It's not supposed to, but if you really want it.. why not?
Here is an idea, not a complete solution.
There are two useful lines in StyleCop.Targets
file. First one imports StyleCop task:
<UsingTask AssemblyFile=".\StyleCop.dll" TaskName="StyleCopTask"/>
and this one calls it:
<StyleCopTask
ProjectFullPath="$(MSBuildProjectDirectory)"
SourceFiles="@(StyleCopFiles)"
AdditionalAddinPaths="@(StyleCopAdditionalAddinPaths)"
ForceFullAnalysis="$(StyleCopForceFullAnalysis)"
DefineConstants="$(DefineConstants)"
TreatErrorsAsWarnings="$(StyleCopTreatErrorsAsWarnings)"
CacheResults="$(StyleCopCacheResults)"
OverrideSettingsFile="$(StyleCopOverrideSettingsFile)"
OutputFile="$(StyleCopOutputFile)"
MaxViolationCount="$(StyleCopMaxViolationCount)"
/>
So you basically need to call it twice, first one specifying TreatErrorsAsWarnings
as false
(so that it fails if there are any warnings), and second one with true
(resulting in just warning).
Also, you will need to use two separate settings file - first one with stylecop 'errors', second with 'warnings'.