Description:

Currently our tests are logging this error:

PHP Deprecated:  file_exists(): Passing null to parameter #1 ($filename) of type string is deprecated in /home/runner/work/matomo/matomo/matomo/core/ProxyHttp.php on line 71

This is caused by a test explicitly passing null to serverStaticFile.
Had a look through the code where the method serverStaticFile is being used and it seems like in rare conditions it could happen that false or null could be passed through, which the additional check should cover.

Review

• Functional review done
• Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• Security review done
• Wording review done
• Code review done
• Tests were added if useful/possible
• Reviewed for breaking changes
• Developer changelog updated if needed
• Documentation added if needed
• Existing documentation updated if needed