Nicola Crane created ARROW-18200:
------------------------------------
Summary: [R] Misleading error message if opening CSV dataset with
invalid file in directory
Key: ARROW-18200
URL: https://issues.apache.org/jira/browse/ARROW-18200
Project: Apache Arrow
Issue Type: Bug
Components: R
Reporter: Nicola Crane
I made a mistake before where I thought a dataset contained CSVs which were, in
fact, Parquet files, but the error message I got was super unhelpful
{code:r}
library(arrow)
download.file(
url =
"https://github.com/djnavarro/arrow-user2022/releases/download/v0.1/nyc-taxi-tiny.zip";,
destfile = here::here("data/nyc-taxi-tiny.zip")
)
# (unzip the zip file into the data directory but don't delete it after)
open_dataset("data", format = "csv")
{code}
{code:r}
Error in nchar(x) : invalid multibyte string, element 1
In addition: Warning message:
In grepl("No match for FieldRef.Name(__filename)", msg, fixed = TRUE) :
input string 1 is invalid in this locale
{code}
Note, this only occurs with {{format="csv"}} and omitting this argument (i.e.
the default of {{format="parquet"}} leaves us with the much better error:
{code:r}
Error in `open_dataset()`:
! Invalid: Error creating dataset. Could not read schema from
'/home/nic2/arrow_10_twitter/data/nyc-taxi-tiny.zip': Could not open Parquet
input source '/home/nic2/arrow_10_twitter/data/nyc-taxi-tiny.zip': Parquet
magic bytes not found in footer. Either the file is corrupted or this is not a
parquet file.
/home/nic2/arrow/cpp/src/arrow/dataset/file_parquet.cc:338 GetReader(source,
scan_options). Is this a 'parquet' file?
/home/nic2/arrow/cpp/src/arrow/dataset/discovery.cc:44
InspectSchemas(std::move(options))
/home/nic2/arrow/cpp/src/arrow/dataset/discovery.cc:265
Inspect(options.inspect_options)
ℹ Did you mean to specify a 'format' other than the default (parquet)?
{code}
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