Support for ALTREP [deferred_string] function

Question

Support for ALTREP [deferred_string] function

ofajardo opened this issue 5 years ago · 7 comments

I have here an apparently inoffensive rds file with one single character vector of two elements, each with the value "14901". When trying to read it "Unable to read from file" error arises. I don't see anything special on it. The file was saved using R 3.6.1.

File attached

Thanks for the help!
RR2.zip

Answer 1 · 2020-04-30T11:47:49.000Z

Thanks for the report. It looks like some new internal attributes were added to the R format in version 3. I'll work on it.

Answer 2 · 2020-04-30T13:02:51.000Z

This file appears to use an ALTREP structure - still trying to understand it. Can you please provide the EXACT steps used to create this file?

Answer 3 · 2020-04-30T13:08:04.000Z

@pedrohcrocha could you please explain the steps to reproduce this file?

Answer 4 · 2020-09-11T03:45:58.000Z

This file uses the deferred_string function, which stores strings in the file as double-precision numbers (!). Now that I have started to crack the ALTREP structure I should have a fix soon.

Answer 5 · 2020-09-11T12:31:28.000Z

Try 49200c1

Answer 6 · 2020-09-11T13:15:04.000Z

looks good! thanks!

Answer 7 · 2020-09-11T13:43:13.000Z

Okay great. I expect there to be similar errors in the future, so don't hesitate to open new bug reports.

I have added debugging information, so if you have an error handler set up, it will now report the name of the unrecognized class (function) in an ALTREP structure.