seconds to 1.4 seconds.
There is further scope for improvement here: for a single file or a small set
of files, it is probably more efficient to use filelog linkrevs when possible.
However there will always be cases where that will fail (multiple commits
pointing to the same file revision, removed files...), so this is independently
useful.
http://mercurial.selenic.com/bts/issue619
$ hg init
$ echo a > a
$ hg ci -Ama
adding a
$ echo b > b
$ hg branch b
marked working directory as branch b
(branches are permanent and global, did you want a bookmark?)
$ hg ci -Amb
adding b
$ hg co -C 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
Fast-forward:
$ hg merge b
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -Ammerge
Bogus fast-forward should fail:
$ hg merge b
abort: merging with a working directory ancestor has no effect
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