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Bug #17405

closed

irb ---nomultiline gets exception when output contains some non-ascii characters

Added by rsharman (Richard Sharman) over 1 year ago. Updated over 1 year ago.

Status:
Closed
Priority:
Normal
Target version:
-
ruby -v:
ruby 3.0.0dev (2020-12-21T02:23:01Z master ac78d90d5e) [x86_64-darwin18]
[ruby-core:101513]

Description

When irb is called with the --nomultiline option (for example, when called from emacs), then if the output contains some special characters (such as the square root sign, or a single quotation mark), then irb gets an exception.

Without the --multiline option the problem does not happen.

Here is an example with a string assignment to variable m.

Without fix: Without --nomultiline there is no problem:

henry:tmp richard$ irb
irb(main):001:0> source 'test.rb'
test.rb(main):002:0> # coding: utf-8
=> nil
test.rb(main):003:0> m = "√10"
=> "√10"
test.rb(main):004:0> m
=> "√10"
=> nil

But with --nomultiline irb gets an exception (but the assignment did work):

henry:tmp richard$ irb --nomultiline
irb(main):001:0> source 'test.rb'
test.rb(main):002:0> # coding: utf-8
=> nil
test.rb(main):003:0> m = "√10"
Traceback (most recent call last):
8: from /Users/richard/.rbenv/versions/2.7.2/bin/irb:23:in <main>' 7: from /Users/richard/.rbenv/versions/2.7.2/bin/irb:23:in load'
6: from /Users/richard/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/irb-1.2.6/exe/irb:11:in <top (required)>' 5: from (irb):1 4: from /Users/richard/.rbenv/versions/2.7.2/lib/ruby/2.7.0/reline/unicode.rb:99:in calculate_width'
3: from /Users/richard/.rbenv/versions/2.7.2/lib/ruby/2.7.0/reline/unicode.rb:99:in scan' 2: from /Users/richard/.rbenv/versions/2.7.2/lib/ruby/2.7.0/reline/unicode.rb:108:in block in calculate_width'
1: from /Users/richard/.rbenv/versions/2.7.2/lib/ruby/2.7.0/reline/unicode.rb:108:in `+'
TypeError (nil can't be coerced into Integer)
test.rb(main):004:0> m
=> "√10"
=> nil

The problem is that in method get_mbchar_width of class Reline::Unicode Reline.ambiguous_width can have a nil value, whereas the code seems to expect a low integer (unicode.rb line 84). This causes method calculate_width to add a nil value to width (line 109).

I don’t know what value Reline.ambiguous_width should be in these cases; the simple change below uses a value of 1 to avoid the exception:

bash-5.1$ diff unicode.rb{.orig,}
84c84,85
<       Reline.ambiguous_width
---
>       width = Reline.ambiguous_width
>       width.nil? ? 1 : width  # if nil then assume 1
bash-5.1$

With above fix:

henry:tmp richard$ irb --nomultiline
irb(main):001:0> source 'test.rb'
test.rb(main):002:0> # coding: utf-8
=> nil
test.rb(main):003:0> m = "√10"
=> "√10"
test.rb(main):004:0> m
=> "√10"
=> nil
henry:tmp richard$


Files

test.rb (30 Bytes) test.rb Test file -- source this in irb rsharman (Richard Sharman), 12/18/2020 05:49 PM
Patch (456 Bytes) Patch Suggested patch (unified diff format) rsharman (Richard Sharman), 12/18/2020 05:49 PM
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