0000416: mutable thread_local java backend missing initialValue()

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Date Submitted

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0000416

mercury

Bug

public

2016-08-31 17:04

Reporter

maxime

Assigned To

Priority

normal

Severity

crash

Reproducibility

always

Status

new

Resolution

open

Platform

Java backend

OS Version

Product Version

Target Version

Fixed in Version

Summary

0000416: mutable thread_local java backend missing initialValue()

Description

In the java backend, when compiling a thread_local mutable, mmc generates a static field
static java.lang.ThreadLocal<Type> module__mutable_variable_name_of_mutable = new java.lang.InheritableThreadLocal<Type>();
which is set via set(...) to the initial value into a initialise declaration (static code block).
The issue is that the InheritableThreadLocal MUST override the initialValue() method, returning the initial value.
Why? because in threads may have been created by a container before the static block has executed, leading in the end to a NullPointerException, because a such a thread from a thread-pool is executing code using the mutable, which does not have a parent-child relation with the thread in which the mutable was initialized.

Steps To Reproduce

Create a module with a thread_local mutable, compile to a jar, create a main java, which creates threads before calling anything from the jar, then from multiple threads, use the mutable.

Additional Information

The generated code should either be
static java.lang.ThreadLocal<Type> module__mutable_variable_name_of_mutable = new java.lang.InheritableThreadLocal<Type>() {
protected java.lang.Integer initialValue() {return <VALUE>;}
};

Or
static java.lang.ThreadLocal<Type> module__mutable_variable_name_of_mutable;
and in the initialization code, instead of doing a set(...), do a
new java.lang.InheritableThreadLocal<Type>() {
protected java.lang.Integer initialValue() {return <VALUE>;}
};

Date Modified	Username	Field	Change
Issue History
2016-08-31 17:04	maxime	New Issue

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