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
$ hg init
$ echo a > a
$ hg commit -A -ma
adding a
$ echo b >> a
$ hg commit -mb
$ echo c >> a
$ hg commit -mc
$ hg up 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo d >> a
$ hg commit -md
created new head
$ hg up 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo e >> a
$ hg commit -me
created new head
$ hg up 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Should fail because not at a head:
$ hg merge
abort: working directory not at a head revision
(use 'hg update' or merge with an explicit revision)
[255]
$ hg up
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
updated to "f25cbe84d8b3: e"
2 other heads for branch "default"
Should fail because > 2 heads:
$ HGMERGE=internal:other; export HGMERGE
$ hg merge
abort: branch 'default' has 3 heads - please merge with an explicit rev
(run 'hg heads .' to see heads)
[255]
Should succeed:
$ hg merge 2
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg id -Tjson
[
{
"bookmarks": [],
"branch": "default",
"dirty": "+",
"id": "f25cbe84d8b320e298e7703f18a25a3959518c23+2d95304fed5d89bc9d70b2a0d02f0d567469c3ab+",
"node": "ffffffffffffffffffffffffffffffffffffffff",
"parents": ["f25cbe84d8b320e298e7703f18a25a3959518c23", "2d95304fed5d89bc9d70b2a0d02f0d567469c3ab"],
"tags": ["tip"]
}
]
$ hg commit -mm1
Should succeed - 2 heads:
$ hg merge -P
changeset: 3:ea9ff125ff88
parent: 1:1846eede8b68
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: d
$ hg merge
0 files updated, 1 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg commit -mm2
$ hg id -r 1 -Tjson
[
{
"bookmarks": [],
"branch": "default",
"id": "1846eede8b6886d8cc8a88c96a687b7fe8f3b9d1",
"node": "1846eede8b6886d8cc8a88c96a687b7fe8f3b9d1",
"tags": []
}
]
Should fail because at tip:
$ hg merge
abort: nothing to merge
[255]
$ hg up 0
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Should fail because there is only one head:
$ hg merge
abort: nothing to merge
(use 'hg update' instead)
[255]
$ hg up 3
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo f >> a
$ hg branch foobranch
marked working directory as branch foobranch
(branches are permanent and global, did you want a bookmark?)
$ hg commit -mf
Should fail because merge with other branch:
$ hg merge
abort: branch 'foobranch' has one head - please merge with an explicit rev
(run 'hg heads' to see all heads)
[255]
Test for issue2043: ensure that 'merge -P' shows ancestors of 6 that
are not ancestors of 7, regardless of where their common ancestors are.
Merge preview not affected by common ancestor:
$ hg up -q 7
$ hg merge -q -P 6
2:2d95304fed5d
4:f25cbe84d8b3
5:a431fabd6039
6:e88e33f3bf62
Test experimental destination revset
$ hg log -r '_destmerge()'
abort: branch 'foobranch' has one head - please merge with an explicit rev
(run 'hg heads' to see all heads)
[255]
(on a branch with a two heads)
$ hg up 5
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo f >> a
$ hg commit -mf
created new head
$ hg log -r '_destmerge()'
changeset: 6:e88e33f3bf62
parent: 5:a431fabd6039
parent: 3:ea9ff125ff88
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: m2
(from the other head)
$ hg log -r '_destmerge(e88e33f3bf62)'
changeset: 8:b613918999e2
tag: tip
parent: 5:a431fabd6039
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: f
(from unrelated branch)
$ hg log -r '_destmerge(foobranch)'
abort: branch 'foobranch' has one head - please merge with an explicit rev
(run 'hg heads' to see all heads)
[255]