[rfile] Throw exception for .zip files

Author: silverweed

io/io/src/RFile.cxx

@@ -30,13 +30,17 @@ using ROOT::Experimental::Internal::RFileLog;
 
 static void CheckExtension(std::string_view path)
 {
-   if (ROOT::EndsWith(path, ".xml")) {
+   // Throw an exception for all non-ROOT extensions that are supported by TFile.
+   // We don't want to "accidentally" support them as this would require us to keep supporting them
+   // "forever" and that would bite us back if we at some point change the implementation to not rely on TFile anymore.
+   if (ROOT::EndsWith(path, ".xml"))
       throw ROOT::RException(R__FAIL("ROOT::RFile doesn't support XML files."));
-   }
 
-   if (!ROOT::EndsWith(path, ".root")) {
+   if (ROOT::EndsWith(path, ".zip"))
+      throw ROOT::RException(R__FAIL("ROOT::RFile doesn't support Zip files."));
+
+   if (!ROOT::EndsWith(path, ".root"))
       R__LOG_INFO(RFileLog()) << "ROOT::RFile only supports ROOT files. The preferred file extension is \".root\"";
-   }
 }
 
 namespace {