From 19ed71c8d035e14d6ca39af4e52fb6630cb56c23 Mon Sep 17 00:00:00 2001
From: marcandre <marcandre@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Tue, 6 Nov 2012 17:13:33 +0000
Subject: [PATCH] * hash.c: Support for enumerators created by Hash:      
 delete_if, reject!, ...   [Feature #6636]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37511 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 hash.c                       | 18 ++++++++++--------
 test/ruby/test_enumerator.rb |  7 +++++++
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/hash.c b/hash.c
index db83da0eca..126fd41dc8 100644
--- a/hash.c
+++ b/hash.c
@@ -911,6 +911,8 @@ delete_if_i(VALUE key, VALUE value, VALUE hash)
     return ST_CONTINUE;
 }
 
+static VALUE rb_hash_size(VALUE hash);
+
 /*
  *  call-seq:
  *     hsh.delete_if {| key, value | block }  -> hsh
@@ -929,7 +931,7 @@ delete_if_i(VALUE key, VALUE value, VALUE hash)
 VALUE
 rb_hash_delete_if(VALUE hash)
 {
-    RETURN_ENUMERATOR(hash, 0, 0);
+    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
     rb_hash_modify_check(hash);
     if (RHASH(hash)->ntbl)
 	rb_hash_foreach(hash, delete_if_i, hash);
@@ -950,7 +952,7 @@ rb_hash_reject_bang(VALUE hash)
 {
     st_index_t n;
 
-    RETURN_ENUMERATOR(hash, 0, 0);
+    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
     rb_hash_modify(hash);
     if (!RHASH(hash)->ntbl)
         return Qnil;
@@ -1027,7 +1029,7 @@ rb_hash_select(VALUE hash)
 {
     VALUE result;
 
-    RETURN_ENUMERATOR(hash, 0, 0);
+    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
     result = rb_hash_new();
     rb_hash_foreach(hash, select_i, result);
     return result;
@@ -1056,7 +1058,7 @@ rb_hash_select_bang(VALUE hash)
 {
     st_index_t n;
 
-    RETURN_ENUMERATOR(hash, 0, 0);
+    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
     rb_hash_modify_check(hash);
     if (!RHASH(hash)->ntbl)
         return Qnil;
@@ -1081,7 +1083,7 @@ rb_hash_select_bang(VALUE hash)
 VALUE
 rb_hash_keep_if(VALUE hash)
 {
-    RETURN_ENUMERATOR(hash, 0, 0);
+    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
     rb_hash_modify_check(hash);
     if (RHASH(hash)->ntbl)
 	rb_hash_foreach(hash, keep_if_i, hash);
@@ -1310,7 +1312,7 @@ each_value_i(VALUE key, VALUE value)
 static VALUE
 rb_hash_each_value(VALUE hash)
 {
-    RETURN_ENUMERATOR(hash, 0, 0);
+    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
     rb_hash_foreach(hash, each_value_i, 0);
     return hash;
 }
@@ -1343,7 +1345,7 @@ each_key_i(VALUE key, VALUE value)
 static VALUE
 rb_hash_each_key(VALUE hash)
 {
-    RETURN_ENUMERATOR(hash, 0, 0);
+    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
     rb_hash_foreach(hash, each_key_i, 0);
     return hash;
 }
@@ -1380,7 +1382,7 @@ each_pair_i(VALUE key, VALUE value)
 static VALUE
 rb_hash_each_pair(VALUE hash)
 {
-    RETURN_ENUMERATOR(hash, 0, 0);
+    RETURN_SIZED_ENUMERATOR(hash, 0, 0, rb_hash_size);
     rb_hash_foreach(hash, each_pair_i, 0);
     return hash;
 }
diff --git a/test/ruby/test_enumerator.rb b/test/ruby/test_enumerator.rb
index 66d5e28a14..af41341227 100644
--- a/test/ruby/test_enumerator.rb
+++ b/test/ruby/test_enumerator.rb
@@ -443,6 +443,13 @@ class TestEnumerator < Test::Unit::TestCase
     assert_equal 42, @sized.each_with_object(nil).size
   end
 
+  def test_size_for_enum_created_from_hash
+    h = {a: 1, b: 2, c: 3}
+    %i[delete_if reject! select select! keep_if each each_key each_pair].each do |method|
+      assert_equal 3, h.send(method).size
+    end
+  end
+
   def check_consistency_for_combinatorics(method)
     [ [], [:a, :b, :c, :d, :e] ].product([-2, 0, 2, 5, 6]) do |array, arg|
       assert_equal array.send(method, arg).to_a.size, array.send(method, arg).size,