From: "jeremyevans0 (Jeremy Evans)" <noreply@...>
Date: 2022-06-09T15:20:40+00:00
Subject: [ruby-core:108837] [Ruby master Bug#18768] Inconsistent behavior of IO, StringIO and String each_line methods when return paragraph and chomp: true passed

Issue #18768 has been updated by jeremyevans0 (Jeremy Evans).


mame (Yusuke Endoh) wrote in #note-6:
> I have no strong opinion about this issue and am never against Jeremy's change, but I'm just curious. I thought that `each_line(..., chomp: true) {|s| ... }` was equal to `each_line(...) {|s| s = s.chomp; ... }`. In the above examples, StringIO's result (`["a\n", "b\n", "c"]`) was the simplest to me. @jeremyevans0 How did you think the IO behavior made the most sense?

My thought here is that `chomp: true`, does not mean `chomp` with no arguments, it means `chomp` with the separator used for the `each_line`.  So when you call each_line with `''` (paragraph separator), it only chomps the paragraph separator.  That's what the IO behavior already was, and I thought it best to make String/StringIO consistent with that.

----------------------------------------
Bug #18768: Inconsistent behavior of IO, StringIO and String each_line methods when return paragraph and chomp: true passed
https://bugs.ruby-lang.org/issues/18768#change-97913

* Author: andrykonchin (Andrew Konchin)
* Status: Open
* Priority: Normal
* ruby -v: 3.0.3
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
In IO, StringIO and String methods that return lines (e.g. `each`, `each_line`, `gets`, `readline`, `readlines`) behave in a different way when the following parameters are passed
- separator is `""` and
- `chomp` is `true`.

They truncate the new line characters between paragraphs and the trailing one differently:

```ruby
"a\n\nb\n\nc\n".each_line("", chomp: true).to_a
#=> ["a\n", "b\n", "c\n"]

StringIO.new("a\n\nb\n\nc\n").each_line("", chomp: true).to_a
#=> ["a\n", "b\n", "c"]

File.open('chomp.txt').each_line("", chomp: true).to_a
#=> ["a", "b", "c\n"]
```

The text file content is the same:

```ruby
File.read('chomp.txt')
#=> "a\n\nb\n\nc\n"
```

Expected behavior - they return the same result.



-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request@ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>