Merge branch 'python:master' into fix-20103

Author: bzoracler

mypy/checker.py

@@ -395,6 +395,8 @@ class TypeChecker(NodeVisitor[None], TypeCheckerSharedApi):
 
     # A helper state to produce unique temporary names on demand.
     _unique_id: int
+    # Fake concrete type used when checking variance
+    _variance_dummy_type: Instance | None
 
     def __init__(
         self,
@@ -469,6 +471,7 @@ def __init__(
 
         self.pattern_checker = PatternChecker(self, self.msg, self.plugin, options)
         self._unique_id = 0
+        self._variance_dummy_type = None
 
     @property
     def expr_checker(self) -> mypy.checkexpr.ExpressionChecker:
@@ -2918,17 +2921,19 @@ def check_protocol_variance(self, defn: ClassDef) -> None:
         info = defn.info
         object_type = Instance(info.mro[-1], [])
         tvars = info.defn.type_vars
+        if self._variance_dummy_type is None:
+            _, dummy_info = self.make_fake_typeinfo("<dummy>", "Dummy", "Dummy", [])
+            self._variance_dummy_type = Instance(dummy_info, [])
+        dummy = self._variance_dummy_type
         for i, tvar in enumerate(tvars):
             if not isinstance(tvar, TypeVarType):
                 # Variance of TypeVarTuple and ParamSpec is underspecified by PEPs.
                 continue
             up_args: list[Type] = [
-                object_type if i == j else AnyType(TypeOfAny.special_form)
-                for j, _ in enumerate(tvars)
+                object_type if i == j else dummy.copy_modified() for j, _ in enumerate(tvars)
             ]
             down_args: list[Type] = [
-                UninhabitedType() if i == j else AnyType(TypeOfAny.special_form)
-                for j, _ in enumerate(tvars)
+                UninhabitedType() if i == j else dummy.copy_modified() for j, _ in enumerate(tvars)
             ]
             up, down = Instance(info, up_args), Instance(info, down_args)
             # TODO: add advanced variance checks for recursive protocols

mypy/expandtype.py

@@ -251,9 +251,9 @@ def visit_type_var(self, t: TypeVarType) -> Type:
             if (tvar_id := repl.id) in self.recursive_tvar_guard:
                 return self.recursive_tvar_guard[tvar_id] or repl
             self.recursive_tvar_guard[tvar_id] = None
-            repl = repl.accept(self)
-            if isinstance(repl, TypeVarType):
-                repl.default = repl.default.accept(self)
+            repl.default = repl.default.accept(self)
+            expanded = repl.accept(self)  # Note: `expanded is repl` may be true.
+            repl = repl if isinstance(expanded, TypeVarType) else expanded
             self.recursive_tvar_guard[tvar_id] = repl
         return repl
 

mypy/report.py

@@ -141,12 +141,9 @@ def should_skip_path(path: str) -> bool:
 
 def iterate_python_lines(path: str) -> Iterator[tuple[int, str]]:
     """Return an iterator over (line number, line text) from a Python file."""
-    try:
+    if not os.path.isdir(path):  # can happen with namespace packages
         with tokenize.open(path) as input_file:
             yield from enumerate(input_file, 1)
-    except IsADirectoryError:
-        # can happen with namespace packages
-        pass
 
 
 class FuncCounterVisitor(TraverserVisitor):
@@ -172,11 +169,10 @@ def on_file(
     ) -> None:
         # Count physical lines.  This assumes the file's encoding is a
         # superset of ASCII (or at least uses \n in its line endings).
-        try:
+        if not os.path.isdir(tree.path):  # can happen with namespace packages
             with open(tree.path, "rb") as f:
                 physical_lines = len(f.readlines())
-        except IsADirectoryError:
-            # can happen with namespace packages
+        else:
             physical_lines = 0
 
         func_counter = FuncCounterVisitor()
@@ -424,6 +420,9 @@ def on_file(
         type_map: dict[Expression, Type],
         options: Options,
     ) -> None:
+        if os.path.isdir(tree.path):  # can happen with namespace packages
+            return
+
         with open(tree.path) as f:
             tree_source = f.readlines()
 

test-data/unit/check-protocols.test

@@ -1373,6 +1373,19 @@ main:16: note:         def meth(self, x: int) -> int
 main:16: note:         @overload
 main:16: note:         def meth(self, x: bytes) -> str
 
+[case testProtocolWithMultiContravariantTypeVarOverloads]
+from typing import overload, Protocol, TypeVar
+
+T1 = TypeVar("T1", contravariant=True)
+T2 = TypeVar("T2", contravariant=True)
+
+class A(Protocol[T1, T2]):
+    @overload
+    def method(self, a: T1) -> None: ...
+    @overload
+    def method(self, a: T2) -> None: ...
+
+
 -- Join and meet with protocol types
 -- ---------------------------------
 

test-data/unit/check-typevar-defaults.test

@@ -416,6 +416,38 @@ def func_c4(
     reveal_type(m)  # N: Revealed type is "__main__.ClassC4[builtins.int, builtins.float]"
 [builtins fixtures/tuple.pyi]
 
+[case testTypeVarDefaultsSwap]
+from typing import TypeVar, Generic
+
+T = TypeVar("T")
+X = TypeVar("X", default=object)
+Y = TypeVar("Y", default=object)
+
+
+class Foo(Generic[T, Y]):
+    def test(self) -> None:
+        reveal_type( Foo[Y, T]() )  # N: Revealed type is "__main__.Foo[Y`2 = builtins.object, T`1]"
+
+
+class Bar(Generic[X, Y]):
+    def test(self) -> None:
+        reveal_type( Bar[Y, X]() )  # N: Revealed type is "__main__.Bar[Y`2 = builtins.object, X`1 = builtins.object]"
+
+
+[case testTypeVarDefaultsSwap2]
+from typing import TypeVar, Generic
+
+X = TypeVar("X", default=object)
+Y = TypeVar("Y", default=object)
+U = TypeVar("U", default=object)
+V = TypeVar("V", default=object)
+
+class Transform(Generic[X, Y]):
+    def invert(self) -> "Transform[Y, X]": ...
+
+class Foo(Transform[U, V], Generic[U, V]):
+    def invert(self) -> "Foo[V, U]": ...
+
 [case testTypeVarDefaultsClassRecursive1]
 # flags: --disallow-any-generics
 from typing import Generic, TypeVar, List

test-data/unit/reports.test

@@ -547,3 +547,52 @@ namespace_packages = True
 </table>
 </body>
 </html>
+
+[case testLinecountReportCrashOnNamespacePackages]
+# cmd: mypy --linecount-report report -p folder
+-- Regression test for https://github.com/python/mypy/issues/15979
+[file folder/subfolder/something.py]
+class Something:
+    pass
+
+[case testReportIsADirectoryErrorCrashOnNamespacePackages]
+# cmd: mypy --linecoverage-report report -p folder
+-- Regression test for https://github.com/python/mypy/issues/18128
+-- "IsADirectoryError for namespace packages when using --linecoverage-report"
+[file folder/subfolder/something.py]
+class Something:
+    pass
+
+[case testReportCoberturaCrashOnNamespacePackages]
+# cmd: mypy --cobertura-xml-report report -p folder
+-- Regression test for https://github.com/python/mypy/issues/19843
+[file folder/subfolder/something.py]
+-- This output is not important, but due to the way tests are run we need to check it.
+[outfile report/cobertura.xml]
+<coverage timestamp="$TIMESTAMP" version="$VERSION" line-rate="1.0" branch-rate="0" lines-covered="0" lines-valid="0">
+  <sources>
+    <source>$PWD</source>
+  </sources>
+  <packages>
+    <package complexity="1.0" name="folder" branch-rate="0" line-rate="1.0">
+      <classes>
+        <class complexity="1.0" filename="folder" name="folder" branch-rate="0" line-rate="1.0">
+          <methods/>
+          <lines/>
+        </class>
+        <class complexity="1.0" filename="folder/subfolder" name="subfolder" branch-rate="0" line-rate="1.0">
+          <methods/>
+          <lines/>
+        </class>
+      </classes>
+    </package>
+    <package complexity="1.0" name="folder.subfolder" branch-rate="0" line-rate="1.0">
+      <classes>
+        <class complexity="1.0" filename="folder/subfolder/something.py" name="something.py" branch-rate="0" line-rate="1.0">
+          <methods/>
+          <lines/>
+        </class>
+      </classes>
+    </package>
+  </packages>
+</coverage>