Bug #17467: What makes strip() and lstrip() not stripping \u0000 from beginning of the string?

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [x86_64-linux]
• Backport: 2.6: UNKNOWN, 2.7: REQUIRED, 3.0: DONE

[SouravGoswami (Sourav Goswami)]

Both strip(), and rstrip() will delete \u0000 from the end of a string. But I have a string that has "\u0000hello\u0000".

Output from strip, lstrip and rstrip:

"\u0000hello\u0000".strip # => "\u0000hello"
"\u0000hello\u0000".lstrip # => "\u0000hello\u0000"
"\u0000hello\u0000".rstrip # => "\u0000hello"

Same goes for \x00 as well.

While it's quite ridiculous to have NULL at the beginning of the string, but what makes it not strip? Is that slow or is that because it's never used?

[SouravGoswami (Sourav Goswami)]

• Subject changed from What makes strip() and lstrip() not stripping \u0000? to What makes strip() and lstrip() not stripping \u0000 from beginning of the string?

[jeremyevans0 (Jeremy Evans)]

I agree that this is a bug. The documentation for strip and lstrip specifies that the whitespace should be stripped, and defines whitespace to include null. I have submitted a pull request to fix it: https://github.com/ruby/ruby/pull/4164

• Status changed from Open to Closed

Applied in changeset git|cfd162d535c7a4f8b1f95255cc6be696a8b75557.

---

Make String#{strip,lstrip}{,!} strip leading NUL bytes

The documentation already specifies that they strip whitespace
and defines whitespace to include null.

This wraps the new behavior in the appropriate guards in the specs,
but does not specify behavior for previous versions, because this
is a bug that could be backported.

Fixes [Bug #17467]

[znz (Kazuhiro NISHIYAMA)]

Japanese reference manual mentions treatment "\0".
(for example: https://docs.ruby-lang.org/ja/latest/method/String/i/strip.html )

If this will backport to released versions, it affects version branching in Japanese reference manual.

Which versions will have backports?

I have no opinion to backport or not.
I only want to know how to mention changed version in Japanese reference manual.

[byroot (Jean Boussier)]

I believe this fix should be backported.

[jeremyevans0 (Jeremy Evans)]

• Backport changed from 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN to 2.6: UNKNOWN, 2.7: REQUIRED, 3.0: REQUIRED

@byroot (Jean Boussier) I marked this for backporting. Here's the guide for how to do that: https://bugs.ruby-lang.org/projects/ruby/wiki/HowToRequestBackport

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.6: UNKNOWN, 2.7: REQUIRED, 3.0: REQUIRED to 2.6: UNKNOWN, 2.7: REQUIRED, 3.0: DONE

ruby_3_0 5af5ea7f860ed64062796e54e73274e7a56c7280 merged revision(s) cfd162d535c7a4f8b1f95255cc6be696a8b75557.