Fix a race in ClassHOW new_type #4482
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Anonymous class ID is storead in a class `my` variable and was incremented by `new_type` method without a lock protection. In my testing the probablity of creating a clashing name was ~0.25% for concurrently invoked `new_type` methods.
niner
approved these changes
Jul 28, 2021
src/Perl6/Metamodel/ClassHOW.nqp
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| $metaclass.set_name($obj, $name // "<anon|{$anon_id++}>"); | ||
| $id_lock.protect: { | ||
| $metaclass.set_name($obj, $name // "<anon|{$anon_id++}>"); | ||
| } |
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Probably won't make a difference, but you could improve parallelization by only protecting $anon_id++ like in
Line 484 in 22f78f4
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I thought about it, but how much sense does it make? The current way is more readable.
In either case, nqp::cas_i would be even better here, but NQP seemingly doesn't support it.
Minor performance improvement. Especially for cases where class name is provided.
niner
approved these changes
Jul 29, 2021
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Anonymous class ID is storead in a class
myvariable and was incremented bynew_typemethod without a lock protection. In my testing the probablity of creating a clashing name was ~0.25% for concurrently invokednew_typemethods.