Bug #22063: Regexp timeout accepts NaN and disables timeout

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 4.1.0dev (2026-05-11T07:56:09Z master d0ea61cb87) +PRISM [arm64-darwin25]
• Backport: 3.3: UNKNOWN, 3.4: UNKNOWN, 4.0: UNKNOWN

[afurm (Andrii Furmanets)]

Regexp.timeout= and Regexp.new(..., timeout:) currently accept Float::NAN.
The value passes the positive-timeout validation because NaN <= 0 is false, and
then double2hrtime stores it as a zero timeout value.

This makes both APIs behave as if no timeout was configured:

p Regexp.new("foo", timeout: Float::NAN).timeout
#=> nil

Regexp.timeout = Float::NAN
p Regexp.timeout
#=> nil

Float::NAN is not a valid positive timeout value, so I expect it to raise
ArgumentError, the same as 0 and negative values.

Reproduced on master:

ruby 4.1.0dev (2026-05-11T07:56:09Z master d0ea61cb87) +PRISM [arm64-darwin25]

Proposed fix:

Reject NaN in the shared regexp timeout validation helper before converting the
double to rb_hrtime_t.

Pull request: https://github.com/ruby/ruby/pull/16917

[hsbt (Hiroshi SHIBATA)]

FYI: I deleted duplicated issues like #22061 and 22062

[afurm (Andrii Furmanets)]

Thank you, I had some issues publishing so it might be that case.

[afurm (Andrii Furmanets)]

• Status changed from Open to Closed

Applied in changeset git|d7ef97204d907561eb67828382f7bb17397313c6.

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[Bug #22063] Reject NaN Regexp timeout values