The C++ wrapper defaults it to true, so the behaviour hasn't changed for
existing callers that don't pass a value for the evaluateConditions
parameter, i.e. that call GetGeneralMessages().
Since the new parameter comes before evaluateConditions,
existing GetGeneralMessages(true) and GetGeneralMessages(false) calls
need to be replaced with GetGeneralMessages(true, true) and
GetGeneralMessages(true, false) to retain their existing behaviour. The
parameter order was chosen to match that of GetPluginMetadata(), at the
cost of this backwards incompatibility.
Replace the boolean parameters for including user metadata and evaluating conditions with MergeMode and EvalMode enums.
The C++ and Python wrappers still use booleans because they're more constrained than enums in those languages, which can be given invalid values.
Oliver Hamlet