tests/test-mactext.t

import-checker: treat "from mercurial import XXXX" style correctly

Before this patch, "import-checker.py" assumes that the name of
Mercurial module recognized by "imported_modules" doesn't have package
part: for example, "util".

This is reason why "import-checker.py" always builds fully qualified
module name up relatively, if the given module doesn't belong to
standard Python library.

But in fact, modules imported in "from mercurial import XXXX" style
already have fully qualified name: for example, "mercurial.util"
module imported by "mercurial.parsers" is treated as
"mercurial.mercurial.util" because of building module name up
relatively.

This prevents "import-checker.py" from correctly checking about cyclic
dependency in them.

This patch avoids building module name up relatively, also if module
name starts with "mercurial.", to treat modules imported in "from
mercurial import XXXX" style correctly.

  $ cat > unix2mac.py <<EOF
  > import sys
  > 
  > for path in sys.argv[1:]:
  >     data = file(path, 'rb').read()
  >     data = data.replace('\n', '\r')
  >     file(path, 'wb').write(data)
  > EOF
  $ cat > print.py <<EOF
  > import sys
  > print(sys.stdin.read().replace('\n', '<LF>').replace('\r', '<CR>').replace('\0', '<NUL>'))
  > EOF
  $ hg init
  $ echo '[hooks]' >> .hg/hgrc
  $ echo 'pretxncommit.cr = python:hgext.win32text.forbidcr' >> .hg/hgrc
  $ echo 'pretxnchangegroup.cr = python:hgext.win32text.forbidcr' >> .hg/hgrc
  $ cat .hg/hgrc
  [hooks]
  pretxncommit.cr = python:hgext.win32text.forbidcr
  pretxnchangegroup.cr = python:hgext.win32text.forbidcr

  $ echo hello > f
  $ hg add f
  $ hg ci -m 1

  $ python unix2mac.py f
  $ hg ci -m 2
  attempt to commit or push text file(s) using CR line endings
  in dea860dc51ec: f
  transaction abort!
  rollback completed
  abort: pretxncommit.cr hook failed
  [255]
  $ hg cat f | python print.py
  hello<LF>
  $ cat f | python print.py
  hello<CR>