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https://issues.apache.org/jira/browse/ARROW-17784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17607303#comment-17607303
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Nicola Crane commented on ARROW-17784:
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CC [~westonpace] I think this is the example we discussed earlier that you said
was worth opening a ticket for?
> [C++] Opening a dataset where partitioning variable is in the dataset should
> error differently
> ----------------------------------------------------------------------------------------------
>
> Key: ARROW-17784
> URL: https://issues.apache.org/jira/browse/ARROW-17784
> Project: Apache Arrow
> Issue Type: Bug
> Components: C++
> Reporter: Nicola Crane
> Priority: Major
>
> The error message given when the name of the partition given matches a field
> in the dataset is a bit misleading - can we catch this earlier and give a
> different error message?
> {code:r}
> /library(dplyr)
> library(arrow)
> tf <- tempfile()
> dir.create(tf)
> write_dataset(mtcars, tf, partitioning = "cyl", hive_style = FALSE)
> # The schema fed into `partitioning` should refer to `cyl` and not `wt`, but
> the error message doesn't refer to the duplication here
> open_dataset(tf, partitioning = schema(wt = int64())) %>% collect()
> #> Error in `open_dataset()`:
> #> ! Invalid: Unable to merge: Field wt has incompatible types: double vs
> int64
> #> /home/nic2/arrow/cpp/src/arrow/type.cc:1692 fields_[i]->MergeWith(field)
> #> /home/nic2/arrow/cpp/src/arrow/type.cc:1755 AddField(field)
> #> /home/nic2/arrow/cpp/src/arrow/type.cc:1826 builder.AddSchema(schema)
> #> /home/nic2/arrow/cpp/src/arrow/dataset/discovery.cc:262
> Inspect(options.inspect_options)
> {code}
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