JavaScript heap out of memory due to memory leak

[zhihuahuang]

• Rollup Version: 2.15.2
• Operating System (or Browser): any
• Node Version (if applicable): 14
• Link to reproduction (IMPORTANT, read below):

Expected Behavior

When rollup watch restart, the modules of last time will be released.

Actual Behavior

But it will be not. these modules are still keep by ARRAY_PROTOTYPE.
So it cause a memory leak.

I take memory snapshot before and after watch restart. Please see the picture below:

I read the code of ARRAY_PROTOTYPE, then find some code maybe cause memory leak.

expressionsToBeDeoptimizedByKey & thisParametersToBeDeoptimized

ARRAY_PROTOTYPE is a global variable, so the propertyexpressionsToBeDeoptimizedByKey and thisParametersToBeDeoptimized never clear.

[lukastaegert]

Good catch! At the moment, these variables are actually supposed to be stateless, but as they are reusing the stateful ObjectEntity, this is obviously not the case. I will think about how to improve here, maybe an "immutable" flag for now.

[lukastaegert]

Can you verify if #4142 resolves this?

[zhihuahuang]

Can you verify if #4142 resolves this?

I have tried and it can resolve this problem.
Please merge the branch and publish a version quickly, thanks~

[lukastaegert]

Done