merge: minimize conflicts when common base is not shown (
issue4447)
Previously, two changes that were nearly, but not quite, identical would result
in large merge conflict regions that looked very similar, and were thus very
confusing to users, and lead people used to other source control systems to
claim that "mercurial's merge algorithms suck". In the relatively common case
of a new file being introduced in two branches with very slight modifications,
the old behavior would show the entire file as a conflict, and it would be very
difficult for a user to determine what was going on.
In the past, mercurial attempted to solve this with a "very smart" algorithm
that would find all common lines, but this has significant problems as
described in
2ea6d906cf9b.
Instead, we use a "very dumb" algorithm introduced in the previous patch that
simply matches lines at the periphery of conflict regions. This minimizes most
conflict regions well, though there may still be some degenerate edge cases,
like small modification to the beginning and end of a large file.
#require cvs
$ cvscall()
> {
> cvs -f "$@"
> }
$ hgcat()
> {
> hg --cwd src-hg cat -r tip "$1"
> }
$ echo "[extensions]" >> $HGRCPATH
$ echo "convert = " >> $HGRCPATH
$ cat > cvshooks.py <<EOF
> def cvslog(ui,repo,hooktype,log):
> print "%s hook: %d entries"%(hooktype,len(log))
>
> def cvschangesets(ui,repo,hooktype,changesets):
> print "%s hook: %d changesets"%(hooktype,len(changesets))
> EOF
$ hookpath=`pwd`
$ cat <<EOF >> $HGRCPATH
> [hooks]
> cvslog = python:$hookpath/cvshooks.py:cvslog
> cvschangesets = python:$hookpath/cvshooks.py:cvschangesets
> EOF
create cvs repository
$ mkdir cvsrepo
$ cd cvsrepo
$ CVSROOT=`pwd`
$ export CVSROOT
$ CVS_OPTIONS=-f
$ export CVS_OPTIONS
$ cd ..
$ rmdir cvsrepo
$ cvscall -q -d "$CVSROOT" init
create source directory
$ mkdir src-temp
$ cd src-temp
$ echo a > a
$ mkdir b
$ cd b
$ echo c > c
$ cd ..
import source directory
$ cvscall -q import -m import src INITIAL start
N src/a
N src/b/c
No conflicts created by this import
$ cd ..
checkout source directory
$ cvscall -q checkout src
U src/a
U src/b/c
commit a new revision changing b/c
$ cd src
$ sleep 1
$ echo c >> b/c
$ cvscall -q commit -mci0 . | grep '<--'
$TESTTMP/cvsrepo/src/b/c,v <-- *c (glob)
$ cd ..
convert fresh repo and also check localtimezone option
NOTE: This doesn't check all time zones -- it merely determines that
the configuration option is taking effect.
An arbitrary (U.S.) time zone is used here. TZ=US/Hawaii is selected
since it does not use DST (unlike other U.S. time zones) and is always
a fixed difference from UTC.
$ TZ=US/Hawaii hg convert --config convert.localtimezone=True src src-hg
initializing destination src-hg repository
connecting to $TESTTMP/cvsrepo
scanning source...
collecting CVS rlog
5 log entries
cvslog hook: 5 entries
creating changesets
3 changeset entries
cvschangesets hook: 3 changesets
sorting...
converting...
2 Initial revision
1 ci0
0 import
updating tags
$ hgcat a
a
$ hgcat b/c
c
c
convert fresh repo with --filemap
$ echo include b/c > filemap
$ hg convert --filemap filemap src src-filemap
initializing destination src-filemap repository
connecting to $TESTTMP/cvsrepo
scanning source...
collecting CVS rlog
5 log entries
cvslog hook: 5 entries
creating changesets
3 changeset entries
cvschangesets hook: 3 changesets
sorting...
converting...
2 Initial revision
1 ci0
0 import
filtering out empty revision
repository tip rolled back to revision 1 (undo convert)
updating tags
$ hgcat b/c
c
c
$ hg -R src-filemap log --template '{rev} {desc} files: {files}\n'
2 update tags files: .hgtags
1 ci0 files: b/c
0 Initial revision files: b/c
convert full repository (issue1649)
$ cvscall -q -d "$CVSROOT" checkout -d srcfull "." | grep -v CVSROOT
U srcfull/src/a
U srcfull/src/b/c
$ ls srcfull
CVS
CVSROOT
src
$ hg convert srcfull srcfull-hg \
> | grep -v 'log entries' | grep -v 'hook:' \
> | grep -v '^[0-3] .*' # filter instable changeset order
initializing destination srcfull-hg repository
connecting to $TESTTMP/cvsrepo
scanning source...
collecting CVS rlog
creating changesets
4 changeset entries
sorting...
converting...
updating tags
$ hg cat -r tip --cwd srcfull-hg src/a
a
$ hg cat -r tip --cwd srcfull-hg src/b/c
c
c
commit new file revisions
$ cd src
$ echo a >> a
$ echo c >> b/c
$ cvscall -q commit -mci1 . | grep '<--'
$TESTTMP/cvsrepo/src/a,v <-- a
$TESTTMP/cvsrepo/src/b/c,v <-- *c (glob)
$ cd ..
convert again
$ TZ=US/Hawaii hg convert --config convert.localtimezone=True src src-hg
connecting to $TESTTMP/cvsrepo
scanning source...
collecting CVS rlog
7 log entries
cvslog hook: 7 entries
creating changesets
4 changeset entries
cvschangesets hook: 4 changesets
sorting...
converting...
0 ci1
$ hgcat a
a
a
$ hgcat b/c
c
c
c
convert again with --filemap
$ hg convert --filemap filemap src src-filemap
connecting to $TESTTMP/cvsrepo
scanning source...
collecting CVS rlog
7 log entries
cvslog hook: 7 entries
creating changesets
4 changeset entries
cvschangesets hook: 4 changesets
sorting...
converting...
0 ci1
$ hgcat b/c
c
c
c
$ hg -R src-filemap log --template '{rev} {desc} files: {files}\n'
3 ci1 files: b/c
2 update tags files: .hgtags
1 ci0 files: b/c
0 Initial revision files: b/c
commit branch
$ cd src
$ cvs -q update -r1.1 b/c
U b/c
$ cvs -q tag -b branch
T a
T b/c
$ cvs -q update -r branch > /dev/null
$ sleep 1
$ echo d >> b/c
$ cvs -q commit -mci2 . | grep '<--'
$TESTTMP/cvsrepo/src/b/c,v <-- *c (glob)
$ cd ..
convert again
$ TZ=US/Hawaii hg convert --config convert.localtimezone=True src src-hg
connecting to $TESTTMP/cvsrepo
scanning source...
collecting CVS rlog
8 log entries
cvslog hook: 8 entries
creating changesets
5 changeset entries
cvschangesets hook: 5 changesets
sorting...
converting...
0 ci2
$ hgcat b/c
c
d
convert again with --filemap
$ TZ=US/Hawaii hg convert --config convert.localtimezone=True --filemap filemap src src-filemap
connecting to $TESTTMP/cvsrepo
scanning source...
collecting CVS rlog
8 log entries
cvslog hook: 8 entries
creating changesets
5 changeset entries
cvschangesets hook: 5 changesets
sorting...
converting...
0 ci2
$ hgcat b/c
c
d
$ hg -R src-filemap log --template '{rev} {desc} files: {files}\n'
4 ci2 files: b/c
3 ci1 files: b/c
2 update tags files: .hgtags
1 ci0 files: b/c
0 Initial revision files: b/c
commit a new revision with funny log message
$ cd src
$ sleep 1
$ echo e >> a
$ cvscall -q commit -m'funny
> ----------------------------
> log message' . | grep '<--' |\
> sed -e 's:.*src/\(.*\),v.*:checking in src/\1,v:g'
checking in src/a,v
commit new file revisions with some fuzz
$ sleep 1
$ echo f >> a
$ cvscall -q commit -mfuzzy . | grep '<--'
$TESTTMP/cvsrepo/src/a,v <-- a
$ sleep 4 # the two changes will be split if fuzz < 4
$ echo g >> b/c
$ cvscall -q commit -mfuzzy . | grep '<--'
$TESTTMP/cvsrepo/src/b/c,v <-- *c (glob)
$ cd ..
convert again
$ TZ=US/Hawaii hg convert --config convert.cvsps.fuzz=2 --config convert.localtimezone=True src src-hg
connecting to $TESTTMP/cvsrepo
scanning source...
collecting CVS rlog
11 log entries
cvslog hook: 11 entries
creating changesets
8 changeset entries
cvschangesets hook: 8 changesets
sorting...
converting...
2 funny
1 fuzzy
0 fuzzy
$ hg -R src-hg log -G --template '{rev} ({branches}) {desc} date: {date|date} files: {files}\n'
o 8 (branch) fuzzy date: * -1000 files: b/c (glob)
|
o 7 (branch) fuzzy date: * -1000 files: a (glob)
|
o 6 (branch) funny
| ----------------------------
| log message date: * -1000 files: a (glob)
o 5 (branch) ci2 date: * -1000 files: b/c (glob)
o 4 () ci1 date: * -1000 files: a b/c (glob)
|
o 3 () update tags date: * +0000 files: .hgtags (glob)
|
| o 2 (INITIAL) import date: * -1000 files: (glob)
| |
o | 1 () ci0 date: * -1000 files: b/c (glob)
|/
o 0 () Initial revision date: * -1000 files: a b/c (glob)
testing debugcvsps
$ cd src
$ hg debugcvsps --fuzz=2 -x >/dev/null
commit a new revision changing a and removing b/c
$ cvscall -q update -A
U a
U b/c
$ sleep 1
$ echo h >> a
$ cvscall -Q remove -f b/c
$ cvscall -q commit -mci | grep '<--'
$TESTTMP/cvsrepo/src/a,v <-- a
$TESTTMP/cvsrepo/src/b/c,v <-- *c (glob)
update and verify the cvsps cache
$ hg debugcvsps --fuzz=2 -u
collecting CVS rlog
13 log entries
cvslog hook: 13 entries
creating changesets
11 changeset entries
cvschangesets hook: 11 changesets
---------------------
PatchSet 1
Date: * (glob)
Author: * (glob)
Branch: HEAD
Tag: (none)
Branchpoints: INITIAL
Log:
Initial revision
Members:
a:INITIAL->1.1
---------------------
PatchSet 2
Date: * (glob)
Author: * (glob)
Branch: HEAD
Tag: (none)
Branchpoints: INITIAL, branch
Log:
Initial revision
Members:
b/c:INITIAL->1.1
---------------------
PatchSet 3
Date: * (glob)
Author: * (glob)
Branch: INITIAL
Tag: start
Log:
import
Members:
a:1.1->1.1.1.1
b/c:1.1->1.1.1.1
---------------------
PatchSet 4
Date: * (glob)
Author: * (glob)
Branch: HEAD
Tag: (none)
Log:
ci0
Members:
b/c:1.1->1.2
---------------------
PatchSet 5
Date: * (glob)
Author: * (glob)
Branch: HEAD
Tag: (none)
Branchpoints: branch
Log:
ci1
Members:
a:1.1->1.2
---------------------
PatchSet 6
Date: * (glob)
Author: * (glob)
Branch: HEAD
Tag: (none)
Log:
ci1
Members:
b/c:1.2->1.3
---------------------
PatchSet 7
Date: * (glob)
Author: * (glob)
Branch: branch
Tag: (none)
Log:
ci2
Members:
b/c:1.1->1.1.2.1
---------------------
PatchSet 8
Date: * (glob)
Author: * (glob)
Branch: branch
Tag: (none)
Log:
funny
----------------------------
log message
Members:
a:1.2->1.2.2.1
---------------------
PatchSet 9
Date: * (glob)
Author: * (glob)
Branch: branch
Tag: (none)
Log:
fuzzy
Members:
a:1.2.2.1->1.2.2.2
---------------------
PatchSet 10
Date: * (glob)
Author: * (glob)
Branch: branch
Tag: (none)
Log:
fuzzy
Members:
b/c:1.1.2.1->1.1.2.2
---------------------
PatchSet 11
Date: * (glob)
Author: * (glob)
Branch: HEAD
Tag: (none)
Log:
ci
Members:
a:1.2->1.3
b/c:1.3->1.4(DEAD)
$ cd ..