tests/test-import.t

revset: speedup matching() by stopping the match early if a field does not match

Rather than getting all the fields that are being matches from every revision
and then comparing them to those of the target revision, compare each field one
by one and stop the match as soon as there is a match failure.

This can greatly reduce the match time when matching multiple fields.
The impact on match time when matching a single field seems negligible
(according to my measurements).

  $ "$TESTDIR/hghave" unix-permissions || exit 80

  $ hg init a
  $ mkdir a/d1
  $ mkdir a/d1/d2
  $ echo line 1 > a/a
  $ echo line 1 > a/d1/d2/a
  $ hg --cwd a ci -Ama
  adding a
  adding d1/d2/a

  $ echo line 2 >> a/a
  $ hg --cwd a ci -u someone -d '1 0' -m'second change'

import with no args:

  $ hg --cwd a import
  abort: need at least one patch to import
  [255]

generate patches for the test

  $ hg --cwd a export tip > exported-tip.patch
  $ hg --cwd a diff -r0:1 > diffed-tip.patch


import exported patch

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --cwd b import ../exported-tip.patch
  applying ../exported-tip.patch

message and committer should be same

  $ hg --cwd b tip
  changeset:   1:1d4bd90af0e4
  tag:         tip
  user:        someone
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     second change
  
  $ rm -r b


import exported patch with external patcher

  $ cat > dummypatch.py <<EOF
  > print 'patching file a'
  > file('a', 'wb').write('line2\n')
  > EOF
  $ chmod +x dummypatch.py
  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --config ui.patch='python ../dummypatch.py' --cwd b import ../exported-tip.patch
  applying ../exported-tip.patch
  $ cat b/a
  line2
  $ rm -r b


import of plain diff should fail without message

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --cwd b import ../diffed-tip.patch
  applying ../diffed-tip.patch
  abort: empty commit message
  [255]
  $ rm -r b


import of plain diff should be ok with message

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --cwd b import -mpatch ../diffed-tip.patch
  applying ../diffed-tip.patch
  $ rm -r b


import of plain diff with specific date and user

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --cwd b import -mpatch -d '1 0' -u '[e-mail]' ../diffed-tip.patch
  applying ../diffed-tip.patch
  $ hg -R b tip -pv
  changeset:   1:ca68f19f3a40
  tag:         tip
  user:        [e-mail]
  date:        Thu Jan 01 00:00:01 1970 +0000
  files:       a
  description:
  patch
  
  
  diff -r 80971e65b431 -r ca68f19f3a40 a
  --- a/a	Thu Jan 01 00:00:00 1970 +0000
  +++ b/a	Thu Jan 01 00:00:01 1970 +0000
  @@ -1,1 +1,2 @@
   line 1
  +line 2
  
  $ rm -r b


import of plain diff should be ok with --no-commit

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --cwd b import --no-commit ../diffed-tip.patch
  applying ../diffed-tip.patch
  $ hg --cwd b diff --nodates
  diff -r 80971e65b431 a
  --- a/a
  +++ b/a
  @@ -1,1 +1,2 @@
   line 1
  +line 2
  $ rm -r b


import of malformed plain diff should fail

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ sed 's/1,1/foo/' < diffed-tip.patch > broken.patch
  $ hg --cwd b import -mpatch ../broken.patch
  applying ../broken.patch
  abort: bad hunk #1
  [255]
  $ rm -r b


hg -R repo import
put the clone in a subdir - having a directory named "a"
used to hide a bug.

  $ mkdir dir
  $ hg clone -r0 a dir/b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd dir
  $ hg -R b import ../exported-tip.patch
  applying ../exported-tip.patch
  $ cd ..
  $ rm -r dir


import from stdin

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --cwd b import - < exported-tip.patch
  applying patch from stdin
  $ rm -r b


import two patches in one stream

  $ hg init b
  $ hg --cwd a export 0:tip | hg --cwd b import -
  applying patch from stdin
  $ hg --cwd a id
  1d4bd90af0e4 tip
  $ hg --cwd b id
  1d4bd90af0e4 tip
  $ rm -r b


override commit message

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --cwd b import -m 'override' - < exported-tip.patch
  applying patch from stdin
  $ hg --cwd b tip | grep override
  summary:     override
  $ rm -r b

  $ cat > mkmsg.py <<EOF
  > import email.Message, sys
  > msg = email.Message.Message()
  > patch = open(sys.argv[1], 'rb').read()
  > msg.set_payload('email commit message\n' + patch)
  > msg['Subject'] = 'email patch'
  > msg['From'] = 'email patcher'
  > file(sys.argv[2], 'wb').write(msg.as_string())
  > EOF


plain diff in email, subject, message body

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ python mkmsg.py diffed-tip.patch msg.patch
  $ hg --cwd b import ../msg.patch
  applying ../msg.patch
  $ hg --cwd b tip | grep email
  user:        email patcher
  summary:     email patch
  $ rm -r b


plain diff in email, no subject, message body

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ grep -v '^Subject:' msg.patch | hg --cwd b import -
  applying patch from stdin
  $ rm -r b


plain diff in email, subject, no message body

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ grep -v '^email ' msg.patch | hg --cwd b import -
  applying patch from stdin
  $ rm -r b


plain diff in email, no subject, no message body, should fail

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ egrep -v '^(Subject|email)' msg.patch | hg --cwd b import -
  applying patch from stdin
  abort: empty commit message
  [255]
  $ rm -r b


hg export in email, should use patch header

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ python mkmsg.py exported-tip.patch msg.patch
  $ cat msg.patch | hg --cwd b import -
  applying patch from stdin
  $ hg --cwd b tip | grep second
  summary:     second change
  $ rm -r b


subject: duplicate detection, removal of [PATCH]
The '---' tests the gitsendmail handling without proper mail headers

  $ cat > mkmsg2.py <<EOF
  > import email.Message, sys
  > msg = email.Message.Message()
  > patch = open(sys.argv[1], 'rb').read()
  > msg.set_payload('email patch\n\nnext line\n---\n' + patch)
  > msg['Subject'] = '[PATCH] email patch'
  > msg['From'] = 'email patcher'
  > file(sys.argv[2], 'wb').write(msg.as_string())
  > EOF


plain diff in email, [PATCH] subject, message body with subject

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ python mkmsg2.py diffed-tip.patch msg.patch
  $ cat msg.patch | hg --cwd b import -
  applying patch from stdin
  $ hg --cwd b tip --template '{desc}\n'
  email patch
  
  next line
  ---
  $ rm -r b


Issue963: Parent of working dir incorrect after import of multiple
patches and rollback

We weren't backing up the correct dirstate file when importing many
patches: import patch1 patch2; rollback

  $ echo line 3 >> a/a
  $ hg --cwd a ci -m'third change'
  $ hg --cwd a export -o '../patch%R' 1 2
  $ hg clone -qr0 a b
  $ hg --cwd b parents --template 'parent: {rev}\n'
  parent: 0
  $ hg --cwd b import -v ../patch1 ../patch2
  applying ../patch1
  patching file a
  a
  created 1d4bd90af0e4
  applying ../patch2
  patching file a
  a
  created 6d019af21222
  $ hg --cwd b rollback
  repository tip rolled back to revision 0 (undo import)
  working directory now based on revision 0
  $ hg --cwd b parents --template 'parent: {rev}\n'
  parent: 0
  $ rm -r b


importing a patch in a subdirectory failed at the commit stage

  $ echo line 2 >> a/d1/d2/a
  $ hg --cwd a ci -u someoneelse -d '1 0' -m'subdir change'

hg import in a subdirectory

  $ hg clone -r0 a b
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 2 changes to 2 files
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --cwd a export tip > tmp
  $ sed -e 's/d1\/d2\///' < tmp > subdir-tip.patch
  $ dir=`pwd`
  $ cd b/d1/d2 2>&1 > /dev/null
  $ hg import  ../../../subdir-tip.patch
  applying ../../../subdir-tip.patch
  $ cd "$dir"

message should be 'subdir change'
committer should be 'someoneelse'

  $ hg --cwd b tip
  changeset:   1:3577f5aea227
  tag:         tip
  user:        someoneelse
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     subdir change
  

should be empty

  $ hg --cwd b status


Test fuzziness (ambiguous patch location, fuzz=2)

  $ hg init fuzzy
  $ cd fuzzy
  $ echo line1 > a
  $ echo line0 >> a
  $ echo line3 >> a
  $ hg ci -Am adda
  adding a
  $ echo line1 > a
  $ echo line2 >> a
  $ echo line0 >> a
  $ echo line3 >> a
  $ hg ci -m change a
  $ hg export tip > fuzzy-tip.patch
  $ hg up -C 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo line1 > a
  $ echo line0 >> a
  $ echo line1 >> a
  $ echo line0 >> a
  $ hg ci -m brancha
  created new head
  $ hg import --no-commit -v fuzzy-tip.patch
  applying fuzzy-tip.patch
  patching file a
  Hunk #1 succeeded at 2 with fuzz 1 (offset 0 lines).
  applied to working directory
  $ hg revert -a
  reverting a


import with --no-commit should have written .hg/last-message.txt

  $ cat .hg/last-message.txt
  change (no-eol)


test fuzziness with eol=auto

  $ hg --config patch.eol=auto import --no-commit -v fuzzy-tip.patch
  applying fuzzy-tip.patch
  patching file a
  Hunk #1 succeeded at 2 with fuzz 1 (offset 0 lines).
  applied to working directory
  $ cd ..


Test hunk touching empty files (issue906)

  $ hg init empty
  $ cd empty
  $ touch a
  $ touch b1
  $ touch c1
  $ echo d > d
  $ hg ci -Am init
  adding a
  adding b1
  adding c1
  adding d
  $ echo a > a
  $ echo b > b1
  $ hg mv b1 b2
  $ echo c > c1
  $ hg copy c1 c2
  $ rm d
  $ touch d
  $ hg diff --git
  diff --git a/a b/a
  --- a/a
  +++ b/a
  @@ -0,0 +1,1 @@
  +a
  diff --git a/b1 b/b2
  rename from b1
  rename to b2
  --- a/b1
  +++ b/b2
  @@ -0,0 +1,1 @@
  +b
  diff --git a/c1 b/c1
  --- a/c1
  +++ b/c1
  @@ -0,0 +1,1 @@
  +c
  diff --git a/c1 b/c2
  copy from c1
  copy to c2
  --- a/c1
  +++ b/c2
  @@ -0,0 +1,1 @@
  +c
  diff --git a/d b/d
  --- a/d
  +++ b/d
  @@ -1,1 +0,0 @@
  -d
  $ hg ci -m empty
  $ hg export --git tip > empty.diff
  $ hg up -C 0
  4 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg import empty.diff
  applying empty.diff
  $ for name in a b1 b2 c1 c2 d; do
  >   echo % $name file
  >   test -f $name && cat $name
  >   done
  % a file
  a
  % b1 file
  % b2 file
  b
  % c1 file
  c
  % c2 file
  c
  % d file
  $ cd ..


Test importing a patch ending with a binary file removal

  $ hg init binaryremoval
  $ cd binaryremoval
  $ echo a > a
  $ python -c "file('b', 'wb').write('a\x00b')"
  $ hg ci -Am addall
  adding a
  adding b
  $ hg rm a
  $ hg rm b
  $ hg st
  R a
  R b
  $ hg ci -m remove
  $ hg export --git . > remove.diff
  $ cat remove.diff | grep git
  diff --git a/a b/a
  diff --git a/b b/b
  $ hg up -C 0
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg import remove.diff
  applying remove.diff
  $ hg manifest
  $ cd ..


Issue927: test update+rename with common name

  $ hg init t
  $ cd t
  $ touch a
  $ hg ci -Am t
  adding a
  $ echo a > a

Here, bfile.startswith(afile)

  $ hg copy a a2
  $ hg ci -m copya
  $ hg export --git tip > copy.diff
  $ hg up -C 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg import copy.diff
  applying copy.diff

a should contain an 'a'

  $ cat a
  a

and a2 should have duplicated it

  $ cat a2
  a
  $ cd ..


test -p0

  $ hg init p0
  $ cd p0
  $ echo a > a
  $ hg ci -Am t
  adding a
  $ hg import -p0 - << EOF
  > foobar
  > --- a	Sat Apr 12 22:43:58 2008 -0400
  > +++ a	Sat Apr 12 22:44:05 2008 -0400
  > @@ -1,1 +1,1 @@
  > -a
  > +bb
  > EOF
  applying patch from stdin
  $ hg status
  $ cat a
  bb
  $ cd ..


test paths outside repo root

  $ mkdir outside
  $ touch outside/foo
  $ hg init inside
  $ cd inside
  $ hg import - <<EOF
  > diff --git a/a b/b
  > rename from ../outside/foo
  > rename to bar
  > EOF
  applying patch from stdin
  abort: path contains illegal component: ../outside/foo
  [255]
  $ cd ..


test import with similarity and git and strip (issue295 et al.)

  $ hg init sim
  $ cd sim
  $ echo 'this is a test' > a
  $ hg ci -Ama
  adding a
  $ cat > ../rename.diff <<EOF
  > diff --git a/foo/a b/foo/a
  > deleted file mode 100644
  > --- a/foo/a
  > +++ /dev/null
  > @@ -1,1 +0,0 @@
  > -this is a test
  > diff --git a/foo/b b/foo/b
  > new file mode 100644
  > --- /dev/null
  > +++ b/foo/b
  > @@ -0,0 +1,2 @@
  > +this is a test
  > +foo
  > EOF
  $ hg import --no-commit -v -s 1 ../rename.diff -p2
  applying ../rename.diff
  patching file a
  patching file b
  adding b
  recording removal of a as rename to b (88% similar)
  applied to working directory
  $ hg st -C
  A b
    a
  R a
  $ hg revert -a
  undeleting a
  forgetting b
  $ rm b
  $ hg import --no-commit -v -s 100 ../rename.diff -p2
  applying ../rename.diff
  patching file a
  patching file b
  adding b
  applied to working directory
  $ hg st -C
  A b
  R a
  $ cd ..


Issue1495: add empty file from the end of patch

  $ hg init addemptyend
  $ cd addemptyend
  $ touch a
  $ hg addremove
  adding a
  $ hg ci -m "commit"
  $ cat > a.patch <<EOF
  > add a, b
  > diff --git a/a b/a
  > --- a/a
  > +++ b/a
  > @@ -0,0 +1,1 @@
  > +a
  > diff --git a/b b/b
  > new file mode 100644
  > EOF
  $ hg import --no-commit a.patch
  applying a.patch

apply a good patch followed by an empty patch (mainly to ensure
that dirstate is *not* updated when import crashes)
  $ hg update -q -C .
  $ rm b
  $ touch empty.patch
  $ hg import a.patch empty.patch
  applying a.patch
  applying empty.patch
  transaction abort!
  rollback completed
  abort: empty.patch: no diffs found
  [255]
  $ hg tip --template '{rev}  {desc|firstline}\n'
  0  commit
  $ hg -q status
  M a
  $ cd ..

create file when source is not /dev/null

  $ cat > create.patch <<EOF
  > diff -Naur proj-orig/foo proj-new/foo
  > --- proj-orig/foo       1969-12-31 16:00:00.000000000 -0800
  > +++ proj-new/foo        2009-07-17 16:50:45.801368000 -0700
  > @@ -0,0 +1,1 @@
  > +a
  > EOF

some people have patches like the following too

  $ cat > create2.patch <<EOF
  > diff -Naur proj-orig/foo proj-new/foo
  > --- proj-orig/foo.orig  1969-12-31 16:00:00.000000000 -0800
  > +++ proj-new/foo        2009-07-17 16:50:45.801368000 -0700
  > @@ -0,0 +1,1 @@
  > +a
  > EOF
  $ hg init oddcreate
  $ cd oddcreate
  $ hg import --no-commit ../create.patch
  applying ../create.patch
  $ cat foo
  a
  $ rm foo
  $ hg revert foo
  $ hg import --no-commit ../create2.patch
  applying ../create2.patch
  $ cat foo
  a


Issue1859: first line mistaken for email headers

  $ hg init emailconfusion
  $ cd emailconfusion
  $ cat > a.patch <<EOF
  > module: summary
  > 
  > description
  > 
  > 
  > diff -r 000000000000 -r 9b4c1e343b55 test.txt
  > --- /dev/null
  > +++ b/a
  > @@ -0,0 +1,1 @@
  > +a
  > EOF
  $ hg import -d '0 0' a.patch
  applying a.patch
  $ hg parents -v
  changeset:   0:5a681217c0ad
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       a
  description:
  module: summary
  
  description
  
  
  $ cd ..


--- in commit message

  $ hg init commitconfusion
  $ cd commitconfusion
  $ cat > a.patch <<EOF
  > module: summary
  > 
  > --- description
  > 
  > diff --git a/a b/a
  > new file mode 100644
  > --- /dev/null
  > +++ b/a
  > @@ -0,0 +1,1 @@
  > +a
  > EOF
  > hg import -d '0 0' a.patch
  > hg parents -v
  > cd ..
  > 
  > echo '% tricky header splitting'
  > cat > trickyheaders.patch <<EOF
  > From: User A <user@a>
  > Subject: [PATCH] from: tricky!
  > 
  > # HG changeset patch
  > # User User B
  > # Date 1266264441 18000
  > # Branch stable
  > # Node ID f2be6a1170ac83bf31cb4ae0bad00d7678115bc0
  > # Parent  0000000000000000000000000000000000000000
  > from: tricky!
  > 
  > That is not a header.
  > 
  > diff -r 000000000000 -r f2be6a1170ac foo
  > --- /dev/null
  > +++ b/foo
  > @@ -0,0 +1,1 @@
  > +foo
  > EOF
  applying a.patch
  changeset:   0:f34d9187897d
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       a
  description:
  module: summary
  
  
  % tricky header splitting

  $ hg init trickyheaders
  $ cd trickyheaders
  $ hg import -d '0 0' ../trickyheaders.patch
  applying ../trickyheaders.patch
  $ hg export --git tip
  # HG changeset patch
  # User User B
  # Date 0 0
  # Node ID eb56ab91903632294ac504838508cb370c0901d2
  # Parent  0000000000000000000000000000000000000000
  from: tricky!
  
  That is not a header.
  
  diff --git a/foo b/foo
  new file mode 100644
  --- /dev/null
  +++ b/foo
  @@ -0,0 +1,1 @@
  +foo
  $ cd ..


Issue2102: hg export and hg import speak different languages

  $ hg init issue2102
  $ cd issue2102
  $ mkdir -p src/cmd/gc
  $ touch src/cmd/gc/mksys.bash
  $ hg ci -Am init
  adding src/cmd/gc/mksys.bash
  $ hg import - <<EOF
  > # HG changeset patch
  > # User Rob Pike
  > # Date 1216685449 25200
  > # Node ID 03aa2b206f499ad6eb50e6e207b9e710d6409c98
  > # Parent  93d10138ad8df586827ca90b4ddb5033e21a3a84
  > help management of empty pkg and lib directories in perforce
  > 
  > R=gri
  > DELTA=4  (4 added, 0 deleted, 0 changed)
  > OCL=13328
  > CL=13328
  > 
  > diff --git a/lib/place-holder b/lib/place-holder
  > new file mode 100644
  > --- /dev/null
  > +++ b/lib/place-holder
  > @@ -0,0 +1,2 @@
  > +perforce does not maintain empty directories.
  > +this file helps.
  > diff --git a/pkg/place-holder b/pkg/place-holder
  > new file mode 100644
  > --- /dev/null
  > +++ b/pkg/place-holder
  > @@ -0,0 +1,2 @@
  > +perforce does not maintain empty directories.
  > +this file helps.
  > diff --git a/src/cmd/gc/mksys.bash b/src/cmd/gc/mksys.bash
  > old mode 100644
  > new mode 100755
  > EOF
  applying patch from stdin
  $ hg sum
  parent: 1:d59915696727 tip
   help management of empty pkg and lib directories in perforce
  branch: default
  commit: (clean)
  update: (current)
  $ hg diff --git -c tip
  diff --git a/lib/place-holder b/lib/place-holder
  new file mode 100644
  --- /dev/null
  +++ b/lib/place-holder
  @@ -0,0 +1,2 @@
  +perforce does not maintain empty directories.
  +this file helps.
  diff --git a/pkg/place-holder b/pkg/place-holder
  new file mode 100644
  --- /dev/null
  +++ b/pkg/place-holder
  @@ -0,0 +1,2 @@
  +perforce does not maintain empty directories.
  +this file helps.
  diff --git a/src/cmd/gc/mksys.bash b/src/cmd/gc/mksys.bash
  old mode 100644
  new mode 100755
  $ cd ..


diff lines looking like headers

  $ hg init difflineslikeheaders
  $ cd difflineslikeheaders
  $ echo a >a
  $ echo b >b
  $ echo c >c
  $ hg ci -Am1
  adding a
  adding b
  adding c

  $ echo "key: value" >>a
  $ echo "key: value" >>b
  $ echo "foo" >>c
  $ hg ci -m2

  $ hg up -C 0
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg diff --git -c1 >want
  $ hg diff -c1 | hg import --no-commit -
  applying patch from stdin
  $ hg diff --git >have
  $ diff want have
  $ cd ..

import a unified diff with no lines of context (diff -U0)

  $ hg init diffzero
  $ cd diffzero
  $ cat > f << EOF
  > c2
  > c4
  > c5
  > EOF
  $ hg commit -Am0
  adding f

  $ hg import --no-commit - << EOF
  > # HG changeset patch
  > # User test
  > # Date 0 0
  > # Node ID f4974ab632f3dee767567b0576c0ec9a4508575c
  > # Parent  8679a12a975b819fae5f7ad3853a2886d143d794
  > 1
  > diff -r 8679a12a975b -r f4974ab632f3 f
  > --- a/f	Thu Jan 01 00:00:00 1970 +0000
  > +++ b/f	Thu Jan 01 00:00:00 1970 +0000
  > @@ -0,0 +1,1 @@
  > +c1
  > @@ -1,0 +3,1 @@
  > +c3
  > @@ -3,1 +4,0 @@
  > -c5
  > EOF
  applying patch from stdin

  $ cat f
  c1
  c2
  c3
  c4

Test corner case involving fuzz and skew

  $ hg init morecornercases
  $ cd morecornercases

  $ cat > 01-no-context-beginning-of-file.diff <<EOF
  > diff --git a/a b/a
  > --- a/a
  > +++ b/a
  > @@ -1,0 +1,1 @@
  > +line
  > EOF

  $ cat > 02-no-context-middle-of-file.diff <<EOF
  > diff --git a/a b/a
  > --- a/a
  > +++ b/a
  > @@ -1,1 +1,1 @@
  > -2
  > +add some skew
  > @@ -2,0 +2,1 @@
  > +line
  > EOF

  $ cat > 03-no-context-end-of-file.diff <<EOF
  > diff --git a/a b/a
  > --- a/a
  > +++ b/a
  > @@ -10,0 +10,1 @@
  > +line
  > EOF

  $ cat > 04-middle-of-file-completely-fuzzed.diff <<EOF
  > diff --git a/a b/a
  > --- a/a
  > +++ b/a
  > @@ -1,1 +1,1 @@
  > -2
  > +add some skew
  > @@ -2,2 +2,3 @@
  >  not matching, should fuzz
  >  ... a bit
  > +line
  > EOF

  $ cat > a <<EOF
  > 1
  > 2
  > 3
  > 4
  > EOF
  $ hg ci -Am adda a
  $ for p in *.diff; do
  >   hg import -v --no-commit $p
  >   cat a
  >   hg revert -aqC a
  >   # patch -p1 < $p
  >   # cat a
  >   # hg revert -aC a
  > done
  applying 01-no-context-beginning-of-file.diff
  patching file a
  applied to working directory
  1
  line
  2
  3
  4
  applying 02-no-context-middle-of-file.diff
  patching file a
  Hunk #1 succeeded at 2 (offset 1 lines).
  Hunk #2 succeeded at 4 (offset 1 lines).
  applied to working directory
  1
  add some skew
  3
  line
  4
  applying 03-no-context-end-of-file.diff
  patching file a
  Hunk #1 succeeded at 5 (offset -6 lines).
  applied to working directory
  1
  2
  3
  4
  line
  applying 04-middle-of-file-completely-fuzzed.diff
  patching file a
  Hunk #1 succeeded at 2 (offset 1 lines).
  Hunk #2 succeeded at 5 with fuzz 2 (offset 1 lines).
  applied to working directory
  1
  add some skew
  3
  4
  line