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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 unittest.mock import Mock
import libcst as cst
from libcst import parse_module
from libcst._exceptions import MetadataException
from libcst._visitors import CSTTransformer
from libcst.metadata import (
BatchableMetadataProvider,
MetadataWrapper,
VisitorMetadataProvider,
)
from libcst.testing.utils import UnitTest
class MetadataProviderTest(UnitTest):
def test_visitor_provider(self) -> None:
"""
Tests that visitor providers are resolved correctly.
Sets 2 metadata entries for every node:
SimpleProvider -> 1
DependentProvider - > 2
"""
test = self
class SimpleProvider(VisitorMetadataProvider[int]):
def on_visit(self, node: cst.CSTNode) -> bool:
self.set_metadata(node, 1)
return True
class DependentProvider(VisitorMetadataProvider[int]):
METADATA_DEPENDENCIES = (SimpleProvider,)
def on_visit(self, node: cst.CSTNode) -> bool:
self.set_metadata(node, self.get_metadata(SimpleProvider, node) + 1)
return True
class DependentVisitor(CSTTransformer):
# Declare both providers so the visitor has acesss to both types of metadata
METADATA_DEPENDENCIES = (DependentProvider, SimpleProvider)
def visit_Module(self, node: cst.Module) -> None:
# Check metadata is set
test.assertEqual(self.get_metadata(SimpleProvider, node), 1)
test.assertEqual(self.get_metadata(DependentProvider, node), 2)
def visit_Pass(self, node: cst.Pass) -> None:
# Check metadata is set
test.assertEqual(self.get_metadata(SimpleProvider, node), 1)
test.assertEqual(self.get_metadata(DependentProvider, node), 2)
module = parse_module("pass")
MetadataWrapper(module).visit(DependentVisitor())
def test_batched_provider(self) -> None:
"""
Tests that batchable providers are resolved correctly.
Sets metadata on:
- pass: BatchedProviderA -> 1
BatchedProviderB -> "a"
"""
test = self
mock = Mock()
class BatchedProviderA(BatchableMetadataProvider[int]):
def visit_Pass(self, node: cst.Pass) -> None:
mock.visited_a()
self.set_metadata(node, 1)
class BatchedProviderB(BatchableMetadataProvider[str]):
def visit_Pass(self, node: cst.Pass) -> None:
mock.visited_b()
self.set_metadata(node, "a")
class DependentVisitor(CSTTransformer):
METADATA_DEPENDENCIES = (BatchedProviderA, BatchedProviderB)
def visit_Pass(self, node: cst.Pass) -> None:
# Check metadata is set
test.assertEqual(self.get_metadata(BatchedProviderA, node), 1)
test.assertEqual(self.get_metadata(BatchedProviderB, node), "a")
module = parse_module("pass")
MetadataWrapper(module).visit(DependentVisitor())
# Check that each batchable visitor is only called once
mock.visited_a.assert_called_once()
mock.visited_b.assert_called_once()
def test_mixed_providers(self) -> None:
"""
Tests that a mixed set of providers is resolved properly.
Sets metadata on pass:
BatchedProviderA -> 2
BatchedProviderB -> 3
DependentProvider -> 5
DependentBatched -> 4
"""
test = self
mock = Mock()
class SimpleProvider(VisitorMetadataProvider[int]):
def visit_Pass(self, node: cst.CSTNode) -> None:
mock.visited_simple()
self.set_metadata(node, 1)
class BatchedProviderA(BatchableMetadataProvider[int]):
METADATA_DEPENDENCIES = (SimpleProvider,)
def visit_Pass(self, node: cst.Pass) -> None:
mock.visited_a()
self.set_metadata(node, 2)
class BatchedProviderB(BatchableMetadataProvider[int]):
METADATA_DEPENDENCIES = (SimpleProvider,)
def visit_Pass(self, node: cst.Pass) -> None:
mock.visited_b()
self.set_metadata(node, 3)
class DependentProvider(VisitorMetadataProvider[int]):
METADATA_DEPENDENCIES = (BatchedProviderA, BatchedProviderB)
def on_visit(self, node: cst.CSTNode) -> bool:
sum = self.get_metadata(BatchedProviderA, node, 0) + self.get_metadata(
BatchedProviderB, node, 0
)
self.set_metadata(node, sum)
return True
class BatchedProviderC(BatchableMetadataProvider[int]):
METADATA_DEPENDENCIES = (BatchedProviderA,)
def visit_Pass(self, node: cst.Pass) -> None:
mock.visited_c()
self.set_metadata(node, self.get_metadata(BatchedProviderA, node) * 2)
class DependentVisitor(CSTTransformer):
METADATA_DEPENDENCIES = (
BatchedProviderA,
BatchedProviderB,
BatchedProviderC,
DependentProvider,
)
def visit_Module(self, node: cst.Module) -> None:
# Dependent visitor set metadata on all nodes but for module it
# defaulted to 0 because BatchedProviderA/B only set metadata on
# pass nodes
test.assertEqual(self.get_metadata(DependentProvider, node), 0)
def visit_Pass(self, node: cst.Pass) -> None:
# Check metadata is set
test.assertEqual(self.get_metadata(BatchedProviderA, node), 2)
test.assertEqual(self.get_metadata(BatchedProviderB, node), 3)
test.assertEqual(self.get_metadata(BatchedProviderC, node), 4)
test.assertEqual(self.get_metadata(DependentProvider, node), 5)
module = parse_module("pass")
MetadataWrapper(module).visit(DependentVisitor())
# Check each visitor is called once
mock.visited_simple.assert_called_once()
mock.visited_a.assert_called_once()
mock.visited_b.assert_called_once()
mock.visited_c.assert_called_once()
def test_inherited_metadata(self) -> None:
"""
Tests that classes inherit access to metadata declared by their base
classes.
"""
test_runner = self
mock = Mock()
class SimpleProvider(VisitorMetadataProvider[int]):
def visit_Pass(self, node: cst.Pass) -> None:
mock.visited_simple()
self.set_metadata(node, 1)
class VisitorA(CSTTransformer):
METADATA_DEPENDENCIES = (SimpleProvider,)
class VisitorB(VisitorA):
def visit_Pass(self, node: cst.Pass) -> None:
test_runner.assertEqual(self.get_metadata(SimpleProvider, node), 1)
module = parse_module("pass")
MetadataWrapper(module).visit(VisitorB())
# Check each visitor is called once
mock.visited_simple.assert_called_once()
def test_provider_inherited_metadata(self) -> None:
"""
Tests that providers inherit access to metadata declared by their base
classes.
"""
test_runner = self
mock = Mock()
class ProviderA(VisitorMetadataProvider[int]):
def visit_Pass(self, node: cst.Pass) -> None:
mock.visited_a()
self.set_metadata(node, 1)
class ProviderB(VisitorMetadataProvider[int]):
METADATA_DEPENDENCIES = (ProviderA,)
class ProviderC(ProviderB):
def visit_Pass(self, node: cst.Pass) -> None:
mock.visited_c()
test_runner.assertEqual(self.get_metadata(ProviderA, node), 1)
class Visitor(CSTTransformer):
METADATA_DEPENDENCIES = (ProviderC,)
module = parse_module("pass")
MetadataWrapper(module).visit(Visitor())
# Check each visitor is called once
mock.visited_a.assert_called_once()
mock.visited_c.assert_called_once()
def test_batchable_provider_inherited_metadata(self) -> None:
"""
Tests that batchable providers inherit access to metadata declared by
their base classes.
"""
test_runner = self
mock = Mock()
class ProviderA(VisitorMetadataProvider[int]):
def visit_Pass(self, node: cst.Pass) -> None:
mock.visited_a()
self.set_metadata(node, 1)
class ProviderB(BatchableMetadataProvider[int]):
METADATA_DEPENDENCIES = (ProviderA,)
class ProviderC(ProviderB):
def visit_Pass(self, node: cst.Pass) -> None:
mock.visited_c()
test_runner.assertEqual(self.get_metadata(ProviderA, node), 1)
class VisitorA(CSTTransformer):
METADATA_DEPENDENCIES = (ProviderC,)
module = parse_module("pass")
MetadataWrapper(module).visit(VisitorA())
# Check each visitor is called once
mock.visited_a.assert_called_once()
mock.visited_c.assert_called_once()
def test_self_metadata(self) -> None:
"""
Tests a provider can access its own metadata (assuming it has been
set properly.)
"""
test_runner = self
class ProviderA(VisitorMetadataProvider[bool]):
def on_visit(self, node: cst.CSTNode) -> bool:
self.set_metadata(node, True)
return True
def on_leave(self, original_node: cst.CSTNode) -> None:
test_runner.assertEqual(
self.get_metadata(type(self), original_node), True
)
class AVisitor(CSTTransformer):
METADATA_DEPENDENCIES = (ProviderA,)
cst.Module([]).visit(AVisitor())
def test_unset_metadata(self) -> None:
"""
Tests that access to unset metadata throws a key error.
"""
class ProviderA(VisitorMetadataProvider[bool]):
pass
class AVisitor(CSTTransformer):
METADATA_DEPENDENCIES = (ProviderA,)
def on_visit(self, node: cst.CSTNode) -> bool:
self.get_metadata(ProviderA, node)
return True
with self.assertRaisesRegex(
KeyError,
"ProviderA is a dependency, but not set; did you forget a MetadataWrapper?",
):
cst.Module([]).visit(AVisitor())
def test_undeclared_metadata(self) -> None:
"""
Tests that access to undeclared metadata throws a key error.
"""
class ProviderA(VisitorMetadataProvider[bool]):
pass
class ProviderB(VisitorMetadataProvider[bool]):
pass
class AVisitor(CSTTransformer):
METADATA_DEPENDENCIES = (ProviderA,)
def on_visit(self, node: cst.CSTNode) -> bool:
self.get_metadata(ProviderA, node, True)
self.get_metadata(ProviderB, node)
return True
with self.assertRaisesRegex(
KeyError,
"ProviderB is not declared as a dependency in AVisitor.METADATA_DEPENDENCIES.",
):
MetadataWrapper(cst.Module([])).visit(AVisitor())
def test_circular_dependency(self) -> None:
"""
Tests that circular dependencies are detected.
"""
class ProviderA(VisitorMetadataProvider[str]):
pass
ProviderA.METADATA_DEPENDENCIES = (ProviderA,)
class BadVisitor(CSTTransformer):
METADATA_DEPENDENCIES = (ProviderA,)
with self.assertRaisesRegex(
MetadataException, "Detected circular dependencies in ProviderA"
):
MetadataWrapper(cst.Module([])).visit(BadVisitor())
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