Fix #5868: TypeError in move_wheel_files(). (#5883)

news/5868.bugfix

@@ -0,0 +1 @@
+Fix sorting `TypeError` in `move_wheel_files()` when installing some packages.

src/pip/_internal/wheel.py

@@ -204,6 +204,26 @@ def message_about_scripts_not_on_PATH(scripts):
     return "\n".join(msg_lines)
 
 
+def sorted_outrows(outrows):
+    """
+    Return the given rows of a RECORD file in sorted order.
+
+    Each row is a 3-tuple (path, hash, size) and corresponds to a record of
+    a RECORD file (see PEP 376 and PEP 427 for details).  For the rows
+    passed to this function, the size can be an integer as an int or string,
+    or the empty string.
+    """
+    # Normally, there should only be one row per path, in which case the
+    # second and third elements don't come into play when sorting.
+    # However, in cases in the wild where a path might happen to occur twice,
+    # we don't want the sort operation to trigger an error (but still want
+    # determinism).  Since the third element can be an int or string, we
+    # coerce each element to a string to avoid a TypeError in this case.
+    # For additional background, see--
+    # https://github.com/pypa/pip/issues/5868
+    return sorted(outrows, key=lambda row: tuple(str(x) for x in row))
+
+
 def move_wheel_files(name, req, wheeldir, user=False, home=None, root=None,
                      pycompile=True, scheme=None, isolated=False, prefix=None,
                      warn_script_location=True):
@@ -511,7 +531,8 @@ def _get_script_text(entry):
                 outrows.append((normpath(f, lib_dir), digest, length))
             for f in installed:
                 outrows.append((installed[f], '', ''))
-            for row in sorted(outrows):
+            # Sort to simplify testing.
+            for row in sorted_outrows(outrows):
                 writer.writerow(row)
     shutil.move(temp_record, record)
 

tests/unit/test_wheel.py

@@ -33,6 +33,29 @@ def test_get_entrypoints(tmpdir, console_scripts):
     )
 
 
+@pytest.mark.parametrize("outrows, expected", [
+    ([
+        ('', '', 'a'),
+        ('', '', ''),
+    ], [
+        ('', '', ''),
+        ('', '', 'a'),
+    ]),
+    ([
+        # Include an int to check avoiding the following error:
+        # > TypeError: '<' not supported between instances of 'str' and 'int'
+        ('', '', 1),
+        ('', '', ''),
+    ], [
+        ('', '', ''),
+        ('', '', 1),
+    ]),
+])
+def test_sorted_outrows(outrows, expected):
+    actual = wheel.sorted_outrows(outrows)
+    assert actual == expected
+
+
 def test_wheel_version(tmpdir, data):
     future_wheel = 'futurewheel-1.9-py2.py3-none-any.whl'
     broken_wheel = 'brokenwheel-1.0-py2.py3-none-any.whl'