From: "byroot (Jean Boussier) via ruby-core" <ruby-core@...>
Date: 2024-01-19T12:45:52+00:00
Subject: [ruby-core:116328] [Ruby master Bug#20188] `Module#const_source_location` returns wrong information when real constant was defined but autoload is still ongoing

Issue #20188 has been updated by byroot (Jean Boussier).


Alright, I guess I better see what you mean now, there is a spec for `defined?` during autoload, that ensure other threads see the constant as not defined until the autoload completed:

```ruby
    it "defined? returns nil in autoload thread and 'constant' otherwise for defined?" do
      results = check_before_during_thread_after {
        defined?(ModuleSpecs::Autoload::DuringAutoload)
      }
      results.should == ['constant', nil, 'constant', 'constant']
    end
```

I wouldn't have specified like that, but given it's the current behavior, it would make sense for `const_source_location` to be consistent with that. I'll see if I can make it work like this in my PR.

----------------------------------------
Bug #20188: `Module#const_source_location` returns wrong information when real constant was defined but autoload is still ongoing
https://bugs.ruby-lang.org/issues/20188#change-106354

* Author: byroot (Jean Boussier)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [arm64-darwin23]
* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
Ref: https://github.com/fxn/zeitwerk/issues/281

`const_source_location` keeps returning the location of the `autoload` call, even after the real constant was defined. It only starts returning the real constant location once the autoload was fully completed.

```ruby
# /tmp/autoload.rb
File.write("/tmp/const.rb", <<~RUBY)
module Const
  LOCATION = Object.const_source_location(:Const)
end
RUBY

autoload :Const, "/tmp/const"

p Const::LOCATION
```

Expected Output:

```ruby
["/tmp/const.rb", 1]
```

Actual Output:

```ruby
["/tmp/autoload.rb", 8]
```

Potential patch: https://github.com/ruby/ruby/pull/9549



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