view tests/test-commit.t @ 32697:19b9fc40cc51

revlog: skeleton support for version 2 revlogs

There are a number of improvements we want to make to revlogs
that will require a new version - version 2. It is unclear what the
full set of improvements will be or when we'll be done with them.
What I do know is that the process will likely take longer than a
single release, will require input from various stakeholders to
evaluate changes, and will have many contentious debates and
bikeshedding.

It is unrealistic to develop revlog version 2 up front: there
are just too many uncertainties that we won't know until things
are implemented and experiments are run. Some changes will also
be invasive and prone to bit rot, so sitting on dozens of patches
is not practical.

This commit introduces skeleton support for version 2 revlogs in
a way that is flexible and not bound by backwards compatibility
concerns.

An experimental repo requirement for denoting revlog v2 has been
added. The requirement string has a sub-version component to it.
This will allow us to declare multiple requirements in the course
of developing revlog v2. Whenever we change the in-development
revlog v2 format, we can tweak the string, creating a new
requirement and locking out old clients. This will allow us to
make as many backwards incompatible changes and experiments to
revlog v2 as we want. In other words, we can land code and make
meaningful progress towards revlog v2 while still maintaining
extreme format flexibility up until the point we freeze the
format and remove the experimental labels.

To enable the new repo requirement, you must supply an experimental
and undocumented config option. But not just any boolean flag
will do: you need to explicitly use a value that no sane person
should ever type. This is an additional guard against enabling
revlog v2 on an installation it shouldn't be enabled on. The
specific scenario I'm trying to prevent is say a user with a
4.4 client with a frozen format enabling the option but then
downgrading to 4.3 and accidentally creating repos with an
outdated and unsupported repo format. Requiring a "challenge"
string should prevent this.

Because the format is not yet finalized and I don't want to take
any chances, revlog v2's version is currently 0xDEAD. I figure
squatting on a value we're likely never to use as an actual revlog
version to mean "internal testing only" is acceptable. And
"dead" is easily recognized as something meaningful.

There is a bunch of cleanup that is needed before work on revlog
v2 begins in earnest. I plan on doing that work once this patch
is accepted and we're comfortable with the idea of starting down
this path.

commit date test

  $ hg init test
  $ cd test
  $ echo foo > foo
  $ hg add foo
  $ cat > $TESTTMP/checkeditform.sh <<EOF
  > env | grep HGEDITFORM
  > true
  > EOF
  $ HGEDITOR="sh $TESTTMP/checkeditform.sh" hg commit -m ""
  HGEDITFORM=commit.normal.normal
  abort: empty commit message
  [255]
  $ hg commit -d '0 0' -m commit-1
  $ echo foo >> foo
  $ hg commit -d '1 4444444' -m commit-3
  hg: parse error: impossible time zone offset: 4444444
  [255]
  $ hg commit -d '1	15.1' -m commit-4
  hg: parse error: invalid date: '1\t15.1'
  [255]
  $ hg commit -d 'foo bar' -m commit-5
  hg: parse error: invalid date: 'foo bar'
  [255]
  $ hg commit -d ' 1 4444' -m commit-6
  $ hg commit -d '111111111111 0' -m commit-7
  hg: parse error: date exceeds 32 bits: 111111111111
  [255]
  $ hg commit -d '-111111111111 0' -m commit-7
  hg: parse error: date exceeds 32 bits: -111111111111
  [255]
  $ echo foo >> foo
  $ hg commit -d '1901-12-13 20:45:52 +0000' -m commit-7-2
  $ echo foo >> foo
  $ hg commit -d '-2147483648 0' -m commit-7-3
  $ hg log -T '{rev} {date|isodatesec}\n' -l2
  3 1901-12-13 20:45:52 +0000
  2 1901-12-13 20:45:52 +0000
  $ hg commit -d '1901-12-13 20:45:51 +0000' -m commit-7
  hg: parse error: date exceeds 32 bits: -2147483649
  [255]
  $ hg commit -d '-2147483649 0' -m commit-7
  hg: parse error: date exceeds 32 bits: -2147483649
  [255]

commit added file that has been deleted

  $ echo bar > bar
  $ hg add bar
  $ rm bar
  $ hg commit -m commit-8
  nothing changed (1 missing files, see 'hg status')
  [1]
  $ hg commit -m commit-8-2 bar
  abort: bar: file not found!
  [255]

  $ hg -q revert -a --no-backup

  $ mkdir dir
  $ echo boo > dir/file
  $ hg add
  adding dir/file (glob)
  $ hg -v commit -m commit-9 dir
  committing files:
  dir/file
  committing manifest
  committing changelog
  committed changeset 4:1957363f1ced

  $ echo > dir.file
  $ hg add
  adding dir.file
  $ hg commit -m commit-10 dir dir.file
  abort: dir: no match under directory!
  [255]

  $ echo >> dir/file
  $ mkdir bleh
  $ mkdir dir2
  $ cd bleh
  $ hg commit -m commit-11 .
  abort: bleh: no match under directory!
  [255]
  $ hg commit -m commit-12 ../dir ../dir2
  abort: dir2: no match under directory!
  [255]
  $ hg -v commit -m commit-13 ../dir
  committing files:
  dir/file
  committing manifest
  committing changelog
  committed changeset 5:a31d8f87544a
  $ cd ..

  $ hg commit -m commit-14 does-not-exist
  abort: does-not-exist: * (glob)
  [255]

#if symlink
  $ ln -s foo baz
  $ hg commit -m commit-15 baz
  abort: baz: file not tracked!
  [255]
#endif

  $ touch quux
  $ hg commit -m commit-16 quux
  abort: quux: file not tracked!
  [255]
  $ echo >> dir/file
  $ hg -v commit -m commit-17 dir/file
  committing files:
  dir/file
  committing manifest
  committing changelog
  committed changeset 6:32d054c9d085

An empty date was interpreted as epoch origin

  $ echo foo >> foo
  $ hg commit -d '' -m commit-no-date --config devel.default-date=
  $ hg tip --template '{date|isodate}\n' | grep '1970'
  [1]

Make sure we do not obscure unknown requires file entries (issue2649)

  $ echo foo >> foo
  $ echo fake >> .hg/requires
  $ hg commit -m bla
  abort: repository requires features unknown to this Mercurial: fake!
  (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
  [255]

  $ cd ..


partial subdir commit test

  $ hg init test2
  $ cd test2
  $ mkdir foo
  $ echo foo > foo/foo
  $ mkdir bar
  $ echo bar > bar/bar
  $ hg add
  adding bar/bar (glob)
  adding foo/foo (glob)
  $ HGEDITOR=cat hg ci -e -m commit-subdir-1 foo
  commit-subdir-1
  
  
  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  HG: Leave message empty to abort commit.
  HG: --
  HG: user: test
  HG: branch 'default'
  HG: added foo/foo


  $ hg ci -m commit-subdir-2 bar

subdir log 1

  $ hg log -v foo
  changeset:   0:f97e73a25882
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       foo/foo
  description:
  commit-subdir-1
  
  

subdir log 2

  $ hg log -v bar
  changeset:   1:aa809156d50d
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       bar/bar
  description:
  commit-subdir-2
  
  

full log

  $ hg log -v
  changeset:   1:aa809156d50d
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       bar/bar
  description:
  commit-subdir-2
  
  
  changeset:   0:f97e73a25882
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       foo/foo
  description:
  commit-subdir-1
  
  
  $ cd ..


dot and subdir commit test

  $ hg init test3
  $ echo commit-foo-subdir > commit-log-test
  $ cd test3
  $ mkdir foo
  $ echo foo content > foo/plain-file
  $ hg add foo/plain-file
  $ HGEDITOR=cat hg ci --edit -l ../commit-log-test foo
  commit-foo-subdir
  
  
  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  HG: Leave message empty to abort commit.
  HG: --
  HG: user: test
  HG: branch 'default'
  HG: added foo/plain-file


  $ echo modified foo content > foo/plain-file
  $ hg ci -m commit-foo-dot .

full log

  $ hg log -v
  changeset:   1:95b38e3a5b2e
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       foo/plain-file
  description:
  commit-foo-dot
  
  
  changeset:   0:65d4e9386227
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       foo/plain-file
  description:
  commit-foo-subdir
  
  

subdir log

  $ cd foo
  $ hg log .
  changeset:   1:95b38e3a5b2e
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit-foo-dot
  
  changeset:   0:65d4e9386227
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit-foo-subdir
  
  $ cd ..
  $ cd ..

Issue1049: Hg permits partial commit of merge without warning

  $ hg init issue1049
  $ cd issue1049
  $ echo a > a
  $ hg ci -Ama
  adding a
  $ echo a >> a
  $ hg ci -mb
  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo b >> a
  $ hg ci -mc
  created new head
  $ HGMERGE=true hg merge
  merging a
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

should fail because we are specifying a file name

  $ hg ci -mmerge a
  abort: cannot partially commit a merge (do not specify files or patterns)
  [255]

should fail because we are specifying a pattern

  $ hg ci -mmerge -I a
  abort: cannot partially commit a merge (do not specify files or patterns)
  [255]

should succeed

  $ HGEDITOR="sh $TESTTMP/checkeditform.sh" hg ci -mmerge --edit
  HGEDITFORM=commit.normal.merge
  $ cd ..


test commit message content

  $ hg init commitmsg
  $ cd commitmsg
  $ echo changed > changed
  $ echo removed > removed
  $ hg book activebookmark
  $ hg ci -qAm init

  $ hg rm removed
  $ echo changed >> changed
  $ echo added > added
  $ hg add added
  $ HGEDITOR=cat hg ci -A
  
  
  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  HG: Leave message empty to abort commit.
  HG: --
  HG: user: test
  HG: branch 'default'
  HG: bookmark 'activebookmark'
  HG: added added
  HG: changed changed
  HG: removed removed
  abort: empty commit message
  [255]

test saving last-message.txt

  $ hg init sub
  $ echo a > sub/a
  $ hg -R sub add sub/a
  $ cat > sub/.hg/hgrc <<EOF
  > [hooks]
  > precommit.test-saving-last-message = false
  > EOF

  $ echo 'sub = sub' > .hgsub
  $ hg add .hgsub

  $ cat > $TESTTMP/editor.sh <<EOF
  > echo "==== before editing:"
  > cat \$1
  > echo "===="
  > echo "test saving last-message.txt" >> \$1
  > EOF

  $ rm -f .hg/last-message.txt
  $ HGEDITOR="sh $TESTTMP/editor.sh" hg commit -S -q
  ==== before editing:
  
  
  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  HG: Leave message empty to abort commit.
  HG: --
  HG: user: test
  HG: branch 'default'
  HG: bookmark 'activebookmark'
  HG: subrepo sub
  HG: added .hgsub
  HG: added added
  HG: changed .hgsubstate
  HG: changed changed
  HG: removed removed
  ====
  abort: precommit.test-saving-last-message hook exited with status 1 (in subrepo sub)
  [255]
  $ cat .hg/last-message.txt
  
  
  test saving last-message.txt

test that '[committemplate] changeset' definition and commit log
specific template keywords work well

  $ cat >> .hg/hgrc <<EOF
  > [committemplate]
  > changeset.commit.normal = 'HG: this is "commit.normal" template
  >     HG: {extramsg}
  >     {if(activebookmark,
  >    "HG: bookmark '{activebookmark}' is activated\n",
  >    "HG: no bookmark is activated\n")}{subrepos %
  >    "HG: subrepo '{subrepo}' is changed\n"}'
  > 
  > changeset.commit = HG: this is "commit" template
  >     HG: {extramsg}
  >     {if(activebookmark,
  >    "HG: bookmark '{activebookmark}' is activated\n",
  >    "HG: no bookmark is activated\n")}{subrepos %
  >    "HG: subrepo '{subrepo}' is changed\n"}
  > 
  > changeset = HG: this is customized commit template
  >     HG: {extramsg}
  >     {if(activebookmark,
  >    "HG: bookmark '{activebookmark}' is activated\n",
  >    "HG: no bookmark is activated\n")}{subrepos %
  >    "HG: subrepo '{subrepo}' is changed\n"}
  > EOF

  $ hg init sub2
  $ echo a > sub2/a
  $ hg -R sub2 add sub2/a
  $ echo 'sub2 = sub2' >> .hgsub

  $ HGEDITOR=cat hg commit -S -q
  HG: this is "commit.normal" template
  HG: Leave message empty to abort commit.
  HG: bookmark 'activebookmark' is activated
  HG: subrepo 'sub' is changed
  HG: subrepo 'sub2' is changed
  abort: empty commit message
  [255]

  $ cat >> .hg/hgrc <<EOF
  > [committemplate]
  > changeset.commit.normal =
  > # now, "changeset.commit" should be chosen for "hg commit"
  > EOF

  $ hg bookmark --inactive activebookmark
  $ hg forget .hgsub
  $ HGEDITOR=cat hg commit -q
  HG: this is "commit" template
  HG: Leave message empty to abort commit.
  HG: no bookmark is activated
  abort: empty commit message
  [255]

  $ cat >> .hg/hgrc <<EOF
  > [committemplate]
  > changeset.commit =
  > # now, "changeset" should be chosen for "hg commit"
  > EOF

  $ HGEDITOR=cat hg commit -q
  HG: this is customized commit template
  HG: Leave message empty to abort commit.
  HG: no bookmark is activated
  abort: empty commit message
  [255]

  $ cat >> .hg/hgrc <<EOF
  > [committemplate]
  > changeset = {desc}
  >     HG: mods={file_mods}
  >     HG: adds={file_adds}
  >     HG: dels={file_dels}
  >     HG: files={files}
  >     HG:
  >     {splitlines(diff()) % 'HG: {line}\n'
  >    }HG:
  >     HG: mods={file_mods}
  >     HG: adds={file_adds}
  >     HG: dels={file_dels}
  >     HG: files={files}\n
  > EOF
  $ hg status -amr
  M changed
  A added
  R removed
  $ HGEDITOR=cat hg commit -q -e -m "foo bar" changed
  foo bar
  HG: mods=changed
  HG: adds=
  HG: dels=
  HG: files=changed
  HG:
  HG: --- a/changed	Thu Jan 01 00:00:00 1970 +0000
  HG: +++ b/changed	Thu Jan 01 00:00:00 1970 +0000
  HG: @@ -1,1 +1,2 @@
  HG:  changed
  HG: +changed
  HG:
  HG: mods=changed
  HG: adds=
  HG: dels=
  HG: files=changed
  $ hg status -amr
  A added
  R removed
  $ hg parents --template "M {file_mods}\nA {file_adds}\nR {file_dels}\n"
  M changed
  A 
  R 
  $ hg rollback -q

  $ cat >> .hg/hgrc <<EOF
  > [committemplate]
  > changeset = {desc}
  >     HG: mods={file_mods}
  >     HG: adds={file_adds}
  >     HG: dels={file_dels}
  >     HG: files={files}
  >     HG:
  >     {splitlines(diff("changed")) % 'HG: {line}\n'
  >    }HG:
  >     HG: mods={file_mods}
  >     HG: adds={file_adds}
  >     HG: dels={file_dels}
  >     HG: files={files}
  >     HG:
  >     {splitlines(diff("added")) % 'HG: {line}\n'
  >    }HG:
  >     HG: mods={file_mods}
  >     HG: adds={file_adds}
  >     HG: dels={file_dels}
  >     HG: files={files}
  >     HG:
  >     {splitlines(diff("removed")) % 'HG: {line}\n'
  >    }HG:
  >     HG: mods={file_mods}
  >     HG: adds={file_adds}
  >     HG: dels={file_dels}
  >     HG: files={files}\n
  > EOF
  $ HGEDITOR=cat hg commit -q -e -m "foo bar" added removed
  foo bar
  HG: mods=
  HG: adds=added
  HG: dels=removed
  HG: files=added removed
  HG:
  HG:
  HG: mods=
  HG: adds=added
  HG: dels=removed
  HG: files=added removed
  HG:
  HG: --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  HG: +++ b/added	Thu Jan 01 00:00:00 1970 +0000
  HG: @@ -0,0 +1,1 @@
  HG: +added
  HG:
  HG: mods=
  HG: adds=added
  HG: dels=removed
  HG: files=added removed
  HG:
  HG: --- a/removed	Thu Jan 01 00:00:00 1970 +0000
  HG: +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
  HG: @@ -1,1 +0,0 @@
  HG: -removed
  HG:
  HG: mods=
  HG: adds=added
  HG: dels=removed
  HG: files=added removed
  $ hg status -amr
  M changed
  $ hg parents --template "M {file_mods}\nA {file_adds}\nR {file_dels}\n"
  M 
  A added
  R removed
  $ hg rollback -q

  $ cat >> .hg/hgrc <<EOF
  > # disable customizing for subsequent tests
  > [committemplate]
  > changeset =
  > EOF

  $ cd ..


commit copy

  $ hg init dir2
  $ cd dir2
  $ echo bleh > bar
  $ hg add bar
  $ hg ci -m 'add bar'

  $ hg cp bar foo
  $ echo >> bar
  $ hg ci -m 'cp bar foo; change bar'

  $ hg debugrename foo
  foo renamed from bar:26d3ca0dfd18e44d796b564e38dd173c9668d3a9
  $ hg debugindex bar
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       6  .....       0 26d3ca0dfd18 000000000000 000000000000 (re)
       1         6       7  .....       1 d267bddd54f7 26d3ca0dfd18 000000000000 (re)

Test making empty commits
  $ hg commit --config ui.allowemptycommit=True -m "empty commit"
  $ hg log -r . -v --stat
  changeset:   2:d809f3644287
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  description:
  empty commit
  
  
  
verify pathauditor blocks evil filepaths
  $ cat > evil-commit.py <<EOF
  > from mercurial import ui, hg, context, node
  > notrc = u".h\u200cg".encode('utf-8') + '/hgrc'
  > u = ui.ui.load()
  > r = hg.repository(u, '.')
  > def filectxfn(repo, memctx, path):
  >     return context.memfilectx(repo, path, '[hooks]\nupdate = echo owned')
  > c = context.memctx(r, [r['tip'].node(), node.nullid],
  >                    'evil', [notrc], filectxfn, 0)
  > r.commitctx(c)
  > EOF
  $ $PYTHON evil-commit.py
#if windows
  $ hg co --clean tip
  abort: path contains illegal component: .h\xe2\x80\x8cg\\hgrc (esc)
  [255]
#else
  $ hg co --clean tip
  abort: path contains illegal component: .h\xe2\x80\x8cg/hgrc (esc)
  [255]
#endif

  $ hg rollback -f
  repository tip rolled back to revision 2 (undo commit)
  $ cat > evil-commit.py <<EOF
  > from mercurial import ui, hg, context, node
  > notrc = "HG~1/hgrc"
  > u = ui.ui.load()
  > r = hg.repository(u, '.')
  > def filectxfn(repo, memctx, path):
  >     return context.memfilectx(repo, path, '[hooks]\nupdate = echo owned')
  > c = context.memctx(r, [r['tip'].node(), node.nullid],
  >                    'evil', [notrc], filectxfn, 0)
  > r.commitctx(c)
  > EOF
  $ $PYTHON evil-commit.py
  $ hg co --clean tip
  abort: path contains illegal component: HG~1/hgrc (glob)
  [255]

  $ hg rollback -f
  repository tip rolled back to revision 2 (undo commit)
  $ cat > evil-commit.py <<EOF
  > from mercurial import ui, hg, context, node
  > notrc = "HG8B6C~2/hgrc"
  > u = ui.ui.load()
  > r = hg.repository(u, '.')
  > def filectxfn(repo, memctx, path):
  >     return context.memfilectx(repo, path, '[hooks]\nupdate = echo owned')
  > c = context.memctx(r, [r['tip'].node(), node.nullid],
  >                    'evil', [notrc], filectxfn, 0)
  > r.commitctx(c)
  > EOF
  $ $PYTHON evil-commit.py
  $ hg co --clean tip
  abort: path contains illegal component: HG8B6C~2/hgrc (glob)
  [255]

# test that an unmodified commit template message aborts

  $ hg init unmodified_commit_template
  $ cd unmodified_commit_template
  $ echo foo > foo
  $ hg add foo
  $ hg commit -m "foo"
  $ cat >> .hg/hgrc <<EOF
  > [committemplate]
  > changeset.commit = HI THIS IS NOT STRIPPED
  >     HG: this is customized commit template
  >     HG: {extramsg}
  >     {if(activebookmark,
  >    "HG: bookmark '{activebookmark}' is activated\n",
  >    "HG: no bookmark is activated\n")}{subrepos %
  >    "HG: subrepo '{subrepo}' is changed\n"}
  > EOF
  $ cat > $TESTTMP/notouching.sh <<EOF
  > true
  > EOF
  $ echo foo2 > foo2
  $ hg add foo2
  $ HGEDITOR="sh $TESTTMP/notouching.sh" hg commit
  abort: commit message unchanged
  [255]

test that text below the --- >8 --- special string is ignored

  $ cat <<'EOF' > $TESTTMP/lowercaseline.sh
  > cat $1 | sed s/LINE/line/ | tee $1.new
  > mv $1.new $1
  > EOF

  $ hg init ignore_below_special_string
  $ cd ignore_below_special_string
  $ echo foo > foo
  $ hg add foo
  $ hg commit -m "foo"
  $ cat >> .hg/hgrc <<EOF
  > [committemplate]
  > changeset.commit = first LINE
  >     HG: this is customized commit template
  >     HG: {extramsg}
  >     HG: ------------------------ >8 ------------------------
  >     {diff()}
  > EOF
  $ echo foo2 > foo2
  $ hg add foo2
  $ HGEDITOR="sh $TESTTMP/notouching.sh" hg ci
  abort: commit message unchanged
  [255]
  $ HGEDITOR="sh $TESTTMP/lowercaseline.sh" hg ci
  first line
  HG: this is customized commit template
  HG: Leave message empty to abort commit.
  HG: ------------------------ >8 ------------------------
  diff -r e63c23eaa88a foo2
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/foo2	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +foo2
  $ hg log -T '{desc}\n' -r .
  first line

test that the special string --- >8 --- isn't used when not at the beginning of
a line

  $ cat >> .hg/hgrc <<EOF
  > [committemplate]
  > changeset.commit = first LINE2
  >     another line HG: ------------------------ >8 ------------------------
  >     HG: this is customized commit template
  >     HG: {extramsg}
  >     HG: ------------------------ >8 ------------------------
  >     {diff()}
  > EOF
  $ echo foo >> foo
  $ HGEDITOR="sh $TESTTMP/lowercaseline.sh" hg ci
  first line2
  another line HG: ------------------------ >8 ------------------------
  HG: this is customized commit template
  HG: Leave message empty to abort commit.
  HG: ------------------------ >8 ------------------------
  diff -r 3661b22b0702 foo
  --- a/foo	Thu Jan 01 00:00:00 1970 +0000
  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,2 @@
   foo
  +foo
  $ hg log -T '{desc}\n' -r .
  first line2
  another line HG: ------------------------ >8 ------------------------

also test that this special string isn't accepted when there is some extra text
at the end

  $ cat >> .hg/hgrc <<EOF
  > [committemplate]
  > changeset.commit = first LINE3
  >     HG: ------------------------ >8 ------------------------foobar
  >     second line
  >     HG: this is customized commit template
  >     HG: {extramsg}
  >     HG: ------------------------ >8 ------------------------
  >     {diff()}
  > EOF
  $ echo foo >> foo
  $ HGEDITOR="sh $TESTTMP/lowercaseline.sh" hg ci
  first line3
  HG: ------------------------ >8 ------------------------foobar
  second line
  HG: this is customized commit template
  HG: Leave message empty to abort commit.
  HG: ------------------------ >8 ------------------------
  diff -r ce648f5f066f foo
  --- a/foo	Thu Jan 01 00:00:00 1970 +0000
  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,2 +1,3 @@
   foo
   foo
  +foo
  $ hg log -T '{desc}\n' -r .
  first line3
  second line

  $ cd ..