From eee38b0c018b3279f77d03dff796f440f40d3516 Mon Sep 17 00:00:00 2001
From: Feng Xiao <xfxyjwf@gmail.com>
Date: Sat, 22 Aug 2015 18:25:48 -0700
Subject: Down-integrate from google3.

---
 src/google/protobuf/compiler/command_line_interface.cc | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'src/google/protobuf/compiler/command_line_interface.cc')

diff --git a/src/google/protobuf/compiler/command_line_interface.cc b/src/google/protobuf/compiler/command_line_interface.cc
index e8871861..26a4f0b0 100644
--- a/src/google/protobuf/compiler/command_line_interface.cc
+++ b/src/google/protobuf/compiler/command_line_interface.cc
@@ -70,6 +70,7 @@
 #include <google/protobuf/io/coded_stream.h>
 #include <google/protobuf/io/zero_copy_stream_impl.h>
 #include <google/protobuf/io/printer.h>
+#include <google/protobuf/stubs/logging.h>
 #include <google/protobuf/stubs/strutil.h>
 #include <google/protobuf/stubs/substitute.h>
 #include <google/protobuf/stubs/map_util.h>
@@ -1657,7 +1658,11 @@ bool CommandLineInterface::WriteDescriptorSet(
                                 &already_seen, file_set.mutable_file());
     }
   } else {
+    set<const FileDescriptor*> already_seen;
     for (int i = 0; i < parsed_files.size(); i++) {
+      if (!already_seen.insert(parsed_files[i]).second) {
+        continue;
+      }
       FileDescriptorProto* file_proto = file_set.add_file();
       parsed_files[i]->CopyTo(file_proto);
       if (source_info_in_descriptor_set_) {
-- 
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