diff --git a/Makefile.am b/Makefile.am
index 564bff48a9..d0f033af79 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -656,6 +656,7 @@ php_EXTRA_DIST=                                                       \
   php/tests/map_field_test.php                                        \
   php/tests/memory_leak_test.php                                      \
   php/tests/php_implementation_test.php                               \
+  php/tests/proto/test_import_descriptor_proto.proto                  \
   php/tests/proto/test_include.proto                                  \
   php/tests/proto/test.proto                                          \
   php/tests/proto/test_prefix.proto                                   \
diff --git a/php/src/Google/Protobuf/Internal/MapField.php b/php/src/Google/Protobuf/Internal/MapField.php
index f65bd9b864..55cc12ce85 100644
--- a/php/src/Google/Protobuf/Internal/MapField.php
+++ b/php/src/Google/Protobuf/Internal/MapField.php
@@ -155,7 +155,6 @@ function checkKey($key_type, &$key)
             GPBUtil::checkString($key, true);
             break;
         default:
-            var_dump($key_type);
             trigger_error(
                 "Given type cannot be map key.",
                 E_USER_ERROR);
diff --git a/php/src/Google/Protobuf/Internal/Message.php b/php/src/Google/Protobuf/Internal/Message.php
index 0fb6cdc006..887c86ca6e 100644
--- a/php/src/Google/Protobuf/Internal/Message.php
+++ b/php/src/Google/Protobuf/Internal/Message.php
@@ -71,7 +71,6 @@ class Message
             return;
         }
         $pool = DescriptorPool::getGeneratedPool();
-        var_dump(get_class($this));
         $this->desc = $pool->getDescriptorByClassName(get_class($this));
         foreach ($this->desc->getField() as $field) {
             $setter = $field->getSetter();
diff --git a/php/tests/gdb_test.sh b/php/tests/gdb_test.sh
index 484e2edfbb..0809bef3b9 100755
--- a/php/tests/gdb_test.sh
+++ b/php/tests/gdb_test.sh
@@ -3,7 +3,7 @@
 # gdb --args php -dextension=../ext/google/protobuf/modules/protobuf.so `which
 # phpunit` --bootstrap autoload.php tmp_test.php
 #
-gdb --args php -dextension=../ext/google/protobuf/modules/protobuf.so `which phpunit` --bootstrap autoload.php encode_decode_test.php
+gdb --args php -dextension=../ext/google/protobuf/modules/protobuf.so `which phpunit` --bootstrap autoload.php well_known_test.php
 #
 # gdb --args php -dextension=../ext/google/protobuf/modules/protobuf.so memory_leak_test.php
 #
diff --git a/php/tests/proto/test_import_descriptor_proto.proto b/php/tests/proto/test_import_descriptor_proto.proto
new file mode 100644
index 0000000000..2a19940dec
--- /dev/null
+++ b/php/tests/proto/test_import_descriptor_proto.proto
@@ -0,0 +1,14 @@
+syntax = "proto3";
+
+import "google/protobuf/descriptor.proto";
+
+message TestImportDescriptorProto {
+  extend google.protobuf.MethodOptions {
+    int32 a = 72295727;
+  }
+}
+
+extend google.protobuf.MethodOptions {
+  int32 a = 72295728;
+}
+
diff --git a/php/tests/well_known_test.php b/php/tests/well_known_test.php
index 40ff1c8f03..0c2aec13a9 100644
--- a/php/tests/well_known_test.php
+++ b/php/tests/well_known_test.php
@@ -4,8 +4,14 @@ use Google\Protobuf\GPBEmpty;
 
 class WellKnownTest extends PHPUnit_Framework_TestCase {
 
-    public function testNone() {
-      $msg = new GPBEmpty();
+    public function testNone()
+    {
+        $msg = new GPBEmpty();
+    }
+
+    public function testImportDescriptorProto()
+    {
+        $msg = new TestImportDescriptorProto();
     }
 
 }
diff --git a/src/google/protobuf/compiler/php/php_generator.cc b/src/google/protobuf/compiler/php/php_generator.cc
index d24e1e5ebf..4d475b1f54 100644
--- a/src/google/protobuf/compiler/php/php_generator.cc
+++ b/src/google/protobuf/compiler/php/php_generator.cc
@@ -674,6 +674,12 @@ void GenerateAddFileToPool(const FileDescriptor* file, bool is_descriptor,
   } else {
     for (int i = 0; i < file->dependency_count(); i++) {
       const std::string& name = file->dependency(i)->name();
+      // Currently, descriptor.proto is not ready for external usage. Skip to
+      // import it for now, so that its dependencies can still work as long as
+      // they don't use protos defined in descriptor.proto.
+      if (name == kDescriptorFile) {
+        continue;
+      }
       std::string dependency_filename =
           GeneratedMetadataFileName(name, is_descriptor);
       printer->Print(
@@ -685,6 +691,26 @@ void GenerateAddFileToPool(const FileDescriptor* file, bool is_descriptor,
     FileDescriptorSet files;
     FileDescriptorProto* file_proto = files.add_file();
     file->CopyTo(file_proto);
+
+    // Filter out descriptor.proto as it cannot be depended on for now.
+    RepeatedPtrField<string>* dependency = file_proto->mutable_dependency();
+    for (RepeatedPtrField<string>::iterator it = dependency->begin();
+         it != dependency->end(); ++it) {
+      if (*it != kDescriptorFile) {
+        dependency->erase(it);
+        break;
+      }
+    }
+
+    // Filter out all extensions, since we do not support extension yet.
+    file_proto->clear_extension();
+    RepeatedPtrField<DescriptorProto>* message_type =
+        file_proto->mutable_message_type();
+    for (RepeatedPtrField<DescriptorProto>::iterator it = message_type->begin();
+         it != message_type->end(); ++it) {
+      it->clear_extension();
+    }
+
     string files_data;
     files.SerializeToString(&files_data);
 
diff --git a/tests.sh b/tests.sh
index 8c56172dbe..edb37da7ac 100755
--- a/tests.sh
+++ b/tests.sh
@@ -362,6 +362,7 @@ generate_php_test_proto() {
   ../../src/protoc --php_out=generated proto/test.proto proto/test_include.proto proto/test_no_namespace.proto proto/test_prefix.proto
   pushd ../../src
   ./protoc --php_out=../php/tests/generated google/protobuf/empty.proto
+  ./protoc --php_out=../php/tests/generated -I../php/tests -I. ../php/tests/proto/test_import_descriptor_proto.proto
   popd
   popd
 }