Beispiel #1
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    def test_extract_simple(self) -> None:
        # Verify true behavior
        expression = cst.parse_expression("a + b[c], d(e, f * g)")
        nodes = m.extract(
            expression,
            m.Tuple(elements=[
                m.Element(
                    m.BinaryOperation(
                        left=m.SaveMatchedNode(m.Name(), "left"))),
                m.Element(m.Call()),
            ]),
        )
        extracted_node = cst.ensure_type(
            cst.ensure_type(expression, cst.Tuple).elements[0].value,
            cst.BinaryOperation,
        ).left
        self.assertEqual(nodes, {"left": extracted_node})

        # Verify false behavior
        nodes = m.extract(
            expression,
            m.Tuple(elements=[
                m.Element(
                    m.BinaryOperation(
                        left=m.SaveMatchedNode(m.Subscript(), "left"))),
                m.Element(m.Call()),
            ]),
        )
        self.assertIsNone(nodes)
Beispiel #2
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    def test_extract_sequence_element(self) -> None:
        # Verify true behavior
        expression = cst.parse_expression("a + b[c], d(e, f * g, h.i.j)")
        nodes = m.extract(
            expression,
            m.Tuple(elements=[
                m.DoNotCare(),
                m.Element(
                    m.Call(args=[m.SaveMatchedNode(m.ZeroOrMore(), "args")])),
            ]),
        )
        extracted_seq = cst.ensure_type(
            cst.ensure_type(expression, cst.Tuple).elements[1].value,
            cst.Call).args
        self.assertEqual(nodes, {"args": extracted_seq})

        # Verify false behavior
        nodes = m.extract(
            expression,
            m.Tuple(elements=[
                m.DoNotCare(),
                m.Element(
                    m.Call(args=[
                        m.SaveMatchedNode(m.ZeroOrMore(m.Arg(m.Subscript())),
                                          "args")
                    ])),
            ]),
        )
        self.assertIsNone(nodes)
 def __name2annotation(self, type_name: str):
     """
     Converts Name nodes to valid annotation nodes
     """
     try:
         return match.extract(
             cst.parse_module("x: %s=None" % type_name).body[0].body[0],
             match.AnnAssign(target=match.Name(value=match.DoNotCare()),
                             annotation=match.SaveMatchedNode(
                                 match.DoNotCare(), "type")))['type']
     except cst._exceptions.ParserSyntaxError:
         # To handle a bug in LibCST's scope provider where a local name shadows a type annotation with the same name
         if (self.last_visited_name.value,
                 cst.metadata.QualifiedNameSource.IMPORT
             ) in self.q_names_cache:
             return match.extract(
                 cst.parse_module(
                     "x: %s=None" %
                     self.q_names_cache[(self.last_visited_name.value,
                                         cst.metadata.QualifiedNameSource.
                                         IMPORT)]).body[0].body[0],
                 match.AnnAssign(target=match.Name(value=match.DoNotCare()),
                                 annotation=match.SaveMatchedNode(
                                     match.DoNotCare(), "type")))['type']
         else:
             return match.extract(
                 cst.parse_module(
                     "x: %s=None" %
                     self.last_visited_name.value).body[0].body[0],
                 match.AnnAssign(target=match.Name(value=match.DoNotCare()),
                                 annotation=match.SaveMatchedNode(
                                     match.DoNotCare(), "type")))['type']
Beispiel #4
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 def handle_any_string(
         self, node: Union[cst.SimpleString,
                           cst.ConcatenatedString]) -> None:
     value = node.evaluated_value
     if value is None:
         return
     mod = cst.parse_module(value)
     extracted_nodes = m.extractall(
         mod,
         m.Name(
             value=m.SaveMatchedNode(m.DoNotCare(), "name"),
             metadata=m.MatchMetadataIfTrue(
                 cst.metadata.ParentNodeProvider,
                 lambda parent: not isinstance(parent, cst.Attribute),
             ),
         )
         | m.SaveMatchedNode(m.Attribute(), "attribute"),
         metadata_resolver=MetadataWrapper(mod, unsafe_skip_copy=True),
     )
     names = {
         cast(str, values["name"])
         for values in extracted_nodes if "name" in values
     } | {
         name
         for values in extracted_nodes if "attribute" in values
         for name, _ in cst.metadata.scope_provider._gen_dotted_names(
             cast(cst.Attribute, values["attribute"]))
     }
     self.names.update(names)
Beispiel #5
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 def __extract_variable_name_type(self, node: cst.AnnAssign):
     """
     Extracts a variable's identifier name and its type annotation
     """
     return match.extract(
         node,
         match.AnnAssign(  # Annotated Assignment
             target=match.OneOf(
                 match.Name(  # Variable name of assignment (only one)
                     value=match.SaveMatchedNode(  # Save result
                         match.MatchRegex(
                             r'(.)+'),  # Match any string literal
                         "name")),
                 # This extracts variables inside __init__ which typically starts with self (e.g. self.x:int=2)
                 match.Attribute(
                     value=match.Name(value=match.SaveMatchedNode(
                         match.MatchRegex(r'(.)+'),
                         "obj_name"  # Object name
                     )),
                     attr=match.Name(
                         match.SaveMatchedNode(match.MatchRegex(r'(.)+'),
                                               "name")),
                 )),
             annotation=match.SaveMatchedNode(  # Save result
                 match.DoNotCare(),  # Match any string literal
                 "type")))
Beispiel #6
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 def test_extract_optional_wildcard_tail(self) -> None:
     expression = cst.parse_expression("[3]")
     nodes = m.extract(
         expression,
         m.List(elements=[
             m.Element(value=m.Integer(value="3")),
             m.SaveMatchedNode(m.ZeroOrMore(), "tail1"),
             m.SaveMatchedNode(m.ZeroOrMore(), "tail2"),
         ]),
     )
     self.assertEqual(nodes, {"tail1": (), "tail2": ()})
Beispiel #7
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 def test_extract_sentinel(self) -> None:
     # Verify behavior when provided a sentinel
     nothing = m.extract(
         cst.RemovalSentinel.REMOVE,
         m.Call(func=m.SaveMatchedNode(m.Name(), name="func")),
     )
     self.assertIsNone(nothing)
     nothing = m.extract(
         cst.MaybeSentinel.DEFAULT,
         m.Call(func=m.SaveMatchedNode(m.Name(), name="func")),
     )
     self.assertIsNone(nothing)
 def __get_var_names_counter(self, node, scope):
     vars_name = match.extractall(
         node,
         match.OneOf(
             match.AssignTarget(target=match.SaveMatchedNode(
                 match.Name(value=match.DoNotCare()), "name")),
             match.AnnAssign(target=match.SaveMatchedNode(
                 match.Name(value=match.DoNotCare()), "name"))))
     return Counter([
         n['name'].value for n in vars_name if isinstance(
             self.get_metadata(cst.metadata.ScopeProvider, n['name']),
             scope)
     ])
Beispiel #9
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    def test_extract_metadata(self) -> None:
        # Verify true behavior
        module = cst.parse_module("a + b[c], d(e, f * g)")
        wrapper = cst.MetadataWrapper(module)
        expression = cst.ensure_type(
            cst.ensure_type(wrapper.module.body[0],
                            cst.SimpleStatementLine).body[0],
            cst.Expr,
        ).value

        nodes = m.extract(
            expression,
            m.Tuple(elements=[
                m.Element(
                    m.BinaryOperation(left=m.Name(metadata=m.SaveMatchedNode(
                        m.MatchMetadata(
                            meta.PositionProvider,
                            self._make_coderange((1, 0), (1, 1)),
                        ),
                        "left",
                    )))),
                m.Element(m.Call()),
            ]),
            metadata_resolver=wrapper,
        )
        extracted_node = cst.ensure_type(
            cst.ensure_type(expression, cst.Tuple).elements[0].value,
            cst.BinaryOperation,
        ).left
        self.assertEqual(nodes, {"left": extracted_node})

        # Verify false behavior
        nodes = m.extract(
            expression,
            m.Tuple(elements=[
                m.Element(
                    m.BinaryOperation(left=m.Name(metadata=m.SaveMatchedNode(
                        m.MatchMetadata(
                            meta.PositionProvider,
                            self._make_coderange((1, 0), (1, 2)),
                        ),
                        "left",
                    )))),
                m.Element(m.Call()),
            ]),
            metadata_resolver=wrapper,
        )
        self.assertIsNone(nodes)
Beispiel #10
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    def test_replace_add_one_to_foo_args(self) -> None:
        def _add_one_to_arg(
            node: cst.CSTNode,
            extraction: Dict[str, Union[cst.CSTNode, Sequence[cst.CSTNode]]],
        ) -> cst.CSTNode:
            return node.deep_replace(
                # This can be either a node or a sequence, pyre doesn't know.
                cst.ensure_type(extraction["arg"], cst.CSTNode),
                # Grab the arg and add one to its value.
                cst.Integer(
                    str(
                        int(
                            cst.ensure_type(extraction["arg"],
                                            cst.Integer).value) + 1)),
            )

        # Verify way more complex transform behavior.
        original = cst.parse_module(
            "foo: int = 37\ndef bar(baz: int) -> int:\n    return baz\n\nbiz: int = bar(41)\n"
        )
        replaced = cst.ensure_type(
            m.replace(
                original,
                m.Call(
                    func=m.Name("bar"),
                    args=[m.Arg(m.SaveMatchedNode(m.Integer(), "arg"))],
                ),
                _add_one_to_arg,
            ),
            cst.Module,
        ).code
        self.assertEqual(
            replaced,
            "foo: int = 37\ndef bar(baz: int) -> int:\n    return baz\n\nbiz: int = bar(42)\n",
        )
Beispiel #11
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    def test_replace_sequence_extract(self) -> None:
        def _reverse_params(
            node: cst.CSTNode,
            extraction: Dict[str, Union[cst.CSTNode, Sequence[cst.CSTNode]]],
        ) -> cst.CSTNode:
            return cst.ensure_type(node, cst.FunctionDef).with_changes(
                # pyre-ignore We know "params" is a Sequence[Parameters] but asserting that
                # to pyre is difficult.
                params=cst.Parameters(
                    params=list(reversed(extraction["params"]))))

        # Verify that we can still extract sequences with replace.
        original = cst.parse_module(
            "def bar(baz: int, foo: int, ) -> int:\n    return baz + foo\n")
        replaced = cst.ensure_type(
            m.replace(
                original,
                m.FunctionDef(params=m.Parameters(params=m.SaveMatchedNode(
                    [m.ZeroOrMore(m.Param())], "params"))),
                _reverse_params,
            ),
            cst.Module,
        ).code
        self.assertEqual(
            replaced,
            "def bar(foo: int, baz: int, ) -> int:\n    return baz + foo\n")
Beispiel #12
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    def test_replace_updated_node_changes(self) -> None:
        def _replace_nested(
            node: cst.CSTNode,
            extraction: Dict[str, Union[cst.CSTNode, Sequence[cst.CSTNode]]],
        ) -> cst.CSTNode:
            return cst.ensure_type(node, cst.Call).with_changes(args=[
                cst.Arg(
                    cst.Name(value=cst.ensure_type(
                        cst.ensure_type(extraction["inner"], cst.Call).func,
                        cst.Name,
                    ).value + "_immediate"))
            ])

        original = cst.parse_module(
            "def foo(val: int) -> int:\n    return val\nbar = foo\nbaz = foo\nbiz = foo\nfoo(bar(baz(biz(5))))\n"
        )
        replaced = cst.ensure_type(
            m.replace(
                original,
                m.Call(args=[m.Arg(m.SaveMatchedNode(m.Call(), "inner"))]),
                _replace_nested,
            ),
            cst.Module,
        ).code
        self.assertEqual(
            replaced,
            "def foo(val: int) -> int:\n    return val\nbar = foo\nbaz = foo\nbiz = foo\nfoo(bar_immediate)\n",
        )
Beispiel #13
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 def test_extract_precedence_sequence(self) -> None:
     expression = cst.parse_expression("a + b[c], d(e, f * g)")
     nodes = m.extract(
         expression,
         m.Tuple(elements=[
             m.DoNotCare(),
             m.Element(
                 m.Call(args=[
                     m.Arg(m.SaveMatchedNode(m.DoNotCare(), "arg")),
                     m.Arg(m.SaveMatchedNode(m.DoNotCare(), "arg")),
                 ])),
         ]),
     )
     extracted_node = (cst.ensure_type(
         cst.ensure_type(expression, cst.Tuple).elements[1].value,
         cst.Call).args[1].value)
     self.assertEqual(nodes, {"arg": extracted_node})
Beispiel #14
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    def visit_With(self, node: cst.With):
        with_names = [
            n.value for n in match.findall(
                match.extract(
                    node,
                    match.With(items=match.SaveMatchedNode(
                        match.DoNotCare(), 'with_items')))['with_items'][0],
                match.Name(
                    value=match.SaveMatchedNode(match.DoNotCare(), 'name')))
        ]
        if len(self.stack) > 0:
            self.fn_may_args_var_use.append(with_names)

        if len(self.cls_stack) > 0:
            if self.cls_stack[0].name in with_names:
                self.cls_may_vars_use.append(with_names)

        self.__find_module_vars_use(with_names)
Beispiel #15
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    def leave_BinaryOperation(
        self, original_node: cst.BinaryOperation, updated_node: cst.BinaryOperation
    ) -> cst.BaseExpression:
        expr_key = "expr"
        extracts = m.extract(
            original_node,
            m.BinaryOperation(
                left=m.MatchIfTrue(_match_simple_string),
                operator=m.Modulo(),
                right=m.SaveMatchedNode(
                    m.MatchIfTrue(_gen_match_simple_expression(self.module)), expr_key,
                ),
            ),
        )

        if extracts:
            expr = extracts[expr_key]
            parts = []
            simple_string = cst.ensure_type(original_node.left, cst.SimpleString)
            innards = simple_string.raw_value.replace("{", "{{").replace("}", "}}")
            tokens = innards.split("%s")
            token = tokens[0]
            if len(token) > 0:
                parts.append(cst.FormattedStringText(value=token))
            expressions = (
                [elm.value for elm in expr.elements]
                if isinstance(expr, cst.Tuple)
                else [expr]
            )
            escape_transformer = EscapeStringQuote(simple_string.quote)
            i = 1
            while i < len(tokens):
                if i - 1 >= len(expressions):
                    # the %-string doesn't come with same number of elements in tuple
                    return original_node
                try:
                    parts.append(
                        cst.FormattedStringExpression(
                            expression=cast(
                                cst.BaseExpression,
                                expressions[i - 1].visit(escape_transformer),
                            )
                        )
                    )
                except Exception:
                    return original_node
                token = tokens[i]
                if len(token) > 0:
                    parts.append(cst.FormattedStringText(value=token))
                i += 1
            start = f"f{simple_string.prefix}{simple_string.quote}"
            return cst.FormattedString(
                parts=parts, start=start, end=simple_string.quote
            )

        return original_node
Beispiel #16
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 def test_extractall_simple(self) -> None:
     expression = cst.parse_expression("a + b[c], d(e, f * g, h.i.j)")
     matches = extractall(expression, m.Arg(m.SaveMatchedNode(~m.Name(), "expr")))
     extracted_args = cst.ensure_type(
         cst.ensure_type(expression, cst.Tuple).elements[1].value, cst.Call
     ).args
     self.assertEqual(
         matches,
         [{"expr": extracted_args[1].value}, {"expr": extracted_args[2].value}],
     )
Beispiel #17
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 def __name2annotation(self, type_name: str):
     ext_annot = lambda t: match.extract(
         cst.parse_module("x: %s=None" % t).body[0].body[0],
         match.AnnAssign(target=match.Name(value=match.DoNotCare()),
                         annotation=match.SaveMatchedNode(
                             match.DoNotCare(), "type")))['type']
     try:
         return ext_annot(type_name)
     except cst._exceptions.ParserSyntaxError:
         return None
Beispiel #18
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    def visit_Element(self, node: libcst.Element) -> bool:
        # See if this is a entry that is a string.
        extraction = self.extract(
            node, m.Element(m.SaveMatchedNode(m.SimpleString(), "string")))
        if extraction:
            string = ensure_type(extraction["string"], libcst.SimpleString)
            self.explicit_exported_objects.add(string.evaluated_value)

        # Don't need to visit children
        return False
Beispiel #19
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 def test_extract_sequence_multiple_wildcards(self) -> None:
     expression = cst.parse_expression("1, 2, 3, 4")
     nodes = m.extract(
         expression,
         m.Tuple(elements=(
             m.SaveMatchedNode(m.ZeroOrMore(), "head"),
             m.SaveMatchedNode(m.Element(value=m.Integer(
                 value="3")), "element"),
             m.SaveMatchedNode(m.ZeroOrMore(), "tail"),
         )),
     )
     tuple_elements = cst.ensure_type(expression, cst.Tuple).elements
     self.assertEqual(
         nodes,
         {
             "head": tuple(tuple_elements[:2]),
             "element": tuple_elements[2],
             "tail": tuple(tuple_elements[3:]),
         },
     )
Beispiel #20
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    def visit_ImportAlias(self, node: cst.ImportAlias):
        """
        Extracts imports.

        Even if an Import has no alias, the Import node will still have an ImportAlias
        with it's real name.
        """
        # Extract information from the Import Alias node.
        # Both the (real) import name and the alias are extracted.
        # Result is returned as a dictionary with a name:node KV pair,
        # and an alias:name KV pair if an alias is present.
        import_info = match.extract(
            node,
            match.ImportAlias(
                asname=match.AsName(  # Attempt to match alias
                    name=match.Name(  # Check for alias name
                        value=match.SaveMatchedNode(  # Save the alias name
                            match.MatchRegex(
                                r'(.)+'),  # Match any string literal
                            "alias"))) | ~match.AsName(),
                # If there is no AsName, we should still match. We negate AsName to and OR to form a tautology.
                name=match.SaveMatchedNode(  # Match & save name of import
                    match.DoNotCare(), "name")))

        # Add import if a name could be extracted.
        if "name" in import_info:
            # Append import name to imports list.
            # We convert the ImportAlias node to the code representation for simplified conversion
            # of multi-level imports (e.g. import.x.y.z)
            # TODO: This might be un-needed after implementing import type extraction change.
            # TODO: So far, no differentiation between import and from imports.
            import_name = self.__convert_node_to_code(import_info["name"])
            import_name = self.__clean_string_whitespace(import_name)
            self.imports.append(import_name)

        if "alias" in import_info:
            import_name = self.__clean_string_whitespace(import_info["alias"])
            self.imports.append(import_name)

        # No need to traverse children, as we already performed the matching.
        return False
Beispiel #21
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 def test_extract_tautology(self) -> None:
     expression = cst.parse_expression("a + b[c], d(e, f * g)")
     nodes = m.extract(
         expression,
         m.SaveMatchedNode(
             m.Tuple(elements=[
                 m.Element(m.BinaryOperation()),
                 m.Element(m.Call())
             ]),
             name="node",
         ),
     )
     self.assertEqual(nodes, {"node": expression})
Beispiel #22
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 def visit_Assign(self, node: cst.Assign) -> None:
     d = m.extract(
         node,
         m.Assign(
             targets=(m.AssignTarget(target=m.Name("CARBON_EXTS")), ),
             value=m.SaveMatchedNode(m.List(), "list"),
         ),
     )
     if d:
         assert isinstance(d["list"], cst.List)
         for item in d["list"].elements:
             if isinstance(item.value, cst.SimpleString):
                 self.extension_names.append(item.value.evaluated_value)
Beispiel #23
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    def __extract_variable_name(self, node: cst.AssignTarget):
        extracted_var_names = match.extract(
            node,
            match.AssignTarget(  # Assignment operator
                target=match.OneOf(  # Two cases exist
                    match.Name(  # Single target
                        value=match.SaveMatchedNode(  # Save result
                            match.MatchRegex(
                                r'(.)+'),  # Match any string literal
                            "name")),
                    match.Tuple(  # Multi-target
                        elements=match.SaveMatchedNode(  # Save result
                            match.DoNotCare(),  # Type of list
                            "names")),
                    # This extracts variables inside __init__ without type annotation (e.g. self.x=2)
                    match.Attribute(
                        value=match.Name(value=match.SaveMatchedNode(
                            match.MatchRegex(r'(.)+'),
                            "obj_name"  # Object name
                        )),
                        attr=match.Name(
                            match.SaveMatchedNode(match.MatchRegex(r'(.)+'),
                                                  "name")),
                    ))))

        if extracted_var_names is not None:
            if "name" in extracted_var_names:
                t = self.__get_type_from_metadata(node.target)
                extracted_var_names['type'] = (t, INF_TYPE_ANNOT
                                               if t else UNK_TYPE_ANNOT)
                return extracted_var_names
            elif "names" in extracted_var_names:
                return {
                    'names':
                    self.__extract_names_multi_assign(
                        list(extracted_var_names['names']))
                }
        else:
            return extracted_var_names
Beispiel #24
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 def test_extract_multiple(self) -> None:
     expression = cst.parse_expression("a + b[c], d(e, f * g)")
     nodes = m.extract(
         expression,
         m.Tuple(elements=[
             m.Element(
                 m.BinaryOperation(
                     left=m.SaveMatchedNode(m.Name(), "left"))),
             m.Element(m.Call(func=m.SaveMatchedNode(m.Name(), "func"))),
         ]),
     )
     extracted_node_left = cst.ensure_type(
         cst.ensure_type(expression, cst.Tuple).elements[0].value,
         cst.BinaryOperation,
     ).left
     extracted_node_func = cst.ensure_type(
         cst.ensure_type(expression, cst.Tuple).elements[1].value,
         cst.Call).func
     self.assertEqual(nodes, {
         "left": extracted_node_left,
         "func": extracted_node_func
     })
Beispiel #25
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 def test_extract_sequence(self) -> None:
     expression = cst.parse_expression("a + b[c], d(e, f * g, h.i.j)")
     nodes = m.extract(
         expression,
         m.Tuple(elements=[
             m.DoNotCare(),
             m.Element(
                 m.Call(args=m.SaveMatchedNode([m.ZeroOrMore()], "args"))),
         ]),
     )
     extracted_seq = cst.ensure_type(
         cst.ensure_type(expression, cst.Tuple).elements[1].value,
         cst.Call).args
     self.assertEqual(nodes, {"args": extracted_seq})
Beispiel #26
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 def test_extract_optional_wildcard(self) -> None:
     expression = cst.parse_expression("a + b[c], d(e, f * g)")
     nodes = m.extract(
         expression,
         m.Tuple(elements=[
             m.DoNotCare(),
             m.Element(
                 m.Call(args=[
                     m.ZeroOrMore(),
                     m.ZeroOrOne(
                         m.Arg(m.SaveMatchedNode(m.Attribute(), "arg"))),
                 ])),
         ]),
     )
     self.assertEqual(nodes, {})
Beispiel #27
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 def visit_Call(self, node: cst.Call) -> None:
     # print(node)
     d = m.extract(
         node,
         m.Call(
             func=m.OneOf(m.Name("Extension"), m.Name("addMacExtension")),
             args=(
                 m.Arg(value=m.SaveMatchedNode(m.SimpleString(),
                                               "extension_name")),
                 m.ZeroOrMore(m.DoNotCare()),
             ),
         ),
     )
     if d:
         assert isinstance(d["extension_name"], cst.SimpleString)
         self.extension_names.append(d["extension_name"].evaluated_value)
Beispiel #28
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    def visit_If(self, node: cst.If):
        if_names = [
            n.value for n in match.findall(
                node.test,
                match.Name(
                    value=match.SaveMatchedNode(match.DoNotCare(), 'name')))
        ]

        if len(self.cls_stack) > 0:
            if self.cls_stack[0].name in if_names:
                self.cls_may_vars_use.append(if_names)

        if len(self.stack) > 0:
            self.fn_may_args_var_use.append(if_names)

        self.__find_module_vars_use(if_names)
Beispiel #29
0
    def visit_SimpleStatementLine(self, node: cst.SimpleStatementLine):
        smt_names = [
            n.value for n in match.findall(
                node,
                match.Name(
                    value=match.SaveMatchedNode(match.DoNotCare(), 'name')))
        ]

        if len(self.stack) > 0:
            self.fn_may_args_var_use.append(smt_names)

        if len(self.cls_stack) > 0:
            if self.cls_stack[0].name in smt_names:
                self.cls_may_vars_use.append(smt_names)

        self.__find_module_vars_use(smt_names)
Beispiel #30
0
 def test_extract_optional_wildcard_present(self) -> None:
     expression = cst.parse_expression("a + b[c], d(e, f * g, h.i.j)")
     nodes = m.extract(
         expression,
         m.Tuple(elements=[
             m.DoNotCare(),
             m.Element(
                 m.Call(args=[
                     m.DoNotCare(),
                     m.DoNotCare(),
                     m.ZeroOrOne(
                         m.Arg(m.SaveMatchedNode(m.Attribute(), "arg"))),
                 ])),
         ]),
     )
     extracted_node = (cst.ensure_type(
         cst.ensure_type(expression, cst.Tuple).elements[1].value,
         cst.Call).args[2].value)
     self.assertEqual(nodes, {"arg": extracted_node})