[#104004] [Ruby master Feature#17883] Load bundler/setup earlier to make `bundle exec ruby -r` respect Gemfile — mame@...
Issue #17883 has been reported by mame (Yusuke Endoh).
21 messages
2021/05/24
[ruby-core:103767] [Ruby master Bug#15928] Constant declaration does not conform to JIS 3017:2013
From:
mame@...
Date:
2021-05-07 02:04:07 UTC
List:
ruby-core #103767
Issue #15928 has been updated by mame (Yusuke Endoh).
Eregon (Benoit Daloze) wrote in #note-10:
> @mame @ko1 @yugui Are we sure we want to go ahead with the change in #4443 and this one? Or should we keep things as they are in 3.0, or as change single assignment like in MRuby?
In my opinion, it should be fixed eventually.
In principle, Ruby's evaluation is left-to-right. Almost all constructions including single assignment follow the principle. Multiple assignment and constant declaration were against it.
I know that the evaluation semantics is challenging to implement, especially on the stack-based virtual machine. However, I don't think that it is good to violate the principle for a implementation-detail reason.
I don't know the background of constant declaration, but in regard to multiple assignment (#4443), I faced the issue when I was writing a practical program to rotate a splay tree. Thus, the problem of evaluation order is not just conceptual but real to me.
That being said, I'm a little concerned about the incompatibility. If an actual issue is reported after preview release, we may have to proceed step by step, such as introducing migration path or something.
----------------------------------------
Bug #15928: Constant declaration does not conform to JIS 3017:2013
https://bugs.ruby-lang.org/issues/15928#change-91878
* Author: yugui (Yuki Sonoda)
* Status: Open
* Priority: Normal
* ruby -v: ruby 2.7.0dev (2019-06-16T14:01:46Z master d4929f5185) [x86_64-darwin18]
* Backport: 2.4: UNKNOWN, 2.5: UNKNOWN, 2.6: UNKNOWN
----------------------------------------
The order of evaluation in constant declaration does not conform to JIS 3017:2013 11.4.2.2.3.
# Problem
Suppose that we are evaluating the following program.
```
expr::C = lhs
```
The standard seems to be requiring the following evaluation order:
1. expr
* raise a TypeError if the value is not a kind of Module
2. lhs
3. rb_const_set(expr, :C, lhs)
However, the actual implementation evaluates in the following order
1. lhs
2. expr
3. rb_const_set(expr, :C, lhs)
* raise a TypeError if the expr is not a kind of Module
# How to reproduce
The next program does not raise "recv" but raises "value"
```
raise("recv")::C = raise("value")
```
The next program does not raise a TypeError but raises a RuntimeError
```
A = 1
A::C = raise("value")
```
# Question
* Is this interpretation of the standard correct?
* If it is, Should we change the current behavior?
* If we shouldn't, does it mean an issue in the standard?
c.f.
* https://twitter.com/n0kada/status/1140234416175763456
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