1 files changed, 36 insertions, 11 deletions

diff --git a/test/ruby/test_hash.rb b/test/ruby/test_hash.rb
index b6c18ea958..32384f5a5c 100644
--- a/test/ruby/test_hash.rb
+++ b/test/ruby/test_hash.rb
@@ -880,21 +880,20 @@ class TestHash < Test::Unit::TestCase
     assert_equal(quote1, eval(quote1).inspect)
     assert_equal(quote2, eval(quote2).inspect)
     assert_equal(quote3, eval(quote3).inspect)
-    begin
-      verbose_bak, $VERBOSE = $VERBOSE, nil
-      enc = Encoding.default_external
-      Encoding.default_external = Encoding::ASCII
+
+    EnvUtil.with_default_external(Encoding::ASCII) do
       utf8_ascii_hash = '{"\\u3042": 1}'
       assert_equal(eval(utf8_ascii_hash).inspect, utf8_ascii_hash)
-      Encoding.default_external = Encoding::UTF_8
+    end
+
+    EnvUtil.with_default_external(Encoding::UTF_8) do
       utf8_hash = "{\u3042: 1}"
       assert_equal(eval(utf8_hash).inspect, utf8_hash)
-      Encoding.default_external = Encoding::Windows_31J
+    end
+
+    EnvUtil.with_default_external(Encoding::Windows_31J) do
       sjis_hash = "{\x87]: 1}".force_encoding('sjis')
       assert_equal(eval(sjis_hash).inspect, sjis_hash)
-    ensure
-      Encoding.default_external = enc
-      $VERBOSE = verbose_bak
     end
   end
 
@@ -1297,6 +1296,17 @@ class TestHash < Test::Unit::TestCase
     assert_equal(@cls[a: 10, b: 2, c: 3, d: 4, e: 5, f: 6, g: 7, h: 8, i: 9, j: 10], h)
   end
 
+  def test_update_modify_in_block
+    a = @cls[]
+    (1..1337).each {|k| a[k] = k}
+    b = {1=>1338}
+    assert_raise_with_message(RuntimeError, /rehash during iteration/) do
+      a.update(b) {|k, o, n|
+        a.rehash
+      }
+    end
+  end
+
   def test_update_on_identhash
     key = +'a'
     i = @cls[].compare_by_identity
@@ -1853,6 +1863,14 @@ class TestHash < Test::Unit::TestCase
       end
     end
     assert_equal(@cls[a: 2, b: 2, c: 3, d: 4, e: 5, f: 6, g: 7, h: 8, i: 9, j: 10], x)
+
+    x = (1..1337).to_h {|k| [k, k]}
+    assert_raise_with_message(RuntimeError, /rehash during iteration/) do
+      x.transform_values! {|v|
+        x.rehash if v == 1337
+        v * 2
+      }
+    end
   end
 
   def hrec h, n, &b
@@ -1989,7 +2007,7 @@ class TestHashOnly < Test::Unit::TestCase
 
     EnvUtil.without_gc do
       before = ObjectSpace.count_objects[:T_STRING]
-      5.times{ h["abc"] }
+      5.times{ h["abc".freeze] }
       assert_equal before, ObjectSpace.count_objects[:T_STRING]
     end
   end
@@ -2119,7 +2137,9 @@ class TestHashOnly < Test::Unit::TestCase
 
   def test_iterlevel_in_ivar_bug19589
     h = { a: nil }
-    hash_iter_recursion(h, 200)
+    # Recursion level should be over 127 to actually test iterlevel being set in an instance variable,
+    # but it should be under 131 not to overflow the stack under MN threads/ractors.
+    hash_iter_recursion(h, 130)
     assert true
   end
 
@@ -2336,6 +2356,11 @@ class TestHashOnly < Test::Unit::TestCase
     end
   end
 
+  def test_bug_21357
+    h = {x: []}.merge(x: nil) { |_k, v1, _v2| v1 }
+    assert_equal({x: []}, h)
+  end
+
   def test_any_hash_fixable
     20.times do
       assert_separately([], "#{<<~"begin;"}\n#{<<~'end;'}")