copies: filter out copies from non-existent source later in _chain()
_changesetforwardcopies() repeatedly calls _chain(). That is very
expensive because _chain() does lookups in the manifest. I hope to
split up the function in two parts: 1) simple chaining, not
considering end points, and 2) filter out files that don't exist in
the end points (and ping-pong copies/renames).
This patches gets us closer to that by moving the check for
non-existent source later in the function. Now there are no more
checks for "src" and "dst" in the first loop; all the filtering of
invalid copies is done in the second loop. The code also looks much
more consistent now.
No measureable impact on `hg debugpathcopies 4.0 4.8`. That shouldn't
be surprising since the only case we're doing more checks now is in
case of chained copies/renames, which are quire rare in practice.
Differential Revision: https://phab.mercurial-scm.org/D6277
Create an empty repo:
$ hg init a
$ cd a
Try some commands:
$ hg log
$ hg grep wah
[1]
$ hg manifest
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checked 0 changesets with 0 changes to 0 files
Check the basic files created:
$ ls .hg
00changelog.i
cache
requires
store
wcache
Should be empty:
$ ls .hg/store
Poke at a clone:
$ cd ..
$ hg clone a b
updating to branch default
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd b
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
checked 0 changesets with 0 changes to 0 files
$ ls .hg
00changelog.i
hgrc
requires
store
Should be empty:
$ ls .hg/store
$ cd ..