Bug in `pak::pkg_deps_explain(".", "foobar")`

[dmurdoch]

I have a local package that is on Github but not on CRAN. If I ask pak to explain a non-existent dependency, this fails:

> pak::pkg_deps_explain(".", "foobar")
Error:                                                                
! error in pak subprocess
Caused by error in `adjlist[[wpkg]] <- deps1`:
! attempt to select more than one element in integerOneIndex
Type .Last.error to see the more details.
> .Last.error
<callr_error/rlib_error_3_0/rlib_error/error>
Error: 
! error in pak subprocess
Caused by error in `adjlist[[wpkg]] <- deps1`:
! attempt to select more than one element in integerOneIndex
---
Backtrace:
1. pak::pkg_deps_explain(".", "foobar")
2. pak:::remote(function(...) { …
3. err$throw(res$error)
---
Subprocess backtrace:
1. base::withCallingHandlers(cli_message = function(msg) { …
2. get("pkg_deps_explain_internal", asNamespace("pak"))(...)
3. base::.handleSimpleError(function (e) …
4. global h(simpleError(msg, call))

It works if I use the Github reference:

> pak::pkg_deps_explain("dmurdoch/mypkg", "foobar")
x foobar