Erroneous detection of list elements as dependencies

[wlandau]

Prework

• Read and abide by drake's code of conduct.
• Search for duplicates among the existing issues, both open and closed.
• Advanced users: verify that the bug still persists in the current development version (i.e. remotes::install_github("ropensci/drake")) and mention the SHA-1 hash of the Git commit you install.

Description

drake accidentally detects list elements as dependencies. Sorry everyone, fixing this bug might invalidate some workflows.

Reproducible example

drake:::analyze_code(quote(x$y))
#> $globals
#> [1] "x" "y"

^{Created on 2019-07-12 by the reprex package (v0.3.0)}

Expected output

y should be ignored.

drake:::analyze_code(quote(x$y))
#> $globals
#> [1] "x" "y"

But isn't this non-standard evaluation?

Yes, $ is technically NSE, and I know I said drake would not get into any of that. But $ is just too clear, simple, predictable, and ubiquitous to ignore.