Bug #10364: Malformed CSV Header Causes NoMethodError

• Status: Rejected
• Assignee: kou (Kouhei Sutou)
• Target version: -
• ruby -v: ruby 2.1.3p242 (2014-09-19 revision 47630) [x86_64-darwin13.0]
• Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN

[jisraelson (Jon Israelson)]

The method CSV#readline raises a "NoMethodError: undefined method 'encode' for nil:NilClass" exception when the CSV file's header row contains a trailing delimiter (a comma in my case). The following CSV data can be used to recreate this error:

col1,col2,
1,2
3,4

The resulting stack trace:

csv.rb:993:in `block in <class:CSV>'
csv.rb:2175:in `[]'
csv.rb:2175:in `block (2 levels) in convert_fields'
csv.rb:2173:in `each'
csv.rb:2173:in `block in convert_fields'
csv.rb:2172:in `map'
csv.rb:2172:in `with_index'
csv.rb:2172:in `convert_fields'
csv.rb:2213:in `parse_headers'
csv.rb:1887:in `block in shift'
csv.rb:1779:in `loop'
csv.rb:1779:in `shift'

Assuming that the header row is considered malformed (IMHO it is), it seems that it would be better to raise a CSV::MalformedCSVError exception, which can be more easily handled.

[hsbt (Hiroshi SHIBATA)]

• Status changed from Open to Assigned
• Assignee set to JEG2 (James Gray)

[jrodrigosm (Rodrigo Serrano)]

This issue is also present in ruby 2.1.5p273 (2014-11-13 revision 48405) [x86_64-linux]

[mame (Yusuke Endoh)]

• Assignee changed from JEG2 (James Gray) to kou (Kouhei Sutou)

@kou (Kouhei Sutou), could you check this ticket?

[kou (Kouhei Sutou)]

• Status changed from Assigned to Rejected

It seems that this has been fixed in master.
If someone knows a script that reproduces this case, you can attach the script and reopen this.