Fix Concurrent::Map default_proc arguments

* Fixes #993

CHANGELOG.md

@@ -1,5 +1,8 @@
 ## Current
 
+## Release v1.2.2 (24 Feb 2023)
+
+* (#993) Fix arguments passed to `Concurrent::Map`'s `default_proc`.
 
 ## Release v1.2.1 (24 Feb 2023)
 

lib/concurrent-ruby/concurrent/collection/map/non_concurrent_map_backend.rb

@@ -14,7 +14,7 @@ class NonConcurrentMapBackend
       # reasons.
       def initialize(options = nil, &default_proc)
         validate_options_hash!(options) if options.kind_of?(::Hash)
-        @backend = Hash.new(&default_proc)
+        set_backend(default_proc)
         @default_proc = default_proc
       end
 
@@ -113,9 +113,17 @@ def get_or_default(key, default_value)
 
       private
 
+      def set_backend(default_proc)
+        if default_proc
+          @backend = ::Hash.new { |_h, key| default_proc.call(self, key) }
+        else
+          @backend = {}
+        end
+      end
+
       def initialize_copy(other)
         super
-        @backend = Hash.new(&@default_proc)
+        set_backend(@default_proc)
         self
       end
 

lib/concurrent-ruby/concurrent/version.rb

@@ -1,3 +1,3 @@
 module Concurrent
-  VERSION = '1.2.1'
+  VERSION = '1.2.2'
 end

spec/concurrent/map_spec.rb

@@ -10,6 +10,23 @@ module Concurrent
       @cache = described_class.new
     end
 
+    it 'default_proc is called with the Concurrent::Map and the key' do
+      map = Concurrent::Map.new do |h, k|
+        [h, k]
+      end
+      expect(map[:foo][0]).to be(map)
+      expect(map[:foo][1]).to eq(:foo)
+    end
+
+    it 'default_proc is called with the Concurrent::Map and the key after #dup' do
+      map = Concurrent::Map.new do |h, k|
+        [h, k]
+      end
+      copy = map.dup
+      expect(copy[:foo][0]).to be(copy)
+      expect(copy[:foo][1]).to eq(:foo)
+    end
+
     it 'concurrency' do
       (1..Concurrent::ThreadSafe::Test::THREADS).map do |i|
         in_thread do
@@ -45,6 +62,14 @@ module Concurrent
     end
 
     describe '#compute_if_absent' do
+      it 'works in default_proc' do
+        map = Concurrent::Map.new do |map, key|
+          map.compute_if_absent(key) { key * 2 }
+        end
+        expect(map[3]).to eq 6
+        expect(map.keys).to eq [3]
+      end
+
       it 'common' do
         with_or_without_default_proc do
           expect_size_change(3) do