Tools for tracking memory "leaks"

[hadley]

obj_size() provides the basic structure for the recursion. The main difference would be that each call returns a nested list containing the current object, and a (potentially named) list of its children. Would want options to control the maximum depth to recurse (so you could explore iteratively, if needed), whether or not to show CHARSXPs, and how to handle ALTREP. By default, would show environments in the same way as lists, rather than exposing the details of their internal hash tables (but needs option to show full details for debugging other code).

Need small S3 class to capture an object — it's address (string), type (string), NAMED (integer?), and id (integer, if seen before, NULL otherwise), and its children (named list). Its print method would take care of generating the tree display.

This would effectively become a replacement for .Internal(inspect(x)), with a better display (i.e. using colour and unicode tree characters) and displaying a spanning tree (instead of potentially getting stuck in infinite loops). Would replace internal obj_formals() etc, and altrep().

[hadley]

Can experiment with https://github.com/rstudio/rstudio/blob/75e5d4a06dfebba0ef0290fc04788b841e26cc8f/src/cpp/session/modules/SessionObjectExplorer.R#L768-L948 to see how customising the viewer might work