tests/test-import-unknown.t

filectx: fix cmp() of file starting with '\1\n'

If file data starts with '\1\n', it will be escaped in the revlog to
create an empty metadata block, thus adding four bytes to the size in
the revlog size index. There's no way to detect that this has happened
in filelog.size() faster than decompressing each revision [1].

For filectx.cmp(), we have the size of the file in the working directory
available. If it differs by exactly four bytes, it may be this case, so
do a full comparison.

 [1]: http://markmail.org/message/5akdbmmqx7vq2fsg

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > purge =
  > EOF

  $ hg init test
  $ cd test
  $ echo a > changed
  $ echo a > removed
  $ echo a > source
  $ hg ci -Am addfiles
  adding changed
  adding removed
  adding source
  $ echo a >> changed
  $ echo a > added
  $ hg add added
  $ hg rm removed
  $ hg cp source copied
  $ hg diff --git > ../unknown.diff

Test adding on top of an unknown file

  $ hg up -qC 0
  $ hg purge
  $ echo a > added
  $ hg import --no-commit ../unknown.diff
  applying ../unknown.diff
  file added already exists
  1 out of 1 hunks FAILED -- saving rejects to file added.rej
  abort: patch failed to apply
  [255]

Test modifying an unknown file

  $ hg revert -aq
  $ hg purge
  $ hg rm changed
  $ hg ci -m removechanged
  $ echo a > changed
  $ hg import --no-commit ../unknown.diff
  applying ../unknown.diff
  abort: cannot patch changed: file is not tracked
  [255]

Test removing an unknown file

  $ hg up -qC 0
  $ hg purge
  $ hg rm removed
  $ hg ci -m removeremoved
  created new head
  $ echo a > removed
  $ hg import --no-commit ../unknown.diff
  applying ../unknown.diff
  abort: cannot patch removed: file is not tracked
  [255]

Test copying onto an unknown file

  $ hg up -qC 0
  $ hg purge
  $ echo a > copied
  $ hg import --no-commit ../unknown.diff
  applying ../unknown.diff
  abort: cannot create copied: destination already exists
  [255]