[ARROW-13887] [R] Capture error produced when reading in CSV file with headers and using a schema, and add suggestion

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 7.0.0
• Component/s: R
• Labels: good-first-issue pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/29503
• Assignee: Dragoș Moldovan-Grünfeld
• Reporter: Nicola Crane
• Created: 03/Sep/21 10:49
• Updated: 11/Jan/23 08:36
• Resolved: 01/Nov/21 20:42

Description

When reading in a CSV with headers, and also using a schema, we get an error as the code tries to read in the header as a line of data.

share_data <- tibble::tibble(
  company = c("AMZN", "GOOG", "BKNG", "TSLA"),
  price = c(3463.12, 2884.38, 2300.46, 732.39)
)

readr::write_csv(share_data, file = "share_data.csv")

share_schema <- schema(
  company = utf8(),
  price = float64()
)

read_csv_arrow("share_data.csv", schema = share_schema)

Error: Invalid: In CSV column #1: CSV conversion error to double: invalid value 'price'
/home/nic2/arrow/cpp/src/arrow/csv/converter.cc:492 decoder_.Decode(data, size, quoted, &value)
/home/nic2/arrow/cpp/src/arrow/csv/parser.h:84 status
/home/nic2/arrow/cpp/src/arrow/csv/converter.cc:496 parser.VisitColumn(col_index, visit) 

The correct thing here would have been for the user to supply the argument skip=1 to read_csv_arrow() but this is not immediately obvious from the error message returned from C++.  We should capture the error and instead supply our own error message using rlang::abort which informs the user of the error and then suggests what they can do to prevent it.

 

For similar examples (and their associated PRs) see ARROW-11766, and ARROW-12791

Issue Links

• links to: GitHub Pull Request #11432