commit: improve the files field of changelog for merges
Currently, the files list of merge commits repeats all the deletions
(either actual deletions, or files that got renamed) that happened
between base and p2 of the merge. If p2 is the main branch, the list
can easily be much bigger than the change being merged.
This results in various problems worth improving:
- changelog is bigger than necessary
- `hg log directory` lists many unrelated merge commits, and `hg log
-v -r commit` frequently fills multiple screens worth of files
- it possibly slows down adjustlinkrev, by forcing it to read more
manifests, and that function can certainly be a bottleneck
- the server side of pulls can waste a lot of time simply opening the
filelogs for pointless files (the constant factors for opening even
a tiny filelog is apparently pretty bad)
So stop listing such files as described in the code. Impacted merge
commits and their descendants get a different hash than they would
have without this. This doesn't seem problematic, except for
convert. The previous commit helped with that in the hg->hg case (but
if you do svn->hg twice from scratch, hashes can still change).
The rest of the description is numbers. I don't have much to report,
because recreating the files list of existing repositories is not
easy:
- debugupgradeformat and bundle/unbundle don't recreate the list
- export/import tends to choke quickly applying patches or on
description that contain diffs,
- merge commits from the convert extension don't have the right files
list for reasons orthogonal to the current commit
- replaying the merge with hg update/hg merge/hg revert --all/hg
commit can end up failing in hg revert
- I wasn't sure that using debugsetparents + debugrebuilddirstate
would really build the right thing
I measured commit time before and after this change, in a case with no
files filtered out, several files filtered out (no difference) and 5k
files filtered out (+1% time).
Recreating the 100 more recent merges in a private repo, the
concatenated uncompressed files lists goes from 1.12MB to
0.52MB. Excluding 3 merges that are not representative, then the size
goes from 570k to 15k.
I converted part of mozilla-central, and observed file list shrinking
quite a bit too, starting at the very first merge,
733641d9feaf, going
from 550 files to 10 files (although they have relatively few merges,
so they probably wouldn't care).
Differential Revision: https://phab.mercurial-scm.org/D6613
#require no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
$ hg init master
$ cd master
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> EOF
$ echo x > x
$ echo y > y
$ echo z > z
$ hg commit -qAm xy
$ cd ..
$ hgcloneshallow ssh://user@dummy/master shallow -q
3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
$ cd shallow
# status
$ clearcache
$ echo xx > x
$ echo yy > y
$ touch a
$ hg status
M x
M y
? a
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ hg add a
$ hg status
M x
M y
A a
# diff
$ hg debugrebuilddirstate # fixes dirstate non-determinism
$ hg add a
$ clearcache
$ hg diff
diff -r f3d0bb0d1e48 x
--- a/x* (glob)
+++ b/x* (glob)
@@ -1,1 +1,1 @@
-x
+xx
diff -r f3d0bb0d1e48 y
--- a/y* (glob)
+++ b/y* (glob)
@@ -1,1 +1,1 @@
-y
+yy
3 files fetched over 1 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
# local commit
$ clearcache
$ echo a > a
$ echo xxx > x
$ echo yyy > y
$ hg commit -m a
? files fetched over 1 fetches - (? misses, 0.00% hit ratio) over *s (glob)
# local commit where the dirstate is clean -- ensure that we do just one fetch
# (update to a commit on the server first)
$ hg --config debug.dirstate.delaywrite=1 up 0
2 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ clearcache
$ hg debugdirstate
n 644 2 * x (glob)
n 644 2 * y (glob)
n 644 2 * z (glob)
$ echo xxxx > x
$ echo yyyy > y
$ hg commit -m x
created new head
2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
# restore state for future tests
$ hg -q strip .
$ hg -q up tip
# rebase
$ clearcache
$ cd ../master
$ echo w > w
$ hg commit -qAm w
$ cd ../shallow
$ hg pull
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
new changesets fed61014d323
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg rebase -d tip
rebasing 1:9abfe7bca547 "a"
saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/9abfe7bca547-8b11e5ff-rebase.hg (glob)
3 files fetched over 2 fetches - (3 misses, 0.00% hit ratio) over *s (glob)
# strip
$ clearcache
$ hg debugrebuilddirstate # fixes dirstate non-determinism
$ hg strip -r .
2 files updated, 0 files merged, 1 files removed, 0 files unresolved
saved backup bundle to $TESTTMP/shallow/.hg/strip-backup/19edf50f4de7-df3d0f74-backup.hg (glob)
4 files fetched over 2 fetches - (4 misses, 0.00% hit ratio) over *s (glob)
# unbundle
$ clearcache
$ ls
w
x
y
z
$ hg debugrebuilddirstate # fixes dirstate non-determinism
$ hg unbundle .hg/strip-backup/19edf50f4de7-df3d0f74-backup.hg
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files
new changesets 19edf50f4de7 (1 drafts)
(run 'hg update' to get a working copy)
$ hg up
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
4 files fetched over 1 fetches - (4 misses, 0.00% hit ratio) over *s (glob)
$ cat a
a
# revert
$ clearcache
$ hg revert -r .~2 y z
no changes needed to z
2 files fetched over 2 fetches - (2 misses, 0.00% hit ratio) over *s (glob)
$ hg checkout -C -r . -q
# explicit bundle should produce full bundle file
$ hg bundle -r 2 --base 1 ../local.bundle
1 changesets found
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ cd ..
$ hgcloneshallow ssh://user@dummy/master shallow2 -q
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ cd shallow2
$ hg unbundle ../local.bundle
adding changesets
adding manifests
adding file changes
added 1 changesets with 3 changes to 3 files
new changesets 19edf50f4de7 (1 drafts)
(run 'hg update' to get a working copy)
$ hg log -r 2 --stat
changeset: 2:19edf50f4de7
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: a
a | 1 +
x | 2 +-
y | 2 +-
3 files changed, 3 insertions(+), 2 deletions(-)
# Merge
$ echo merge >> w
$ hg commit -m w
created new head
$ hg merge 2
3 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg commit -m merge
$ hg strip -q -r ".^"
# commit without producing new node
$ cd $TESTTMP
$ hgcloneshallow ssh://user@dummy/master shallow3 -q
$ cd shallow3
$ echo 1 > A
$ hg commit -m foo -A A
$ hg log -r . -T '{node}\n'
383ce605500277f879b7460a16ba620eb6930b7f
$ hg update -r '.^' -q
$ echo 1 > A
$ hg commit -m foo -A A
$ hg log -r . -T '{node}\n'
383ce605500277f879b7460a16ba620eb6930b7f