copy: add flag for disabling copy tracing
Copy tracing can be up to 80% of rebase time when rebasing stacks of commits in
large repos (hundreds of thousands of files). This provides the option of
turning off the majority of copy tracing. It does not turn off _forwardcopies()
since that is used to carry copy information inside a commit across a rebase.
This will affect the situation where a user edits a file, then rebases on top of
commits that have moved that file. The move will not be detected and the user
will have to manually resolve the issue (possibly by redoing the rebase with
this flag off).
The reason to have a flag instead of trying to fix the actual copy tracing
performance is that copy tracing is fundamentally an O(number of files in the
repo) operation. In order to know if file X in the rebase source was copied
anywhere, we have to walk the filelog for every new file that exists in the
rebase destination (i.e. a file in the destination that is not in the common
ancestor). Without an index that lets us trace forward (i.e. from file Y in the
common ancestor forward to the rebase destination), it will never be an O(number
of changes in my branch) operation.
In mozilla-central, rebasing a 3 commit stack across 20,000 revs goes from 39s
to 11s.
#require cvs
Test config convert.cvsps.mergefrom config setting.
(Should test similar mergeto feature, but I don't understand it yet.)
Requires builtin cvsps.
$ CVSROOT=`pwd`/cvsrepo
$ export CVSROOT
$ cvscall()
> {
> cvs -f "$@"
> }
output of 'cvs ci' varies unpredictably, so just discard it
XXX copied from test-convert-cvs-synthetic
$ cvsci()
> {
> sleep 1
> cvs -f ci "$@" > /dev/null
> }
XXX copied from test-convert-cvs-synthetic
$ cat <<EOF >> $HGRCPATH
> [extensions]
> convert =
> [convert]
> cvsps.cache = 0
> cvsps.mergefrom = \[MERGE from (\S+)\]
> EOF
create cvs repository with one project
$ cvscall -q -d "$CVSROOT" init
$ mkdir cvsrepo/proj
populate cvs repository
$ cvscall -Q co proj
$ cd proj
$ touch file1
$ cvscall -Q add file1
$ cvsci -m"add file1 on trunk"
cvs commit: Examining .
create two release branches
$ cvscall -q tag -b v1_0
T file1
$ cvscall -q tag -b v1_1
T file1
modify file1 on branch v1_0
$ cvscall -Q update -rv1_0
$ sleep 1
$ echo "change" >> file1
$ cvsci -m"add text"
cvs commit: Examining .
make unrelated change on v1_1
$ cvscall -Q update -rv1_1
$ touch unrelated
$ cvscall -Q add unrelated
$ cvsci -m"unrelated change"
cvs commit: Examining .
merge file1 to v1_1
$ cvscall -Q update -jv1_0
RCS file: $TESTTMP/cvsrepo/proj/file1,v
retrieving revision 1.1
retrieving revision 1.1.2.1
Merging differences between 1.1 and 1.1.2.1 into file1
$ cvsci -m"add text [MERGE from v1_0]"
cvs commit: Examining .
merge change to trunk
$ cvscall -Q update -A
$ cvscall -Q update -jv1_1
RCS file: $TESTTMP/cvsrepo/proj/file1,v
retrieving revision 1.1
retrieving revision 1.1.4.1
Merging differences between 1.1 and 1.1.4.1 into file1
$ cvsci -m"add text [MERGE from v1_1]"
cvs commit: Examining .
non-merged change on trunk
$ echo "foo" > file2
$ cvscall -Q add file2
$ cvsci -m"add file2 on trunk" file2
this will create rev 1.3
change on trunk to backport
$ echo "backport me" >> file1
$ cvsci -m"add other text" file1
$ cvscall log file1
RCS file: $TESTTMP/cvsrepo/proj/file1,v
Working file: file1
head: 1.3
branch:
locks: strict
access list:
symbolic names:
v1_1: 1.1.0.4
v1_0: 1.1.0.2
keyword substitution: kv
total revisions: 5; selected revisions: 5
description:
----------------------------
revision 1.3
date: * (glob)
add other text
----------------------------
revision 1.2
date: * (glob)
add text [MERGE from v1_1]
----------------------------
revision 1.1
date: * (glob)
branches: 1.1.2; 1.1.4;
add file1 on trunk
----------------------------
revision 1.1.4.1
date: * (glob)
add text [MERGE from v1_0]
----------------------------
revision 1.1.2.1
date: * (glob)
add text
=============================================================================
XXX how many ways are there to spell "trunk" with CVS?
backport trunk change to v1_1
$ cvscall -Q update -rv1_1
$ cvscall -Q update -j1.2 -j1.3 file1
RCS file: $TESTTMP/cvsrepo/proj/file1,v
retrieving revision 1.2
retrieving revision 1.3
Merging differences between 1.2 and 1.3 into file1
$ cvsci -m"add other text [MERGE from HEAD]" file1
fix bug on v1_1, merge to trunk with error
$ cvscall -Q update -rv1_1
$ echo "merge forward" >> file1
$ cvscall -Q tag unmerged
$ cvsci -m"fix file1"
cvs commit: Examining .
$ cvscall -Q update -A
$ cvscall -Q update -junmerged -jv1_1
RCS file: $TESTTMP/cvsrepo/proj/file1,v
retrieving revision 1.1.4.2
retrieving revision 1.1.4.3
Merging differences between 1.1.4.2 and 1.1.4.3 into file1
note the typo in the commit log message
$ cvsci -m"fix file1 [MERGE from v1-1]"
cvs commit: Examining .
$ cvs -Q tag -d unmerged
convert to hg
$ cd ..
$ hg convert proj proj.hg
initializing destination proj.hg repository
connecting to $TESTTMP/cvsrepo
scanning source...
collecting CVS rlog
12 log entries
creating changesets
warning: CVS commit message references non-existent branch 'v1-1':
fix file1 [MERGE from v1-1]
10 changeset entries
sorting...
converting...
9 add file1 on trunk
8 unrelated change
7 add text
6 add text [MERGE from v1_0]
5 add text [MERGE from v1_1]
4 add file2 on trunk
3 add other text
2 add other text [MERGE from HEAD]
1 fix file1
0 fix file1 [MERGE from v1-1]
complete log
$ template="{rev}: '{branches}' {desc}\n"
$ hg -R proj.hg log --template="$template"
9: '' fix file1 [MERGE from v1-1]
8: 'v1_1' fix file1
7: 'v1_1' add other text [MERGE from HEAD]
6: '' add other text
5: '' add file2 on trunk
4: '' add text [MERGE from v1_1]
3: 'v1_1' add text [MERGE from v1_0]
2: 'v1_0' add text
1: 'v1_1' unrelated change
0: '' add file1 on trunk
graphical log
$ hg -R proj.hg log -G --template="$template"
o 9: '' fix file1 [MERGE from v1-1]
|
| o 8: 'v1_1' fix file1
| |
| o 7: 'v1_1' add other text [MERGE from HEAD]
|/|
o | 6: '' add other text
| |
o | 5: '' add file2 on trunk
| |
o | 4: '' add text [MERGE from v1_1]
|\|
| o 3: 'v1_1' add text [MERGE from v1_0]
| |\
+---o 2: 'v1_0' add text
| |
| o 1: 'v1_1' unrelated change
|/
o 0: '' add file1 on trunk