Unable to load package that depends on package loaded by load_all

[hongooi73]

Say you're working on a package A, that has a reverse dependency B which lists A in Depends: (rather than Imports:).

If you load A with load_all(), and then do library(B), the latter will fail with

Error: package 'A' required by 'B' could not be found

To reproduce this, you can use the foreach package, which is at https://github.com/RevolutionAnalytics/foreach

• Clone the repo
• Run

load_all()
library(doParallel)

This will result in the error message above.

Running a traceback shows that the error comes from base::.getRequiredPackages2. This function is called by base::library, and in turn calls system.file to get the path to one of foreach's package files. But when foreach is loaded via load_all, there are no package files and everything falls down.

[jimhester]

Another example of this is

pkgload::load_all("xml2")
library(rvest)

[lionel-]

In general we don't really have good support for working with two packages at the same time.

I assume the intent is to do some quick tests in a downstream package after having changed the upstream. The workaround would be to install the dev upstream package locally, restart R, and then use library(downstream). I imagine that's sufficient for most workflows, especially if the upstream package is well tested and thus doesn't require trying the downstream to check that things work.

Worth noting that both rvest and foreach, mentioned as real examples in this thread, no longer have a package in Depends.

I'll close for now because it seems like supporting this would require patching the base namespace with devtools' version of system.file() and I'd prefer to avoid this if we can.