ABIChecker: add an internal setting for downgrading ABI breakages to warnings

Author: nkcsgexi

include/swift/APIDigester/ModuleDiagsConsumer.h

@@ -46,12 +46,15 @@ class FilteringDiagnosticConsumer: public DiagnosticConsumer {
   bool HasError = false;
   std::vector<std::unique_ptr<DiagnosticConsumer>> subConsumers;
   std::unique_ptr<llvm::StringSet<>> allowedBreakages;
+  bool DowngradeToWarning;
   bool shouldProceed(const DiagnosticInfo &Info);
 public:
   FilteringDiagnosticConsumer(std::vector<std::unique_ptr<DiagnosticConsumer>> subConsumers,
-                              std::unique_ptr<llvm::StringSet<>> allowedBreakages):
+                              std::unique_ptr<llvm::StringSet<>> allowedBreakages,
+                              bool DowngradeToWarning):
     subConsumers(std::move(subConsumers)),
-    allowedBreakages(std::move(allowedBreakages)) {}
+    allowedBreakages(std::move(allowedBreakages)),
+    DowngradeToWarning(DowngradeToWarning) {}
   ~FilteringDiagnosticConsumer() = default;
 
   void flush() override;

lib/APIDigester/ModuleDiagsConsumer.cpp

@@ -159,8 +159,12 @@ bool swift::ide::api::FilteringDiagnosticConsumer::shouldProceed(const Diagnosti
 
 void swift::ide::api::
 FilteringDiagnosticConsumer::handleDiagnostic(SourceManager &SM,
-                                              const DiagnosticInfo &Info) {
-  if (shouldProceed(Info)) {
+                                              const DiagnosticInfo &RawInfo) {
+  if (shouldProceed(RawInfo)) {
+    DiagnosticInfo Info = RawInfo;
+    if (DowngradeToWarning && Info.Kind == DiagnosticKind::Error) {
+      Info.Kind = DiagnosticKind::Warning;
+    }
     if (Info.Kind == DiagnosticKind::Error) {
       HasError = true;
     }

lib/DriverTool/swift_api_digester_main.cpp

@@ -1932,7 +1932,8 @@ static int diagnoseModuleChange(SDKContext &Ctx, SDKNodeRoot *LeftModule,
   auto pConsumer = std::make_unique<FilteringDiagnosticConsumer>(
       createDiagConsumer(*OS, FailOnError, DisableFailOnError, CompilerStyleDiags,
                          SerializedDiagPath),
-      std::move(allowedBreakages));
+      std::move(allowedBreakages),
+      /*DowngradeToWarning*/false);
   SWIFT_DEFER { pConsumer->finishProcessing(); };
   Ctx.addDiagConsumer(*pConsumer);
   Ctx.setCommonVersion(std::min(LeftModule->getJsonFormatVersion(),