How to update function code in an R package?

I have created and downloaded an R package using roxygen2 development tools. When I update the source code R files, the documentation updates fine, but the function code itself does not. How do I get the function code to update when I reinstall the package with install.packages("package-name")?

I have tried inserting error messages at the beginning of every function using stop("..."). When I reinstall the code, the functions do not output an error message as they should but work as they did before I updated the code.

Each time I update the code, I use the following commands:

devtools::document()
devtools::install()

install.packages("package-name", repos=NULL, type="source")
library(package-name)

Just for further information, when I try to install the package this way:

install.packages("package-name")

I get the following error message:

Warning in install.packages :
  package ‘package-name’ is not available (for R version 3.6.0)

I got this same error message when my R version was 3.6.0, and even now after updating to 3.6.1

I have not uploaded the package to any repositories, so I figured this makes sense, and instead install it locally from my package files with repos=NULL.

#' Roxygen comments - this part updates
#'
#' etc.
functionName <- function(...) {
 stop("...") 
 ...
 # This function should crash with an error message every time it is called, 
 # but instead the function body is never updated.
}

Upon reinstalling the package, I expect the output of my functions to be an error message, but instead, they output the same result as they did before I updated the package.

Documentation updates, function bodies do not.

Solution

So it turns out I found an answer to my own question...

The problem was with a warning message I was getting:

Warning message: 
In body(fun) : argument is not a function

Despite not ever using body(), this function was getting called internally somewhere, and the warning prevented the code from being updated (but the documentation still updates, for some reason).

Clearing my global environment with rm(list=ls()) cleared my error.