[content/test/gpu] Run pylint check of gpu tests in unittest instead of PRESUBMIT

third_party/pylint/pylint/checkers/exceptions.py

+# Copyright (c) 2003-2013 LOGILAB S.A. (Paris, FRANCE).
+# http://www.logilab.fr/ -- mailto:contact@logilab.fr
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+"""exceptions handling (raising, catching, exceptions classes) checker
+"""
+import sys
+
+import astroid
+from astroid import YES, Instance, unpack_infer, List, Tuple
+from logilab.common.compat import builtins
+
+from pylint.checkers import BaseChecker
+from pylint.checkers.utils import (
+    is_empty,
+    is_raising,
+    check_messages,
+    inherit_from_std_ex,
+    EXCEPTIONS_MODULE,
+    has_known_bases,
+    safe_infer)
+from pylint.interfaces import IAstroidChecker, INFERENCE, INFERENCE_FAILURE
+
+
+def _annotated_unpack_infer(stmt, context=None):
+    """
+    Recursively generate nodes inferred by the given statement.
+    If the inferred value is a list or a tuple, recurse on the elements.
+    Returns an iterator which yields tuples in the format
+    ('original node', 'infered node').
+    """
+    if isinstance(stmt, (List, Tuple)):
+        for elt in stmt.elts:
+            inferred = safe_infer(elt)
+            if inferred and inferred is not YES:
+                yield elt, inferred
+        return
+    for infered in stmt.infer(context):
+        if infered is YES:
+            continue
+        yield stmt, infered
+
+
+PY3K = sys.version_info >= (3, 0)
+OVERGENERAL_EXCEPTIONS = ('Exception',)
+BUILTINS_NAME = builtins.__name__
+MSGS = {
+    'E0701': ('Bad except clauses order (%s)',
+              'bad-except-order',
+              'Used when except clauses are not in the correct order (from the '
+              'more specific to the more generic). If you don\'t fix the order, '
+              'some exceptions may not be catched by the most specific handler.'),
+    'E0702': ('Raising %s while only classes or instances are allowed',
+              'raising-bad-type',
+              'Used when something which is neither a class, an instance or a \
+              string is raised (i.e. a `TypeError` will be raised).'),
+    'E0703': ('Exception context set to something which is not an '
+              'exception, nor None',
+              'bad-exception-context',
+              'Used when using the syntax "raise ... from ...", '
+              'where the exception context is not an exception, '
+              'nor None.',
+              {'minversion': (3, 0)}),
+    'E0710': ('Raising a new style class which doesn\'t inherit from BaseException',
+              'raising-non-exception',
+              'Used when a new style class which doesn\'t inherit from \
+               BaseException is raised.'),
+    'E0711': ('NotImplemented raised - should raise NotImplementedError',
+              'notimplemented-raised',
+              'Used when NotImplemented is raised instead of \
+              NotImplementedError'),
+    'E0712': ('Catching an exception which doesn\'t inherit from BaseException: %s',
+              'catching-non-exception',
+              'Used when a class which doesn\'t inherit from \
+               BaseException is used as an exception in an except clause.'),
+    'W0702': ('No exception type(s) specified',
+              'bare-except',
+              'Used when an except clause doesn\'t specify exceptions type to \
+              catch.'),
+    'W0703': ('Catching too general exception %s',
+              'broad-except',
+              'Used when an except catches a too general exception, \
+              possibly burying unrelated errors.'),
+    'W0704': ('Except doesn\'t do anything',
+              'pointless-except',
+              'Used when an except clause does nothing but "pass" and there is\
+              no "else" clause.'),
+    'W0710': ('Exception doesn\'t inherit from standard "Exception" class',
+              'nonstandard-exception',
+              'Used when a custom exception class is raised but doesn\'t \
+              inherit from the builtin "Exception" class.',
+              {'maxversion': (3, 0)}),
+    'W0711': ('Exception to catch is the result of a binary "%s" operation',
+              'binary-op-exception',
+              'Used when the exception to catch is of the form \
+              "except A or B:".  If intending to catch multiple, \
+              rewrite as "except (A, B):"'),
+    }
+
+
+class ExceptionsChecker(BaseChecker):
+    """checks for
+    * excepts without exception filter
+    * type of raise argument : string, Exceptions, other values
+    """
+
+    __implements__ = IAstroidChecker
+
+    name = 'exceptions'
+    msgs = MSGS
+    priority = -4
+    options = (('overgeneral-exceptions',
+                {'default' : OVERGENERAL_EXCEPTIONS,
+                 'type' :'csv', 'metavar' : '<comma-separated class names>',
+                 'help' : 'Exceptions that will emit a warning '
+                          'when being caught. Defaults to "%s"' % (
+                              ', '.join(OVERGENERAL_EXCEPTIONS),)}
+               ),
+              )
+
+    @check_messages('nonstandard-exception',
+                    'raising-bad-type', 'raising-non-exception',
+                    'notimplemented-raised', 'bad-exception-context')
+    def visit_raise(self, node):
+        """visit raise possibly inferring value"""
+        # ignore empty raise
+        if node.exc is None:
+            return
+        if PY3K and node.cause:
+            self._check_bad_exception_context(node)
+
+        expr = node.exc
+        if self._check_raise_value(node, expr):
+            return
+        else:
+            try:
+                value = next(unpack_infer(expr))
+            except astroid.InferenceError:
+                return
+            self._check_raise_value(node, value)
+
+    def _check_bad_exception_context(self, node):
+        """Verify that the exception context is properly set.
+
+        An exception context can be only `None` or an exception.
+        """
+        cause = safe_infer(node.cause)
+        if cause in (YES, None):
+            return
+        if isinstance(cause, astroid.Const):
+            if cause.value is not None:
+                self.add_message('bad-exception-context',
+                                 node=node)
+        elif (not isinstance(cause, astroid.Class) and
+              not inherit_from_std_ex(cause)):
+            self.add_message('bad-exception-context',
+                             node=node)
+
+    def _check_raise_value(self, node, expr):
+        """check for bad values, string exception and class inheritance
+        """
+        value_found = True
+        if isinstance(expr, astroid.Const):
+            value = expr.value
+            if not isinstance(value, str):
+                # raising-string will be emitted from python3 porting checker.
+                self.add_message('raising-bad-type', node=node,
+                                 args=value.__class__.__name__)
+        elif ((isinstance(expr, astroid.Name) and
+               expr.name in ('None', 'True', 'False')) or
+              isinstance(expr, (astroid.List, astroid.Dict, astroid.Tuple,
+                                astroid.Module, astroid.Function))):
+            emit = True
+            if not PY3K and isinstance(expr, astroid.Tuple):
+                # On Python 2, using the following is not an error:
+                #    raise (ZeroDivisionError, None)
+                #    raise (ZeroDivisionError, )
+                # What's left to do is to check that the first
+                # argument is indeed an exception.
+                # Verifying the other arguments is not
+                # the scope of this check.
+                first = expr.elts[0]
+                inferred = safe_infer(first)
+                if isinstance(inferred, Instance):
+                    # pylint: disable=protected-access
+                    inferred = inferred._proxied
+                if (inferred is YES or
+                        isinstance(inferred, astroid.Class)
+                        and inherit_from_std_ex(inferred)):
+                    emit = False
+            if emit:
+                self.add_message('raising-bad-type',
+                                 node=node,
+                                 args=expr.name)
+        elif ((isinstance(expr, astroid.Name) and expr.name == 'NotImplemented')
+              or (isinstance(expr, astroid.CallFunc) and
+                  isinstance(expr.func, astroid.Name) and
+                  expr.func.name == 'NotImplemented')):
+            self.add_message('notimplemented-raised', node=node)
+        elif isinstance(expr, (Instance, astroid.Class)):
+            if isinstance(expr, Instance):
+                # pylint: disable=protected-access
+                expr = expr._proxied
+            if (isinstance(expr, astroid.Class) and
+                    not inherit_from_std_ex(expr)):
+                if expr.newstyle:
+                    self.add_message('raising-non-exception', node=node)
+                else:
+                    if has_known_bases(expr):
+                        confidence = INFERENCE
+                    else:
+                        confidence = INFERENCE_FAILURE
+                    self.add_message(
+                        'nonstandard-exception', node=node,
+                        confidence=confidence)
+            else:
+                value_found = False
+        else:
+            value_found = False
+        return value_found
+
+    def _check_catching_non_exception(self, handler, exc, part):
+        if isinstance(exc, astroid.Tuple):
+            # Check if it is a tuple of exceptions.
+            inferred = [safe_infer(elt) for elt in exc.elts]
+            if any(node is astroid.YES for node in inferred):
+                # Don't emit if we don't know every component.
+                return
+            if all(node and inherit_from_std_ex(node)
+                   for node in inferred):
+                return
+
+        if not isinstance(exc, astroid.Class):
+            # Don't emit the warning if the infered stmt
+            # is None, but the exception handler is something else,
+            # maybe it was redefined.
+            if (isinstance(exc, astroid.Const) and
+                    exc.value is None):
+                if ((isinstance(handler.type, astroid.Const) and
+                     handler.type.value is None) or
+                        handler.type.parent_of(exc)):
+                    # If the exception handler catches None or
+                    # the exception component, which is None, is
+                    # defined by the entire exception handler, then
+                    # emit a warning.
+                    self.add_message('catching-non-exception',
+                                     node=handler.type,
+                                     args=(part.as_string(), ))
+            else:
+                self.add_message('catching-non-exception',
+                                 node=handler.type,
+                                 args=(part.as_string(), ))
+            return
+        if (not inherit_from_std_ex(exc) and
+                exc.root().name != BUILTINS_NAME):
+            if has_known_bases(exc):
+                self.add_message('catching-non-exception',
+                                 node=handler.type,
+                                 args=(exc.name, ))
+
+    @check_messages('bare-except', 'broad-except', 'pointless-except',
+                    'binary-op-exception', 'bad-except-order',
+                    'catching-non-exception')
+    def visit_tryexcept(self, node):
+        """check for empty except"""
+        exceptions_classes = []
+        nb_handlers = len(node.handlers)
+        for index, handler in enumerate(node.handlers):
+            # single except doing nothing but "pass" without else clause
+            if is_empty(handler.body) and not node.orelse:
+                self.add_message('pointless-except',
+                                 node=handler.type or handler.body[0])
+            if handler.type is None:
+                if not is_raising(handler.body):
+                    self.add_message('bare-except', node=handler)
+                # check if a "except:" is followed by some other
+                # except
+                if index < (nb_handlers - 1):
+                    msg = 'empty except clause should always appear last'
+                    self.add_message('bad-except-order', node=node, args=msg)
+
+            elif isinstance(handler.type, astroid.BoolOp):
+                self.add_message('binary-op-exception',
+                                 node=handler, args=handler.type.op)
+            else:
+                try:
+                    excs = list(_annotated_unpack_infer(handler.type))
+                except astroid.InferenceError:
+                    continue
+                for part, exc in excs:
+                    if exc is YES:
+                        continue
+                    if (isinstance(exc, astroid.Instance)
+                            and inherit_from_std_ex(exc)):
+                        # pylint: disable=protected-access
+                        exc = exc._proxied
+
+                    self._check_catching_non_exception(handler, exc, part)
+
+                    if not isinstance(exc, astroid.Class):
+                        continue
+
+                    exc_ancestors = [anc for anc in exc.ancestors()
+                                     if isinstance(anc, astroid.Class)]
+                    for previous_exc in exceptions_classes:
+                        if previous_exc in exc_ancestors:
+                            msg = '%s is an ancestor class of %s' % (
+                                previous_exc.name, exc.name)
+                            self.add_message('bad-except-order',
+                                             node=handler.type, args=msg)
+                    if (exc.name in self.config.overgeneral_exceptions
+                            and exc.root().name == EXCEPTIONS_MODULE
+                            and not is_raising(handler.body)):
+                        self.add_message('broad-except',
+                                         args=exc.name, node=handler.type)
+
+                exceptions_classes += [exc for _, exc in excs]
+
+
+def register(linter):
+    """required method to auto register this checker"""
+    linter.register_checker(ExceptionsChecker(linter))