dplyr normally produces useful error messages which you can dig deep into with rlang::last_trace() and rlang::last_error().
When running in Shiny, dplyr's error messages are not as helpful as the error messages for base R functions like [ which tell you in the error exactly where the issue is. The only way I am able to find dplyr errors in a shiny file where the error might occur in any of a number of sourced files is to set options(shiny.error = browser) and run rlang::last_error() or rlang::last_trace().
Is there a way I can set dplyr to return simpler error messages like [ from base and data.table, and to make sure that that simple error message appears in Shiny?
Here is my reprex:
library(shiny)
#> Warning: package 'shiny' was built under R version 3.6.3
library(dplyr)
#> Warning: package 'dplyr' was built under R version 3.6.3
#>
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#>
#> filter, lag
#> The following objects are masked from 'package:base':
#>
#> intersect, setdiff, setequal, union
#options(shiny.error = browser) errors for dplyr are unfriendly without this, but base errors still very friendly.
first_function <- function(df){
select(df, chad) #selecting for a non-existing column
#df[,chad] #will work nicely
}
ui <- fluidPage(
verbatimTextOutput("example")
)
server <- function(input, output, session) {
output$example <- renderPrint({first_function(iris)})
}
shinyApp(ui, server)
#> PhantomJS not found. You can install it with webshot::install_phantomjs(). If it is installed, please make sure the phantomjs executable can be found via the PATH variable.
Shiny applications not supported in static R Markdown documents
Created on 2020-12-01 by the reprex package (v0.3.0)
And here is my sessionInfo:
R version 3.6.2 (2019-12-12)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 19041)
Matrix products: default
locale:
[1] LC_COLLATE=English_South Africa.1252 LC_CTYPE=English_South Africa.1252 LC_MONETARY=English_South Africa.1252
[4] LC_NUMERIC=C LC_TIME=English_South Africa.1252
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] reprex_0.3.0 shiny_1.4.0.2 data.table_1.12.8 forcats_0.4.0 stringr_1.4.0 dplyr_1.0.2 purrr_0.3.3
[8] readr_1.3.1 tidyr_1.1.1 tibble_3.0.3 ggplot2_3.3.2 tidyverse_1.3.0
loaded via a namespace (and not attached):
[1] xfun_0.12 tidyselect_1.1.0 haven_2.2.0 colorspace_1.4-1 vctrs_0.3.2 generics_0.0.2 htmltools_0.4.0
[8] rlang_0.4.7 pillar_1.4.3 later_1.0.0 glue_1.4.1 withr_2.1.2 DBI_1.1.0 dbplyr_1.4.2
[15] modelr_0.1.5 readxl_1.3.1 lifecycle_0.2.0 munsell_0.5.0 gtable_0.3.0 cellranger_1.1.0 rvest_0.3.5
[22] evaluate_0.14 knitr_1.28 callr_3.4.1 fastmap_1.0.1 ps_1.3.0 httpuv_1.5.2 fansi_0.4.1
[29] broom_0.7.0 Rcpp_1.0.3 xtable_1.8-4 clipr_0.7.0 scales_1.1.0 backports_1.1.5 promises_1.1.0
[36] jsonlite_1.6.1 mime_0.8 fs_1.5.0 hms_0.5.3 digest_0.6.23 stringi_1.4.4 processx_3.4.1
[43] grid_3.6.2 cli_2.0.2 tools_3.6.2 magrittr_1.5 whisker_0.4 crayon_1.3.4 pkgconfig_2.0.3
[50] ellipsis_0.3.0 rsconnect_0.8.16 xml2_1.2.2 lubridate_1.7.4 rmarkdown_2.1 assertthat_0.2.1 httr_1.4.1
[57] rstudioapi_0.11 R6_2.4.1 compiler_3.6.2