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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 errno

  > import os

  > import time

  > 

  > from mercurial import (

  >     exchange,

  >     extensions,

  >     registrar,

  > )

  > 

  > configtable = {}

  > configitem = registrar.configitem(configtable)

  > 

  > configitem(b'delaypush', b'ready-path',

  >     default=None,

  > )

  > configitem(b'delaypush', b'release-path',

  >     default=None,

  > )

  > 

  > def delaypush(orig, pushop):

  >     # notify we are done preparing

  >     ui = pushop.repo.ui

  >     readypath = ui.config(b'delaypush', b'ready-path')

  >     if readypath is not None:

  >         with open(readypath, 'w') as r:

  >             r.write('foo')

  >         ui.status(b'wrote ready: %s\n' % readypath)

  >     # now wait for the other process to be done

  >     watchpath = ui.config(b'delaypush', b'release-path')

  >     if watchpath is not None:

  >         ui.status(b'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:

  >             ui.warn(b'exiting without watchfile: %s' % watchpath)

  >         else:

  >             # delete the file at the end of the push

  >             def delete():

  >                 try:

  >                     os.unlink(watchpath)

  >                 except FileNotFoundError:

  >                     pass

  >             ui.atexit(delete)

  >     return orig(pushop)

  > 

  > def uisetup(ui):

  >     extensions.wrapfunction(exchange, b'_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]

  > # simplify output

  > logtemplate = {node|short} {desc} ({branch})

  > [phases]

  > publish = no

  > [experimental]

  > evolution=true

  > [alias]

  > graph = log -G --rev 'sort(all(), "topo")'

  > EOF

We tests multiple cases:

* strict: no race detected,

* unrelated: race on unrelated heads are allowed.

#testcases strict unrelated

#if strict

  $ cat >> $HGRCPATH << EOF

  > [server]

  > concurrent-push-mode = strict

  > EOF

#endif

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

  new changesets 842e2fac6304 (1 drafts)

  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

  new changesets 842e2fac6304 (1 drafts)

  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:

  'remote 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)

  new changesets a9149a1428e2 (1 drafts)

  (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)

  new changesets a9149a1428e2 (1 drafts)

  (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)

  new changesets 98217d5a1659 (1 drafts)

  (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

#if strict

  $ cat ./push-log

  pushing to ssh://user@dummy/server

  searching for changes

  wrote ready: $TESTTMP/readyfile

  waiting on: $TESTTMP/watchfile

  abort: push failed:

  'remote 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)

#endif

#if unrelated

(The two heads are unrelated, push should be allowed)

  $ cat ./push-log

  pushing to ssh://user@dummy/server

  searching for changes

  wrote ready: $TESTTMP/readyfile

  waiting on: $TESTTMP/watchfile

  remote: adding changesets

  remote: adding manifests

  remote: adding file changes

  remote: added 1 changesets with 1 changes to 1 files

  $ 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)

#endif

Pushing while someone creates a new head

-----------------------------------------

Pushing a new changeset while someone creates a new branch.

#  a (raced)

#  |

#  * b

#  |/

#  *

(resync-all)

#if strict

  $ 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

  new changesets 59e76faf78bd (1 drafts)

  (run 'hg update' to get a working copy)

#endif

#if unrelated

  $ hg -R ./server pull ./client-racy

  pulling from ./client-racy

  searching for changes

  no changes found

#endif

  $ 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

  new changesets 59e76faf78bd (1 drafts)

  (run 'hg update' to get a working copy)

  $ hg -R ./client-racy pull

  pulling from ssh://user@dummy/server