view tests/test-convert-cvs-detectmerge.t @ 17103:5146de7bce96

convert: keep branch switching merges with ancestors (issue3340)

When running convert with a filemap, merge parents which are ancestors
of other parents are ignored. This is hardly a problem when parents
belong to the same branch, but the result could be confusing when named
branches are involved. With:

  -o-a1-a2-a3...     <- A
    \           \
     b1-b2-b3...-m-  <- B

If all b* revisions are discarded, it is useful to preserve 'm' even if
it is empty after filtering to record the branch switch.

This patch makes filemap preserve "ancestor parents" if there is no
"non-ancestor parent" on the same branch than the merge revision.

Remarks:
- I am not completely convinced by the reasons given above and those
  detailed by Matt in this thread:

http://selenic.com/pipermail/mercurial-devel/2012-May/040627.html

  The properties we try to preserve are not clearly defined. That said,
  I know this patch already helped someone on IRC and the tests output
  look reasonable.

- This is a new version of the original "convert: filemap must preserve
  fast-forward merges" patch. It has exactly the same output for 2
  parents merges, the additional complexity is here to handle more than
  two parents.

Test config convert.cvsps.mergefrom config setting.
(Should test similar mergeto feature, but I don't understand it yet.)
Requires builtin cvsps.

  $ "$TESTDIR/hghave" cvs || exit 80
  $ 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

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "convert = " >> $HGRCPATH
  $ echo "graphlog = " >> $HGRCPATH
  $ echo "[convert]" >> $HGRCPATH
  $ echo "cvsps.cache=0" >> $HGRCPATH
  $ echo "cvsps.mergefrom=\[MERGE from (\S+)\]" >> $HGRCPATH

create cvs repository with one project

  $ mkdir cvsrepo
  $ 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 add text
  7 unrelated change
  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_1' unrelated change
  1: 'v1_0' add text
  0: '' add file1 on trunk

graphical log

  $ hg -R proj.hg glog --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_1' unrelated change
  | |
  | o  1: 'v1_0' add text
  |/
  o  0: '' add file1 on trunk