From 3b6f22ffa660c56ff38eb21531f36651e1c1c77a Mon Sep 17 00:00:00 2001
From: Max Bachmann <max.bachmann@iracing.com>
Date: Wed, 17 Aug 2022 22:05:07 +0200
Subject: [PATCH] fix hashing for custom classes

---
 CHANGELOG.md                       |  4 ++++
 src/rapidfuzz/cpp_common.pxd       | 11 ++++-------
 tests/distance/test_Levenshtein.py | 13 +++++++++++++
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c51966e..ceea184 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 ## Changelog
 
+### [2.6.0] - 2022-08-
+#### Fixed
+- fix hashing for custom classes
+
 ### [2.5.0] - 2022-08-14
 #### Added
 - added support for KeyboardInterrupt in processor module
diff --git a/src/rapidfuzz/cpp_common.pxd b/src/rapidfuzz/cpp_common.pxd
index 2582003..752c9b0 100644
--- a/src/rapidfuzz/cpp_common.pxd
+++ b/src/rapidfuzz/cpp_common.pxd
@@ -238,11 +238,6 @@ cdef extern from "cpp_common.hpp":
     RF_String convert_string(object py_str)
     void validate_string(object py_str, const char* err) except +
 
-cdef inline uint64_t rf_hash(val) except *:
-    if val == -1:
-        return <uint64_t>-1
-    return <uint64_t>hash(val)
-
 cdef inline RF_String hash_array(arr) except *:
     # TODO on Cpython this does not require any copies
     cdef RF_String s_proc
@@ -283,7 +278,7 @@ cdef inline RF_String hash_array(arr) except *:
         else: # float/double are hashed
             s_proc.kind = RF_StringType.RF_UINT64
             for i in range(s_proc.length):
-                (<uint64_t*>s_proc.data)[i] = rf_hash(arr[i])
+                (<uint64_t*>s_proc.data)[i] = <uint64_t>hash(arr[i])
     except Exception as e:
         free(s_proc.data)
         s_proc.data = NULL
@@ -309,8 +304,10 @@ cdef inline RF_String hash_sequence(seq) except *:
             # this is required so e.g. a list of char can be compared to a string
             if isinstance(elem, str) and len(elem) == 1:
                 (<uint64_t*>s_proc.data)[i] = <uint64_t><Py_UCS4>elem
+            elif isinstance(elem, int) and elem == -1:
+                (<uint64_t*>s_proc.data)[i] = <uint64_t>-1
             else:
-                (<uint64_t*>s_proc.data)[i] = rf_hash(elem)
+                (<uint64_t*>s_proc.data)[i] = <uint64_t>hash(elem)
     except Exception as e:
         free(s_proc.data)
         s_proc.data = NULL
diff --git a/tests/distance/test_Levenshtein.py b/tests/distance/test_Levenshtein.py
index 8e8e03c..b70bfde 100644
--- a/tests/distance/test_Levenshtein.py
+++ b/tests/distance/test_Levenshtein.py
@@ -10,6 +10,18 @@ from rapidfuzz.distance import Opcodes, Opcode, Levenshtein_cpp, Levenshtein_py
 def isclose(a, b, rel_tol=1e-09, abs_tol=0.0):
     return abs(a - b) <= max(rel_tol * max(abs(a), abs(b)), abs_tol)
 
+class CustomHashable:
+    def __init__(self, string):
+        self._string = string
+
+    def __eq__(self, other):
+        raise NotImplementedError
+
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
+    def __hash__(self):
+        return hash(self._string)
 
 class Levenshtein:
     @staticmethod
@@ -61,6 +73,7 @@ def test_cross_type_matching():
     # todo add support in pure python
     assert Levenshtein_cpp.distance("aaaa", [ord("a"), ord("a"), "a", "a"]) == 0
     assert Levenshtein_cpp.distance([0, -1], [0, -2]) == 1
+    assert Levenshtein_cpp.distance([CustomHashable("aa"), CustomHashable("aa")], [CustomHashable("aa"), CustomHashable("bb")]) == 1
 
 
 def test_word_error_rate():