diff options
Diffstat (limited to 'pylint/checkers/utils.py')
| -rw-r--r-- | pylint/checkers/utils.py | 55 |
1 files changed, 44 insertions, 11 deletions
diff --git a/pylint/checkers/utils.py b/pylint/checkers/utils.py index a3c8c01..b85c237 100644 --- a/pylint/checkers/utils.py +++ b/pylint/checkers/utils.py @@ -24,7 +24,6 @@ import string import warnings import astroid -from astroid import helpers from astroid import scoped_nodes import six from six.moves import map, builtins # pylint: disable=redefined-builtin @@ -644,7 +643,7 @@ def is_inside_abstract_class(node): def is_iterable(value): if isinstance(value, astroid.ClassDef): - if not helpers.has_known_bases(value): + if not has_known_bases(value): return True # classobj can only be iterable if it has an iterable metaclass meta = value.metaclass() @@ -652,7 +651,7 @@ def is_iterable(value): if _supports_iteration_protocol(meta): return True if isinstance(value, astroid.Instance): - if not helpers.has_known_bases(value): + if not has_known_bases(value): return True if _supports_iteration_protocol(value): return True @@ -661,7 +660,7 @@ def is_iterable(value): def is_mapping(value): if isinstance(value, astroid.ClassDef): - if not helpers.has_known_bases(value): + if not has_known_bases(value): return True # classobj can only be a mapping if it has a metaclass is mapping meta = value.metaclass() @@ -669,7 +668,7 @@ def is_mapping(value): if _supports_mapping_protocol(meta): return True if isinstance(value, astroid.Instance): - if not helpers.has_known_bases(value): + if not has_known_bases(value): return True if _supports_mapping_protocol(value): return True @@ -678,13 +677,13 @@ def is_mapping(value): def supports_membership_test(value): if isinstance(value, astroid.ClassDef): - if not helpers.has_known_bases(value): + if not has_known_bases(value): return True meta = value.metaclass() if meta is not None and _supports_membership_test_protocol(meta): return True if isinstance(value, astroid.Instance): - if not helpers.has_known_bases(value): + if not has_known_bases(value): return True if _supports_membership_test_protocol(value): return True @@ -693,18 +692,52 @@ def supports_membership_test(value): def supports_subscript(value): if isinstance(value, astroid.ClassDef): - if not helpers.has_known_bases(value): + if not has_known_bases(value): return False meta = value.metaclass() if meta is not None and _supports_subscript_protocol(meta): return True if isinstance(value, astroid.Instance): - if not helpers.has_known_bases(value): + if not has_known_bases(value): return True if _supports_subscript_protocol(value): return True return False # TODO(cpopa): deprecate these or leave them as aliases? -safe_infer = astroid.helpers.safe_infer -has_known_bases = astroid.helpers.has_known_bases +def safe_infer(node, context=None): + """Return the inferred value for the given node. + + Return None if inference failed or if there is some ambiguity (more than + one node has been inferred). + """ + try: + inferit = node.infer(context=context) + value = next(inferit) + except astroid.InferenceError: + return + try: + next(inferit) + return # None if there is ambiguity on the inferred node + except astroid.InferenceError: + return # there is some kind of ambiguity + except StopIteration: + return value + + +def has_known_bases(klass, context=None): + """Return true if all base classes of a class could be inferred.""" + try: + return klass._all_bases_known + except AttributeError: + pass + for base in klass.bases: + result = safe_infer(base, context=context) + # TODO: check for A->B->A->B pattern in class structure too? + if (not isinstance(result, astroid.ClassDef) or + result is klass or + not has_known_bases(result, context=context)): + klass._all_bases_known = False + return False + klass._all_bases_known = True + return True |