From b206ebc51956805f557c5eebdf3f2303bd5499f5 Mon Sep 17 00:00:00 2001
From: Anders Kaseorg <andersk@mit.edu>
Date: Thu, 26 Aug 2021 17:49:15 -0700
Subject: [PATCH] Remove FreezableDefaultDict

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
---
 importlib_metadata/__init__.py     | 19 ++++++++-----------
 importlib_metadata/_collections.py | 23 -----------------------
 2 files changed, 8 insertions(+), 34 deletions(-)

diff --git a/importlib_metadata/__init__.py b/importlib_metadata/__init__.py
index 6c554558..34fa389f 100644
--- a/importlib_metadata/__init__.py
+++ b/importlib_metadata/__init__.py
@@ -15,7 +15,7 @@
 import collections
 
 from . import _adapters, _meta
-from ._collections import FreezableDefaultDict, Pair
+from ._collections import Pair
 from ._compat import (
     NullFinder,
     PyPy_repr,
@@ -30,7 +30,7 @@
 from importlib import import_module
 from importlib.abc import MetaPathFinder
 from itertools import starmap
-from typing import List, Mapping, Optional, Union
+from typing import Dict, List, Mapping, Optional, Union
 
 
 __all__ = [
@@ -783,8 +783,8 @@ class Lookup:
     def __init__(self, path: FastPath):
         base = os.path.basename(path.root).lower()
         base_is_egg = base.endswith(".egg")
-        self.infos = FreezableDefaultDict(list)
-        self.eggs = FreezableDefaultDict(list)
+        self.infos: Dict[Optional[str], List[pathlib.Path]] = {}
+        self.eggs: Dict[Optional[str], List[pathlib.Path]] = {}
 
         for child in path.children():
             low = child.lower()
@@ -792,23 +792,20 @@ def __init__(self, path: FastPath):
                 # rpartition is faster than splitext and suitable for this purpose.
                 name = low.rpartition(".")[0].partition("-")[0]
                 normalized = Prepared.normalize(name)
-                self.infos[normalized].append(path.joinpath(child))
+                self.infos.setdefault(normalized, []).append(path.joinpath(child))
             elif base_is_egg and low == "egg-info":
                 name = base.rpartition(".")[0].partition("-")[0]
                 legacy_normalized = Prepared.legacy_normalize(name)
-                self.eggs[legacy_normalized].append(path.joinpath(child))
-
-        self.infos.freeze()
-        self.eggs.freeze()
+                self.eggs.setdefault(legacy_normalized, []).append(path.joinpath(child))
 
     def search(self, prepared):
         infos = (
-            self.infos[prepared.normalized]
+            self.infos.get(prepared.normalized, [])
             if prepared
             else itertools.chain.from_iterable(self.infos.values())
         )
         eggs = (
-            self.eggs[prepared.legacy_normalized]
+            self.eggs.get(prepared.legacy_normalized, [])
             if prepared
             else itertools.chain.from_iterable(self.eggs.values())
         )
diff --git a/importlib_metadata/_collections.py b/importlib_metadata/_collections.py
index cf0954e1..359b3ba0 100644
--- a/importlib_metadata/_collections.py
+++ b/importlib_metadata/_collections.py
@@ -1,29 +1,6 @@
 import collections
 
 
-# from jaraco.collections 3.3
-class FreezableDefaultDict(collections.defaultdict):
-    """
-    Often it is desirable to prevent the mutation of
-    a default dict after its initial construction, such
-    as to prevent mutation during iteration.
-
-    >>> dd = FreezableDefaultDict(list)
-    >>> dd[0].append('1')
-    >>> dd.freeze()
-    >>> dd[1]
-    []
-    >>> len(dd)
-    1
-    """
-
-    def __missing__(self, key):
-        return getattr(self, '_frozen', super().__missing__)(key)
-
-    def freeze(self):
-        self._frozen = lambda key: self.default_factory()
-
-
 class Pair(collections.namedtuple('Pair', 'name value')):
     @classmethod
     def parse(cls, text):