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
#testcases obsstore-off obsstore-on
$ cat << EOF >> $HGRCPATH
> [extensions]
> amend =
> EOF
#if obsstore-on
$ cat << EOF >> $HGRCPATH
> [experimental]
> evolution.createmarkers = True
> EOF
#endif
Prepare parent repo
-------------------
$ hg init r
$ cd r
$ echo a > a
$ hg ci -Am0
adding a
Link first subrepo
------------------
$ echo 's = s' >> .hgsub
$ hg add .hgsub
$ hg init s
amend without .hgsub
$ hg amend s
abort: can't commit subrepos without .hgsub
[255]
amend with subrepo
$ hg amend
saved backup bundle to * (glob) (obsstore-off !)
$ hg status --change .
A .hgsub
A .hgsubstate
A a
$ cat .hgsubstate
0000000000000000000000000000000000000000 s
Update subrepo
--------------
add new commit to be amended
$ echo a >> a
$ hg ci -m1
amend with dirty subrepo
$ echo a >> s/a
$ hg add -R s
adding s/a
$ hg amend
abort: uncommitted changes in subrepository "s"
(use --subrepos for recursive commit)
[255]
amend with modified subrepo
$ hg ci -R s -m0
$ hg amend
saved backup bundle to * (glob) (obsstore-off !)
$ hg status --change .
M .hgsubstate
M a
$ cat .hgsubstate
f7b1eb17ad24730a1651fccd46c43826d1bbc2ac s
revert subrepo change
$ hg up -R s -q null
$ hg amend
saved backup bundle to * (glob) (obsstore-off !)
$ hg status --change .
M a
Link another subrepo
--------------------
add new commit to be amended
$ echo b >> b
$ hg ci -qAm2
also checks if non-subrepo change is included
$ echo a >> a
amend with another subrepo
$ hg init t
$ echo b >> t/b
$ hg ci -R t -Am0
adding b
$ echo 't = t' >> .hgsub
$ hg amend
saved backup bundle to * (glob) (obsstore-off !)
$ hg status --change .
M .hgsub
M .hgsubstate
M a
A b
$ cat .hgsubstate
0000000000000000000000000000000000000000 s
bfb1a4fb358498a9533dabf4f2043d94162f1fcd t
Unlink one subrepo
------------------
add new commit to be amended
$ echo a >> a
$ hg ci -m3
$ echo 't = t' > .hgsub
--interactive won't silently ignore dirty subrepos
$ echo modified > t/b
$ hg amend --interactive --config ui.interactive=True
abort: uncommitted changes in subrepository "t"
[255]
$ hg amend --interactive --config ui.interactive=True --config ui.commitsubrepos=True
abort: uncommitted changes in subrepository "t"
[255]
$ hg -R t revert -q --all --no-backup
amend with one subrepo dropped
$ hg amend
saved backup bundle to * (glob) (obsstore-off !)
$ hg status --change .
M .hgsub
M .hgsubstate
M a
$ cat .hgsubstate
bfb1a4fb358498a9533dabf4f2043d94162f1fcd t
Unlink subrepos completely
--------------------------
add new commit to be amended
$ echo a >> a
$ hg ci -m3
amend with .hgsub removed
$ hg rm .hgsub
$ hg amend
saved backup bundle to * (glob) (obsstore-off !)
$ hg status --change .
M a
R .hgsub
R .hgsubstate
$ cd ..