Passing formula variables to combination_model fails

[jfeltonnee]

Error in combination_model():
! combination_model() must use component models with the same response variable.

Example to reproduce error:
library(fable)
library(tsibbledata)

f1 <- formula(Tobacco ~ Beer)
f2 <- formula(Tobacco ~ Gas)

fabletools::model(aus_production
, cmbn1 = combination_model(
NNETAR(formula = f1)
, NNETAR(formula = f2)
, cmbn_args = list(weights = "inv_var")))
__

[mitchelloharawild]

This isn't working because it is treating f1 and f2 as response variables, rather than formulas.
You need to use !!f1 and !!f2 to substitute the names f1 and f2 with their values.

library(fable)
#> Loading required package: fabletools
library(tsibbledata)

f1 <- formula(Tobacco ~ Beer)
f2 <- formula(Tobacco ~ Gas)

aus_production |> 
  model(
    cmbn1 = combination_model(
      NNETAR(formula = !!f1),
      NNETAR(formula = !!f2), 
      cmbn_args = list(weights = "inv_var")
    )
  )
#> # A mable: 1 x 1
#>           cmbn1
#>         <model>
#> 1 <COMBINATION>

^{Created on 2024-06-02 with reprex v2.1.0}