From 7afa8a5bd78a99e7750a74c60432a307b7cbd761 Mon Sep 17 00:00:00 2001
From: John McPherson <johnmcp@microsoft.com>
Date: Tue, 11 Aug 2020 12:52:46 -0700
Subject: [PATCH] Handle empty and flat out invalid files better

---
 src/AppInstallerCommonCore/Public/AppInstallerErrors.h | 1 +
 src/AppInstallerRepositoryCore/Manifest/YamlParser.cpp | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/src/AppInstallerCommonCore/Public/AppInstallerErrors.h b/src/AppInstallerCommonCore/Public/AppInstallerErrors.h
index 8e82b5b06e..a3542da57d 100644
--- a/src/AppInstallerCommonCore/Public/AppInstallerErrors.h
+++ b/src/AppInstallerCommonCore/Public/AppInstallerErrors.h
@@ -51,6 +51,7 @@
 #define APPINSTALLER_CLI_ERROR_LIBYAML_ERROR                    ((HRESULT)0x8A150027)
 #define APPINSTALLER_CLI_ERROR_MANIFEST_VALIDATION_WARNING      ((HRESULT)0x8A150028)
 #define APPINSTALLER_CLI_ERROR_MANIFEST_VALIDATION_FAILURE      ((HRESULT)0x8A150029)
+#define APPINSTALLER_CLI_ERROR_INVALID_MANIFEST                 ((HRESULT)0x8A15002A)
 
 namespace AppInstaller
 {
diff --git a/src/AppInstallerRepositoryCore/Manifest/YamlParser.cpp b/src/AppInstallerRepositoryCore/Manifest/YamlParser.cpp
index 9ff40524ba..30b5f806ca 100644
--- a/src/AppInstallerRepositoryCore/Manifest/YamlParser.cpp
+++ b/src/AppInstallerRepositoryCore/Manifest/YamlParser.cpp
@@ -196,6 +196,12 @@ namespace AppInstaller::Manifest
 
     std::vector<ValidationError> YamlParser::ParseManifest(const YAML::Node& rootNode, Manifest& manifest, bool fullValidation)
     {
+        // Detects empty files with a better error.
+        if (!rootNode.IsMap())
+        {
+            THROW_EXCEPTION_MSG(ManifestException(APPINSTALLER_CLI_ERROR_INVALID_MANIFEST), "The manifest does not contain a valid root.");
+        }
+
         // Detect manifest version first to determine expected fields
         // Use index to access ManifestVersion directly. If there're duplicates or other general errors, it'll be detected in later
         // processing of iterating the whole manifest.