test: add a push race case where non-contiguous branch head are created

We check case where the raced push an update to branch default head while the
racing push update that same head but through another named branch.

tests/test-push-race.t

@@ -1,897 +1,1074 b''
 ============================================================================================
 Test cases where there are race condition between two clients pushing to the same repository
 ============================================================================================
 
 This file tests cases where two clients push to a server at the same time. The
 "raced" client is done preparing it push bundle when the "racing" client
 perform its push. The "raced" client starts its actual push after the "racing"
 client push is fully complete.
 
 A set of extension and shell functions ensures this scheduling.
 
   $ cat >> delaypush.py << EOF
   > """small extension orchestrate push race
   > 
   > Client with the extensions will create a file when ready and get stuck until
   > a file is created."""
   > 
   > import atexit
   > import errno
   > import os
   > import time
   > 
   > from mercurial import (
   >     exchange,
   >     extensions,
   > )
   > 
   > def delaypush(orig, pushop):
   >     # notify we are done preparing
   >     readypath = pushop.repo.ui.config('delaypush', 'ready-path', None)
   >     if readypath is not None:
   >         with open(readypath, 'w') as r:
   >             r.write('foo')
   >         pushop.repo.ui.status('wrote ready: %s\n' % readypath)
   >     # now wait for the other process to be done
   >     watchpath = pushop.repo.ui.config('delaypush', 'release-path', None)
   >     if watchpath is not None:
   >         pushop.repo.ui.status('waiting on: %s\n' % watchpath)
   >         limit = 100
   >         while 0 < limit and not os.path.exists(watchpath):
   >             limit -= 1
   >             time.sleep(0.1)
   >         if limit <= 0:
   >             repo.ui.warn('exiting without watchfile: %s' % watchpath)
   >         else:
   >             # delete the file at the end of the push
   >             def delete():
   >                 try:
   >                     os.unlink(watchpath)
   >                 except OSError as exc:
   >                     if exc.errno != errno.ENOENT:
   >                         raise
   >             atexit.register(delete)
   >     return orig(pushop)
   > 
   > def uisetup(ui):
   >     extensions.wrapfunction(exchange, '_pushbundle2', delaypush)
   > EOF
 
   $ waiton () {
   >     # wait for a file to be created (then delete it)
   >     count=100
   >     while [ ! -f $1 ] ;
   >     do
   >         sleep 0.1;
   >         count=`expr $count - 1`;
   >         if [ $count -lt 0 ];
   >         then
   >              break
   >         fi;
   >     done
   >     [ -f $1 ] || echo "ready file still missing: $1"
   >     rm -f $1
   > }
 
   $ release () {
   >     # create a file and wait for it be deleted
   >     count=100
   >     touch $1
   >     while [ -f $1 ] ;
   >     do
   >         sleep 0.1;
   >         count=`expr $count - 1`;
   >         if [ $count -lt 0 ];
   >         then
   >              break
   >         fi;
   >     done
   >     [ ! -f $1 ] || echo "delay file still exist: $1"
   > }
 
   $ cat >> $HGRCPATH << EOF
   > [ui]
   > ssh = python "$TESTDIR/dummyssh"
   > # simplify output
   > logtemplate = {node|short} {desc} ({branch})
   > [alias]
   > graph = log -G --rev 'sort(all(), "topo")'
   > EOF
 
 Setup
 -----
 
 create a repo with one root
 
   $ hg init server
   $ cd server
   $ echo root > root
   $ hg ci -Am "C-ROOT"
   adding root
   $ cd ..
 
 clone it in two clients
 
   $ hg clone ssh://user@dummy/server client-racy
   requesting all changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   updating to branch default
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg clone ssh://user@dummy/server client-other
   requesting all changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   updating to branch default
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
 setup one to allow race on push
 
   $ cat >> client-racy/.hg/hgrc << EOF
   > [extensions]
   > delaypush = $TESTTMP/delaypush.py
   > [delaypush]
   > ready-path = $TESTTMP/readyfile
   > release-path = $TESTTMP/watchfile
   > EOF
 
 Simple race, both try to push to the server at the same time
 ------------------------------------------------------------
 
 Both try to replace the same head
 
 #  a
 #  | b
 #  |/
 #  *
 
 Creating changesets
 
   $ echo b > client-other/a
   $ hg -R client-other/ add client-other/a
   $ hg -R client-other/ commit -m "C-A"
   $ echo b > client-racy/b
   $ hg -R client-racy/ add client-racy/b
   $ hg -R client-racy/ commit -m "C-B"
 
 Pushing
 
   $ hg -R client-racy push -r 'tip' > ./push-log 2>&1 &
 
   $ waiton $TESTTMP/readyfile
 
   $ hg -R client-other push -r 'tip'
   pushing to ssh://user@dummy/server
   searching for changes
   remote: adding changesets
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 1 changes to 1 files
 
   $ release $TESTTMP/watchfile
 
 Check the result of the push
 
   $ cat ./push-log
   pushing to ssh://user@dummy/server
   searching for changes
   wrote ready: $TESTTMP/readyfile
   waiting on: $TESTTMP/watchfile
   abort: push failed:
   'repository changed while pushing - please try again'
 
   $ hg -R server graph
   o  98217d5a1659 C-A (default)
   |
   @  842e2fac6304 C-ROOT (default)
   
 
 Pushing on two different heads
 ------------------------------
 
 Both try to replace a different head
 
 #  a b
 #  | |
 #  * *
 #  |/
 #  *
 
 (resync-all)
 
   $ hg -R ./server pull ./client-racy
   pulling from ./client-racy
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
   (run 'hg heads' to see heads, 'hg merge' to merge)
   $ hg -R ./client-other pull
   pulling from ssh://user@dummy/server
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
   (run 'hg heads' to see heads, 'hg merge' to merge)
   $ hg -R ./client-racy pull
   pulling from ssh://user@dummy/server
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
   (run 'hg heads' to see heads, 'hg merge' to merge)
 
   $ hg -R server graph
   o  a9149a1428e2 C-B (default)
   |
   | o  98217d5a1659 C-A (default)
   |/
   @  842e2fac6304 C-ROOT (default)
   
 
 Creating changesets
 
   $ echo aa >> client-other/a
   $ hg -R client-other/ commit -m "C-C"
   $ echo bb >> client-racy/b
   $ hg -R client-racy/ commit -m "C-D"
 
 Pushing
 
   $ hg -R client-racy push -r 'tip' > ./push-log 2>&1 &
 
   $ waiton $TESTTMP/readyfile
 
   $ hg -R client-other push -r 'tip'
   pushing to ssh://user@dummy/server
   searching for changes
   remote: adding changesets
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 1 changes to 1 files
 
   $ release $TESTTMP/watchfile
 
 Check the result of the push
 
   $ cat ./push-log
   pushing to ssh://user@dummy/server
   searching for changes
   wrote ready: $TESTTMP/readyfile
   waiting on: $TESTTMP/watchfile
   abort: push failed:
   'repository changed while pushing - please try again'
 
   $ hg -R server graph
   o  51c544a58128 C-C (default)
   |
   o  98217d5a1659 C-A (default)
   |
   | o  a9149a1428e2 C-B (default)
   |/
   @  842e2fac6304 C-ROOT (default)
   
 Pushing while someone creates a new head
 -----------------------------------------
 
 Pushing a new changeset while someone creates a new branch.
 
 #  a (raced)
 #  |
 #  * b
 #  |/
 #  *
 
 (resync-all)
 
   $ hg -R ./server pull ./client-racy
   pulling from ./client-racy
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   (run 'hg update' to get a working copy)
   $ hg -R ./client-other pull
   pulling from ssh://user@dummy/server
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   (run 'hg update' to get a working copy)
   $ hg -R ./client-racy pull
   pulling from ssh://user@dummy/server
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   (run 'hg update' to get a working copy)
 
   $ hg -R server graph
   o  59e76faf78bd C-D (default)
   |
   o  a9149a1428e2 C-B (default)
   |
   | o  51c544a58128 C-C (default)
   | |
   | o  98217d5a1659 C-A (default)
   |/
   @  842e2fac6304 C-ROOT (default)
   
 
 Creating changesets
 
 (new head)
 
   $ hg -R client-other/ up 'desc("C-A")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo aaa >> client-other/a
   $ hg -R client-other/ commit -m "C-E"
   created new head
 
 (children of existing head)
 
   $ hg -R client-racy/ up 'desc("C-C")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo bbb >> client-racy/a
   $ hg -R client-racy/ commit -m "C-F"
 
 Pushing
 
   $ hg -R client-racy push -r 'tip' > ./push-log 2>&1 &
 
   $ waiton $TESTTMP/readyfile
 
   $ hg -R client-other push -fr 'tip'
   pushing to ssh://user@dummy/server
   searching for changes
   remote: adding changesets
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 1 changes to 1 files (+1 heads)
 
   $ release $TESTTMP/watchfile
 
 Check the result of the push
 
   $ cat ./push-log
   pushing to ssh://user@dummy/server
   searching for changes
   wrote ready: $TESTTMP/readyfile
   waiting on: $TESTTMP/watchfile
   abort: push failed:
   'repository changed while pushing - please try again'
 
   $ hg -R server graph
   o  d603e2c0cdd7 C-E (default)
   |
   | o  51c544a58128 C-C (default)
   |/
   o  98217d5a1659 C-A (default)
   |
   | o  59e76faf78bd C-D (default)
   | |
   | o  a9149a1428e2 C-B (default)
   |/
   @  842e2fac6304 C-ROOT (default)
   
 
 Pushing touching different named branch (same topo): new branch raced
 ---------------------------------------------------------------------
 
 Pushing two children on the same head, one is a different named branch
 
 #  a (raced, branch-a)
 #  |
 #  | b (default branch)
 #  |/
 #  *
 
 (resync-all)
 
   $ hg -R ./server pull ./client-racy
   pulling from ./client-racy
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   (run 'hg update' to get a working copy)
   $ hg -R ./client-other pull
   pulling from ssh://user@dummy/server
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   (run 'hg update' to get a working copy)
   $ hg -R ./client-racy pull
   pulling from ssh://user@dummy/server
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
   (run 'hg heads .' to see heads, 'hg merge' to merge)
 
   $ hg -R server graph
   o  d9e379a8c432 C-F (default)
   |
   o  51c544a58128 C-C (default)
   |
   | o  d603e2c0cdd7 C-E (default)
   |/
   o  98217d5a1659 C-A (default)
   |
   | o  59e76faf78bd C-D (default)
   | |
   | o  a9149a1428e2 C-B (default)
   |/
   @  842e2fac6304 C-ROOT (default)
   
 
 Creating changesets
 
 (update existing head)
 
   $ hg -R client-other/ up 'desc("C-F")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo aaa >> client-other/a
   $ hg -R client-other/ commit -m "C-G"
 
 (new named branch from that existing head)
 
   $ hg -R client-racy/ up 'desc("C-F")'
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo bbb >> client-racy/a
   $ hg -R client-racy/ branch my-first-test-branch
   marked working directory as branch my-first-test-branch
   (branches are permanent and global, did you want a bookmark?)
   $ hg -R client-racy/ commit -m "C-H"
 
 Pushing
 
   $ hg -R client-racy push -r 'tip' --new-branch > ./push-log 2>&1 &
 
   $ waiton $TESTTMP/readyfile
 
   $ hg -R client-other push -fr 'tip'
   pushing to ssh://user@dummy/server
   searching for changes
   remote: adding changesets
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 1 changes to 1 files
 
   $ release $TESTTMP/watchfile
 
 Check the result of the push
 
   $ cat ./push-log
   pushing to ssh://user@dummy/server
   searching for changes
   wrote ready: $TESTTMP/readyfile
   waiting on: $TESTTMP/watchfile
   abort: push failed:
   'repository changed while pushing - please try again'
 
   $ hg -R server graph
   o  75d69cba5402 C-G (default)
   |
   o  d9e379a8c432 C-F (default)
   |
   o  51c544a58128 C-C (default)
   |
   | o  d603e2c0cdd7 C-E (default)
   |/
   o  98217d5a1659 C-A (default)
   |
   | o  59e76faf78bd C-D (default)
   | |
   | o  a9149a1428e2 C-B (default)
   |/
   @  842e2fac6304 C-ROOT (default)
   
 
 pushing touching different named branch (same topo): old branch raced
 ---------------------------------------------------------------------
 
 Pushing two children on the same head, one is a different named branch
 
 #  a (raced, default-branch)
 #  |
 #  | b (new branch)
 #  |/
 #  * (default-branch)
 
 (resync-all)
 
   $ hg -R ./server pull ./client-racy
   pulling from ./client-racy
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
   (run 'hg heads .' to see heads, 'hg merge' to merge)
   $ hg -R ./client-other pull
   pulling from ssh://user@dummy/server
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
   (run 'hg heads .' to see heads, 'hg merge' to merge)
   $ hg -R ./client-racy pull
   pulling from ssh://user@dummy/server
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
   (run 'hg heads' to see heads)
 
   $ hg -R server graph
   o  833be552cfe6 C-H (my-first-test-branch)
   |
   | o  75d69cba5402 C-G (default)
   |/
   o  d9e379a8c432 C-F (default)
   |
   o  51c544a58128 C-C (default)
   |
   | o  d603e2c0cdd7 C-E (default)
   |/
   o  98217d5a1659 C-A (default)
   |
   | o  59e76faf78bd C-D (default)
   | |
   | o  a9149a1428e2 C-B (default)
   |/
   @  842e2fac6304 C-ROOT (default)
   
 
 Creating changesets
 
 (new named branch from one head)
 
   $ hg -R client-other/ up 'desc("C-G")'
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo aaa >> client-other/a
   $ hg -R client-other/ branch my-second-test-branch
   marked working directory as branch my-second-test-branch
   $ hg -R client-other/ commit -m "C-I"
 
 (children "updating" that same head)
 
   $ hg -R client-racy/ up 'desc("C-G")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo bbb >> client-racy/a
   $ hg -R client-racy/ commit -m "C-J"
 
 Pushing
 
   $ hg -R client-racy push -r 'tip' > ./push-log 2>&1 &
 
   $ waiton $TESTTMP/readyfile
 
   $ hg -R client-other push -fr 'tip' --new-branch
   pushing to ssh://user@dummy/server
   searching for changes
   remote: adding changesets
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 1 changes to 1 files
 
   $ release $TESTTMP/watchfile
 
 Check the result of the push
 
   $ cat ./push-log
   pushing to ssh://user@dummy/server
   searching for changes
   wrote ready: $TESTTMP/readyfile
   waiting on: $TESTTMP/watchfile
   abort: push failed:
   'repository changed while pushing - please try again'
 
   $ hg -R server graph
   o  b35ed749f288 C-I (my-second-test-branch)
   |
   o  75d69cba5402 C-G (default)
   |
   | o  833be552cfe6 C-H (my-first-test-branch)
   |/
   o  d9e379a8c432 C-F (default)
   |
   o  51c544a58128 C-C (default)
   |
   | o  d603e2c0cdd7 C-E (default)
   |/
   o  98217d5a1659 C-A (default)
   |
   | o  59e76faf78bd C-D (default)
   | |
   | o  a9149a1428e2 C-B (default)
   |/
   @  842e2fac6304 C-ROOT (default)
   
 
 pushing racing push touch multiple heads
 ----------------------------------------
 
 There are multiple heads, but the racing push touch all of them
 
 #  a (raced)
 #  | b
 #  |/|
 #  * *
 #  |/
 #  *
 
 (resync-all)
 
   $ hg -R ./server pull ./client-racy
   pulling from ./client-racy
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
   (run 'hg heads .' to see heads, 'hg merge' to merge)
   $ hg -R ./client-other pull
   pulling from ssh://user@dummy/server
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
   (run 'hg heads' to see heads)
   $ hg -R ./client-racy pull
   pulling from ssh://user@dummy/server
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
   (run 'hg heads .' to see heads, 'hg merge' to merge)
 
   $ hg -R server graph
   o  89420bf00fae C-J (default)
   |
   | o  b35ed749f288 C-I (my-second-test-branch)
   |/
   o  75d69cba5402 C-G (default)
   |
   | o  833be552cfe6 C-H (my-first-test-branch)
   |/
   o  d9e379a8c432 C-F (default)
   |
   o  51c544a58128 C-C (default)
   |
   | o  d603e2c0cdd7 C-E (default)
   |/
   o  98217d5a1659 C-A (default)
   |
   | o  59e76faf78bd C-D (default)
   | |
   | o  a9149a1428e2 C-B (default)
   |/
   @  842e2fac6304 C-ROOT (default)
   
 
 Creating changesets
 
 (merges heads)
 
   $ hg -R client-other/ up 'desc("C-E")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg -R client-other/ merge 'desc("C-D")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg -R client-other/ commit -m "C-K"
 
 (update one head)
 
   $ hg -R client-racy/ up 'desc("C-D")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo bbb >> client-racy/b
   $ hg -R client-racy/ commit -m "C-L"
 
 Pushing
 
   $ hg -R client-racy push -r 'tip' > ./push-log 2>&1 &
 
   $ waiton $TESTTMP/readyfile
 
   $ hg -R client-other push -fr 'tip' --new-branch
   pushing to ssh://user@dummy/server
   searching for changes
   remote: adding changesets
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 0 changes to 0 files (-1 heads)
 
   $ release $TESTTMP/watchfile
 
 Check the result of the push
 
   $ cat ./push-log
   pushing to ssh://user@dummy/server
   searching for changes
   wrote ready: $TESTTMP/readyfile
   waiting on: $TESTTMP/watchfile
   abort: push failed:
   'repository changed while pushing - please try again'
 
   $ hg -R server graph
   o    be705100c623 C-K (default)
   |\
   | o  d603e2c0cdd7 C-E (default)
   | |
   o |  59e76faf78bd C-D (default)
   | |
   | | o  89420bf00fae C-J (default)
   | | |
   | | | o  b35ed749f288 C-I (my-second-test-branch)
   | | |/
   | | o  75d69cba5402 C-G (default)
   | | |
   | | | o  833be552cfe6 C-H (my-first-test-branch)
   | | |/
   | | o  d9e379a8c432 C-F (default)
   | | |
   | | o  51c544a58128 C-C (default)
   | |/
   o |  a9149a1428e2 C-B (default)
   | |
   | o  98217d5a1659 C-A (default)
   |/
   @  842e2fac6304 C-ROOT (default)
   
 
 pushing raced push touch multiple heads
 ---------------------------------------
 
 There are multiple heads, the raced push touch all of them
 
 #  b
 #  | a (raced)
 #  |/|
 #  * *
 #  |/
 #  *
 
 (resync-all)
 
   $ hg -R ./server pull ./client-racy
   pulling from ./client-racy
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
   (run 'hg heads .' to see heads, 'hg merge' to merge)
   $ hg -R ./client-other pull
   pulling from ssh://user@dummy/server
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files (+1 heads)
   (run 'hg heads .' to see heads, 'hg merge' to merge)
   $ hg -R ./client-racy pull
   pulling from ssh://user@dummy/server
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 0 changes to 0 files
   (run 'hg update' to get a working copy)
 
   $ hg -R server graph
   o  cac2cead0ff0 C-L (default)
   |
   | o  be705100c623 C-K (default)
   |/|
   | o  d603e2c0cdd7 C-E (default)
   | |
   o |  59e76faf78bd C-D (default)
   | |
   | | o  89420bf00fae C-J (default)
   | | |
   | | | o  b35ed749f288 C-I (my-second-test-branch)
   | | |/
   | | o  75d69cba5402 C-G (default)
   | | |
   | | | o  833be552cfe6 C-H (my-first-test-branch)
   | | |/
   | | o  d9e379a8c432 C-F (default)
   | | |
   | | o  51c544a58128 C-C (default)
   | |/
   o |  a9149a1428e2 C-B (default)
   | |
   | o  98217d5a1659 C-A (default)
   |/
   @  842e2fac6304 C-ROOT (default)
   
 
 Creating changesets
 
 (update existing head)
 
   $ echo aaa >> client-other/a
   $ hg -R client-other/ commit -m "C-M"
 
 (merge heads)
 
   $ hg -R client-racy/ merge 'desc("C-K")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg -R client-racy/ commit -m "C-N"
 
 Pushing
 
   $ hg -R client-racy push -r 'tip' > ./push-log 2>&1 &
 
   $ waiton $TESTTMP/readyfile
 
   $ hg -R client-other push -fr 'tip' --new-branch
   pushing to ssh://user@dummy/server
   searching for changes
   remote: adding changesets
   remote: adding manifests
   remote: adding file changes
   remote: added 1 changesets with 1 changes to 1 files
 
   $ release $TESTTMP/watchfile
 
 Check the result of the push
 
   $ cat ./push-log
   pushing to ssh://user@dummy/server
   searching for changes
   wrote ready: $TESTTMP/readyfile
   waiting on: $TESTTMP/watchfile
   abort: push failed:
   'repository changed while pushing - please try again'
 
   $ hg -R server graph
   o  6fd3090135df C-M (default)
   |
   o    be705100c623 C-K (default)
   |\
   | o  d603e2c0cdd7 C-E (default)
   | |
   +---o  cac2cead0ff0 C-L (default)
   | |
   o |  59e76faf78bd C-D (default)
   | |
   | | o  89420bf00fae C-J (default)
   | | |
   | | | o  b35ed749f288 C-I (my-second-test-branch)
   | | |/
   | | o  75d69cba5402 C-G (default)
   | | |
   | | | o  833be552cfe6 C-H (my-first-test-branch)
   | | |/
   | | o  d9e379a8c432 C-F (default)
   | | |
   | | o  51c544a58128 C-C (default)
   | |/
   o |  a9149a1428e2 C-B (default)
   | |
   | o  98217d5a1659 C-A (default)
   |/
   @  842e2fac6304 C-ROOT (default)
   
+
+racing commit push a new head behind another named branch
+---------------------------------------------------------
+
+non-continuous branch are valid case, we tests for them.
+
+#  b (branch default)
+#  |
+#  o (branch foo)
+#  |
+#  | a (raced, branch default)
+#  |/
+#  * (branch foo)
+#  |
+#  * (branch default)
+
+(resync-all + other branch)
+
+  $ hg -R ./server pull ./client-racy
+  pulling from ./client-racy
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 0 changes to 0 files
+  (run 'hg update' to get a working copy)
+
+(creates named branch on head)
+
+  $ hg -R ./server/ up 'desc("C-N")'
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg -R ./server/ branch other
+  marked working directory as branch other
+  $ hg -R ./server/ ci -m "C-Z"
+  $ hg -R ./server/ up null
+  0 files updated, 0 files merged, 3 files removed, 0 files unresolved
+
+(sync client)
+
+  $ hg -R ./client-other pull
+  pulling from ssh://user@dummy/server
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 2 changesets with 0 changes to 0 files
+  (run 'hg update' to get a working copy)
+  $ hg -R ./client-racy pull
+  pulling from ssh://user@dummy/server
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 2 changesets with 1 changes to 1 files (+1 heads)
+  (run 'hg heads .' to see heads, 'hg merge' to merge)
+
+  $ hg -R server graph
+  o  55a6f1c01b48 C-Z (other)
+  |
+  o    866a66e18630 C-N (default)
+  |\
+  +---o  6fd3090135df C-M (default)
+  | |
+  | o  cac2cead0ff0 C-L (default)
+  | |
+  o |  be705100c623 C-K (default)
+  |\|
+  o |  d603e2c0cdd7 C-E (default)
+  | |
+  | o  59e76faf78bd C-D (default)
+  | |
+  | | o  89420bf00fae C-J (default)
+  | | |
+  | | | o  b35ed749f288 C-I (my-second-test-branch)
+  | | |/
+  | | o  75d69cba5402 C-G (default)
+  | | |
+  | | | o  833be552cfe6 C-H (my-first-test-branch)
+  | | |/
+  | | o  d9e379a8c432 C-F (default)
+  | | |
+  +---o  51c544a58128 C-C (default)
+  | |
+  | o  a9149a1428e2 C-B (default)
+  | |
+  o |  98217d5a1659 C-A (default)
+  |/
+  o  842e2fac6304 C-ROOT (default)
+  
+
+Creating changesets
+
+(update default head through another named branch one)
+
+  $ hg -R client-other/ up 'desc("C-Z")'
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ echo aaa >> client-other/a
+  $ hg -R client-other/ commit -m "C-O"
+  $ echo aaa >> client-other/a
+  $ hg -R client-other/ branch --force default
+  marked working directory as branch default
+  $ hg -R client-other/ commit -m "C-P"
+  created new head
+
+(update default head)
+
+  $ hg -R client-racy/ up 'desc("C-Z")'
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ echo bbb >> client-other/a
+  $ hg -R client-racy/ branch --force default
+  marked working directory as branch default
+  $ hg -R client-racy/ commit -m "C-Q"
+  created new head
+
+Pushing
+
+  $ hg -R client-racy push -r 'tip' > ./push-log 2>&1 &
+
+  $ waiton $TESTTMP/readyfile
+
+  $ hg -R client-other push -fr 'tip' --new-branch
+  pushing to ssh://user@dummy/server
+  searching for changes
+  remote: adding changesets
+  remote: adding manifests
+  remote: adding file changes
+  remote: added 2 changesets with 1 changes to 1 files
+
+  $ release $TESTTMP/watchfile
+
+Check the result of the push
+
+  $ cat ./push-log
+  pushing to ssh://user@dummy/server
+  searching for changes
+  wrote ready: $TESTTMP/readyfile
+  waiting on: $TESTTMP/watchfile
+  abort: push failed:
+  'repository changed while pushing - please try again'
+
+  $ hg -R server graph
+  o  1b58ee3f79e5 C-P (default)
+  |
+  o  d0a85b2252a9 C-O (other)
+  |
+  o  55a6f1c01b48 C-Z (other)
+  |
+  o    866a66e18630 C-N (default)
+  |\
+  +---o  6fd3090135df C-M (default)
+  | |
+  | o  cac2cead0ff0 C-L (default)
+  | |
+  o |  be705100c623 C-K (default)
+  |\|
+  o |  d603e2c0cdd7 C-E (default)
+  | |
+  | o  59e76faf78bd C-D (default)
+  | |
+  | | o  89420bf00fae C-J (default)
+  | | |
+  | | | o  b35ed749f288 C-I (my-second-test-branch)
+  | | |/
+  | | o  75d69cba5402 C-G (default)
+  | | |
+  | | | o  833be552cfe6 C-H (my-first-test-branch)
+  | | |/
+  | | o  d9e379a8c432 C-F (default)
+  | | |
+  +---o  51c544a58128 C-C (default)
+  | |
+  | o  a9149a1428e2 C-B (default)
+  | |
+  o |  98217d5a1659 C-A (default)
+  |/
+  o  842e2fac6304 C-ROOT (default)
+