Refactor mypy.experiments (new name mypy.state) (#6134)

The old name made no sense any more. Also don't use ALL_CAPS
with a non-final name.

Author: JukkaL

mypy/checker.py

@@ -62,8 +62,7 @@
 from mypy.plugin import Plugin, CheckerPluginInterface
 from mypy.sharedparse import BINARY_MAGIC_METHODS
 from mypy.scope import Scope
-
-from mypy import experiments
+from mypy import state
 
 MYPY = False
 if MYPY:
@@ -273,7 +272,7 @@ def check_first_pass(self) -> None:
         Deferred functions will be processed by check_second_pass().
         """
         self.recurse_into_functions = True
-        with experiments.strict_optional_set(self.options.strict_optional):
+        with state.strict_optional_set(self.options.strict_optional):
             self.errors.set_file(self.path, self.tree.fullname(), scope=self.tscope)
             self.tscope.enter_file(self.tree.fullname())
             with self.enter_partial_types():
@@ -308,7 +307,7 @@ def check_second_pass(self,
         This goes through deferred nodes, returning True if there were any.
         """
         self.recurse_into_functions = True
-        with experiments.strict_optional_set(self.options.strict_optional):
+        with state.strict_optional_set(self.options.strict_optional):
             if not todo and not self.deferred_nodes:
                 return False
             self.errors.set_file(self.path, self.tree.fullname(), scope=self.tscope)
@@ -505,7 +504,7 @@ def check_overlapping_overloads(self, defn: OverloadedFuncDef) -> None:
                     #     def foo(x: str) -> str: ...
                     #
                     # See Python 2's map function for a concrete example of this kind of overload.
-                    with experiments.strict_optional_set(True):
+                    with state.strict_optional_set(True):
                         if is_unsafe_overlapping_overload_signatures(sig1, sig2):
                             self.msg.overloaded_signatures_overlap(
                                 i + 1, i + j + 2, item.func)

mypy/checkmember.py

@@ -26,7 +26,7 @@
 if MYPY:  # import for forward declaration only
     import mypy.checker
 
-from mypy import experiments
+from mypy import state
 
 
 class MemberContext:
@@ -151,10 +151,10 @@ def analyze_instance_member_access(name: str,
     if override_info:
         info = override_info
 
-    if (experiments.find_occurrences and
-            info.name() == experiments.find_occurrences[0] and
-            name == experiments.find_occurrences[1]):
-        mx.msg.note("Occurrence of '{}.{}'".format(*experiments.find_occurrences), mx.context)
+    if (state.find_occurrences and
+            info.name() == state.find_occurrences[0] and
+            name == state.find_occurrences[1]):
+        mx.msg.note("Occurrence of '{}.{}'".format(*state.find_occurrences), mx.context)
 
     # Look up the member. First look up the method dictionary.
     method = info.get_method(name)

mypy/experiments.py

@@ -14,8 +14,7 @@
     is_protocol_implementation, find_member
 )
 from mypy.nodes import ARG_NAMED, ARG_NAMED_OPT
-
-from mypy import experiments
+from mypy import state
 
 
 def join_simple(declaration: Optional[Type], s: Type, t: Type) -> Type:
@@ -114,7 +113,7 @@ def visit_any(self, t: AnyType) -> Type:
         return t
 
     def visit_none_type(self, t: NoneTyp) -> Type:
-        if experiments.STRICT_OPTIONAL:
+        if state.strict_optional:
             if isinstance(self.s, (NoneTyp, UninhabitedType)):
                 return t
             elif isinstance(self.s, UnboundType):

mypy/join.py

@@ -13,7 +13,7 @@
 
 from mypy import build
 from mypy import defaults
-from mypy import experiments
+from mypy import state
 from mypy import util
 from mypy.modulefinder import BuildSource, FindModuleCache, mypy_path, SearchPaths
 from mypy.find_sources import create_source_list, InvalidSourceList
@@ -746,11 +746,11 @@ def add_invertible_flag(flag: str,
         # TODO: Deprecate, then kill this flag
         options.strict_optional = True
     if special_opts.find_occurrences:
-        experiments.find_occurrences = special_opts.find_occurrences.split('.')
-        assert experiments.find_occurrences is not None
-        if len(experiments.find_occurrences) < 2:
+        state.find_occurrences = special_opts.find_occurrences.split('.')
+        assert state.find_occurrences is not None
+        if len(state.find_occurrences) < 2:
             parser.error("Can only find occurrences of class members.")
-        if len(experiments.find_occurrences) != 2:
+        if len(state.find_occurrences) != 2:
             parser.error("Can only find occurrences of non-nested class members.")
 
     # Set reports.

mypy/main.py

@@ -15,8 +15,7 @@
 )
 from mypy.erasetype import erase_type
 from mypy.maptype import map_instance_to_supertype
-
-from mypy import experiments
+from mypy import state
 
 # TODO Describe this module.
 
@@ -41,7 +40,7 @@ def narrow_declared_type(declared: Type, narrowed: Type) -> Type:
                                                 for x in declared.relevant_items()])
     elif not is_overlapping_types(declared, narrowed,
                                   prohibit_none_typevar_overlap=True):
-        if experiments.STRICT_OPTIONAL:
+        if state.strict_optional:
             return UninhabitedType()
         else:
             return NoneTyp()
@@ -137,7 +136,7 @@ def _is_overlapping_types(left: Type, right: Type) -> bool:
     # When running under non-strict optional mode, simplify away types of
     # the form 'Union[A, B, C, None]' into just 'Union[A, B, C]'.
 
-    if not experiments.STRICT_OPTIONAL:
+    if not state.strict_optional:
         if isinstance(left, UnionType):
             left = UnionType.make_union(left.relevant_items())
         if isinstance(right, UnionType):
@@ -191,7 +190,7 @@ def is_none_typevar_overlap(t1: Type, t2: Type) -> bool:
     # We must perform this check after the TypeVar checks because
     # a TypeVar could be bound to None, for example.
 
-    if experiments.STRICT_OPTIONAL and isinstance(left, NoneTyp) != isinstance(right, NoneTyp):
+    if state.strict_optional and isinstance(left, NoneTyp) != isinstance(right, NoneTyp):
         return False
 
     # Next, we handle single-variant types that may be inherently partially overlapping:
@@ -362,7 +361,7 @@ def __init__(self, s: Type) -> None:
 
     def visit_unbound_type(self, t: UnboundType) -> Type:
         if isinstance(self.s, NoneTyp):
-            if experiments.STRICT_OPTIONAL:
+            if state.strict_optional:
                 return AnyType(TypeOfAny.special_form)
             else:
                 return self.s
@@ -386,7 +385,7 @@ def visit_union_type(self, t: UnionType) -> Type:
         return UnionType.make_simplified_union(meets)
 
     def visit_none_type(self, t: NoneTyp) -> Type:
-        if experiments.STRICT_OPTIONAL:
+        if state.strict_optional:
             if isinstance(self.s, NoneTyp) or (isinstance(self.s, Instance) and
                                                self.s.type.fullname() == 'builtins.object'):
                 return t
@@ -400,7 +399,7 @@ def visit_uninhabited_type(self, t: UninhabitedType) -> Type:
 
     def visit_deleted_type(self, t: DeletedType) -> Type:
         if isinstance(self.s, NoneTyp):
-            if experiments.STRICT_OPTIONAL:
+            if state.strict_optional:
                 return t
             else:
                 return self.s
@@ -430,7 +429,7 @@ def visit_instance(self, t: Instance) -> Type:
                         args.append(self.meet(t.args[i], si.args[i]))
                     return Instance(t.type, args)
                 else:
-                    if experiments.STRICT_OPTIONAL:
+                    if state.strict_optional:
                         return UninhabitedType()
                     else:
                         return NoneTyp()
@@ -441,7 +440,7 @@ def visit_instance(self, t: Instance) -> Type:
                     # See also above comment.
                     return self.s
                 else:
-                    if experiments.STRICT_OPTIONAL:
+                    if state.strict_optional:
                         return UninhabitedType()
                     else:
                         return NoneTyp()
@@ -559,7 +558,7 @@ def default(self, typ: Type) -> Type:
         if isinstance(typ, UnboundType):
             return AnyType(TypeOfAny.special_form)
         else:
-            if experiments.STRICT_OPTIONAL:
+            if state.strict_optional:
                 return UninhabitedType()
             else:
                 return NoneTyp()

mypy/meet.py

@@ -77,7 +77,7 @@
 from mypy.exprtotype import expr_to_unanalyzed_type, TypeTranslationError
 from mypy.sametypes import is_same_type
 from mypy.options import Options
-from mypy import experiments
+from mypy import state
 from mypy.plugin import (
     Plugin, ClassDefContext, SemanticAnalyzerPluginInterface,
     DynamicClassDefContext
@@ -283,7 +283,7 @@ def visit_file(self, file_node: MypyFile, fnam: str, options: Options,
         self.enum_call_analyzer = EnumCallAnalyzer(options, self)
         self.newtype_analyzer = NewTypeAnalyzer(options, self, self.msg)
 
-        with experiments.strict_optional_set(options.strict_optional):
+        with state.strict_optional_set(options.strict_optional):
             if 'builtins' in self.modules:
                 self.globals['__builtins__'] = SymbolTableNode(MODULE_REF,
                                                                self.modules['builtins'])

mypy/semanal.py

@@ -19,7 +19,7 @@
 
 from typing import List, Tuple
 
-from mypy import experiments
+from mypy import state
 from mypy.nodes import (
     MypyFile, SymbolTable, SymbolTableNode, Var, Block, AssignmentStmt, FuncDef, Decorator,
     ClassDef, TypeInfo, ImportFrom, Import, ImportAll, IfStmt, WhileStmt, ForStmt, WithStmt,
@@ -76,7 +76,7 @@ def visit_file(self, file: MypyFile, fnam: str, mod_id: str, options: Options) -
 
         defs = file.defs
 
-        with experiments.strict_optional_set(options.strict_optional):
+        with state.strict_optional_set(options.strict_optional):
             # Add implicit definitions of module '__name__' etc.
             for name, t in implicit_module_attrs.items():
                 # unicode docstrings should be accepted in Python 2

mypy/semanal_pass1.py

@@ -12,7 +12,7 @@
 from collections import OrderedDict
 from typing import Dict, List, Callable, Optional, Union, cast, Tuple
 
-from mypy import messages, experiments
+from mypy import messages, state
 from mypy.nodes import (
     Node, Expression, MypyFile, FuncDef, Decorator, RefExpr, Context, TypeInfo, ClassDef,
     Block, TypedDictExpr, NamedTupleExpr, AssignmentStmt, IndexExpr, TypeAliasExpr, NameExpr,
@@ -65,7 +65,7 @@ def visit_file(self, file_node: MypyFile, fnam: str, options: Options,
         self.sem.cur_mod_id = file_node.fullname()
         self.cur_mod_node = file_node
         self.sem.globals = file_node.names
-        with experiments.strict_optional_set(options.strict_optional):
+        with state.strict_optional_set(options.strict_optional):
             self.scope.enter_file(file_node.fullname())
             self.update_imported_vars()
             self.accept(file_node)

mypy/semanal_pass3.py

@@ -0,0 +1,18 @@
+from contextlib import contextmanager
+from typing import Optional, Tuple, Iterator
+
+# These are global mutable state. Don't add anything here unless there's a very
+# good reason.
+
+# Value varies by file being processed
+strict_optional = False
+find_occurrences = None  # type: Optional[Tuple[str, str]]
+
+
+@contextmanager
+def strict_optional_set(value: bool) -> Iterator[None]:
+    global strict_optional
+    saved = strict_optional
+    strict_optional = value
+    yield
+    strict_optional = saved