Tonya Mork 8aa625b795 Media: Fix TypeError and improve wp_exif_frac2dec() to only return int or float.
For certain images, `wp_exif_frac2dec()` unexpectedly returned a string instead of `int` or `float`. This can occur when an image is missing meta and calls the function with `'0/0'`. For those images, a fatal error was thrown on PHP 8.0+:

{{{
TypeError: round(): Argument #1 ($num) must be of type int|float, string given
}}}

Upon deeper review, inconsistent and unexpected results were returned from different types of input values passed to the function.

Changes are:

* Maintains backwards-compatibility for valid input values.
* Fixes handling of invalid input values by bailing out to return the documented type of `int|float` by returning `0`.
* Improves the fractional conditional check.
* Improves the calculated fraction handling to ensure (a) the numerator and denominator are both numeric and (b) the denominator is not equal to zero.
* Safeguards the behavior via tests for all possible ways code could flow through the function.
* Safeguards the backwards-compatibility of the `wp_read_image_metadata()` by adding some defensive coding around the calls to the `wp_exif_frac2dec()` function.

These changes fix the fatal error and make the function more secure, stable, and predictable while maintaining backwards-compatibility for valid input values.

Follow-up to [6313], [9119], [22319], [28367], [45611], [47287].

Props adamsilverstein, jrf, peterwilsoncc, praem90, stevegs, tobiasbg.
Fixes #54385.

git-svn-id: https://develop.svn.wordpress.org/trunk@52269 602fd350-edb4-49c9-b593-d223f7449a82
2021-11-29 19:34:51 +00:00
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