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https://issues.apache.org/jira/browse/GROOVY-9981?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Paul King updated GROOVY-9981:
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Component/s: (was: Groovysh)
> CLONE - println(-0.0f) does not comply with IEEE754
> ---------------------------------------------------
>
> Key: GROOVY-9981
> URL: https://issues.apache.org/jira/browse/GROOVY-9981
> Project: Groovy
> Issue Type: Bug
> Affects Versions: 2.5.7, 2.4.17, 2.5.13, 3.0.6
> Environment: Linux
> Reporter: Jubilee
> Assignee: Paul King
> Priority: Minor
> Labels: double, float
> Fix For: 4.0.0-alpha-3
>
> Original Estimate: 24h
> Remaining Estimate: 24h
>
> In GROOVY-9797 we fixed a bug where Groovy wasn't correctly writing the -0.0f
> constant when writing bytecode (symptoms as per quoted text). This issue is
> to fix documentation and provide helper methods for anyone relying on the
> previous behavior.
> {quote}
> IEEE754-2019 (which supersedes all previous floating point standards for
> decimal or binary floating point) states that an implementation *shall* (that
> means "is required to") preserve the sign on floating point numbers when it
> converts numbers to an "external decimal character sequence" (that means
> "prints them the way everyone does, unless you use special formatting
> characters I guess"), singling out the two zeros and the two infinities in
> particular for this treatment.
> IEEE754-2019 does not say this for no reason. It's because conformant
> floating point implementations can print the float out and then later read it
> back into its original floating point bit-pattern. A close reading of
> IEEE754-1985 suggests this was always the intention, but this requirement was
> made unambiguously explicit for signed zeros as early as IEEE854-1987.
> On all the versions of Apache Groovy's REPL that I was able to trivially
> easily test, println(-0.0f) does not output "-0.0", but outputs "0.0"
> instead. While I am aware that printf is also available in Groovy and can
> allow one to select formatting, this should probably be considered a bug,
> especially given that println in Java (OpenJDK 14) outputs "-0.0" and so do
> Kotlin, Scala, and Clojure with their relevant commands.
> This bug suggests there are other errors relevant to IEEE754 compliance in
> relevant formatting and parsing code, so it is a good idea to do a more
> thorough audit as well.
> {quote}
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