From: "jeremyevans0 (Jeremy Evans)" <noreply@...>
Date: 2022-04-10T05:10:41+00:00
Subject: [ruby-core:108205] [Ruby master Bug#18688] when array's default value is empty hash adding a hash key value changes all array elements

Issue #18688 has been updated by jeremyevans0 (Jeremy Evans).

Status changed from Open to Rejected

This is expected behavior and not a bug.  As you mentioned, you want to use the block form if you want a new object for each default value.

----------------------------------------
Bug #18688: when array's default value is empty hash adding a hash key value changes all array elements
https://bugs.ruby-lang.org/issues/18688#change-97189

* Author: pan (Pan Pan)
* Status: Rejected
* Priority: Normal
* ruby -v: ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-linux]
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
```ruby
ah = Array.new(3, {})
ah[1][:foo] = 'bar'
p ah # [{:foo=>"bar"}, {:foo=>"bar"}, {:foo=>"bar"}]
```

This is not expected result. The expected result is `[{}, {:foo=>"bar"}, {}]`. 
Alternatively, below code works as expected.

```ruby
ah = Array.new(3) {{}}
ah[1][:foo] = 'bar'
p ah # [{}, {:foo=>"bar"}, {}]





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