SERVER-68837: removed the double hashing in AbslHashValue for TenantId

3 files changed, 26 insertions, 10 deletions

diff --git a/src/mongo/bson/oid.h b/src/mongo/bson/oid.h
index afe716e5b17..3ff6a0e12ab 100644
--- a/src/mongo/bson/oid.h
+++ b/src/mongo/bson/oid.h
@@ -72,15 +72,6 @@ class SecureRandom;
  */
 class OID {
 public:
-    /**
-     * Functor compatible with std::hash for std::unordered_{map,set}
-     * Warning: The hash function is subject to change. Do not use in cases where hashes need
-     *          to be consistent across versions.
-     */
-    struct Hasher {
-        size_t operator()(const OID& oid) const;
-    };
-
     OID() : _data() {}
 
     enum { kOIDSize = 12, kTimestampSize = 4, kInstanceUniqueSize = 5, kIncrementSize = 3 };
@@ -180,11 +171,29 @@ public:
     }
 
     /**
+     * Functor compatible with std::hash for std::unordered_{map,set}
+     * Warning: The hash function is subject to change. Do not use in cases where hashes need
+     *          to be consistent across versions.
+     */
+    struct Hasher {
+        size_t operator()(const OID& oid) const;
+    };
+
+    /**
      * this is not consistent
      * do not store on disk
      */
     void hash_combine(size_t& seed) const;
 
+    /**
+     * Hash function compatible with absl::Hash for absl::unordered_{map,set}
+     */
+    template <typename H>
+    friend H AbslHashValue(H h, const OID& oid) {
+        const auto& d = oid._data;
+        return H::combine(std::move(h), std::string_view(d, sizeof(d)));
+    }
+
     /** call this after a fork to update the process id */
     static void justForked();
 
diff --git a/src/mongo/bson/oid_test.cpp b/src/mongo/bson/oid_test.cpp
index a33db2d90b1..5a34e6af7c1 100644
--- a/src/mongo/bson/oid_test.cpp
+++ b/src/mongo/bson/oid_test.cpp
@@ -166,4 +166,11 @@ TEST(Basic, FromTerm) {
     ASSERT_OK(mongo::NumberParser::strToAny()(oidTail, &oidTailInt));
     ASSERT_EQUALS(term, oidTailInt);
 }
+
+TEST(Basic, AbslHash) {
+    OID o1 = OID::gen();
+    OID o2 = o1;
+    ASSERT_EQUALS(absl::Hash<OID>{}(o1), absl::Hash<OID>{}(o2));
+}
+
 }  // namespace
diff --git a/src/mongo/db/tenant_id.h b/src/mongo/db/tenant_id.h
index dc9b46705c3..c3eedb66053 100644
--- a/src/mongo/db/tenant_id.h
+++ b/src/mongo/db/tenant_id.h
@@ -89,7 +89,7 @@ public:
      */
     template <typename H>
     friend H AbslHashValue(H h, const TenantId& tenantId) {
-        return H::combine(std::move(h), tenantId.hash());
+        return H::combine(std::move(h), tenantId._oid);
     }
 
     /**