[Redis 6.2] Add ZDIFFSTORE command

lib/redis.rb

@@ -2279,20 +2279,10 @@ def zinter(*args)
   #   sorted sets
   #   - `:aggregate => String`: aggregate function to use (sum, min, max)
   # @return [Integer] number of elements in the resulting sorted set
-  def zinterstore(destination, keys, weights: nil, aggregate: nil)
-    args = [:zinterstore, destination, keys.size, *keys]
-
-    if weights
-      args << "WEIGHTS"
-      args.concat(weights)
-    end
-
-    args << "AGGREGATE" << aggregate if aggregate
-
-    synchronize do |client|
-      client.call(args)
-    end
+  def zinterstore(*args)
+    _zsets_operation_store(:zinterstore, *args)
   end
+  ruby2_keywords(:zinterstore) if respond_to?(:ruby2_keywords, true)
 
   # Return the union of multiple sorted sets
   #
@@ -2331,20 +2321,10 @@ def zunion(*args)
   #   sorted sets
   #   - `:aggregate => String`: aggregate function to use (sum, min, max, ...)
   # @return [Integer] number of elements in the resulting sorted set
-  def zunionstore(destination, keys, weights: nil, aggregate: nil)
-    args = [:zunionstore, destination, keys.size, *keys]
-
-    if weights
-      args << "WEIGHTS"
-      args.concat(weights)
-    end
-
-    args << "AGGREGATE" << aggregate if aggregate
-
-    synchronize do |client|
-      client.call(args)
-    end
+  def zunionstore(*args)
+    _zsets_operation_store(:zunionstore, *args)
   end
+  ruby2_keywords(:zunionstore) if respond_to?(:ruby2_keywords, true)
 
   # Return the difference between the first and all successive input sorted sets
   #
@@ -2370,6 +2350,23 @@ def zdiff(*keys, with_scores: false)
     _zsets_operation(:zdiff, *keys, with_scores: with_scores)
   end
 
+  # Compute the difference between the first and all successive input sorted sets
+  # and store the resulting sorted set in a new key
+  #
+  # @example
+  #   redis.zadd("zsetA", [[1.0, "v1"], [2.0, "v2"]])
+  #   redis.zadd("zsetB", [[3.0, "v2"], [2.0, "v3"]])
+  #   redis.zdiffstore("zsetA", "zsetB")
+  #     # => 1
+  #
+  # @param [String] destination destination key
+  # @param [Array<String>] keys source keys
+  # @return [Integer] number of elements in the resulting sorted set
+  def zdiffstore(*args)
+    _zsets_operation_store(:zdiffstore, *args)
+  end
+  ruby2_keywords(:zdiffstore) if respond_to?(:ruby2_keywords, true)
+
   # Get the number of fields in a hash.
   #
   # @param [String] key
@@ -3924,6 +3921,21 @@ def _zsets_operation(cmd, *keys, weights: nil, aggregate: nil, with_scores: fals
       client.call(command, &block)
     end
   end
+
+  def _zsets_operation_store(cmd, destination, keys, weights: nil, aggregate: nil)
+    command = [cmd, destination, keys.size, *keys]
+
+    if weights
+      command << "WEIGHTS"
+      command.concat(weights)
+    end
+
+    command << "AGGREGATE" << aggregate if aggregate
+
+    synchronize do |client|
+      client.call(command)
+    end
+  end
 end
 
 require_relative "redis/version"

lib/redis/distributed.rb

@@ -750,6 +750,14 @@ def zdiff(*keys, **options)
       end
     end
 
+    # Compute the difference between the first and all successive input sorted sets
+    # and store the resulting sorted set in a new key.
+    def zdiffstore(destination, keys, **options)
+      ensure_same_node(:zdiffstore, [destination] + keys) do |node|
+        node.zdiffstore(destination, keys, **options)
+      end
+    end
+
     # Get the number of fields in a hash.
     def hlen(key)
       node_for(key).hlen(key)

test/cluster_commands_on_sorted_sets_test.rb

@@ -60,4 +60,8 @@ def test_zunionstore_with_weights
   def test_zdiff
     assert_raises(Redis::CommandError) { super }
   end
+
+  def test_zdiffstore
+    assert_raises(Redis::CommandError) { super }
+  end
 end

test/distributed_commands_on_sorted_sets_test.rb

@@ -86,4 +86,8 @@ def test_zunionstore_with_weights
   def test_zdiff
     assert_raises(Redis::Distributed::CannotDistribute) { super }
   end
+
+  def test_zdiffstore
+    assert_raises(Redis::Distributed::CannotDistribute) { super }
+  end
 end

test/lint/sorted_sets.rb

@@ -586,6 +586,22 @@ def test_zdiff
       end
     end
 
+    def test_zdiffstore
+      target_version("6.2") do
+        r.zadd 'foo', 1, 's1'
+        r.zadd 'foo', 2, 's2'
+        r.zadd 'bar', 3, 's1'
+        r.zadd 'bar', 5, 's3'
+
+        assert_equal 0, r.zdiffstore('baz', ['foo', 'foo'])
+        assert_equal 2, r.zdiffstore('baz', ['foo'])
+        assert_equal ['s1', 's2'], r.zrange('baz', 0, -1)
+
+        assert_equal 1, r.zdiffstore('baz', ['foo', 'bar'])
+        assert_equal ['s2'], r.zrange('baz', 0, -1)
+      end
+    end
+
     def test_zinter
       target_version("6.2") do
         r.zadd 'foo', 1, 's1'