get rid of 'reference not set to an instance of an object' error, which appears when context is null

[Thrasha]

getting weird error when execute ts script in jint:
Method CalculateLoanConditions has thrown an exception. System.NullReferenceException: Object reference not set to an instance of an object. at Jint.Runtime.Interpreter.Expressions.JintExpression.GetValue(EvaluationContext context) at Jint.EsprimaExtensions.TryGetKey[T](T expression, Engine engine, Boolean resolveComputed) at Jint.Runtime.Interpreter.Expressions.JintObjectExpression.BuildObjectNormal(EvaluationContext context) at Jint.Runtime.Interpreter.Expressions.JintExpression.GetValue(EvaluationContext context) at Jint.Runtime.Interpreter.Expressions.JintCallExpression.ArgumentListEvaluation(EvaluationContext context) at Jint.Runtime.Interpreter.Expressions.JintCallExpression.EvaluateInternal(EvaluationContext context) at Jint.Runtime.Interpreter.Expressions.JintExpression.GetValue(EvaluationContext context) at Jint.Runtime.Interpreter.Statements.JintReturnStatement.ExecuteInternal(EvaluationContext context) at Jint.Native.Function.ScriptFunction.Call(JsValue thisObject, JsValue[] arguments) at Jint.Runtime.Interpreter.Expressions.JintCallExpression.EvaluateInternal(EvaluationContext context) at Jint.Runtime.Interpreter.Expressions.JintExpression.GetValue(EvaluationContext context) at Jint.Runtime.Interpreter.Statements.JintReturnStatement.ExecuteInternal(EvaluationContext context) at Jint.Native.Function.ScriptFunction.Call(JsValue thisObject, JsValue[] arguments)

https://stackoverflow.com/questions/78326684/error-object-reference-not-set-to-an-instance-of-an-object-after-upgrade-jint

after debugging jint, I've found out that for my scripts context is null. I substitute null to new EvaluationContext() and it started to work well

[lahma]

Can you add a test case showing the original problem?

[Thrasha]

I will try to reproduce it wia unit test, however, I'm not positive with that. The script, generated by state machine is huge and complex, and I couldn't determine which part of script has context null when I was debugging jint part. Give me a day, I'll try to find something

[Thrasha]

Hi @lahma. Unfortunately, it is impossible to write a unit test due to protection level of _activeEvaluationContext. What else can I do to make this fix merged?

[lahma]

Jint.Tests projects should be able to see internals?

[Thrasha]

It does see, however, we have to change private method TryGetComputedPropertyKey to internal. If yes, this following test throws JS error after my fix and 'Object reference not set to an instance of an object' before my fix

[lahma]

Thanks for creating a test case, Added some improvements ideas.

[lahma]

I did minor adjustments, thank you for the PR.