object 'ffi_list2' not found: build time capture of `rlang::list2()` has resulted in unfortunate errors for users

[DavisVaughan]

TLDR for users hitting

object 'ffi_list2' not found

I believe if you do the following, you can get back up and running:

• remove.packages("rlang")
• Restart R to be safe
• install.packages("rlang")
• Restart R to be safe
• Try your code again

That should put you on rlang 1.1.7, which has ffi_list2.

---

ggplot2 seems to capture rlang::list2() at package build time, meaning that whatever definition of rlang::list2() is available at build time is the one that all users of ggplot2 must have.

ggplot2/R/make-constructor.R

Lines 142 to 143 in 4ea78a4

	# We encapsulate rlang::list2
	new_env <- new_environment(list(list2 = list2), env)

This constructor seems to then be called at package build time in many places, like

ggplot2/R/geom-contour.R

Line 84 in 4ea78a4

geom_contour <- make_constructor(

In rlang 1.1.7, we changed the internals of list2() to directly drop into a new C function called ffi_list2.

Unfortunately I believe this can cause a large variety of errors.

See r-lib/rlang#1866

And https://stackoverflow.com/questions/79869479/cannot-plot-geom-point-in-r-ggplot2

Based on looking at these problems, my diagnosis is:

• CRAN builds ggplot2 4.0.1 binaries against rlang 1.1.7 with the ffi_list2 definition. This captures that definition at ggplot2 binary build time for all users who download ggplot2 from CRAN.
• A user downloads ggplot2 4.0.1. This does not necessarily prompt them to update rlang to 1.1.7.
• They have an older rlang and try and plot, this results in the "ffi_list2 not found" error seen in all of the reports.

I believe there is nothing to be done on the rlang side of things.

If ggplot2 could please not capture rlang::list2() at package build time, and could send out a patch release that fixes this, then that would be great!

[teunbrand]

Just noting that if one runs into this, a likely fix is simply updating rlang from CRAN.

[teunbrand]

Considered closed by #6799