[Rd] How to locate references to an environment?

[Tomas Kalibera]

On 5/23/23 20:29, Peter Meilstrup wrote:
> R developers,
>
> I am trying to track down a memory leak in my R package.
>
> I have a complex object O which comprises a lot of closures and such.
> Among which, the object uses an environment E to perform computations
> and keep intermediate values in. When O closes/finishes with its task
> it nulls out its reference to E so that that intermediate data can be
> garbage collected; I've verified that it does null the reference.
>
> However, it seems there is another reference to E floating around. I
> can tell because I can ask O to put a large array in E, then tell O to
> close, which nulls the reference to E, but then if I serialize(O,
> ascii=TRUE) I can still see the array in the output.
>
> Dangling references to E could come from a closure created in E, or an
> unforced promise from a function call evaluated in E that created a
> closure I still have a reference to, or, ... my question is how do I
> locate the reference?
>
> Is there a way to scan the workspace for objects that refer to a given object?
>
> Or is there a tool that will unpack/explain serialize()'s .rds format
> in a more human-readable way so that I can tell where the reference to
> E occurs?

Maybe you could re-use my script used for finding a particular string in 
the R heap (captured temporary installation directory name during staged 
installation). It should be fairly easy to modify it to look for a 
particular environment object.

Best
Tomas

https://github.com/kalibera/rstagedinst/blob/master/sicheck.R
https://blog.r-project.org/2019/02/14/staged-install/index.html
>
> Peter
>
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