gistfile1.txt

  $ cat >> $HGRCPATH <<EOF
  > [phases]
  > publish = False
  > [alias]
  > qlog = log --template='{rev} - {node|short} {desc} ({phase})\n'
  > [diff]
  > git = 1
  > unified = 0
  > [extensions]
  > EOF
  $ echo "evolve=$(echo $(dirname $TESTDIR))/hgext3rd/evolve/" >> $HGRCPATH

  $ mkcommit() {
  >    echo "$1" > "$1"
  >    hg add "$1"
  >    hg ci -m "add $1"
  > }

  $ mkstack() {
  >    # Creates a stack of commit based on $1 with messages from $2, $3 ..
  >    hg update $1 -C
  >    shift
  >    mkcommits $*
  > }

  $ glog() {
  >   hg log -G --template '{rev}:{node|short}@{branch}({phase}) {desc|firstline}\n' "$@"
  > }

  $ shaof() {
  >   hg log -T {node} -r "first(desc($1))"
  > }

  $ mkcommits() {
  >   for i in $@; do mkcommit $i ; done
  > }

Creating And Updating Changeset
===============================

Setup the Base Repo
-------------------

We start with a plain base repo::

  $ hg init main; cd main
  $ cat >main-file-1 <<-EOF
  > One
  > 
  > Two
  > 
  > Three
  > EOF
  $ echo Two >main-file-2
  $ hg add
  adding main-file-1
  adding main-file-2
  $ hg commit --message base
  $ cd ..

and clone this into a new repo where we do our work::

  $ hg clone main work
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd work


Create First Patch
------------------

To begin with, we just do the changes that will be the initial version of the changeset::

  $ echo One >file-from-A
  $ sed -i'' -e s/One/Eins/ main-file-1
  $ hg add file-from-A

So this is what we would like our changeset to be::

  $ hg diff
  diff --git a/file-from-A b/file-from-A
  new file mode 100644
  --- /dev/null
  +++ b/file-from-A
  @@ -0,0 +1,1 @@
  +One
  diff --git a/main-file-1 b/main-file-1
  --- a/main-file-1
  +++ b/main-file-1
  @@ -1,1 +1,1 @@
  -One
  +Eins

To commit it we just - commit it::

  $ hg commit --message "a nifty feature"

and place a bookmark so we can easily refer to it again (which we could have done before the commit)::

  $ hg book feature-A


Create Second Patch
-------------------

Let's do this again for the second changeset::

  $ echo Two >file-from-B
  $ sed -i'' -e s/Two/Zwie/ main-file-1
  $ hg add file-from-B

Before committing, however, we need to switch to a new bookmark for the second
changeset. Otherwise we would inadvertently move the bookmark for our first changeset.
It is therefore advisable to always set the bookmark before committing::

  $ hg book feature-B
  $ hg --config extensions.commitextras commit --extra tagged=feature-b --message "another feature (child of $(hg log -r . -T '{node|short}'))"

So here we are::

  $ hg book
     feature-A                 1:568a468b60fc
   * feature-B                 2:73296a82292a


Fix The Second Patch
--------------------

There's a typo in feature-B. We spelled *Zwie* instead of *Zwei*::

  $ hg diff --change tip | grep -F Zwie
  +Zwie

Fixing this is very easy. Just change::

  $ sed -i'' -e s/Zwie/Zwei/ main-file-1

and **amend**::

  $ hg amend

This results in a new single changeset for our amended changeset, and the old
changeset plus the updating changeset are hidden from view by default::

  $ hg log
  3 feature-B: another feature (child of 568a468b60fc) - test
  1 feature-A: a nifty feature - test
  0 : base - test

  $ hg up feature-A -q
  $ hg bookmark -i feature-A
  $ sed -i'' -e s/Eins/Un/ main-file-1

(amend of public changeset denied)

  $ hg phase --public 0 -v
  phase changed for 1 changesets


(amend of on ancestors)

  $ hg amend
  1 new orphan changesets
  $ hg log
  4 feature-A: a nifty feature - test
  3 feature-B: another feature (child of 568a468b60fc) - test
  1 : a nifty feature - test
  0 : base - test
  $ hg up -q 0
  $ glog --hidden
  o  4:ba0ec09b1bab@default(draft) a nifty feature
  |
  | *  3:6992c59c6b06@default(draft) another feature (child of 568a468b60fc)
  | |
  | | x  2:73296a82292a@default(draft) another feature (child of 568a468b60fc)
  | |/
  | x  1:568a468b60fc@default(draft) a nifty feature
  |/
  @  0:e55e0562ee93@default(public) base
  
  $ hg log -r 3 -T '{join(extras, " ")}\n'
  *tagged=feature-b* (glob)

  $ hg --config extensions.debugretainextras --config retain_extras=tagged evolve
  move:[3] another feature (child of 568a468b60fc)
  atop:[4] a nifty feature
  merging main-file-1
  $ hg log -r 5 -T '{join(extras, " ")}\n'
  *tagged=feature-b* (glob)