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PHP RFC: Prevent number_format() from returning negative zero
- Version: 0.1
- Date: 2017-04-01
- Author: Craig Duncan php@duncanc.co.uk
- Proposed version: PHP 7.2
- Status: Draft
Introduction
Calling number_format(-0.00)
returns string(1) “0”
, however calling number_format(-0.01)
returns string(2) “-0”
.
As number_format()
is commonly used for formatting numbers for human-readable display, this behaviour is unexpected.
Proposal
This RFC proposes keeping number_format()
consistent and not displaying the sign when a number is rounded to zero.
Concerns
There was an argument that all floating point logic in PHP follows IEEE 754, where negative zero is valid.
However number_format()
already prevents negative zero, so this isn't the case.
Backward Incompatible Changes
This change has BC concerns for anybody relying on the current behaviour, but this is thought to be incredibly minor and not unrealistic for a point release.
Proposed PHP Version(s)
PHP 7.2
Proposed Voting Choices
Simple Yes/No vote that doesn't change the language itself so requires 50% + 1 votes to get 'accepted'.
Implementation
Code change: https://github.com/duncan3dc/php-src/commit/cfebe4dd952e8487de613d6a96df94152248ffed
New Test: https://github.com/duncan3dc/php-src/commit/8c323b887fb6b4a6cb2cd1819d333d9ca417b8b2
References
Initial discussion that led to this RFC's creation: https://externals.io/thread/522