tests/test-check-code.t

import-checker: establish modern import convention

We introduce a new convention for declaring imports and enforce it via
the import checker script.

The new convention is only active when absolute imports are used, which is
currently nowhere. Keying off "from __future__ import absolute_import" to
engage the new import convention seems like the easiest solution. It is
also beneficial for Mercurial to use this mode because it means less work
and ambiguity for the importer and potentially better performance due to
fewer stat() system calls because the importer won't look for modules in
relative paths unless explicitly asked.

Once all files are converted to use absolute import, we can refactor
this code to again only have a single import convention and we can
require use of absolute import in the style checker.

The rules for the new convention are documented in the docstring of the
added function. Tests have been added to test-module-imports.t. Some
tests are sensitive to newlines and source column position, which makes
docstring testing difficult and/or impossible.

  $ cat > correct.py <<EOF
  > def toto(arg1, arg2):
  >     del arg2
  >     return (5 + 6, 9)
  > EOF
  $ cat > wrong.py <<EOF
  > def toto( arg1, arg2):
  >     del(arg2)
  >     return ( 5+6, 9)
  > EOF
  $ cat > quote.py <<EOF
  > # let's use quote in comments
  > (''' ( 4x5 )
  > but """\\''' and finally''',
  > """let's fool checkpatch""", '1+2',
  > '"""', 42+1, """and
  > ( 4-1 ) """, "( 1+1 )\" and ")
  > a, '\\\\\\\\', "\\\\\\" x-2", "c-1"
  > EOF
  $ cat > classstyle.py <<EOF
  > class newstyle_class(object):
  >     pass
  > 
  > class oldstyle_class:
  >     pass
  > 
  > class empty():
  >     pass
  > 
  > no_class = 1:
  >     pass
  > EOF
  $ check_code="$TESTDIR"/../contrib/check-code.py
  $ "$check_code" ./wrong.py ./correct.py ./quote.py ./classstyle.py
  ./wrong.py:1:
   > def toto( arg1, arg2):
   gratuitous whitespace in () or []
  ./wrong.py:2:
   >     del(arg2)
   Python keyword is not a function
  ./wrong.py:3:
   >     return ( 5+6, 9)
   gratuitous whitespace in () or []
   missing whitespace in expression
  ./quote.py:5:
   > '"""', 42+1, """and
   missing whitespace in expression
  ./classstyle.py:4:
   > class oldstyle_class:
   old-style class, use class foo(object)
  ./classstyle.py:7:
   > class empty():
   class foo() creates old style object, use class foo(object)
  [1]
  $ cat > python3-compat.py << EOF
  > foo <> bar
  > reduce(lambda a, b: a + b, [1, 2, 3, 4])
  > dict(key=value)
  > EOF
  $ "$check_code" python3-compat.py
  python3-compat.py:1:
   > foo <> bar
   <> operator is not available in Python 3+, use !=
  python3-compat.py:2:
   > reduce(lambda a, b: a + b, [1, 2, 3, 4])
   reduce is not available in Python 3+
  python3-compat.py:3:
   > dict(key=value)
   dict() is different in Py2 and 3 and is slower than {}
  [1]

  $ cat > is-op.py <<EOF
  > # is-operator comparing number or string literal
  > x = None
  > y = x is 'foo'
  > y = x is "foo"
  > y = x is 5346
  > y = x is -6
  > y = x is not 'foo'
  > y = x is not "foo"
  > y = x is not 5346
  > y = x is not -6
  > EOF

  $ "$check_code" ./is-op.py
  ./is-op.py:3:
   > y = x is 'foo'
   object comparison with literal
  ./is-op.py:4:
   > y = x is "foo"
   object comparison with literal
  ./is-op.py:5:
   > y = x is 5346
   object comparison with literal
  ./is-op.py:6:
   > y = x is -6
   object comparison with literal
  ./is-op.py:7:
   > y = x is not 'foo'
   object comparison with literal
  ./is-op.py:8:
   > y = x is not "foo"
   object comparison with literal
  ./is-op.py:9:
   > y = x is not 5346
   object comparison with literal
  ./is-op.py:10:
   > y = x is not -6
   object comparison with literal
  [1]

  $ cat > for-nolineno.py <<EOF
  > except:
  > EOF
  $ "$check_code" for-nolineno.py --nolineno
  for-nolineno.py:0:
   > except:
   naked except clause
  [1]

  $ cat > warning.t <<EOF
  >   $ function warnonly {
  >   > }
  >   $ diff -N aaa
  >   $ function onwarn {}
  > EOF
  $ "$check_code" warning.t
  $ "$check_code" --warn warning.t
  warning.t:1:
   >   $ function warnonly {
   warning: don't use 'function', use old style
  warning.t:3:
   >   $ diff -N aaa
   warning: don't use 'diff -N'
  warning.t:4:
   >   $ function onwarn {}
   warning: don't use 'function', use old style
  [1]
  $ cat > raise-format.py <<EOF
  > raise SomeException, message
  > # this next line is okay
  > raise SomeException(arg1, arg2)
  > EOF
  $ "$check_code" not-existing.py raise-format.py
  Skipping*not-existing.py* (glob)
  raise-format.py:1:
   > raise SomeException, message
   don't use old-style two-argument raise, use Exception(message)
  [1]

  $ cat > rst.py <<EOF
  > """problematic rst text
  > 
  > .. note::
  >     wrong
  > """
  > 
  > '''
  > 
  > .. note::
  > 
  >     valid
  > 
  > new text
  > 
  >     .. note::
  > 
  >         also valid
  > '''
  > 
  > """mixed
  > 
  > .. note::
  > 
  >   good
  > 
  >     .. note::
  >         plus bad
  > """
  > EOF
  $ $check_code -w rst.py
  rst.py:3:
   > .. note::
   warning: add two newlines after '.. note::'
  rst.py:26:
   >     .. note::
   warning: add two newlines after '.. note::'
  [1]

  $ cat > ./map-inside-gettext.py <<EOF
  > print _("map inside gettext %s" % v)
  > 
  > print _("concatenating " " by " " space %s" % v)
  > print _("concatenating " + " by " + " '+' %s" % v)
  > 
  > print _("mapping operation in different line %s"
  >         % v)
  > 
  > print _(
  >         "leading spaces inside of '(' %s" % v)
  > EOF
  $ "$check_code" ./map-inside-gettext.py
  ./map-inside-gettext.py:1:
   > print _("map inside gettext %s" % v)
   don't use % inside _()
  ./map-inside-gettext.py:3:
   > print _("concatenating " " by " " space %s" % v)
   don't use % inside _()
  ./map-inside-gettext.py:4:
   > print _("concatenating " + " by " + " '+' %s" % v)
   don't use % inside _()
  ./map-inside-gettext.py:6:
   > print _("mapping operation in different line %s"
   don't use % inside _()
  ./map-inside-gettext.py:9:
   > print _(
   don't use % inside _()
  [1]

web templates

  $ mkdir -p mercurial/templates
  $ cat > mercurial/templates/example.tmpl <<EOF
  > {desc}
  > {desc|escape}
  > {desc|firstline}
  > {desc|websub}
  > EOF

  $ "$check_code" --warnings mercurial/templates/example.tmpl
  mercurial/templates/example.tmpl:2:
   > {desc|escape}
   warning: follow desc keyword with either firstline or websub
  [1]