Better support for unicode cache entries

Author: sbidoul

src/pip/_internal/cache.py

@@ -5,6 +5,7 @@
 # mypy: strict-optional=False
 
 import hashlib
+import json
 import logging
 import os
 import sys
@@ -29,14 +30,9 @@
 
 def _hash_dict(d):
     # type: (Dict[str, str]) -> str
-    """Return a sha224 of a dictionary where keys and values are strings."""
-    h = hashlib.new('sha224')
-    for k in sorted(d.keys()):
-        h.update(k.encode())
-        h.update("=".encode())
-        h.update(d[k].encode())
-        h.update(b"\0")
-    return h.hexdigest()
+    """Return a stable sha224 of a dictionary."""
+    s = json.dumps(d, sort_keys=True, separators=(",", ":"), ensure_ascii=True)
+    return hashlib.sha224(s.encode("ascii")).hexdigest()
 
 
 class Cache(object):

tests/unit/test_cache.py

@@ -46,9 +46,11 @@ def test_wheel_name_filter(tmpdir):
 
 def test_cache_hash():
     h = _hash_dict({"url": "https://g.c/o/r"})
-    assert h == "c7d60d08b1079254d236e983501fa26c016d58d16010725b27ed0af2"
+    assert h == "72aa79d3315c181d2cc23239d7109a782de663b6f89982624d8c1e86"
     h = _hash_dict({"url": "https://g.c/o/r", "subdirectory": "sd"})
-    assert h == "9cba35d4ccf04b7cde751b44db347fd0f21fa47d1276e32f9d47864c"
+    assert h == "8b13391b6791bf7f3edeabb41ea4698d21bcbdbba7f9c7dc9339750d"
+    h = _hash_dict({"subdirectory": u"/\xe9e"})
+    assert h == "f83b32dfa27a426dec08c21bf006065dd003d0aac78e7fc493d9014d"
 
 
 def test_get_path_for_link_legacy(tmpdir):