Added extension to size calculation (per code review).

src/AppInstallerCLICore/Workflows/DownloadFlow.cpp

@@ -63,10 +63,11 @@ namespace AppInstaller::CLI::Workflow
         {
             // Get file name from download URI
             std::filesystem::path filename = GetFileNameFromURI(context.Get<Execution::Data::Installer>()->Url);
+            std::wstring_view installerExtension = GetInstallerFileExtension(context);
 
             // Assuming that we find a safe stem value in the URI, use it.
             // This should be extremely common, but just in case fall back to the older name style.
-            if (filename.has_stem() && filename.string().size() < MAX_PATH)
+            if (filename.has_stem() && ((filename.string().size() + installerExtension.size()) < MAX_PATH))
             {
                 filename = filename.stem();
             }
@@ -76,7 +77,7 @@ namespace AppInstaller::CLI::Workflow
                 filename = Utility::ConvertToUTF16(manifest.Id + '.' + manifest.Version);
             }
 
-            filename += GetInstallerFileExtension(context);
+            filename += installerExtension;
 
             return filename;
         }