gheatmap() fails on ggplot2 4.0 because attr(p, "mapping") becomes a global aesthetic

[xiehs211]

Summary

gheatmap() attaches the heatmap column metadata via attr(p, "mapping") <- mapping. ggplot2 4.0 treats this as a
global aesthetic, so stat_tree() receives the 3-row heatmap mapping and errors with “Fix the following mappings:
from, to, .panel”.

Environment

• R 4.5.1
• ggtree 3.16.3
• ggplot2 4.0.1
• ape 5.8-1

Minimal Reproduction

library(ggtree)
library(ape)

tree <- rtree(5)
mat <- matrix(runif(10), nrow = 5,
dimnames = list(tree$tip.label, c("A", "B")))

p <- ggtree(tree)
gheatmap(p, mat)

Error in `stat_tree()`:
! Problem while computing aesthetics.
ℹ Error occurred in the 1st layer.
Caused by error in `check_aesthetics()`:
! Aesthetics must be either length 1 or the same as the
  data (9).
✖ Fix the following mappings: `from`, `to`, and `.panel`.
Run `rlang::last_trace()` to see where the error occurred.

Analysis / Workaround

Removing/renaming that attribute restores plotting:
p2 <- gheatmap(p, mat)
attr(p2, "mapping") <- NULL
print(p2)

Suggested Fix

Rename the attribute (e.g. attr(p, "heatmap_mapping")) or drop it so ggplot2 no longer confuses it with the global
mapping slot.

[lou-campbell33]

Thank you for posting the workaround - I had the same error when trying to plot a heatmap with the current version of ggtree. In using your workaround I had a secondary error, which looked like this:

attr(p_final, "mapping") <- NULL
print(p_final)
Error in geom_segment2():
! Problem while converting geom to grob.
Error occurred in the 3rd layer.
Caused by error in is.waive():
! could not find function "is.waive"
Run rlang::last_trace() to see where the error occurred.

Adding the following line has allowed me to (at least temporarily) solve this problem and print my heatmap:
is.waive <- function(x) inherits(x, "waiver")