Warnings are not suppressed via @

[markhuot]

The Yii framework has a file cache driver that checks a file-based cache by calling @filemtime($cacheFile). That returns the modification date of the file, if it exists, or emits a warning (and returns false) if the cache file doesn't exist. The warning it emits is not suppressed by the @ operator so my tests are all littered with ! warning annotations. E.g.,

$./vendor/bin/pest tests/ActingAsTest.php -vvv --display-warnings

   WARN  Tests\ActingAsTest
  ! it logs in users by factory → filemtime(): stat failed for /Users/markhuot/Sites/craft-pest-core/storage/runtime/cache/8e/CraftCMS8e0694a5966c89b99615fb42a4a74296.bin 0.28s
  ✓ it logs in users by email address                                                                 0.01s
  ✓ it logs in user objects                                                                           0.01s
  ! it logs in admins via shorthand → filemtime(): stat failed for /Users/markhuot/Sites/craft-pest-core/storage/runtime/cache/ba/CraftCMSbasePath.bin 0.21s
  ✓ it throws on missing users
  ✓ it should not be logged in on subsequent tests
  ! it acts as a user on get requests → filemtime(): stat failed for /Users/markhuot/Sites/craft-pest-core/storage/runtime/cache/62/CraftCMS62f10a620b432ee970868362b84379c4.bin 0.02s
  ! it creates admin users → filemtime(): stat failed for /Users/markhuot/Sites/craft-pest-core/storage/runtime/cache/62/CraftCMS62f10a620b432ee970868362b84379c4.bin 0.03s
  ! it resets globals during twig parsing → filemtime(): stat failed for /Users/markhuot/Sites/craft-pest-core/storage/runtime/cache/90/CraftCMS90d3d81bc326013c006a844c726840fb.bin 0.02s

I've asked Yii about prepending the filemtime() check with a file_exists() check but there is atomicity concerns if the file exists during the file_exists() check but is deleted before the filemtime() check runs. So the request now bumps back over to Pest: should warnings be suppressed if errors are suppressed via the @ operator?