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Fix crash for special constants in too complex generic ivars

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We should skip reference updating for entries in too complex generic ivars
that are special constants. This fixes the following crash:

    MAX_SHAPES = 0x80000

    MAX_SHAPES.times do |i|
      o = []
      o.instance_variable_set(:"@foo#{i}", 1)
    end

    o = []

    o.instance_variable_set(:"@a", 123)

    GC.compact
This commit is contained in:
Peter Zhu 2025-02-18 16:26:07 -05:00
parent 27ba268b75
commit 0597cbcb1d
Notes: git 2025-02-18 22:09:45 +00:00 
Merged: https://github.com/ruby/ruby/pull/12781
2 changed files with 19 additions and 0 deletions
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2
gc.c
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@ -3441,6 +3441,8 @@ vm_weak_table_gen_ivar_foreach_too_complex_i(st_data_t _key, st_data_t value, st
GC_ASSERT(!iter_data->weak_only);
if (SPECIAL_CONST_P((VALUE)value)) return ST_CONTINUE;
return iter_data->callback((VALUE)value, iter_data->data);
}

17
test/ruby/test_gc_compact.rb
View File

@ -452,4 +452,21 @@ class TestGCCompact < Test::Unit::TestCase
assert_raise(FrozenError) { a.set_a }
end;
end
def test_moving_too_compex_generic_ivar
omit "not compiled with SHAPE_DEBUG" unless defined?(RubyVM::Shape)
assert_separately([], <<~RUBY)
RubyVM::Shape.exhaust_shapes
obj = []
obj.instance_variable_set(:@fixnum, 123)
obj.instance_variable_set(:@str, "hello")
GC.verify_compaction_references(expand_heap: true, toward: :empty)
assert_equal(123, obj.instance_variable_get(:@fixnum))
assert_equal("hello", obj.instance_variable_get(:@str))
RUBY
end
end