Remove MIN_PRE_ALLOC_SIZE from Strings.

This optimisation is no longer helpful now that we use VWA to allocate
strings in larger size pools where they can be embedded.

1 files changed, 21 insertions, 0 deletions

diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
index 1ece47b18a..e34fd116c9 100644
--- a/test/ruby/test_string.rb
+++ b/test/ruby/test_string.rb
@@ -661,6 +661,27 @@ CODE
     assert_equal(Encoding::UTF_8, "#{s}x".encoding)
   end
 
+  def test_string_interpolations_across_size_pools_get_embedded
+    omit if GC::INTERNAL_CONSTANTS[:SIZE_POOL_COUNT] == 1
+
+    require 'objspace'
+    base_slot_size = GC::INTERNAL_CONSTANTS[:BASE_SLOT_SIZE]
+    small_obj_size = (base_slot_size / 2)
+    large_obj_size = base_slot_size * 2
+
+    a = "a" * small_obj_size
+    b = "a" * large_obj_size
+
+    res = "#{a}, #{b}"
+    dump_res = ObjectSpace.dump(res)
+    dump_orig = ObjectSpace.dump(a)
+    new_slot_size = Integer(dump_res.match(/"slot_size":(\d+)/)[1])
+    orig_slot_size = Integer(dump_orig.match(/"slot_size":(\d+)/)[1])
+
+    assert_match(/"embedded":true/, dump_res)
+    assert_operator(new_slot_size, :>, orig_slot_size)
+  end
+
   def test_count
     a = S("hello world")
     assert_equal(5, a.count(S("lo")))