Improve var_export for collections

The current output of var_export for collections isn't very useful. It
outputs a call to __set_state like so:

  Map::__set_state(array(..))

This isn't particularly useful since collections don't implement the
__set_state() method, and it is also suboptimal for the design of
collections since it relies on using PHP arrays.

This diff changes var_export to use collection literal syntax for
collections instead of generating a call to __set_state().

hphp/runtime/base/variable_serializer.cpp

@@ -545,7 +545,12 @@ void VariableSerializer::writeArrayHeader(int size, bool isVectorData) {
     }
     if (!m_objClass.empty()) {
       m_buf->append(m_objClass);
-      m_buf->append("::__set_state(array(\n");
+      if (m_objCode == 'O') {
+        m_buf->append("::__set_state(array(\n");
+      } else {
+        assert(m_objCode == 'V' || m_objCode == 'K');
+        m_buf->append(" {\n");
+      }
     } else {
       m_buf->append("array (\n");
     }
@@ -758,7 +763,6 @@ void VariableSerializer::writeCollectionKey(CVarRef key) {
 }
 
 void VariableSerializer::writeCollectionKeylessPrefix() {
-  ArrayInfo &info = m_arrayInfos.back();
   switch (m_type) {
   case PrintR:
   case VarExport:
@@ -772,7 +776,8 @@ void VariableSerializer::writeCollectionKeylessPrefix() {
   case DebuggerSerialize:
     break;
   case JSON:
-  case DebuggerDump:
+  case DebuggerDump: {
+    ArrayInfo &info = m_arrayInfos.back();
     if (!info.first_element) {
       m_buf->append(',');
     }
@@ -781,6 +786,7 @@ void VariableSerializer::writeCollectionKeylessPrefix() {
       indent();
     }
     break;
+  }
   default:
     assert(false);
     break;
@@ -831,7 +837,12 @@ void VariableSerializer::writeArrayFooter() {
   case PHPOutput:
     indent();
     if (info.is_object) {
-      m_buf->append("))");
+      if (m_objCode == 'O') {
+        m_buf->append("))");
+      } else {
+        assert(m_objCode == 'V' || m_objCode == 'K');
+        m_buf->append("}");
+      }
     } else {
       m_buf->append(')');
     }

hphp/runtime/ext/ext_collections.cpp

@@ -4578,10 +4578,13 @@ void collectionSerialize(ObjectData* obj, VariableSerializer* serializer) {
     serializer->writeArrayHeader(sz, true);
     if (serializer->getType() == VariableSerializer::Serialize ||
         serializer->getType() == VariableSerializer::APCSerialize ||
-        serializer->getType() == VariableSerializer::DebuggerSerialize) {
+        serializer->getType() == VariableSerializer::DebuggerSerialize ||
+        serializer->getType() == VariableSerializer::VarExport ||
+        serializer->getType() == VariableSerializer::PHPOutput) {
       // For the 'V' serialization format, we don't print out keys
       // for Serialize, APCSerialize, DebuggerSerialize
       for (ArrayIter iter(obj); iter; ++iter) {
+        serializer->writeCollectionKeylessPrefix();
         serializer->writeArrayValue(iter.second());
       }
     } else {

hphp/test/slow/collection_classes/806.php.expect

@@ -12,10 +12,10 @@ Vector Object
     [1] => foo
 )
 [7,"foo"]
-Vector::__set_state(array(
-  0 => 7,
-  1 => 'foo',
-))
+Vector {
+  7,
+  'foo',
+}
 object(Vector)#2 (2) {
   [0]=>
   int(7)
@@ -28,7 +28,7 @@ Vector Object
     [1] => foo
 )
 [7,"foo"]
-Vector::__set_state(array(
-  0 => 7,
-  1 => 'foo',
-))
+Vector {
+  7,
+  'foo',
+}

hphp/test/slow/collection_classes/807.php.expect

@@ -9,9 +9,9 @@ Map Object
     [3] => foo
 )
 {"3":"foo"}
-Map::__set_state(array(
+Map {
   3 => 'foo',
-))
+}
 object(Map)#2 (1) {
   [3]=>
   string(3) "foo"
@@ -21,9 +21,9 @@ Map Object
     [3] => foo
 )
 {"3":"foo"}
-Map::__set_state(array(
+Map {
   3 => 'foo',
-))
+}
 ------------------------
 string(28) "K:3:"Map":1:{s:3:"bar";i:7;}"
 ------------------------
@@ -36,9 +36,9 @@ Map Object
     [bar] => 7
 )
 {"bar":7}
-Map::__set_state(array(
+Map {
   'bar' => 7,
-))
+}
 object(Map)#4 (1) {
   ["bar"]=>
   int(7)
@@ -48,6 +48,6 @@ Map Object
     [bar] => 7
 )
 {"bar":7}
-Map::__set_state(array(
+Map {
   'bar' => 7,
-))
+}

hphp/test/slow/collection_classes/808.php.expect

@@ -12,10 +12,10 @@ StableMap Object
     [bar] => 7
 )
 {"3":"foo","bar":7}
-StableMap::__set_state(array(
+StableMap {
   3 => 'foo',
   'bar' => 7,
-))
+}
 object(StableMap)#2 (2) {
   [3]=>
   string(3) "foo"
@@ -28,10 +28,10 @@ StableMap Object
     [bar] => 7
 )
 {"3":"foo","bar":7}
-StableMap::__set_state(array(
+StableMap {
   3 => 'foo',
   'bar' => 7,
-))
+}
 ------------------------
 string(48) "K:9:"StableMap":2:{s:3:"bar";i:7;i:3;s:3:"foo";}"
 ------------------------
@@ -47,10 +47,10 @@ StableMap Object
     [3] => foo
 )
 {"bar":7,"3":"foo"}
-StableMap::__set_state(array(
+StableMap {
   'bar' => 7,
   3 => 'foo',
-))
+}
 object(StableMap)#4 (2) {
   ["bar"]=>
   int(7)
@@ -63,7 +63,7 @@ StableMap Object
     [3] => foo
 )
 {"bar":7,"3":"foo"}
-StableMap::__set_state(array(
+StableMap {
   'bar' => 7,
   3 => 'foo',
-))
+}

hphp/test/slow/collection_classes/836.php.expect

@@ -14,11 +14,11 @@ object(Set)#1 (3) refcount(2){
   long(2) refcount(1)
   long(3) refcount(1)
 }
-Set::__set_state(array(
+Set {
   1,
   2,
   3,
-))
+}
 [1,2,3]
 [
     1,