[ruby-core:102061] [Ruby master Bug#17534] Pattern-matching is broken with find pattern

[ruby-core:102061] [Ruby master Bug#17534] Pattern-matching is broken with find pattern

[zverok.offline]

Issue #17534 has been reported by zverok (Victor Shepelev).

----------------------------------------
Bug #17534: Pattern-matching is broken with find pattern
https://bugs.ruby-lang.org/issues/17534

* Author: zverok (Victor Shepelev)
* Status: Open
* Priority: Normal
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
The minimal reproduction code:

```ruby
case [1, 2, 3]
in y
  puts "branch1"
in [*, x, *]
  puts "branch2"
else
  puts "branch3"
end
```
This outputs long "raw disasm" sequence, and then
```
---------------------
break_pm.rb:6: argument stack underflow (-1)
break_pm.rb: compile error (SyntaxError)
```

```
$ ruby -v
ruby 3.1.0dev (2021-01-13T09:12:49Z master 6f6dfdcc68) [x86_64-linux]
```



-- 
https://bugs.ruby-lang.org/

[ruby-core:102131] [Ruby master Bug#17534] Pattern-matching is broken with find pattern

[dementiev.vm]

Issue #17534 has been updated by palkan (Vladimir Dementyev).


zverok (Victor Shepelev) wrote:
> The minimal reproduction code:
> 
> ```ruby
> case [1, 2, 3]
> in y
>   puts "branch1"
> in [*, x, *]
>   puts "branch2"
> else
>   puts "branch3"
> end
> ```
> This outputs long "raw disasm" sequence, and then
> ```
> ---------------------
> break_pm.rb:6: argument stack underflow (-1)
> break_pm.rb: compile error (SyntaxError)
> ```
> 
> ```
> $ ruby -v
> ruby 3.1.0dev (2021-01-13T09:12:49Z master 6f6dfdcc68) [x86_64-linux]
> ```


That could be related to https://github.com/ruby/ruby/pull/3104.
I'll take a look.

----------------------------------------
Bug #17534: Pattern-matching is broken with find pattern
https://bugs.ruby-lang.org/issues/17534#change-89985

* Author: zverok (Victor Shepelev)
* Status: Open
* Priority: Normal
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
The minimal reproduction code:

```ruby
case [1, 2, 3]
in y
  puts "branch1"
in [*, x, *]
  puts "branch2"
else
  puts "branch3"
end
```
This outputs long "raw disasm" sequence, and then
```
---------------------
break_pm.rb:6: argument stack underflow (-1)
break_pm.rb: compile error (SyntaxError)
```

```
$ ruby -v
ruby 3.1.0dev (2021-01-13T09:12:49Z master 6f6dfdcc68) [x86_64-linux]
```



-- 
https://bugs.ruby-lang.org/

[ruby-core:102140] [Ruby master Bug#17534] Pattern-matching is broken with find pattern

[dementiev.vm]

Issue #17534 has been updated by palkan (Vladimir Dementyev).


palkan (Vladimir Dementyev) wrote in #note-1:
> That could be related to https://github.com/ruby/ruby/pull/3104.
> I'll take a look.

Hm, nope. Reproduced in the older revision (`d6c9c014e2`). Investigating further.


----------------------------------------
Bug #17534: Pattern-matching is broken with find pattern
https://bugs.ruby-lang.org/issues/17534#change-89991

* Author: zverok (Victor Shepelev)
* Status: Open
* Priority: Normal
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
The minimal reproduction code:

```ruby
case [1, 2, 3]
in y
  puts "branch1"
in [*, x, *]
  puts "branch2"
else
  puts "branch3"
end
```
This outputs long "raw disasm" sequence, and then
```
---------------------
break_pm.rb:6: argument stack underflow (-1)
break_pm.rb: compile error (SyntaxError)
```

```
$ ruby -v
ruby 3.1.0dev (2021-01-13T09:12:49Z master 6f6dfdcc68) [x86_64-linux]
```



-- 
https://bugs.ruby-lang.org/

[ruby-core:102144] [Ruby master Bug#17534] Pattern-matching is broken with find pattern

[dementiev.vm]

Issue #17534 has been updated by palkan (Vladimir Dementyev).


So, what I found: the bug is caused by `iseq_peephole_optimize` and find patterns iseq incompatibility; `remove_unreachable_chunk` doesn't remove `while_begin`, `next_loop` and other find_pattern specific labels, but removes general pattern matching instructions (including stack allocation for "local" variables). (Disabling `remove_unreachable_chunk` fixes this).

Possibly, that happens due to the labels cycle (`while_begin` -> `next_loop` -> `while_begin`); though I'm not really familiar with the _peephole optimization_. /cc @nobu @ko1

----------------------------------------
Bug #17534: Pattern-matching is broken with find pattern
https://bugs.ruby-lang.org/issues/17534#change-89995

* Author: zverok (Victor Shepelev)
* Status: Open
* Priority: Normal
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
The minimal reproduction code:

```ruby
case [1, 2, 3]
in y
  puts "branch1"
in [*, x, *]
  puts "branch2"
else
  puts "branch3"
end
```
This outputs long "raw disasm" sequence, and then
```
---------------------
break_pm.rb:6: argument stack underflow (-1)
break_pm.rb: compile error (SyntaxError)
```

```
$ ruby -v
ruby 3.1.0dev (2021-01-13T09:12:49Z master 6f6dfdcc68) [x86_64-linux]
```



-- 
https://bugs.ruby-lang.org/

[ruby-core:102145] [Ruby master Bug#17534] Pattern-matching is broken with find pattern

[dementiev.vm]

Issue #17534 has been updated by palkan (Vladimir Dementyev).


As a quick fix I propose marking patterns as unremoveable: https://github.com/ruby/ruby/pull/4094

----------------------------------------
Bug #17534: Pattern-matching is broken with find pattern
https://bugs.ruby-lang.org/issues/17534#change-89996

* Author: zverok (Victor Shepelev)
* Status: Open
* Priority: Normal
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
The minimal reproduction code:

```ruby
case [1, 2, 3]
in y
  puts "branch1"
in [*, x, *]
  puts "branch2"
else
  puts "branch3"
end
```
This outputs long "raw disasm" sequence, and then
```
---------------------
break_pm.rb:6: argument stack underflow (-1)
break_pm.rb: compile error (SyntaxError)
```

```
$ ruby -v
ruby 3.1.0dev (2021-01-13T09:12:49Z master 6f6dfdcc68) [x86_64-linux]
```



-- 
https://bugs.ruby-lang.org/

[ruby-core:102218] [Ruby master Bug#17534] Pattern-matching is broken with find pattern

[kazuki]

Issue #17534 has been updated by ktsj (Kazuki Tsujimoto).

Backport changed from 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN to 2.5: DONTNEED, 2.6: DONTNEED, 2.7: DONTNEED, 3.0: REQUIRED
Status changed from Open to Closed

@palkan:
Thanks to fix!

@naruse:
Could you backport 1b89b99941548fdb65305dd9a412082e7fdba45a to 3.0?

----------------------------------------
Bug #17534: Pattern-matching is broken with find pattern
https://bugs.ruby-lang.org/issues/17534#change-90065

* Author: zverok (Victor Shepelev)
* Status: Closed
* Priority: Normal
* Backport: 2.5: DONTNEED, 2.6: DONTNEED, 2.7: DONTNEED, 3.0: REQUIRED
----------------------------------------
The minimal reproduction code:

```ruby
case [1, 2, 3]
in y
  puts "branch1"
in [*, x, *]
  puts "branch2"
else
  puts "branch3"
end
```
This outputs long "raw disasm" sequence, and then
```
---------------------
break_pm.rb:6: argument stack underflow (-1)
break_pm.rb: compile error (SyntaxError)
```

```
$ ruby -v
ruby 3.1.0dev (2021-01-13T09:12:49Z master 6f6dfdcc68) [x86_64-linux]
```



-- 
https://bugs.ruby-lang.org/

[ruby-core:102381] [Ruby master Bug#17534] Pattern-matching is broken with find pattern

[naruse]

Issue #17534 has been updated by naruse (Yui NARUSE).

Backport changed from 2.5: DONTNEED, 2.6: DONTNEED, 2.7: DONTNEED, 3.0: REQUIRED to 2.5: DONTNEED, 2.6: DONTNEED, 2.7: DONTNEED, 3.0: DONE

ruby_3_0 2dc39e2fd45aacd5fcd33ed80f602bd6f2ddb504 merged revision(s) 1b89b99941548fdb65305dd9a412082e7fdba45a.

----------------------------------------
Bug #17534: Pattern-matching is broken with find pattern
https://bugs.ruby-lang.org/issues/17534#change-90242

* Author: zverok (Victor Shepelev)
* Status: Closed
* Priority: Normal
* Backport: 2.5: DONTNEED, 2.6: DONTNEED, 2.7: DONTNEED, 3.0: DONE
----------------------------------------
The minimal reproduction code:

```ruby
case [1, 2, 3]
in y
  puts "branch1"
in [*, x, *]
  puts "branch2"
else
  puts "branch3"
end
```
This outputs long "raw disasm" sequence, and then
```
---------------------
break_pm.rb:6: argument stack underflow (-1)
break_pm.rb: compile error (SyntaxError)
```

```
$ ruby -v
ruby 3.1.0dev (2021-01-13T09:12:49Z master 6f6dfdcc68) [x86_64-linux]
```



-- 
https://bugs.ruby-lang.org/