ACR Rules

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  5. Check for empty string should be done properly

Check for empty string should be done properly

Introduced in version: 1.3 (29 Jan 2020)

‘This is very likely a bug and should be changed. There are only two correct ways to check for empty string

Noncompliant example:

  • $Str = empty and trim($Str) != '' – equal used instead of not equal or other way around
  • $Str = empty and trim($Str) = ''and is used instead of or or other way around
  • trim($Str) != ''and $Str != empty – the order of expression is reversed resulting in a null pointer exception

Compliant example:

Only two ways how to correctly check for empty string

  • if $Str != empty and trim($Str) != '' then $Str else 'empty'
  • if $Str = empty or trim($Str) = '' then 'empty' else $Str