fread from v.1.11.0+ no longer reads the .csv correctly, which was read perfectly in v.1.10.4-3

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
25/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Stale
Tech stack
r

Research direction

Start with the linked verbose output and sessionInfo(), then compare fread() behavior between data.table v1.10.4-3 and v1.11.0+ using a small representative CSV derived from the reported file. Done means isolating a reproducible failure and documenting a verified resolution for the mid-file termination.

Written by the indexing model from the issue text.

Description

fread regression

I've encountered a possible bug in the newer versions of data.table. I have a 2GB .csv file with c. 3 million rows and 67 columns. I can use fread() to read it all fine from data.table v.1.10.4-3, but v.1.11.0+ terminates at a row somewhere in the middle.

The base read.csv() also hits the same problem, while fread() from v.1.10.4-3 worked perfectly.

I really like data.table and want to help troubleshoot this, but obviously I can't upload the 2GB data file anywhere as it is too big and private.

I can upload a few rows though, but I don't know a way of splicing the .csv without reading it into R. I am keen to get any help though in order to create a reproducible example.

The verbose output is here.

The sessionInfo() is here.

Dominant language
R
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