Using box::reload within a function

[TymekDev]

Hi! I am tinkering with box::reload and ran into an inconsistent behavior - reload depends on its caller. A quick glance at its source code show shenanigans going on with environments.

Is there a way to escape "local" reloading and make the following example reload the module from within the function in this example?

writeLines("foo <- 1", "module.R")
box::use(./module)
module$foo
# [1] 1

writeLines("foo <- 2", "module.R")
box::reload(module)
module$foo
# [1] 2

writeLines("foo <- 3", "module.R")
f <- function() { box::reload(module); module$foo }
f()
# [1] 3
module$foo
# [1] 2

[klmr]

reload depends on its caller

It certainly does! And, since it’s intended exclusively for interactive development, it is designed to be only ever called from the global environment (and on modules that are loaded in the global environment). Calling it from anywhere else doesn’t really make sense, except (as I suspect you are trying to) inside a function that acts as a convenience shortcut for interactive use. — If this isn’t your intended use, would you mind telling me more about your use-case? Maybe I have a better solution, or this is a legitimate use-case I hadn’t thought of, and which ‘box’ should accommodate in the future.

At any rate, you can make your code work with a bit of scope hackery:

f <- function() {
    evalq(box::reload(module), envir = parent.frame())
    module$foo
}

[TymekDev]

Thank you for your answer!

My use case is autoreload in Shiny. Recently going down a rabbit hole as to why autoreload depends on how you start your app, that's when I stumbled upon a way to register an autoreload callback in Shiny. I know you have autoreload for box in the works, but it just begged to take box::reload for a ride in the Shiny's autoreload callback. Thanks to your answer I managed to make it work (the relevant bit)! 🎉

There are more examples in the repo:
https://github.com/TymekDev/shiny-box-autoreload