[GitHub] [arrow] nealrichardson commented on a change in pull request #10381: ARROW-12722: [R] Raise error when attemping to print table with duplicated naming

[GitBox <gi...@apache.org>]

nealrichardson commented on a change in pull request #10381:
URL: https://github.com/apache/arrow/pull/10381#discussion_r640168884



##########
File path: r/R/dplyr.R
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@@ -74,7 +74,13 @@ print.arrow_dplyr_query <- function(x, ...) {
     name <- expr$field_name
     if (nzchar(name)) {
       # Just a field_ref, so look up in the schema
-      schm$GetFieldByName(name)$type$ToString()
+      field_name <- schm$GetFieldByName(name)

Review comment:
       I checked with @bkietz and (currently at least) evaluating expressions on a dataset with duplicated field names will error, so if that's the case (perhaps you could verify), we should check this sooner than the print method. How about instead we put a check around L33 above, like
   
   ```r
   if (anyDuplicated(names(.data))) {
     abort("useful message")
   }
   ```




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