Fix crash caused by ResponseJson::MarkCompleted() failing to set application_data_ if parsing the JSON body fails (#692)

Author: dconeybe

app/rest/response_json.h

@@ -22,6 +22,7 @@
 
 #include "app/rest/response.h"
 #include "app/src/assert.h"
+#include "app/src/log.h"
 #include "flatbuffers/idl.h"
 #include "flatbuffers/stl_emulation.h"
 
@@ -74,12 +75,24 @@ class ResponseJson : public Response {
     // Parse and verify JSON string in body. FlatBuffer parser does not support
     // online parsing. So we only parse the body when we get everything.
     bool parse_status = parser_->Parse(GetBody());
-    FIREBASE_ASSERT_RETURN_VOID(parse_status);
+    if (!parse_status) {
+      LogError("flatbuffers::Parser::Parse() failed: %s",
+               parser_->error_.c_str());
+      application_data_.reset(new FbsTypeT());
+      Response::MarkCompleted();
+      return;
+    }
+
     const flatbuffers::FlatBufferBuilder& builder = parser_->builder_;
     flatbuffers::Verifier verifier(builder.GetBufferPointer(),
                                    builder.GetSize());
     bool verify_status = verifier.VerifyBuffer<FbsType>(nullptr);
-    FIREBASE_ASSERT_RETURN_VOID(verify_status);
+    if (!verify_status) {
+      LogError("flatbuffers::Verifier::VerifyBuffer() failed");
+      application_data_.reset(new FbsTypeT());
+      Response::MarkCompleted();
+      return;
+    }
 
     // UnPack application data object from FlatBuffer.
     const FbsType* body_fbs =

release_build_files/readme.md

@@ -576,6 +576,9 @@ code.
     -   Messaging (Android): Fixes an issue to receive token when
         initialize the app. 
         ([#667](https://github.com/firebase/firebase-cpp-sdk/pull/667)).
+    -   Auth (Desktop): Fix a crash that would occur if parsing the JSON
+        response from the server failed
+        ([#692](https://github.com/firebase/firebase-cpp-sdk/pull/692)).
 
 ### 8.5.0
 -   Changes