From d96b6e705d2a6de5b8ac928317472e29a84d6c22 Mon Sep 17 00:00:00 2001
From: "rupesh.kumar" <57129475+rupeshkumaar@users.noreply.github.com>
Date: Sun, 21 Jan 2024 12:04:24 +0530
Subject: [PATCH] Merging (Identically Specified) MinHashLSH objects Fixes #205

---
 datasketch/lsh.py | 10 +++++----
 test/test_lsh.py  | 52 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/datasketch/lsh.py b/datasketch/lsh.py
index a25f5891..069e23be 100644
--- a/datasketch/lsh.py
+++ b/datasketch/lsh.py
@@ -301,14 +301,16 @@ def _insert(
         for H, hashtable in zip(Hs, self.hashtables):
             hashtable.insert(H, key, buffer=buffer)
 
-    def __eq__(self, other:MinHashLSH) -> bool:
+    def __equivalent(self, other:MinHashLSH) -> bool:
         """
         Returns:
-            bool: If the two MinHashLSH has equal num_perm then two are equivalent.
+            bool: If the two MinHashLSH has equal num_perm, band size and size of each bands then two are equivalent.
         """
         return (
             type(self) is type(other) and
-            self.h == other.h
+            self.h == other.h and
+            self.b == other.b and
+            self.r == other.r
         )
 
     def _merge(
@@ -317,7 +319,7 @@ def _merge(
         check_disjointness: bool = False,
         buffer: bool = False
     ) -> MinHashLSH:
-        if self == other:
+        if self.__equivalent(other):
             if check_disjointness and set(self.keys).intersection(set(other.keys)):
                 raise ValueError("The keys are not disjoint, duplicate key exists.")
             for key in other.keys:
diff --git a/test/test_lsh.py b/test/test_lsh.py
index a15be323..c2b080f8 100644
--- a/test/test_lsh.py
+++ b/test/test_lsh.py
@@ -267,6 +267,8 @@ def test_merge(self):
             self.assertTrue("d" in items)
         self.assertTrue("a" in lsh1)
         self.assertTrue("b" in lsh1)
+        self.assertTrue("c" in lsh1)
+        self.assertTrue("d" in lsh1)
         for i, H in enumerate(lsh1.keys["c"]):
             self.assertTrue("c" in lsh1.hashtables[i][H])
 
@@ -280,6 +282,56 @@ def test_merge(self):
 
         self.assertRaises(ValueError, lsh1.merge, lsh3, check_disjointness=True)
 
+    def test_merge_redis(self):
+        with patch('redis.Redis', fake_redis) as mock_redis:
+            lsh1 = MinHashLSH(threshold=0.5, num_perm=16, storage_config={
+                'type': 'redis', 'redis': {'host': 'localhost', 'port': 6379}
+            })
+            lsh2 = MinHashLSH(threshold=0.5, num_perm=16, storage_config={
+                'type': 'redis', 'redis': {'host': 'localhost', 'port': 6379}
+            })
+
+            m1 = MinHash(16)
+            m1.update("a".encode("utf8"))
+            m2 = MinHash(16)
+            m2.update("b".encode("utf8"))
+            lsh1.insert("a", m1)
+            lsh1.insert("b", m2)
+
+            m3 = MinHash(16)
+            m3.update("c".encode("utf8"))
+            m4 = MinHash(16)
+            m4.update("d".encode("utf8"))
+            lsh2.insert("c", m3)
+            lsh2.insert("d", m4)
+
+            lsh1.merge(lsh2)
+            for t in lsh1.hashtables:
+                self.assertTrue(len(t) >= 1)
+                items = []
+                for H in t:
+                    items.extend(t[H])
+                self.assertTrue(pickle.dumps("c") in items)
+                self.assertTrue(pickle.dumps("d") in items)
+            self.assertTrue("a" in lsh1)
+            self.assertTrue("b" in lsh1)
+            self.assertTrue("c" in lsh1)
+            self.assertTrue("d" in lsh1)
+            for i, H in enumerate(lsh1.keys[pickle.dumps("c")]):
+                self.assertTrue(pickle.dumps("c") in lsh1.hashtables[i][H])
+
+            self.assertTrue(lsh1.merge, lsh2)
+            self.assertRaises(ValueError, lsh1.merge, lsh2, check_disjointness=True)
+
+            m5 = MinHash(32)
+            m5.update("e".encode("utf-8"))
+            lsh3 = MinHashLSH(threshold=0.5, num_perm=32, storage_config={
+                'type': 'redis', 'redis': {'host': 'localhost', 'port': 6379}
+            })
+            lsh3.insert("a",m5)
+
+            self.assertRaises(ValueError, lsh1.merge, lsh3, check_disjointness=True)
+
 class TestWeightedMinHashLSH(unittest.TestCase):
 
     def test_init(self):