[Cuis-dev] A bug in Context Part>>contextEnsure:

[Jaromir Matas]

Hi Juan,
Here’s a fix of a nasty bug in Context Part>>contextEnsure:

It shows while debugging or stepping; try this sequence that would get you right before the bug:

p _ [ContextPart contextEnsure: [42]] newProcess.
[p suspendedContext selectorToSendOrSelf = #jump] whileFalse: [p step].
[p suspendedContext selectorToSendOrSelf = #privSender:] whileFalse: [p step].
3 timesRepeat: [p stepToCallee].
p step.
p suspendedContext explore.
p suspendedContext method inspect.

Please notice that the suspendedContext only has stackp=2 and hence the next instruction will fail in the next step:

p step

The root cause is contextEnsure: mistakenly treats ctxt as a top context (i.e. one that has a return value already at the top of the stack); the fix is trivial: add a fake return value – see enclosed.

Best,

--

Jaromír Matas

mail at jaromir.net


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