As initially proposed here in the "Trim a flag" rule action does not provide for permissions to be overridden when doing the trim. Since a trim is effectively a bulk unflag, it seems appropriate to support overrides as the unflag rule action does.
Provide this parameter as a checkbox in the rules configuration.
Patch rolling shortly, reviews needed
User interface changes
New checkbox for "Skip permission check" in the Trim a flag rule action configuration form.
The procedural function flag_trim_flag() now accepts $skip_permission_check as an optional argument, defaults to FALSE.
PASSED: [[SimpleTest]]: [MySQL] 266 pass(es). View