$ hg init

Setup:

  $ echo a >> a

  $ hg ci -Am 'base'

  adding a

Refuse to amend public csets:

  $ hg phase -r . -p

  $ hg ci --amend

  abort: cannot amend public changesets

  [255]

  $ hg phase -r . -f -d

  $ echo a >> a

  $ hg ci -Am 'base1'

Nothing to amend:

  $ hg ci --amend

  nothing changed

  [1]

Amending changeset with changes in working dir:

  $ echo a >> a

  $ hg ci --amend -m 'amend base1'

  saved backup bundle to $TESTTMP/.hg/strip-backup/489edb5b847d-amend-backup.hg

  $ hg diff -c .

  diff -r ad120869acf0 -r 9cd25b479c51 a

  --- a/a	Thu Jan 01 00:00:00 1970 +0000

  +++ b/a	Thu Jan 01 00:00:00 1970 +0000

  @@ -1,1 +1,3 @@

   a

  +a

  +a

  $ hg log

  changeset:   1:9cd25b479c51

  tag:         tip

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  summary:     amend base1

  changeset:   0:ad120869acf0

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  summary:     base

Add new file:

  $ echo b > b

  $ hg ci --amend -Am 'amend base1 new file'

  adding b

  saved backup bundle to $TESTTMP/.hg/strip-backup/9cd25b479c51-amend-backup.hg

Remove file that was added in amended commit:

  $ hg rm b

  $ hg ci --amend -m 'amend base1 remove new file'

  saved backup bundle to $TESTTMP/.hg/strip-backup/e2bb3ecffd2f-amend-backup.hg

  $ hg cat b

  b: no such file in rev 664a9b2d60cd

  [1]

No changes, just a different message:

  $ hg ci -v --amend -m 'no changes, new message'

  amending changeset 664a9b2d60cd

  copying changeset 664a9b2d60cd to ad120869acf0

  a

  stripping amended changeset 664a9b2d60cd

  1 changesets found

  saved backup bundle to $TESTTMP/.hg/strip-backup/664a9b2d60cd-amend-backup.hg

  1 changesets found

  adding branch

  adding changesets

  adding manifests

  adding file changes

  added 1 changesets with 1 changes to 1 files

  committed changeset 1:ea6e356ff2ad

  $ hg diff -c .

  diff -r ad120869acf0 -r ea6e356ff2ad a

  --- a/a	Thu Jan 01 00:00:00 1970 +0000

  +++ b/a	Thu Jan 01 00:00:00 1970 +0000

  @@ -1,1 +1,3 @@

   a

  +a

  +a

  $ hg log

  changeset:   1:ea6e356ff2ad

  tag:         tip

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  summary:     no changes, new message

  changeset:   0:ad120869acf0

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  summary:     base

Disable default date on commit so when -d isn't given, the old date is preserved:

  $ echo '[defaults]' >> $HGRCPATH

  $ echo 'commit=' >> $HGRCPATH

Test -u/-d:

  $ hg ci --amend -u foo -d '1 0'

  saved backup bundle to $TESTTMP/.hg/strip-backup/ea6e356ff2ad-amend-backup.hg

  $ echo a >> a

  $ hg ci --amend -u foo -d '1 0'

  saved backup bundle to $TESTTMP/.hg/strip-backup/377b91ce8b56-amend-backup.hg

  $ hg log -r .

  changeset:   1:2c94e4a5756f

  tag:         tip

  user:        foo

  date:        Thu Jan 01 00:00:01 1970 +0000

  summary:     no changes, new message

Open editor with old commit message if a message isn't given otherwise:

  $ cat > editor << '__EOF__'

  > #!/bin/sh

  > cat $1

  > echo "another precious commit message" > "$1"

  > __EOF__

  $ chmod +x editor

  $ HGEDITOR="'`pwd`'"/editor hg commit --amend -v

  amending changeset 2c94e4a5756f

  copying changeset 2c94e4a5756f to ad120869acf0

  no changes, new message

  HG: Enter commit message.  Lines beginning with 'HG:' are removed.

  HG: Leave message empty to abort commit.

  HG: --

  HG: user: foo

  HG: branch 'default'

  HG: changed a

  a

  stripping amended changeset 2c94e4a5756f

  1 changesets found

  saved backup bundle to $TESTTMP/.hg/strip-backup/2c94e4a5756f-amend-backup.hg

  1 changesets found

  adding branch

  adding changesets

  adding manifests

  adding file changes

  added 1 changesets with 1 changes to 1 files

  committed changeset 1:ffb49186f961

Same, but with changes in working dir (different code path):

  $ echo a >> a

  $ HGEDITOR="'`pwd`'"/editor hg commit --amend -v

  amending changeset ffb49186f961

  another precious commit message

  HG: Enter commit message.  Lines beginning with 'HG:' are removed.

  HG: Leave message empty to abort commit.

  HG: --

  HG: user: foo

  HG: branch 'default'

  HG: changed a

  a

  copying changeset 27f3aacd3011 to ad120869acf0

  a

  stripping intermediate changeset 27f3aacd3011

  stripping amended changeset ffb49186f961

  2 changesets found

  saved backup bundle to $TESTTMP/.hg/strip-backup/ffb49186f961-amend-backup.hg

  1 changesets found

  adding branch

  adding changesets

  adding manifests

  adding file changes

  added 1 changesets with 1 changes to 1 files

  committed changeset 1:fb6cca43446f

  $ rm editor

  $ hg log -r .

  changeset:   1:fb6cca43446f

  tag:         tip

  user:        foo

  date:        Thu Jan 01 00:00:01 1970 +0000

  summary:     another precious commit message

Moving bookmarks, preserve active bookmark:

  $ hg book book1

  $ hg book book2

  $ hg ci --amend -m 'move bookmarks'

  saved backup bundle to $TESTTMP/.hg/strip-backup/fb6cca43446f-amend-backup.hg

  $ hg book

     book1                     1:0cf1c7a51bcf

   * book2                     1:0cf1c7a51bcf

  $ echo a >> a

  $ hg ci --amend -m 'move bookmarks'

  saved backup bundle to $TESTTMP/.hg/strip-backup/0cf1c7a51bcf-amend-backup.hg

  $ hg book

     book1                     1:7344472bd951

   * book2                     1:7344472bd951

  $ echo '[defaults]' >> $HGRCPATH

  $ echo "commit=-d '0 0'" >> $HGRCPATH

Moving branches:

  $ hg branch foo

  marked working directory as branch foo

  (branches are permanent and global, did you want a bookmark?)

  $ echo a >> a

  $ hg ci -m 'branch foo'

  $ hg branch default -f

  marked working directory as branch default

  (branches are permanent and global, did you want a bookmark?)

  $ hg ci --amend -m 'back to default'

  saved backup bundle to $TESTTMP/.hg/strip-backup/1661ca36a2db-amend-backup.hg

  $ hg branches

  default                        2:f24ee5961967

Close branch:

  $ hg up -q 0

  $ echo b >> b

  $ hg branch foo

  marked working directory as branch foo

  (branches are permanent and global, did you want a bookmark?)

  $ hg ci -Am 'fork'

  adding b

  $ echo b >> b

  $ hg ci -mb

  $ hg ci --amend --close-branch -m 'closing branch foo'

  saved backup bundle to $TESTTMP/.hg/strip-backup/c962248fa264-amend-backup.hg

Same thing, different code path:

  $ echo b >> b

  $ hg ci -m 'reopen branch'

  reopening closed branch head 4

  $ echo b >> b

  $ hg ci --amend --close-branch

  saved backup bundle to $TESTTMP/.hg/strip-backup/5e302dcc12b8-amend-backup.hg

  $ hg branches

  default                        2:f24ee5961967

Refuse to amend merges:

  $ hg up -q default

  $ hg merge foo

  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  (branch merge, don't forget to commit)

  $ hg ci --amend

  abort: cannot amend while merging

  [255]

  $ hg ci -m 'merge'

  $ hg ci --amend

  abort: cannot amend merge changesets

  [255]

Follow copies/renames:

  $ hg mv b c

  $ hg ci -m 'b -> c'

  $ hg mv c d

  $ hg ci --amend -m 'b -> d'

  saved backup bundle to $TESTTMP/.hg/strip-backup/9c207120aa98-amend-backup.hg

  $ hg st --rev .^ --copies d

  A d

    b

  $ hg cp d e

  $ hg ci -m 'e = d'

  $ hg cp e f

  $ hg ci --amend -m 'f = d'

  saved backup bundle to $TESTTMP/.hg/strip-backup/fda2b3b27b22-amend-backup.hg

  $ hg st --rev .^ --copies f

  A f

    d

Can't rollback an amend:

  $ hg rollback

  no rollback information available

  [1]