can't modify frozen String (FrozenError) in open_office.rb

[rknmag]

Steps to reproduce

require 'roo'
require 'rspreadsheet'

fname = 'test_apos.ods'
wb = Rspreadsheet.new
sheet = wb.create_worksheet('Sheet1')
sheet[1,1] = '' ### Note : The cell contain empty string
wb.save(fname)

wb = Roo::Spreadsheet.open(fname)
pp wb.last_row
wb.close()

Issue

I write ods file using rspreadsheet gem. When I read back the file using roo, If any cell value contain empty string , then I get following error
..gems/roo-2.8.2/lib/roo/open_office.rb|520| in `gsub!': can't modify frozen String (FrozenError)

System configuration

Roo version: 2.8.2

Ruby version:2.6.1

[rubycoder]

I'm not using the rspreadsheet gem, but I'm seeing exactly the same error with Ruby 2.7.2 and roo 2.8.3, 2.8.2, 2.8.1, and 2.8.0 when reading a .csv file.
However, it works with roo 2.7.1. I'm not using any of the roo 2.8.x features, so 2.7.1 is fine for me, at least for now.

[vanboom]

This is caused by the "frozen_string_literal: true" directive at the top of lib/roo/open_office.rb.

The logic in this file is not compatible with "frozen_string_literal: true" directive so it should be removed.

e.g.

str_v = ''   # <--- line 480
str_v.gsub!(/&apos;/, "'") # special case not supported by unescapeHTML, <--- line 518

This is not possible when treating all string literals as frozen.

[vanboom]

Is this gem still maintained? Please consider my PR to resolve this issue.

[patrickkulling]

@rknmag I know this issue is old, but can you provide a .ods file in order to reproduce the issue? I can't use the rspreadsheet gem since it's not working properly on mac anymore.

[patrickkulling]

@vanboom
alternatively, your PR is doing two things.
Can you create a separate PR including a test to reproduce the issue and/or validate the fix?

I 100% agree it's the frozen string literal and the fix is trivial, but it would be good to get the test coverage up so that this problem doesn't happen again.

[rknmag]

test_apos.ods
I have re-run the program and attached the file. Hope it helps

[patrickkulling]

Thanks for the file @rknmag
Can you still reproduce this with roo 2.9.0?

I was trying with ruby 2.7.0 & 3.1.2 and did no longer run into that issue

[rknmag]

Recent past I have not updated my Ruby, but I have Ruby 3.0 with roo 2.9.0. I ran the same program again and got the following trace back. I am not sure whether I have to update any other gem(s)

.rvm/gems/ruby-3.0.0@sprsheet/gems/roo-2.9.0/lib/roo/open_office.rb:520:in gsub!': can't modify frozen String: "" (FrozenError) from .rvm/gems/ruby-3.0.0@sprsheet/gems/roo-2.9.0/lib/roo/open_office.rb:520:in block (4 levels) in read_cells'
from .rvm/gems/ruby-3.0.0@sprsheet/gems/nokogiri-1.13.3-x86_64-linux/lib/nokogiri/xml/node_set.rb:233:in block in each' from .rvm/gems/ruby-3.0.0@sprsheet/gems/nokogiri-1.13.3-x86_64-linux/lib/nokogiri/xml/node_set.rb:232:in upto'
from .rvm/gems/ruby-3.0.0@sprsheet/gems/nokogiri-1.13.3-x86_64-linux/lib/nokogiri/xml/node_set.rb:232:in each' from .rvm/gems/ruby-3.0.0@sprsheet/gems/roo-2.9.0/lib/roo/open_office.rb:485:in block (3 levels) in read_cells'
from .rvm/gems/ruby-3.0.0@sprsheet/gems/nokogiri-1.13.3-x86_64-linux/lib/nokogiri/xml/node_set.rb:233:in block in each' from .rvm/gems/ruby-3.0.0@sprsheet/gems/nokogiri-1.13.3-x86_64-linux/lib/nokogiri/xml/node_set.rb:232:in upto'
from .rvm/gems/ruby-3.0.0@sprsheet/gems/nokogiri-1.13.3-x86_64-linux/lib/nokogiri/xml/node_set.rb:232:in each' from .rvm/gems/ruby-3.0.0@sprsheet/gems/roo-2.9.0/lib/roo/open_office.rb:474:in block (2 levels) in read_cells'
from .rvm/gems/ruby-3.0.0@sprsheet/gems/nokogiri-1.13.3-x86_64-linux/lib/nokogiri/xml/node_set.rb:233:in block in each' from .rvm/gems/ruby-3.0.0@sprsheet/gems/nokogiri-1.13.3-x86_64-linux/lib/nokogiri/xml/node_set.rb:232:in upto'
from .rvm/gems/ruby-3.0.0@sprsheet/gems/nokogiri-1.13.3-x86_64-linux/lib/nokogiri/xml/node_set.rb:232:in each' from .rvm/gems/ruby-3.0.0@sprsheet/gems/roo-2.9.0/lib/roo/open_office.rb:465:in block in read_cells'
from .rvm/gems/ruby-3.0.0@sprsheet/gems/nokogiri-1.13.3-x86_64-linux/lib/nokogiri/xml/node_set.rb:233:in block in each' from .rvm/gems/ruby-3.0.0@sprsheet/gems/nokogiri-1.13.3-x86_64-linux/lib/nokogiri/xml/node_set.rb:232:in upto'
from .rvm/gems/ruby-3.0.0@sprsheet/gems/nokogiri-1.13.3-x86_64-linux/lib/nokogiri/xml/node_set.rb:232:in each' from .rvm/gems/ruby-3.0.0@sprsheet/gems/roo-2.9.0/lib/roo/open_office.rb:459:in read_cells'
from .rvm/gems/ruby-3.0.0@sprsheet/gems/roo-2.9.0/lib/roo/base.rb:119:in block (2 levels) in <class:Base>' from test_roo_apos.rb:11:in

'

[patrickkulling]

@rknmag Would you feel comfortable creating a unit test for it and open up a Pull Request with the fix (basically removing the frozen string literal comment from that file).

I would be happy to review it and merge it back

[patrickkulling]

@rknmag I was able to reproduce the issue and submitted a fix. I have decided to keep the frozen string literal due to it's performance optimisation potential but simply fixed the gsub! API