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# Copyright (c) Meta Platforms, Inc. and affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
#
from textwrap import dedent
from typing import Optional, Sequence
import libcst as cst
import libcst.matchers as m
import libcst.metadata as meta
from libcst.matchers import extractall, findall
from libcst.testing.utils import UnitTest
class MatchersFindAllTest(UnitTest):
def assertNodeSequenceEqual(
self,
seq1: Sequence[cst.CSTNode],
seq2: Sequence[cst.CSTNode],
msg: Optional[str] = None,
) -> None:
suffix = "" if msg is None else f"\n{msg}"
if len(seq1) != len(seq2):
raise AssertionError(
f"\n{seq1!r}\nis not deeply equal to \n{seq2!r}{suffix}"
)
for node1, node2 in zip(seq1, seq2):
if not node1.deep_equals(node2):
raise AssertionError(
f"\n{seq1!r}\nis not deeply equal to \n{seq2!r}{suffix}"
)
def test_findall_with_sentinels(self) -> None:
# Verify behavior when provided a sentinel
nothing = findall(cst.RemovalSentinel.REMOVE, m.Name("True") | m.Name("False"))
self.assertNodeSequenceEqual(nothing, [])
nothing = findall(cst.MaybeSentinel.DEFAULT, m.Name("True") | m.Name("False"))
self.assertNodeSequenceEqual(nothing, [])
def test_simple_findall(self) -> None:
# Find all booleans in a tree
code = """
a = 1
b = True
def foo(bar: int) -> bool:
return False
"""
module = cst.parse_module(dedent(code))
booleans = findall(module, m.Name("True") | m.Name("False"))
self.assertNodeSequenceEqual(booleans, [cst.Name("True"), cst.Name("False")])
def test_findall_with_metadata_wrapper(self) -> None:
# Find all assignments in a tree
code = """
a = 1
b = True
def foo(bar: int) -> bool:
return False
"""
module = cst.parse_module(dedent(code))
wrapper = meta.MetadataWrapper(module)
# Test that when we find over a wrapper, we implicitly use it for
# metadata as well as traversal.
booleans = findall(
wrapper,
m.MatchMetadata(
meta.ExpressionContextProvider, meta.ExpressionContext.STORE
),
)
self.assertNodeSequenceEqual(
booleans,
[
cst.Name("a"),
cst.Name("b"),
cst.Name("foo"),
cst.Name("bar"),
],
)
# Test that we can provide an explicit resolver and tree
booleans = findall(
wrapper.module,
m.MatchMetadata(
meta.ExpressionContextProvider, meta.ExpressionContext.STORE
),
metadata_resolver=wrapper,
)
self.assertNodeSequenceEqual(
booleans,
[
cst.Name("a"),
cst.Name("b"),
cst.Name("foo"),
cst.Name("bar"),
],
)
# Test that failing to provide metadata leads to raising an informative exception
with self.assertRaises(
LookupError,
msg="ExpressionContextProvider is not resolved; did you forget a MetadataWrapper?",
):
booleans = findall(
wrapper.module,
m.MatchMetadata(
meta.ExpressionContextProvider, meta.ExpressionContext.STORE
),
)
def test_findall_with_visitors(self) -> None:
# Find all assignments in a tree
class TestVisitor(m.MatcherDecoratableVisitor):
METADATA_DEPENDENCIES: Sequence[meta.ProviderT] = (
meta.ExpressionContextProvider,
)
def __init__(self) -> None:
super().__init__()
self.results: Sequence[cst.CSTNode] = ()
def visit_Module(self, node: cst.Module) -> None:
self.results = self.findall(
node,
m.MatchMetadata(
meta.ExpressionContextProvider, meta.ExpressionContext.STORE
),
)
code = """
a = 1
b = True
def foo(bar: int) -> bool:
return False
"""
module = cst.parse_module(dedent(code))
wrapper = meta.MetadataWrapper(module)
visitor = TestVisitor()
wrapper.visit(visitor)
self.assertNodeSequenceEqual(
visitor.results,
[
cst.Name("a"),
cst.Name("b"),
cst.Name("foo"),
cst.Name("bar"),
],
)
def test_findall_with_transformers(self) -> None:
# Find all assignments in a tree
class TestTransformer(m.MatcherDecoratableTransformer):
METADATA_DEPENDENCIES: Sequence[meta.ProviderT] = (
meta.ExpressionContextProvider,
)
def __init__(self) -> None:
super().__init__()
self.results: Sequence[cst.CSTNode] = ()
def visit_Module(self, node: cst.Module) -> None:
self.results = self.findall(
node,
m.MatchMetadata(
meta.ExpressionContextProvider, meta.ExpressionContext.STORE
),
)
code = """
a = 1
b = True
def foo(bar: int) -> bool:
return False
"""
module = cst.parse_module(dedent(code))
wrapper = meta.MetadataWrapper(module)
visitor = TestTransformer()
wrapper.visit(visitor)
self.assertNodeSequenceEqual(
visitor.results,
[
cst.Name("a"),
cst.Name("b"),
cst.Name("foo"),
cst.Name("bar"),
],
)
class MatchersExtractAllTest(UnitTest):
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}],
)
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