[ruby-core:102175] [Ruby master Bug#17563] FrozenError raised from Module#const_set when receiver is not frozen
From:
merch-redmine@...
Date:
2021-01-19 22:34:32 UTC
List:
ruby-core #102175
Issue #17563 has been updated by jeremyevans0 (Jeremy Evans).
Assignee changed from jeremyevans0 (Jeremy Evans) to nobu (Nobuyoshi Nakada)
Using `ivar_set` seems reasonable to me, but I'd like to get @nobu's input as to whether this is acceptable.
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Bug #17563: FrozenError raised from Module#const_set when receiver is not frozen
https://bugs.ruby-lang.org/issues/17563#change-90024
* Author: ryannevell (Ryan Nevell)
* Status: Open
* Priority: Normal
* Assignee: nobu (Nobuyoshi Nakada)
* ruby -v: ruby 3.1.0dev (2021-01-19T16:58:26Z master a8dc5156e1) [x86_64-darwin20]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
The following code executed without error on Ruby 2.7.1 and many earlier 2.* versions. The behavior has changed on Ruby 3.0.0 and now raises a Frozen Error:
```
% ruby -e 'Module.new.const_set(:Foo, Class.new.freeze)'
-e:1:in `const_set': can't modify frozen #<Class:#<Class:0x00007fe883886698>>: #<Class:0x00007fe883886698> (FrozenError)
from -e:1:in `<main>'
```
It seems that const_set is attempting to modify the (frozen) object being passed in, not just the receiver of the const_set call. This seems to only happen if that object is a Module or Class.
This may be due to this change to rb_const_set.
On 2.7.1, no action was taken if `parental_path` was `nil`:
``` c
int parental_path_permanent;
VALUE parental_path = classname(klass, &parental_path_permanent);
if (!NIL_P(parental_path)) {
if (parental_path_permanent && !val_path_permanent) {
set_namespace_path(val, build_const_path(parental_path, id));
}
else if (!parental_path_permanent && NIL_P(val_path)) {
rb_ivar_set(val, tmp_classpath, build_const_path(parental_path, id));
}
}
```
On 3.0, a temporary class path is created, and then it goes on to call `rb_ivar_set` on `val`, which will error out if `val.frozen? == true`:
``` c
int parental_path_permanent;
VALUE parental_path = classname(klass, &parental_path_permanent);
if (NIL_P(parental_path)) {
int throwaway;
parental_path = rb_tmp_class_path(klass, &throwaway, make_temporary_path);
}
if (parental_path_permanent && !val_path_permanent) {
set_namespace_path(val, build_const_path(parental_path, id));
}
else if (!parental_path_permanent && NIL_P(val_path)) {
rb_ivar_set(val, tmp_classpath, build_const_path(parental_path, id));
}
```
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