Move some stuff back *out* of mypyc_hacks (#5488)

Faced with needing to move like 7 more exception classes into mypyc_hacks, I went and implemented defining new exceptions in mypyc, so we can move `DecodeError` back.

`SymbolTable` (inherits from `dict`) can be also now moved back.

Author: msullivan

mypy/mypyc_hacks.py

@@ -1,14 +1,6 @@
 """Stuff that we had to move out of its right place because of mypyc limitations."""
 
 
-# Moved from util.py, because it inherits from Exception
-class DecodeError(Exception):
-    """Exception raised when a file cannot be decoded due to an unknown encoding type.
-
-    Essentially a wrapper for the LookupError raised by `bytearray.decode`
-    """
-
-
 # Moved from types.py, because it inherits from Enum, which uses a
 # metaclass in a nontrivial way.
 from enum import Enum
@@ -36,60 +28,3 @@ class TypeOfAny(Enum):
     from_another_any = 'from_another_any'
     # Does this Any come from an implementation limitation/bug?
     implementation_artifact = 'implementation_artifact'
-
-
-# Moved from nodes.py, because it inherits from dict
-from typing import Dict, List, Any
-
-JsonDict = Dict[str, Any]
-
-MYPY = False
-if MYPY:
-    from mypy.nodes import SymbolTableNode
-
-
-class SymbolTable(Dict[str, 'SymbolTableNode']):
-    def __str__(self) -> str:
-        from mypy.nodes import implicit_module_attrs, SymbolTableNode  # noqa
-
-        a = []  # type: List[str]
-        for key, value in self.items():
-            # Filter out the implicit import of builtins.
-            if isinstance(value, SymbolTableNode):
-                if (value.fullname != 'builtins' and
-                        (value.fullname or '').split('.')[-1] not in
-                        implicit_module_attrs):
-                    a.append('  ' + str(key) + ' : ' + str(value))
-            else:
-                a.append('  <invalid item>')
-        a = sorted(a)
-        a.insert(0, 'SymbolTable(')
-        a[-1] += ')'
-        return '\n'.join(a)
-
-    def copy(self) -> 'SymbolTable':
-        return SymbolTable((key, node.copy())
-                           for key, node in self.items())
-
-    def serialize(self, fullname: str) -> JsonDict:
-        data = {'.class': 'SymbolTable'}  # type: JsonDict
-        for key, value in self.items():
-            # Skip __builtins__: it's a reference to the builtins
-            # module that gets added to every module by
-            # SemanticAnalyzerPass2.visit_file(), but it shouldn't be
-            # accessed by users of the module.
-            if key == '__builtins__' or value.no_serialize:
-                continue
-            data[key] = value.serialize(fullname, key)
-        return data
-
-    @classmethod
-    def deserialize(cls, data: JsonDict) -> 'SymbolTable':
-        from mypy.nodes import SymbolTableNode  # noqa
-
-        assert data['.class'] == 'SymbolTable'
-        st = SymbolTable()
-        for key, value in data.items():
-            if key != '.class':
-                st[key] = SymbolTableNode.deserialize(value)
-        return st

mypy/nodes.py

@@ -14,7 +14,6 @@
 import mypy.strconv
 from mypy.util import short_type
 from mypy.visitor import NodeVisitor, StatementVisitor, ExpressionVisitor
-from mypy.mypyc_hacks import SymbolTable
 
 from mypy.bogus_type import Bogus
 
@@ -2747,6 +2746,49 @@ def deserialize(cls, data: JsonDict) -> 'SymbolTableNode':
         return stnode
 
 
+class SymbolTable(Dict[str, SymbolTableNode]):
+    def __str__(self) -> str:
+        a = []  # type: List[str]
+        for key, value in self.items():
+            # Filter out the implicit import of builtins.
+            if isinstance(value, SymbolTableNode):
+                if (value.fullname != 'builtins' and
+                        (value.fullname or '').split('.')[-1] not in
+                        implicit_module_attrs):
+                    a.append('  ' + str(key) + ' : ' + str(value))
+            else:
+                a.append('  <invalid item>')
+        a = sorted(a)
+        a.insert(0, 'SymbolTable(')
+        a[-1] += ')'
+        return '\n'.join(a)
+
+    def copy(self) -> 'SymbolTable':
+        return SymbolTable((key, node.copy())
+                           for key, node in self.items())
+
+    def serialize(self, fullname: str) -> JsonDict:
+        data = {'.class': 'SymbolTable'}  # type: JsonDict
+        for key, value in self.items():
+            # Skip __builtins__: it's a reference to the builtins
+            # module that gets added to every module by
+            # SemanticAnalyzerPass2.visit_file(), but it shouldn't be
+            # accessed by users of the module.
+            if key == '__builtins__' or value.no_serialize:
+                continue
+            data[key] = value.serialize(fullname, key)
+        return data
+
+    @classmethod
+    def deserialize(cls, data: JsonDict) -> 'SymbolTable':
+        assert data['.class'] == 'SymbolTable'
+        st = SymbolTable()
+        for key, value in data.items():
+            if key != '.class':
+                st[key] = SymbolTableNode.deserialize(value)
+        return st
+
+
 def get_flags(node: Node, names: List[str]) -> List[str]:
     return [name for name in names if getattr(node, name)]
 

mypy/util.py

@@ -13,8 +13,6 @@
 if MYPY:
     from typing import Type
 
-from mypy.mypyc_hacks import DecodeError
-
 T = TypeVar('T')
 
 ENCODING_RE = re.compile(br'([ \t\v]*#.*(\r\n?|\n))??[ \t\v]*#.*coding[:=][ \t]*([-\w.]+)')
@@ -69,6 +67,13 @@ def find_python_encoding(text: bytes, pyversion: Tuple[int, int]) -> Tuple[str,
         return default_encoding, -1
 
 
+class DecodeError(Exception):
+    """Exception raised when a file cannot be decoded due to an unknown encoding type.
+
+    Essentially a wrapper for the LookupError raised by `bytearray.decode`
+    """
+
+
 def decode_python_encoding(source: bytes, pyversion: Tuple[int, int]) -> str:
     """Read the Python file with while obeying PEP-263 encoding detection.