Added proto3 presence support for PHP (#7724)

* WIP.

* Added proto3 presence support for PHP.

* Added compatibility code for old generated code.

php/tests/encode_decode_test.php

diff --git a/php/tests/encode_decode_test.php b/php/tests/encode_decode_test.php
index 5442f50..ea8bd65 100644
--- a/php/tests/encode_decode_test.php
+++ b/php/tests/encode_decode_test.php
@@ -326,6 +326,24 @@
 
     }
 
+    public function testEncodeDecodeOptional()
+    {
+      $m = new TestMessage();
+      $this->assertFalse($m->hasTrueOptionalInt32());
+      $data = $m->serializeToString();
+      $this->assertSame("", $data);
+
+      $m->setTrueOptionalInt32(0);
+      $this->assertTrue($m->hasTrueOptionalInt32());
+      $data = $m->serializeToString();
+      $this->assertNotSame("", $data);
+
+      $m2 = new TestMessage();
+      $m2->mergeFromString($data);
+      $this->assertTrue($m2->hasTrueOptionalInt32());
+      $this->assertSame(0, $m2->getTrueOptionalInt32());
+    }
+
     public function testJsonEncodeDecodeOneof()
     {
         $m = new TestMessage();

php/tests/generate_protos.sh

diff --git a/php/tests/generate_protos.sh b/php/tests/generate_protos.sh
index 0c2a555..e83c3c1 100755
--- a/php/tests/generate_protos.sh
+++ b/php/tests/generate_protos.sh
@@ -7,10 +7,10 @@
 rm -rf generated
 mkdir -p generated
 
-find proto -type f -name "*.proto"| xargs ../../src/protoc --php_out=generated -I../../src -I.
+find proto -type f -name "*.proto"| xargs ../../src/protoc --experimental_allow_proto3_optional --php_out=generated -I../../src -I.
 
 if [ "$1" = "--aggregate_metadata" ]; then
   # Overwrite some of the files to use aggregation.
   AGGREGATED_FILES="proto/test.proto proto/test_include.proto proto/test_import_descriptor_proto.proto"
-  ../../src/protoc --php_out=aggregate_metadata=foo#bar:generated -I../../src -I. $AGGREGATED_FILES
+  ../../src/protoc --experimental_allow_proto3_optional --php_out=aggregate_metadata=foo#bar:generated -I../../src -I. $AGGREGATED_FILES
 fi

php/tests/generated_class_test.php

diff --git a/php/tests/generated_class_test.php b/php/tests/generated_class_test.php
index 053697d..f49c4e9 100644
--- a/php/tests/generated_class_test.php
+++ b/php/tests/generated_class_test.php
@@ -72,6 +72,28 @@
     }
 
     #########################################################
+    # Test optional int32 field.
+    #########################################################
+
+    public function testOptionalInt32Field()
+    {
+        $m = new TestMessage();
+
+        $this->assertFalse($m->hasTrueOptionalInt32());
+        $this->assertSame(0, $m->getTrueOptionalInt32());
+
+        // Set integer.
+        $m->setTrueOptionalInt32(MAX_INT32);
+        $this->assertTrue($m->hasTrueOptionalInt32());
+        $this->assertSame(MAX_INT32, $m->getTrueOptionalInt32());
+
+        // Clear integer.
+        $m->clearTrueOptionalInt32();
+        $this->assertFalse($m->hasTrueOptionalInt32());
+        $this->assertSame(0, $m->getTrueOptionalInt32());
+    }
+
+    #########################################################
     # Test uint32 field.
     #########################################################
 

php/tests/proto/test.proto

diff --git a/php/tests/proto/test.proto b/php/tests/proto/test.proto
index 9505709..368b19e 100644
--- a/php/tests/proto/test.proto
+++ b/php/tests/proto/test.proto
@@ -34,6 +34,27 @@
   bar.TestInclude optional_included_message = 18;
   TestMessage recursive = 19;
 
+  // True optional
+  optional int32 true_optional_int32 = 201;
+  optional int64 true_optional_int64 = 202;
+  optional uint32 true_optional_uint32 = 203;
+  optional uint64 true_optional_uint64 = 204;
+  optional sint32 true_optional_sint32 = 205;
+  optional sint64 true_optional_sint64 = 206;
+  optional fixed32 true_optional_fixed32 = 207;
+  optional fixed64 true_optional_fixed64 = 208;
+  optional sfixed32 true_optional_sfixed32 = 209;
+  optional sfixed64 true_optional_sfixed64 = 210;
+  optional float true_optional_float = 211;
+  optional double true_optional_double = 212;
+  optional bool true_optional_bool = 213;
+  optional string true_optional_string = 214;
+  optional bytes true_optional_bytes = 215;
+
+  optional TestEnum true_optional_enum = 216;
+  optional Sub true_optional_message = 217;
+  optional bar.TestInclude true_optional_included_message = 218;
+
   // Repeated
   repeated    int32 repeated_int32    = 31;
   repeated    int64 repeated_int64    = 32;

php/tests/test.sh

diff --git a/php/tests/test.sh b/php/tests/test.sh
index b10b57f..4beeed5 100755
--- a/php/tests/test.sh
+++ b/php/tests/test.sh
@@ -51,8 +51,8 @@
 
 export ZEND_DONT_UNLOAD_MODULES=1
 export USE_ZEND_ALLOC=0
-valgrind --leak-check=yes php -dextension=../ext/google/protobuf/modules/protobuf.so memory_leak_test.php
-valgrind --leak-check=yes php -d protobuf.keep_descriptor_pool_after_request=1 -dextension=../ext/google/protobuf/modules/protobuf.so memory_leak_test.php
+valgrind --suppressions=valgrind.supp --leak-check=yes php -dextension=../ext/google/protobuf/modules/protobuf.so memory_leak_test.php
+valgrind --suppressions=valgrind.supp --leak-check=yes php -d protobuf.keep_descriptor_pool_after_request=1 -dextension=../ext/google/protobuf/modules/protobuf.so memory_leak_test.php
 
 # TODO(teboring): Only for debug (phpunit has memory leak which blocks this beging used by
 # regresssion test.)

php/tests/valgrind.supp

diff --git a/php/tests/valgrind.supp b/php/tests/valgrind.supp
new file mode 100644
index 0000000..e83b0a3
--- /dev/null
+++ b/php/tests/valgrind.supp
@@ -0,0 +1,12 @@
+{
+   PHP_Equal_Val
+   Memcheck:Cond
+   fun:zend_string_equal_val
+}
+
+{
+   PHP_ScanDir_Tail
+   Memcheck:Cond
+   obj:/usr/bin/php7.3
+   fun:__scandir64_tail
+}