Patch bug 27628 (clang-tidy should exit with a failure code when there are errors)

[antoyo]

Summary

Update clang-tidy to return 1 when there's an error.

[alexfh]

Looks good! Thank you!

[alexfh]

This patch breaks a number of tests. Please run the tests and fix the failures.

[alexfh]

clang-tidy/tool/ClangTidyMain.cpp

452

Failed tests reminded me of the -fix-errors flag.

I suppose, clang-tidy should not return an error code, when all errors it noticed, contained fixes that were successfully applied by -fix-errors.

clang-tidy/tool/ClangTidyMain.cpp

if (WErrorCount) {
     if (!Quiet) {
       StringRef Plural = WErrorCount == 1 ? "" : "s";
       llvm::errs() << WErrorCount << " warning" << Plural << " treated as error"
                    << Plural << "\n";
     }
     return WErrorCount;
   }
 
+  if (FoundErrors) {
+      return 1;
+  }
+
   return 0;
 }
 
 // This anchor is used to force the linker to link the CERTModule.
 extern volatile int CERTModuleAnchorSource;
 static int LLVM_ATTRIBUTE_UNUSED CERTModuleAnchorDestination =
     CERTModuleAnchorSource;