[ARROW-13543] [R] Handle summarize() with 0 arguments or no aggregate functions

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 6.0.0
• Component/s: R
• Labels: pull-request-available query-engine
• External issue URL: https://github.com/apache/arrow/issues/29195
• Assignee: Neal Richardson
• Reporter: Ian Cook
• Created: 04/Aug/21 04:03
• Updated: 11/Jan/23 08:33
• Resolved: 03/Sep/21 17:51

Description

Following ARROW-13344, we should handle the case in which the user calls summarise() but does not call any aggregate functions in it.

Currently this is unhandled and results in errors (which are then are converted to warnings) like:

Warning: Error in x[c("fun", "options")] : object of type 'environment' is not subsettable ; pulling data into R

or when the expression in summarise() has only scalar literals:

Warning: Error : $ operator is invalid for atomic vectors
; pulling data into R 

or when there are zero arguments passed to summarise() and there is no group_by() preceding it:

Warning: Error : Invalid input type, expected 'character' actual 'NULL'
; pulling data into R 

We should aim for consistency with dplyr::summarise() in these cases, but if that's not practical then we should detect this case and throw a more informative error.

Issue Links

• blocks: ARROW-13618 [R] Use Arrow engine for summarize() by default
• is depended upon by: ARROW-10415 [R] Support for dplyr::distinct()
• relates to: ARROW-13344 [R] Initial bindings for ExecPlan/ExecNode
• links to: GitHub Pull Request #11078