diff --git a/src/google/protobuf/compiler/command_line_interface.cc b/src/google/protobuf/compiler/command_line_interface.cc
index b0b2963d2dcd..3705e369c623 100644
--- a/src/google/protobuf/compiler/command_line_interface.cc
+++ b/src/google/protobuf/compiler/command_line_interface.cc
@@ -586,10 +586,12 @@ bool CommandLineInterface::GeneratorContextImpl::WriteAllToZip(
 
   if (stream.GetErrno() != 0) {
     std::cerr << filename << ": " << strerror(stream.GetErrno()) << std::endl;
+    return false;
   }
 
   if (!stream.Close()) {
     std::cerr << filename << ": " << strerror(stream.GetErrno()) << std::endl;
+    return false;
   }
 
   return true;