Mutable History and collaboration
=====================================================================


History mutation
=====================

.. Albert Beugras

.. René de Robert


Here is small introduction of 

Single Developer Usage
======================

This tutorial shows how to use evolution to replace the basics of *mq*.


Amending a changeset
---------------------


First there is some setup phase you will understand later.

there is a local repository and a remote one.

Please close your eyes.

  $ hg init local
  $ cat >> local/.hg/hgrc << EOF
  > [paths]
  > remote = ../remote
  > [ui]
  > user = Albert Beugras
  > [diff]
  > git = 1
  > [alias]
  > amend = amend -d '0 0'
  > tlog = log --template "{node|short}: '{desc}'\n"
  > ttlog = log --template "{node|short}: '{desc}' ({state})\n"
  > tglog = log -G --template "{node|short}: '{desc}' {branches}\n"
  > [extensions]
  > hgext.graphlog=
  > hgext.rebase=
  > EOF
  $ echo "states=$(echo $(dirname $TESTDIR))/hgext/states.py" >> local/.hg/hgrc
  $ echo "obsolete=$(echo $(dirname $TESTDIR))/hgext/obsolete.py" >> local/.hg/hgrc
  $ echo "evolution=$(echo $(dirname $TESTDIR))/hgext/evolution.py" >> local/.hg/hgrc
  $ hg init remote
  $ cat >> remote/.hg/hgrc << EOF
  > [paths]
  > local = ../local
  > [ui]
  > user = René de Robert
  > [diff]
  > git = 1
  > [alias]
  > amend = amend -d '0 0'
  > tlog = log --template "{node|short}: '{desc}' {branches}\n"
  > ttlog = log --template "{node|short}: '{desc}' {state}\n"
  > tglog = log -G --template "{node|short}: '{desc}' {branches}\n"
  > [extensions]
  > hgext.graphlog=
  > hgext.rebase=
  > EOF
  $ echo "states=$(echo $(dirname $TESTDIR))/hgext/states.py" >> remote/.hg/hgrc
  $ echo "obsolete=$(echo $(dirname $TESTDIR))/hgext/obsolete.py" >> remote/.hg/hgrc
  $ echo "evolution=$(echo $(dirname $TESTDIR))/hgext/evolution.py" >> remote/.hg/hgrc
  $ cd local

You can reopen you eyes.

Now we make a first version of our shopping list.

  $ cat  >> shopping << EOF
  > Spam
  > Whizzo butter
  > Albatross
  > Rat (rather a lot)
  > Jugged fish
  > Blancmange
  > Salmon mousse
  > EOF
  $ hg commit -A -m "Monthy Python Shopping list"
  adding shopping

We share this first version with the outside.

  $ hg push remote
  pushing to $TESTTMP/remote
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files

Later I add additional item to my list

  $ cat >> shopping << EOF
  > Egg
  > Suggar
  > Vinegar
  > Oil
  > EOF
  $ hg commit -m "adding condiment"
  $ cat >> shopping << EOF
  > Bananos
  > Pear
  > Apple
  > EOF
  $ hg commit -m "adding fruit"

I now have the following history:

  $ hg tlog
  d85de4546133: 'adding fruit'
  4d5dc8187023: 'adding condiment'
  7e82d3f3c2cb: 'Monthy Python Shopping list'

But, I just notice, I made a typo in Banana.

  $ hg export tip
  # HG changeset patch
  # User test
  # Date 0 0
  # Node ID d85de4546133030c82d257bbcdd9b1b416d0c31c
  # Parent  4d5dc81870237d492284826e21840b2ca00e26d1
  adding fruit
  
  diff --git a/shopping b/shopping
  --- a/shopping
  +++ b/shopping
  @@ -9,3 +9,6 @@
   Suggar
   Vinegar
   Oil
  +Bananos
  +Pear
  +Apple

hopefully. I can use hg amend to rewrite my faulty changeset!

  $ sed -i'' -e s/Bananos/Banana/ shopping
  $ hg diff
  diff --git a/shopping b/shopping
  --- a/shopping
  +++ b/shopping
  @@ -9,6 +9,6 @@
   Suggar
   Vinegar
   Oil
  -Bananos
  +Banana
   Pear
   Apple
  $ hg amend
  abort: can not rewrite immutable changeset d85de4546133
  [255]

By default all changeset are considered "published" and can't be rewrittent.

 $ hg ttlog

You need to enable a mutable state in your repo the "ready" one

  $ hg states ready --clever
  $ hg ttlog
  d85de4546133: 'adding fruit' (ready)
  4d5dc8187023: 'adding condiment' (ready)
  7e82d3f3c2cb: 'Monthy Python Shopping list' (published)

Notice that changeset you already shared with the outside have been keep
published.

The changeset we want to rewrite is now in a mutable state.

  $ hg amend

A new changeset with the right diff replace the wrong one.

  $ hg tlog
  0cacb48f4482: 'adding fruit'
  4d5dc8187023: 'adding condiment'
  7e82d3f3c2cb: 'Monthy Python Shopping list'
  $ hg export tip
  # HG changeset patch
  # User test
  # Date 0 0
  # Node ID 0cacb48f44828d2fd31c4e45e18fde32a5b2f07b
  # Parent  4d5dc81870237d492284826e21840b2ca00e26d1
  adding fruit
  
  diff --git a/shopping b/shopping
  --- a/shopping
  +++ b/shopping
  @@ -9,3 +9,6 @@
   Suggar
   Vinegar
   Oil
  +Banana
  +Pear
  +Apple

Getting Ride of branchy history
----------------------------------

While I was working on my list. someone help made a change remotly.

close your eyes

  $ cd ../remote
  $ hg up -q
  $ sed -i'' -e 's/Spam/Spam Spam Spam/' shopping
  $ hg ci -m 'SPAM'
  $ cd ../local

open your eyes

  $ hg pull remote
  pulling from $TESTTMP/remote
  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)

I now have a new heads. Note that the remote head is immutable

  $ hg ttlog
  9ca060c80d74: 'SPAM' (published)
  0cacb48f4482: 'adding fruit' (ready)
  4d5dc8187023: 'adding condiment' (ready)
  7e82d3f3c2cb: 'Monthy Python Shopping list' (published)
  $ hg tglog -r "::(9ca060c80d74 + 0cacb48f4482)"
  o  9ca060c80d74: 'SPAM'
  |
  | @  0cacb48f4482: 'adding fruit'
  | |
  | o  4d5dc8187023: 'adding condiment'
  |/
  o  7e82d3f3c2cb: 'Monthy Python Shopping list'
  

instead of merging my head with the new one. I'm going to rebase my work

  $ hg diff
  $ hg rebase -d 9ca060c80d74 -s 4d5dc8187023
  merging shopping
  merging shopping
  merging shopping
  merging shopping


My local work is now rebase on the remote one.

  $ hg kill e7a71e229632 ad97bbd3e37d # XXX fix me instead
  $ hg ttlog
  387187ad9bd9: 'adding fruit' (ready)
  dfd3a2d7691e: 'adding condiment' (ready)
  9ca060c80d74: 'SPAM' (published)
  7e82d3f3c2cb: 'Monthy Python Shopping list' (published)
  $ hg tglog -r '::.'
  @  387187ad9bd9: 'adding fruit'
  |
  o  dfd3a2d7691e: 'adding condiment'
  |
  o  9ca060c80d74: 'SPAM'
  |
  o  7e82d3f3c2cb: 'Monthy Python Shopping list'
  

Removing changeset
------------------------

I add new item to my list

  $ cat >> shopping << EOF
  > car
  > bus
  > plane
  > boat
  > EOF
  $ hg ci -m 'transport'
  $ hg ttlog
  d58c77aa15d7: 'transport' (ready)
  387187ad9bd9: 'adding fruit' (ready)
  dfd3a2d7691e: 'adding condiment' (ready)
  9ca060c80d74: 'SPAM' (published)
  7e82d3f3c2cb: 'Monthy Python Shopping list' (published)

I have a new commit but I realize that don't want it. (transport shop list does
not fit well in my standard shopping list)

  $ hg kill . # . is for working directory parent.
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  working directory now at 387187ad9bd9

The silly changeset is gone.

  $ hg ttlog
  387187ad9bd9: 'adding fruit' (ready)
  dfd3a2d7691e: 'adding condiment' (ready)
  9ca060c80d74: 'SPAM' (published)
  7e82d3f3c2cb: 'Monthy Python Shopping list' (published)

Reordering changeset
------------------------


We create two changeset.


  $ cat >> shopping << EOF
  > Shampoo
  > Toothbrush
  > ... More bathroom stuff to come
  > Towel
  > Soap
  > EOF
  $ hg ci -m 'bathroom stuff' -q # XXX remove the -q

  $ sed -i'' -e 's/Spam/Spam Spam Spam/g' shopping
  $ hg ci -m 'SPAM SPAM'
  $ hg ttlog
  c48f32fb1787: 'SPAM SPAM' (ready)
  8d39a843582d: 'bathroom stuff' (ready)
  387187ad9bd9: 'adding fruit' (ready)
  dfd3a2d7691e: 'adding condiment' (ready)
  9ca060c80d74: 'SPAM' (published)
  7e82d3f3c2cb: 'Monthy Python Shopping list' (published)

.. note: don't amend changeset 7e82d3f3c2cb or 9ca060c80d74 as they are
immutable.

I now want to push to remote all my change but the bathroom one that i'm not totally happy with yet.

To be able to push "SPAM SPAM" I need a version of "SPAM SPAM" not children of "bathroom stuff"

You can use rebase or relocate for that:

  $ hg relocate 'p1(8d39a843582d)' --traceback
  merging shopping
  $ hg tglog -r '::(. + 8d39a843582d)'
  @  02e33960e937: 'SPAM SPAM'
  |
  | o  8d39a843582d: 'bathroom stuff'
  |/
  o  387187ad9bd9: 'adding fruit'
  |
  o  dfd3a2d7691e: 'adding condiment'
  |
  o  9ca060c80d74: 'SPAM'
  |
  o  7e82d3f3c2cb: 'Monthy Python Shopping list'
  

We have a new SPAM SPAM version without the bathroom stuff

  $ grep Spam shopping  # enouth spamm
  Spam Spam Spam Spam Spam Spam Spam Spam Spam
  $ grep Toothbrush shopping # no Toothbrush
  [1]
  $ hg export .
  # HG changeset patch
  # User test
  # Date 0 0
  # Node ID 02e33960e937ad1bd59241ebdafd7a2494240ddf
  # Parent  387187ad9bd9d8f9a00a9fa804a26231db547429
  SPAM SPAM
  
  diff --git a/shopping b/shopping
  --- a/shopping
  +++ b/shopping
  @@ -1,4 +1,4 @@
  -Spam Spam Spam
  +Spam Spam Spam Spam Spam Spam Spam Spam Spam
   Whizzo butter
   Albatross
   Rat (rather a lot)

we can now push our change:

  $ hg push -r . remote
  pushing to $TESTTMP/remote
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files

for simplicity shake we relocate the bathroom changeset

  $ hg relocate -r 8d39a843582d 02e33960e937
  merging shopping


Splitting change
------------------

To be done (currently achieve with "two commit + debugobsolete")

Collapsing change
------------------

To be done (currently achieve with "revert + debugobsolete" or "rebase --collapse")

collaboration
====================


sharing mutable changeset
----------------------------

To share mutable changeset with other just check that both have the "ready"
state activated. Otherwise you will get the previously observe behavior where
exchanged changeset are automatically published.

  $ cd ../remote
  $ hg states 
  published

The remote repository have only the immutable "published" state activated. Any
changeset echanged from "local" to "remote" will be set in the publised state:

  $ hg -R ../local push -f remote # XXX we should pull but the support is awful
  pushing to $TESTTMP/remote
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  $ hg ttlog
  a3515e5d0332: 'bathroom stuff' published
  02e33960e937: 'SPAM SPAM' published
  387187ad9bd9: 'adding fruit' published
  dfd3a2d7691e: 'adding condiment' published
  9ca060c80d74: 'SPAM' published
  7e82d3f3c2cb: 'Monthy Python Shopping list' published



We do not want to publish the "bathroom changeset". Let's rollback the last transaction

  $ hg rollback
  repository tip rolled back to revision 4 (undo push)
  working directory now based on revision 1
  $ hg ttlog
  02e33960e937: 'SPAM SPAM' published
  387187ad9bd9: 'adding fruit' published
  dfd3a2d7691e: 'adding condiment' published
  9ca060c80d74: 'SPAM' published
  7e82d3f3c2cb: 'Monthy Python Shopping list' published
  $ rm ../local/.hg/states/published-heads     # XXX USE --exact
  $ hg -R ../local publish 02e33960e937 # XXX FIX THE BUG

To enable the mutable "ready" state in a repository, use the states command.

  $ hg states ready
  $ hg states 
  published
  ready

I can nom exchange mutable changeset between "remote" and "local" repository.

  $ hg pull local # XXX We pull too much stuff
  pulling from $TESTTMP/local
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 10 changesets with 10 changes to 1 files (+5 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg ttlog
  a3515e5d0332: 'bathroom stuff' ready
  02e33960e937: 'SPAM SPAM' published
  387187ad9bd9: 'adding fruit' published
  dfd3a2d7691e: 'adding condiment' published
  9ca060c80d74: 'SPAM' published
  7e82d3f3c2cb: 'Monthy Python Shopping list' published

Rebasing out-of-sync change after update
----------------------------------------------

Remotely someone add a new changeset on top of our mutable "bathroom" on.

  $ hg up a3515e5d0332 -q
  $ cat >> shopping << EOF
  > Giraffe
  > Rhino
  > Lion
  > Bear
  > EOF
  $ hg ci -m 'animals' -q # XXX remove the -q

While this time locally, we rebase the updated the "bathroom changeset"

  $ cd ../local
  $ hg up a3515e5d0332 -q
  $ sed -i'' -e 's/... More bathroom stuff to come/Bath Robe/' shopping
  $ hg amend
  $ hg tlog
  962d3a7d27ad: 'bathroom stuff'
  02e33960e937: 'SPAM SPAM'
  387187ad9bd9: 'adding fruit'
  dfd3a2d7691e: 'adding condiment'
  9ca060c80d74: 'SPAM'
  7e82d3f3c2cb: 'Monthy Python Shopping list'


When we pull from remote again we get an unstable state!

  $ hg pull remote
  pulling from $TESTTMP/remote
  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 tlog
  0b061760b677: 'animals'
  962d3a7d27ad: 'bathroom stuff'
  a3515e5d0332: 'bathroom stuff'
  02e33960e937: 'SPAM SPAM'
  387187ad9bd9: 'adding fruit'
  dfd3a2d7691e: 'adding condiment'
  9ca060c80d74: 'SPAM'
  7e82d3f3c2cb: 'Monthy Python Shopping list'

The new changeset "animal" is based one an old changeset of "bathroom". You can
see both version showing up the log.

  $ hg tglog -r '::(962d3a7d27ad + 0b061760b677)'
  o  0b061760b677: 'animals'
  |
  | @  962d3a7d27ad: 'bathroom stuff'
  | |
  o |  a3515e5d0332: 'bathroom stuff'
  |/
  o  02e33960e937: 'SPAM SPAM'
  |
  o  387187ad9bd9: 'adding fruit'
  |
  o  dfd3a2d7691e: 'adding condiment'
  |
  o  9ca060c80d74: 'SPAM'
  |
  o  7e82d3f3c2cb: 'Monthy Python Shopping list'
  

In hgviewn there is a nice doted relation highlighting 962d3a7d27ad  is a new
version of a3515e5d0332. this is not yet ported to graphlog.

To resolve this unstable state, you need to relocate 0b061760b677 onto
962d3a7d27ad the "hg evolve" will make the thinking for you and suggest it to
you.

  $ hg evolve
  hg relocate --rev 0b061760b677 962d3a7d27ad

Let's do it

  $ hg relocate --rev 0b061760b677 962d3a7d27ad
  merging shopping

The old vesion of bathroom is hidden again now.

  $ hg tlog
  39a85a192689: 'animals'
  962d3a7d27ad: 'bathroom stuff'
  02e33960e937: 'SPAM SPAM'
  387187ad9bd9: 'adding fruit'
  dfd3a2d7691e: 'adding condiment'
  9ca060c80d74: 'SPAM'
  7e82d3f3c2cb: 'Monthy Python Shopping list'

We can push this evolution to remote

  $ hg push -f remote # XXX should not require -f
  pushing to $TESTTMP/remote
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files (+1 heads)

remote get a warning that current working directory is based on an obsolete changeset

  $ cd ../remote
  $ hg up . # XXX "loulz"
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  Working directory parent is obsolete

  $ hg up 39a85a192689
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Relocating out-of-sync change after kill
----------------------------------------------

The remote guy keep working

  $ sed -i'' -e 's/Spam/Spam Spam Spam Spam/g' shopping
  $ hg commit -m "SPAM SPAM SPAM"

Work I can keep getting localy

  $ cd ../local
  $ hg pull remote
  pulling from $TESTTMP/remote
  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 tlog
  e768beeb835c: 'SPAM SPAM SPAM'
  39a85a192689: 'animals'
  962d3a7d27ad: 'bathroom stuff'
  02e33960e937: 'SPAM SPAM'
  387187ad9bd9: 'adding fruit'
  dfd3a2d7691e: 'adding condiment'
  9ca060c80d74: 'SPAM'
  7e82d3f3c2cb: 'Monthy Python Shopping list'

In the mean time I noticed you can't buy animals in a super market and I kill the animal changeset:

  $ hg kill 39a85a192689 # issue warning here
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  working directory now at 962d3a7d27ad

The animals changeset is still displayed because the "SPAM SPAM SPAM" changeset
is neither dead or obsolete.  My repository is in an unstable state again.

  $ hg tlog 
  e768beeb835c: 'SPAM SPAM SPAM'
  39a85a192689: 'animals'
  962d3a7d27ad: 'bathroom stuff'
  02e33960e937: 'SPAM SPAM'
  387187ad9bd9: 'adding fruit'
  dfd3a2d7691e: 'adding condiment'
  9ca060c80d74: 'SPAM'
  7e82d3f3c2cb: 'Monthy Python Shopping list'
  $ hg tglog  -r '::e768beeb835c'
  o  e768beeb835c: 'SPAM SPAM SPAM'
  |
  o  39a85a192689: 'animals'
  |
  @  962d3a7d27ad: 'bathroom stuff'
  |
  o  02e33960e937: 'SPAM SPAM'
  |
  o  387187ad9bd9: 'adding fruit'
  |
  o  dfd3a2d7691e: 'adding condiment'
  |
  o  9ca060c80d74: 'SPAM'
  |
  o  7e82d3f3c2cb: 'Monthy Python Shopping list'
  

#  $ hg evolve # XXX not ready yet
#  hg relocate --rev  e768beeb835c 962d3a7d27ad

  $ hg relocate -r  e768beeb835c 'p1(39a85a192689)'
  merging shopping

  $ hg tlog 
  19098f8178f3: 'SPAM SPAM SPAM'
  962d3a7d27ad: 'bathroom stuff'
  02e33960e937: 'SPAM SPAM'
  387187ad9bd9: 'adding fruit'
  dfd3a2d7691e: 'adding condiment'
  9ca060c80d74: 'SPAM'
  7e82d3f3c2cb: 'Monthy Python Shopping list'

Handling Conflicting amend
----------------------------------------------

We can detect that multiple diverging//conflicting amend have been made. There
will be a "evol-merge" command to merge conflicting amend

collaboration
====================

Turning changeset immutable
----------------------------------------------

* push on published//only repo

* tag

* explicite published command

Handling Invalid amend on published changeset
----------------------------------------------

you can't amend published changeset. changeset that do this will have an "invalid amend" obsolete-status