19 files changed, 105 insertions, 53 deletions
diff --git a/php/src/Google/Protobuf/Internal/DescriptorProto.php b/php/src/Google/Protobuf/Internal/DescriptorProto.php
index 4676269e..3b215d52 100644
--- a/php/src/Google/Protobuf/Internal/DescriptorProto.php
+++ b/php/src/Google/Protobuf/Internal/DescriptorProto.php
@@ -82,10 +82,10 @@ class DescriptorProto extends \Google\Protobuf\Internal\Message
      *     @type \Google\Protobuf\Internal\FieldDescriptorProto[]|\Google\Protobuf\Internal\RepeatedField $extension
      *     @type \Google\Protobuf\Internal\DescriptorProto[]|\Google\Protobuf\Internal\RepeatedField $nested_type
      *     @type \Google\Protobuf\Internal\EnumDescriptorProto[]|\Google\Protobuf\Internal\RepeatedField $enum_type
-     *     @type \Google\Protobuf\Internal\DescriptorProto_ExtensionRange[]|\Google\Protobuf\Internal\RepeatedField $extension_range
+     *     @type \Google\Protobuf\Internal\DescriptorProto\ExtensionRange[]|\Google\Protobuf\Internal\RepeatedField $extension_range
      *     @type \Google\Protobuf\Internal\OneofDescriptorProto[]|\Google\Protobuf\Internal\RepeatedField $oneof_decl
      *     @type \Google\Protobuf\Internal\MessageOptions $options
-     *     @type \Google\Protobuf\Internal\DescriptorProto_ReservedRange[]|\Google\Protobuf\Internal\RepeatedField $reserved_range
+     *     @type \Google\Protobuf\Internal\DescriptorProto\ReservedRange[]|\Google\Protobuf\Internal\RepeatedField $reserved_range
      *     @type string[]|\Google\Protobuf\Internal\RepeatedField $reserved_name
      *           Reserved field names, which may not be used by fields in the same message.
      *           A given name may only be reserved once.
@@ -247,12 +247,12 @@ class DescriptorProto extends \Google\Protobuf\Internal\Message
 
     /**
      * Generated from protobuf field <code>repeated .google.protobuf.DescriptorProto.ExtensionRange extension_range = 5;</code>
-     * @param \Google\Protobuf\Internal\DescriptorProto_ExtensionRange[]|\Google\Protobuf\Internal\RepeatedField $var
+     * @param \Google\Protobuf\Internal\DescriptorProto\ExtensionRange[]|\Google\Protobuf\Internal\RepeatedField $var
      * @return $this
      */
     public function setExtensionRange($var)
     {
-        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\DescriptorProto_ExtensionRange::class);
+        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\DescriptorProto\ExtensionRange::class);
         $this->extension_range = $arr;
         $this->has_extension_range = true;
 
@@ -331,12 +331,12 @@ class DescriptorProto extends \Google\Protobuf\Internal\Message
 
     /**
      * Generated from protobuf field <code>repeated .google.protobuf.DescriptorProto.ReservedRange reserved_range = 9;</code>
-     * @param \Google\Protobuf\Internal\DescriptorProto_ReservedRange[]|\Google\Protobuf\Internal\RepeatedField $var
+     * @param \Google\Protobuf\Internal\DescriptorProto\ReservedRange[]|\Google\Protobuf\Internal\RepeatedField $var
      * @return $this
      */
     public function setReservedRange($var)
     {
-        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\DescriptorProto_ReservedRange::class);
+        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\DescriptorProto\ReservedRange::class);
         $this->reserved_range = $arr;
         $this->has_reserved_range = true;
 
diff --git a/php/src/Google/Protobuf/Internal/DescriptorProto_ExtensionRange.php b/php/src/Google/Protobuf/Internal/DescriptorProto/ExtensionRange.php
index d926ee6e..c06a0a6e 100644
--- a/php/src/Google/Protobuf/Internal/DescriptorProto_ExtensionRange.php
+++ b/php/src/Google/Protobuf/Internal/DescriptorProto/ExtensionRange.php
@@ -2,7 +2,7 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: google/protobuf/descriptor.proto
 
-namespace Google\Protobuf\Internal;
+namespace Google\Protobuf\Internal\DescriptorProto;
 
 use Google\Protobuf\Internal\GPBType;
 use Google\Protobuf\Internal\GPBWire;
@@ -13,7 +13,7 @@ use Google\Protobuf\Internal\GPBUtil;
 /**
  * Generated from protobuf message <code>google.protobuf.DescriptorProto.ExtensionRange</code>
  */
-class DescriptorProto_ExtensionRange extends \Google\Protobuf\Internal\Message
+class ExtensionRange extends \Google\Protobuf\Internal\Message
 {
     /**
      * Generated from protobuf field <code>optional int32 start = 1;</code>
@@ -133,3 +133,6 @@ class DescriptorProto_ExtensionRange extends \Google\Protobuf\Internal\Message
 
 }
 
+// Adding a class alias for backwards compatibility with the previous class name.
+class_alias(ExtensionRange::class, \Google\Protobuf\Internal\DescriptorProto_ExtensionRange::class);
+
diff --git a/php/src/Google/Protobuf/Internal/DescriptorProto_ReservedRange.php b/php/src/Google/Protobuf/Internal/DescriptorProto/ReservedRange.php
index 302eaaa9..73c964fa 100644
--- a/php/src/Google/Protobuf/Internal/DescriptorProto_ReservedRange.php
+++ b/php/src/Google/Protobuf/Internal/DescriptorProto/ReservedRange.php
@@ -2,7 +2,7 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: google/protobuf/descriptor.proto
 
-namespace Google\Protobuf\Internal;
+namespace Google\Protobuf\Internal\DescriptorProto;
 
 use Google\Protobuf\Internal\GPBType;
 use Google\Protobuf\Internal\GPBWire;
@@ -17,7 +17,7 @@ use Google\Protobuf\Internal\GPBUtil;
  *
  * Generated from protobuf message <code>google.protobuf.DescriptorProto.ReservedRange</code>
  */
-class DescriptorProto_ReservedRange extends \Google\Protobuf\Internal\Message
+class ReservedRange extends \Google\Protobuf\Internal\Message
 {
     /**
      * Inclusive.
@@ -117,3 +117,6 @@ class DescriptorProto_ReservedRange extends \Google\Protobuf\Internal\Message
 
 }
 
+// Adding a class alias for backwards compatibility with the previous class name.
+class_alias(ReservedRange::class, \Google\Protobuf\Internal\DescriptorProto_ReservedRange::class);
+
diff --git a/php/src/Google/Protobuf/Internal/EnumDescriptorProto.php b/php/src/Google/Protobuf/Internal/EnumDescriptorProto.php
index 406bb5b5..da30fa99 100644
--- a/php/src/Google/Protobuf/Internal/EnumDescriptorProto.php
+++ b/php/src/Google/Protobuf/Internal/EnumDescriptorProto.php
@@ -59,7 +59,7 @@ class EnumDescriptorProto extends \Google\Protobuf\Internal\Message
      *     @type string $name
      *     @type \Google\Protobuf\Internal\EnumValueDescriptorProto[]|\Google\Protobuf\Internal\RepeatedField $value
      *     @type \Google\Protobuf\Internal\EnumOptions $options
-     *     @type \Google\Protobuf\Internal\EnumDescriptorProto_EnumReservedRange[]|\Google\Protobuf\Internal\RepeatedField $reserved_range
+     *     @type \Google\Protobuf\Internal\EnumDescriptorProto\EnumReservedRange[]|\Google\Protobuf\Internal\RepeatedField $reserved_range
      *           Range of reserved numeric values. Reserved numeric values may not be used
      *           by enum values in the same enum declaration. Reserved ranges may not
      *           overlap.
@@ -176,12 +176,12 @@ class EnumDescriptorProto extends \Google\Protobuf\Internal\Message
      * overlap.
      *
      * Generated from protobuf field <code>repeated .google.protobuf.EnumDescriptorProto.EnumReservedRange reserved_range = 4;</code>
-     * @param \Google\Protobuf\Internal\EnumDescriptorProto_EnumReservedRange[]|\Google\Protobuf\Internal\RepeatedField $var
+     * @param \Google\Protobuf\Internal\EnumDescriptorProto\EnumReservedRange[]|\Google\Protobuf\Internal\RepeatedField $var
      * @return $this
      */
     public function setReservedRange($var)
     {
-        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\EnumDescriptorProto_EnumReservedRange::class);
+        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\EnumDescriptorProto\EnumReservedRange::class);
         $this->reserved_range = $arr;
         $this->has_reserved_range = true;
 
diff --git a/php/src/Google/Protobuf/Internal/EnumDescriptorProto_EnumReservedRange.php b/php/src/Google/Protobuf/Internal/EnumDescriptorProto/EnumReservedRange.php
index 3d7b008e..e1079585 100644
--- a/php/src/Google/Protobuf/Internal/EnumDescriptorProto_EnumReservedRange.php
+++ b/php/src/Google/Protobuf/Internal/EnumDescriptorProto/EnumReservedRange.php
@@ -2,7 +2,7 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: google/protobuf/descriptor.proto
 
-namespace Google\Protobuf\Internal;
+namespace Google\Protobuf\Internal\EnumDescriptorProto;
 
 use Google\Protobuf\Internal\GPBType;
 use Google\Protobuf\Internal\GPBWire;
@@ -19,7 +19,7 @@ use Google\Protobuf\Internal\GPBUtil;
  *
  * Generated from protobuf message <code>google.protobuf.EnumDescriptorProto.EnumReservedRange</code>
  */
-class EnumDescriptorProto_EnumReservedRange extends \Google\Protobuf\Internal\Message
+class EnumReservedRange extends \Google\Protobuf\Internal\Message
 {
     /**
      * Inclusive.
@@ -119,3 +119,6 @@ class EnumDescriptorProto_EnumReservedRange extends \Google\Protobuf\Internal\Me
 
 }
 
+// Adding a class alias for backwards compatibility with the previous class name.
+class_alias(EnumReservedRange::class, \Google\Protobuf\Internal\EnumDescriptorProto_EnumReservedRange::class);
+
diff --git a/php/src/Google/Protobuf/Internal/FieldDescriptorProto_Label.php b/php/src/Google/Protobuf/Internal/FieldDescriptorProto/Label.php
index f2a32fdf..b105088e 100644
--- a/php/src/Google/Protobuf/Internal/FieldDescriptorProto_Label.php
+++ b/php/src/Google/Protobuf/Internal/FieldDescriptorProto/Label.php
@@ -2,12 +2,12 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: google/protobuf/descriptor.proto
 
-namespace Google\Protobuf\Internal;
+namespace Google\Protobuf\Internal\FieldDescriptorProto;
 
 /**
- * Protobuf enum <code>Google\Protobuf\Internal</code>
+ * Protobuf type <code>google.protobuf.FieldDescriptorProto.Label</code>
  */
-class FieldDescriptorProto_Label
+class Label
 {
     /**
      * 0 is reserved for errors
@@ -25,3 +25,6 @@ class FieldDescriptorProto_Label
     const LABEL_REPEATED = 3;
 }
 
+// Adding a class alias for backwards compatibility with the previous class name.
+class_alias(Label::class, \Google\Protobuf\Internal\FieldDescriptorProto_Label::class);
+
diff --git a/php/src/Google/Protobuf/Internal/FieldDescriptorProto_Type.php b/php/src/Google/Protobuf/Internal/FieldDescriptorProto/Type.php
index 1b022deb..ea228a77 100644
--- a/php/src/Google/Protobuf/Internal/FieldDescriptorProto_Type.php
+++ b/php/src/Google/Protobuf/Internal/FieldDescriptorProto/Type.php
@@ -2,12 +2,12 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: google/protobuf/descriptor.proto
 
-namespace Google\Protobuf\Internal;
+namespace Google\Protobuf\Internal\FieldDescriptorProto;
 
 /**
- * Protobuf enum <code>Google\Protobuf\Internal</code>
+ * Protobuf type <code>google.protobuf.FieldDescriptorProto.Type</code>
  */
-class FieldDescriptorProto_Type
+class Type
 {
     /**
      * 0 is reserved for errors.
@@ -105,3 +105,6 @@ class FieldDescriptorProto_Type
     const TYPE_SINT64 = 18;
 }
 
+// Adding a class alias for backwards compatibility with the previous class name.
+class_alias(Type::class, \Google\Protobuf\Internal\FieldDescriptorProto_Type::class);
+
diff --git a/php/src/Google/Protobuf/Internal/FieldOptions_CType.php b/php/src/Google/Protobuf/Internal/FieldOptions/CType.php
index 0f33072d..016197ac 100644
--- a/php/src/Google/Protobuf/Internal/FieldOptions_CType.php
+++ b/php/src/Google/Protobuf/Internal/FieldOptions/CType.php
@@ -2,12 +2,12 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: google/protobuf/descriptor.proto
 
-namespace Google\Protobuf\Internal;
+namespace Google\Protobuf\Internal\FieldOptions;
 
 /**
- * Protobuf enum <code>Google\Protobuf\Internal</code>
+ * Protobuf type <code>google.protobuf.FieldOptions.CType</code>
  */
-class FieldOptions_CType
+class CType
 {
     /**
      * Default mode.
@@ -25,3 +25,6 @@ class FieldOptions_CType
     const STRING_PIECE = 2;
 }
 
+// Adding a class alias for backwards compatibility with the previous class name.
+class_alias(CType::class, \Google\Protobuf\Internal\FieldOptions_CType::class);
+
diff --git a/php/src/Google/Protobuf/Internal/FieldOptions_JSType.php b/php/src/Google/Protobuf/Internal/FieldOptions/JSType.php
index 73bdf3f2..f7b78a1b 100644
--- a/php/src/Google/Protobuf/Internal/FieldOptions_JSType.php
+++ b/php/src/Google/Protobuf/Internal/FieldOptions/JSType.php
@@ -2,12 +2,12 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: google/protobuf/descriptor.proto
 
-namespace Google\Protobuf\Internal;
+namespace Google\Protobuf\Internal\FieldOptions;
 
 /**
- * Protobuf enum <code>Google\Protobuf\Internal</code>
+ * Protobuf type <code>google.protobuf.FieldOptions.JSType</code>
  */
-class FieldOptions_JSType
+class JSType
 {
     /**
      * Use the default type.
@@ -29,3 +29,6 @@ class FieldOptions_JSType
     const JS_NUMBER = 2;
 }
 
+// Adding a class alias for backwards compatibility with the previous class name.
+class_alias(JSType::class, \Google\Protobuf\Internal\FieldOptions_JSType::class);
+
diff --git a/php/src/Google/Protobuf/Internal/FileOptions.php b/php/src/Google/Protobuf/Internal/FileOptions.php
index 2315ed5e..c6b36bbc 100644
--- a/php/src/Google/Protobuf/Internal/FileOptions.php
+++ b/php/src/Google/Protobuf/Internal/FileOptions.php
@@ -278,6 +278,14 @@ class FileOptions extends \Google\Protobuf\Internal\Message
      *           Use this option to change the namespace of php generated classes. Default
      *           is empty. When this option is empty, the package name will be used for
      *           determining the namespace.
+     *     @type string $php_metadata_namespace
+     *           Use this option to change the namespace of php generated metadata classes.
+     *           Default is empty. When this option is empty, the proto file name will be used
+     *           for determining the namespace.
+     *     @type string $ruby_package
+     *           Use this option to change the package of ruby generated classes. Default
+     *           is empty. When this option is not set, the package name will be used for
+     *           determining the ruby package.
      *     @type \Google\Protobuf\Internal\UninterpretedOption[]|\Google\Protobuf\Internal\RepeatedField $uninterpreted_option
      *           The parser stores options it doesn't recognize here.
      *           See the documentation for the "Options" section above.
diff --git a/php/src/Google/Protobuf/Internal/FileOptions_OptimizeMode.php b/php/src/Google/Protobuf/Internal/FileOptions/OptimizeMode.php
index 4dd56ef8..3dd60bf6 100644
--- a/php/src/Google/Protobuf/Internal/FileOptions_OptimizeMode.php
+++ b/php/src/Google/Protobuf/Internal/FileOptions/OptimizeMode.php
@@ -2,14 +2,14 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: google/protobuf/descriptor.proto
 
-namespace Google\Protobuf\Internal;
+namespace Google\Protobuf\Internal\FileOptions;
 
 /**
  * Generated classes can be optimized for speed or code size.
  *
- * Protobuf enum <code>Google\Protobuf\Internal</code>
+ * Protobuf type <code>google.protobuf.FileOptions.OptimizeMode</code>
  */
-class FileOptions_OptimizeMode
+class OptimizeMode
 {
     /**
      * Generate complete code for parsing, serialization,
@@ -31,3 +31,6 @@ class FileOptions_OptimizeMode
     const LITE_RUNTIME = 3;
 }
 
+// Adding a class alias for backwards compatibility with the previous class name.
+class_alias(OptimizeMode::class, \Google\Protobuf\Internal\FileOptions_OptimizeMode::class);
+
diff --git a/php/src/Google/Protobuf/Internal/GPBUtil.php b/php/src/Google/Protobuf/Internal/GPBUtil.php
index 05d5c393..023b07f4 100644
--- a/php/src/Google/Protobuf/Internal/GPBUtil.php
+++ b/php/src/Google/Protobuf/Internal/GPBUtil.php
@@ -191,7 +191,7 @@ class GPBUtil
         $var = boolval($var);
     }
 
-    public static function checkMessage(&$var, $klass)
+    public static function checkMessage(&$var, $klass, $newClass = null)
     {
         if (!$var instanceof $klass && !is_null($var)) {
             throw new \Exception("Expect $klass.");
@@ -303,8 +303,11 @@ class GPBUtil
         $name,
         $file_proto)
     {
-        $classname = implode('_', explode('.', $name));
-        return static::getClassNamePrefix($classname, $file_proto) . $classname;
+        $parts = explode('.', $name);
+        foreach ($parts as $i => $part) {
+            $parts[$i] = static::getClassNamePrefix($parts[$i], $file_proto) . $parts[$i];
+        }
+        return implode('\\', $parts);
     }
 
     public static function getFullClassName(
@@ -347,9 +350,14 @@ class GPBUtil
         if ($package === "") {
             $classname = $class_name_without_package;
         } else {
+            $parts = array_map('ucwords', explode('.', $package));
+            foreach ($parts as $i => $part) {
+                $parts[$i] = self::getClassNamePrefix($part, $file_proto).$part;
+            }
             $classname =
-                implode('\\', array_map('ucwords', explode('.', $package))).
-                "\\".$class_name_without_package;
+                implode('\\', $parts) .
+                "\\".self::getClassNamePrefix($class_name_without_package,$file_proto).
+                $class_name_without_package;
         }
     }
 
diff --git a/php/src/Google/Protobuf/Internal/GeneratedCodeInfo.php b/php/src/Google/Protobuf/Internal/GeneratedCodeInfo.php
index c2b41a29..f5a65bea 100644
--- a/php/src/Google/Protobuf/Internal/GeneratedCodeInfo.php
+++ b/php/src/Google/Protobuf/Internal/GeneratedCodeInfo.php
@@ -34,7 +34,7 @@ class GeneratedCodeInfo extends \Google\Protobuf\Internal\Message
      * @param array $data {
      *     Optional. Data for populating the Message object.
      *
-     *     @type \Google\Protobuf\Internal\GeneratedCodeInfo_Annotation[]|\Google\Protobuf\Internal\RepeatedField $annotation
+     *     @type \Google\Protobuf\Internal\GeneratedCodeInfo\Annotation[]|\Google\Protobuf\Internal\RepeatedField $annotation
      *           An Annotation connects some span of text in generated code to an element
      *           of its generating .proto file.
      * }
@@ -61,12 +61,12 @@ class GeneratedCodeInfo extends \Google\Protobuf\Internal\Message
      * of its generating .proto file.
      *
      * Generated from protobuf field <code>repeated .google.protobuf.GeneratedCodeInfo.Annotation annotation = 1;</code>
-     * @param \Google\Protobuf\Internal\GeneratedCodeInfo_Annotation[]|\Google\Protobuf\Internal\RepeatedField $var
+     * @param \Google\Protobuf\Internal\GeneratedCodeInfo\Annotation[]|\Google\Protobuf\Internal\RepeatedField $var
      * @return $this
      */
     public function setAnnotation($var)
     {
-        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\GeneratedCodeInfo_Annotation::class);
+        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\GeneratedCodeInfo\Annotation::class);
         $this->annotation = $arr;
         $this->has_annotation = true;
 
diff --git a/php/src/Google/Protobuf/Internal/GeneratedCodeInfo_Annotation.php b/php/src/Google/Protobuf/Internal/GeneratedCodeInfo/Annotation.php
index 75182007..09f958d2 100644
--- a/php/src/Google/Protobuf/Internal/GeneratedCodeInfo_Annotation.php
+++ b/php/src/Google/Protobuf/Internal/GeneratedCodeInfo/Annotation.php
@@ -2,7 +2,7 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: google/protobuf/descriptor.proto
 
-namespace Google\Protobuf\Internal;
+namespace Google\Protobuf\Internal\GeneratedCodeInfo;
 
 use Google\Protobuf\Internal\GPBType;
 use Google\Protobuf\Internal\GPBWire;
@@ -13,7 +13,7 @@ use Google\Protobuf\Internal\GPBUtil;
 /**
  * Generated from protobuf message <code>google.protobuf.GeneratedCodeInfo.Annotation</code>
  */
-class GeneratedCodeInfo_Annotation extends \Google\Protobuf\Internal\Message
+class Annotation extends \Google\Protobuf\Internal\Message
 {
     /**
      * Identifies the element in the original source .proto file. This field
@@ -211,3 +211,6 @@ class GeneratedCodeInfo_Annotation extends \Google\Protobuf\Internal\Message
 
 }
 
+// Adding a class alias for backwards compatibility with the previous class name.
+class_alias(Annotation::class, \Google\Protobuf\Internal\GeneratedCodeInfo_Annotation::class);
+
diff --git a/php/src/Google/Protobuf/Internal/MethodOptions_IdempotencyLevel.php b/php/src/Google/Protobuf/Internal/MethodOptions/IdempotencyLevel.php
index 9e06d8ee..dcc30e27 100644
--- a/php/src/Google/Protobuf/Internal/MethodOptions_IdempotencyLevel.php
+++ b/php/src/Google/Protobuf/Internal/MethodOptions/IdempotencyLevel.php
@@ -2,16 +2,16 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: google/protobuf/descriptor.proto
 
-namespace Google\Protobuf\Internal;
+namespace Google\Protobuf\Internal\MethodOptions;
 
 /**
  * Is this method side-effect-free (or safe in HTTP parlance), or idempotent,
  * or neither? HTTP based RPC implementation may choose GET verb for safe
  * methods, and PUT verb for idempotent methods instead of the default POST.
  *
- * Protobuf enum <code>Google\Protobuf\Internal</code>
+ * Protobuf type <code>google.protobuf.MethodOptions.IdempotencyLevel</code>
  */
-class MethodOptions_IdempotencyLevel
+class IdempotencyLevel
 {
     /**
      * Generated from protobuf enum <code>IDEMPOTENCY_UNKNOWN = 0;</code>
@@ -31,3 +31,6 @@ class MethodOptions_IdempotencyLevel
     const IDEMPOTENT = 2;
 }
 
+// Adding a class alias for backwards compatibility with the previous class name.
+class_alias(IdempotencyLevel::class, \Google\Protobuf\Internal\MethodOptions_IdempotencyLevel::class);
+
diff --git a/php/src/Google/Protobuf/Internal/SourceCodeInfo.php b/php/src/Google/Protobuf/Internal/SourceCodeInfo.php
index 2305a792..6e413f77 100644
--- a/php/src/Google/Protobuf/Internal/SourceCodeInfo.php
+++ b/php/src/Google/Protobuf/Internal/SourceCodeInfo.php
@@ -72,7 +72,7 @@ class SourceCodeInfo extends \Google\Protobuf\Internal\Message
      * @param array $data {
      *     Optional. Data for populating the Message object.
      *
-     *     @type \Google\Protobuf\Internal\SourceCodeInfo_Location[]|\Google\Protobuf\Internal\RepeatedField $location
+     *     @type \Google\Protobuf\Internal\SourceCodeInfo\Location[]|\Google\Protobuf\Internal\RepeatedField $location
      *           A Location identifies a piece of source code in a .proto file which
      *           corresponds to a particular definition.  This information is intended
      *           to be useful to IDEs, code indexers, documentation generators, and similar
@@ -216,12 +216,12 @@ class SourceCodeInfo extends \Google\Protobuf\Internal\Message
      *   be recorded in the future.
      *
      * Generated from protobuf field <code>repeated .google.protobuf.SourceCodeInfo.Location location = 1;</code>
-     * @param \Google\Protobuf\Internal\SourceCodeInfo_Location[]|\Google\Protobuf\Internal\RepeatedField $var
+     * @param \Google\Protobuf\Internal\SourceCodeInfo\Location[]|\Google\Protobuf\Internal\RepeatedField $var
      * @return $this
      */
     public function setLocation($var)
     {
-        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\SourceCodeInfo_Location::class);
+        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\SourceCodeInfo\Location::class);
         $this->location = $arr;
         $this->has_location = true;
 
diff --git a/php/src/Google/Protobuf/Internal/SourceCodeInfo_Location.php b/php/src/Google/Protobuf/Internal/SourceCodeInfo/Location.php
index f930aac1..bad247a1 100644
--- a/php/src/Google/Protobuf/Internal/SourceCodeInfo_Location.php
+++ b/php/src/Google/Protobuf/Internal/SourceCodeInfo/Location.php
@@ -2,7 +2,7 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: google/protobuf/descriptor.proto
 
-namespace Google\Protobuf\Internal;
+namespace Google\Protobuf\Internal\SourceCodeInfo;
 
 use Google\Protobuf\Internal\GPBType;
 use Google\Protobuf\Internal\GPBWire;
@@ -13,7 +13,7 @@ use Google\Protobuf\Internal\GPBUtil;
 /**
  * Generated from protobuf message <code>google.protobuf.SourceCodeInfo.Location</code>
  */
-class SourceCodeInfo_Location extends \Google\Protobuf\Internal\Message
+class Location extends \Google\Protobuf\Internal\Message
 {
     /**
      * Identifies which part of the FileDescriptorProto was defined at this
@@ -458,3 +458,6 @@ class SourceCodeInfo_Location extends \Google\Protobuf\Internal\Message
 
 }
 
+// Adding a class alias for backwards compatibility with the previous class name.
+class_alias(Location::class, \Google\Protobuf\Internal\SourceCodeInfo_Location::class);
+
diff --git a/php/src/Google/Protobuf/Internal/UninterpretedOption.php b/php/src/Google/Protobuf/Internal/UninterpretedOption.php
index 36a18688..3b517ec5 100644
--- a/php/src/Google/Protobuf/Internal/UninterpretedOption.php
+++ b/php/src/Google/Protobuf/Internal/UninterpretedOption.php
@@ -67,7 +67,7 @@ class UninterpretedOption extends \Google\Protobuf\Internal\Message
      * @param array $data {
      *     Optional. Data for populating the Message object.
      *
-     *     @type \Google\Protobuf\Internal\UninterpretedOption_NamePart[]|\Google\Protobuf\Internal\RepeatedField $name
+     *     @type \Google\Protobuf\Internal\UninterpretedOption\NamePart[]|\Google\Protobuf\Internal\RepeatedField $name
      *     @type string $identifier_value
      *           The value of the uninterpreted option, in whatever type the tokenizer
      *           identified it as during parsing. Exactly one of these should be set.
@@ -94,12 +94,12 @@ class UninterpretedOption extends \Google\Protobuf\Internal\Message
 
     /**
      * Generated from protobuf field <code>repeated .google.protobuf.UninterpretedOption.NamePart name = 2;</code>
-     * @param \Google\Protobuf\Internal\UninterpretedOption_NamePart[]|\Google\Protobuf\Internal\RepeatedField $var
+     * @param \Google\Protobuf\Internal\UninterpretedOption\NamePart[]|\Google\Protobuf\Internal\RepeatedField $var
      * @return $this
      */
     public function setName($var)
     {
-        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\UninterpretedOption_NamePart::class);
+        $arr = GPBUtil::checkRepeatedField($var, \Google\Protobuf\Internal\GPBType::MESSAGE, \Google\Protobuf\Internal\UninterpretedOption\NamePart::class);
         $this->name = $arr;
         $this->has_name = true;
 
diff --git a/php/src/Google/Protobuf/Internal/UninterpretedOption_NamePart.php b/php/src/Google/Protobuf/Internal/UninterpretedOption/NamePart.php
index d4369fda..92ee4b44 100644
--- a/php/src/Google/Protobuf/Internal/UninterpretedOption_NamePart.php
+++ b/php/src/Google/Protobuf/Internal/UninterpretedOption/NamePart.php
@@ -2,7 +2,7 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: google/protobuf/descriptor.proto
 
-namespace Google\Protobuf\Internal;
+namespace Google\Protobuf\Internal\UninterpretedOption;
 
 use Google\Protobuf\Internal\GPBType;
 use Google\Protobuf\Internal\GPBWire;
@@ -19,7 +19,7 @@ use Google\Protobuf\Internal\GPBUtil;
  *
  * Generated from protobuf message <code>google.protobuf.UninterpretedOption.NamePart</code>
  */
-class UninterpretedOption_NamePart extends \Google\Protobuf\Internal\Message
+class NamePart extends \Google\Protobuf\Internal\Message
 {
     /**
      * Generated from protobuf field <code>required string name_part = 1;</code>
@@ -105,3 +105,6 @@ class UninterpretedOption_NamePart extends \Google\Protobuf\Internal\Message
 
 }
 
+// Adding a class alias for backwards compatibility with the previous class name.
+class_alias(NamePart::class, \Google\Protobuf\Internal\UninterpretedOption_NamePart::class);
+