From: nobu@ruby-lang.org
To: ruby-core@ruby-lang.org
Subject: [ruby-core:99321] [Ruby master Bug#17048] Calling initialize_copy on live modules leads to crashes
Date: Sat, 25 Jul 2020 02:35:20 +0000 (UTC) [thread overview]
Message-ID: <redmine.journal-86715.20200725023519.16806@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-17048.20200724160919.16806@ruby-lang.org
Issue #17048 has been updated by nobu (Nobuyoshi Nakada).
I agree with @alanwu, that it won't be worth.
```diff
diff --git c/class.c i/class.c
index 6835d2d7289..f7a56601634 100644
--- c/class.c
+++ i/class.c
@@ -354,6 +354,13 @@ static void ensure_origin(VALUE klass);
VALUE
rb_mod_init_copy(VALUE clone, VALUE orig)
{
+ if (RCLASS_EXT(clone)->subclasses ||
+ RCLASS_EXT(clone)->parent_subclasses ||
+ RCLASS_EXT(clone)->module_subclasses) {
+ rb_raise(rb_eTypeError, "cannot replace %s in use",
+ (RB_TYPE_P(clone, T_MODULE) ? "module" : "class"));
+ }
+
/* cloned flag is refer at constant inline cache
* see vm_get_const_key_cref() in vm_insnhelper.c
*/
diff --git c/test/ruby/test_module.rb i/test/ruby/test_module.rb
index d2da384cbd1..8d986f13413 100644
--- c/test/ruby/test_module.rb
+++ i/test/ruby/test_module.rb
@@ -435,6 +435,12 @@
assert_empty(m.constants, bug9813)
end
+ def test_initialize_copy_in_use
+ m = Module.new
+ Class.new {include m}
+ assert_raise(TypeError) {m.send(:initialize_copy, Module.new)}
+ end
+
def test_dup
OtherSetup.call
```
----------------------------------------
Bug #17048: Calling initialize_copy on live modules leads to crashes
https://bugs.ruby-lang.org/issues/17048#change-86715
* Author: alanwu (Alan Wu)
* Status: Open
* Priority: Normal
* ruby -v: ruby 2.8.0dev (2020-07-23T14:44:25Z master 098e8c2873) [x86_64-linux]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
Here's a repro script
```ruby
loop do
m = Module.new do
prepend Module.new
def hello
end
end
klass = Class.new { include m }
m.send(:initialize_copy, Module.new)
GC.start
klass.new.hello rescue nil
end
```
Here's a script that shows that it has broken semantics even
when it happens to not crash.
```ruby
module A
end
class B
include A
end
module C
Const = :C
end
module D
Const = :D
end
A.send(:initialize_copy, C)
p B::Const # :C, makes sense
A.send(:initialize_copy, D)
p B::Const # :D, makes sense
A.send(:initialize_copy, Module.new)
p (begin B::Const rescue NameError; 'NameError' end) # NameError, makes sense
A.send(:initialize_copy, C)
p B::Const # still NameErorr. Weird
```
This example shows that the problem exists [as far back as 2.0.0](https://wandbox.org/permlink/4dVDY9sNXJ803jh8).
I think the easiest way to fix this is to forbid calling `:initialize_copy`
on modules that have children. Another option is to try to decide on
the semantics of this. Though I don't think it's worth the effort as this
has been broken for a long time and people don't seem to to be using it.
Thoughts?
--
https://bugs.ruby-lang.org/
next prev parent reply other threads:[~2020-07-25 2:35 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-24 16:09 [ruby-core:99311] [Ruby master Bug#17048] Calling initialize_copy on live modules leads to crashes XrXr
2020-07-24 16:40 ` [ruby-core:99312] " merch-redmine
2020-07-24 17:23 ` [ruby-core:99313] " XrXr
2020-07-24 17:52 ` [ruby-core:99314] " merch-redmine
2020-07-24 22:29 ` [ruby-core:99317] " XrXr
2020-07-25 2:35 ` nobu [this message]
2020-07-25 10:32 ` [ruby-core:99331] " eregontp
2020-07-25 18:33 ` [ruby-core:99336] " XrXr
2020-07-26 6:21 ` [ruby-core:99343] " nobu
2020-07-26 16:23 ` [ruby-core:99349] " eregontp
2020-07-28 23:45 ` [ruby-core:99379] " XrXr
2020-08-12 7:30 ` [ruby-core:99567] " ko1
2020-08-26 20:27 ` [ruby-core:99715] " XrXr
2021-07-02 17:11 ` [ruby-core:104475] " merch-redmine
2021-09-16 7:18 ` [ruby-core:105288] " nobu (Nobuyoshi Nakada)
2021-09-16 16:03 ` [ruby-core:105312] " jeremyevans0 (Jeremy Evans)
2021-09-16 21:00 ` [ruby-core:105314] " alanwu (Alan Wu)
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