predict_newdata_fast not working with GraphLearner #961
Description
I'm using $predict_newdata_fast internally in a package and was surprised to see it break when I used a GraphLearner. I didn't find anything in the docs or NEWS that suggest that this is expected behavior.
Tried with CRAN mlr3pipelines and GH version just now.
Reprex:
library(mlr3)
library(mlr3pipelines)
learner = lrn("regr.rpart")
task = tsk("mtcars")
learner$train(task)
# Regular learner can do all the things as epxected
pred = learner$predict(task)
pred = learner$predict_newdata(task$data())
pred = learner$predict_newdata_fast(task$data())
# constructing a simple graph learner
grlrn = po("removeconstants") %>>%
po("learner", learner) |>
as_learner()
grlrn$train(task)
# as expected
pred = grlrn$predict(task)
# yup
pred = grlrn$predict_newdata(task$data())
# nope
pred = grlrn$predict_newdata_fast(task$data())
#> Error: attempt to apply non-functionsession info
sessioninfo::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
#> setting value
#> version R version 4.5.1 (2025-06-13)
#> os macOS Sequoia 15.7
#> system aarch64, darwin20
#> ui X11
#> language (EN)
#> collate en_US.UTF-8
#> ctype en_US.UTF-8
#> tz Europe/Berlin
#> date 2025-10-11
#> pandoc 3.7.0.2 @ /opt/homebrew/bin/ (via rmarkdown)
#> quarto 1.7.34 @ /usr/local/bin/quarto
#>
#> ─ Packages ───────────────────────────────────────────────────────────────────
#> package * version date (UTC) lib source
#> backports 1.5.0 2024-05-23 [1] CRAN (R 4.5.0)
#> checkmate 2.3.3 2025-08-18 [1] CRAN (R 4.5.0)
#> cli 3.6.5 2025-04-23 [1] CRAN (R 4.5.0)
#> codetools 0.2-20 2024-03-31 [2] CRAN (R 4.5.1)
#> crayon 1.5.3 2024-06-20 [1] CRAN (R 4.5.0)
#> data.table 1.17.8 2025-07-10 [1] CRAN (R 4.5.0)
#> digest 0.6.37 2024-08-19 [1] CRAN (R 4.5.0)
#> evaluate 1.0.5 2025-08-27 [1] CRAN (R 4.5.0)
#> fastmap 1.2.0 2024-05-15 [1] CRAN (R 4.5.0)
#> fs 1.6.6 2025-04-12 [1] CRAN (R 4.5.0)
#> future 1.67.0 2025-07-29 [1] CRAN (R 4.5.0)
#> globals 0.18.0 2025-05-08 [1] CRAN (R 4.5.0)
#> glue 1.8.0 2024-09-30 [1] CRAN (R 4.5.0)
#> htmltools 0.5.8.1 2024-04-04 [1] CRAN (R 4.5.0)
#> knitr 1.50 2025-03-16 [1] CRAN (R 4.5.0)
#> lgr 0.5.0 2025-07-23 [1] CRAN (R 4.5.0)
#> lifecycle 1.0.4 2023-11-07 [1] CRAN (R 4.5.0)
#> listenv 0.9.1 2024-01-29 [1] CRAN (R 4.5.0)
#> mlr3 * 1.2.0.9000 2025-10-03 [1] Github (mlr-org/mlr3@a333e13)
#> mlr3misc 0.19.0.9000 2025-09-19 [1] Github (mlr-org/mlr3misc@73e6117)
#> mlr3pipelines * 0.9.0-9000 2025-10-11 [1] Github (mlr-org/mlr3pipelines@73a4fe6)
#> palmerpenguins 0.1.1 2022-08-15 [1] CRAN (R 4.5.0)
#> paradox 1.0.1 2024-07-09 [1] CRAN (R 4.5.0)
#> parallelly 1.45.1 2025-07-24 [1] CRAN (R 4.5.1)
#> R6 2.6.1 2025-02-15 [1] CRAN (R 4.5.0)
#> reprex 2.1.1 2024-07-06 [1] CRAN (R 4.5.0)
#> rlang 1.1.6 2025-04-11 [1] CRAN (R 4.5.0)
#> rmarkdown 2.30 2025-09-28 [1] CRAN (R 4.5.0)
#> rpart 4.1.24 2025-01-07 [2] CRAN (R 4.5.1)
#> sessioninfo 1.2.3 2025-02-05 [1] CRAN (R 4.5.0)
#> uuid 1.2-1 2024-07-29 [1] CRAN (R 4.5.0)
#> withr 3.0.2 2024-10-28 [1] CRAN (R 4.5.0)
#> xfun 0.53 2025-08-19 [1] CRAN (R 4.5.0)
#> yaml 2.3.10 2024-07-26 [1] CRAN (R 4.5.0)
#>
#> [1] /Users/Lukas/Library/R/arm64/4.5/library
#> [2] /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/library
#> * ── Packages attached to the search path.
#>
#> ──────────────────────────────────────────────────────────────────────────────