Emit deprecation notice when serializing resources

PHP itself is converting many resources to objects that throw an Error on
serialization attempts starting in php 8.0.
Continue to represent resources as null in the serialized data.

Fixes #300

.azure/job.yml

@@ -13,8 +13,6 @@ jobs:
       vmImage: ${{ parameters.vmImage }}
     steps:
     # E.g. ondrej/php sometimes updates the latest version
-    - script: |
-      displayName: 'Refresh apt-get'
     - script: |
         sudo apt-get install -y valgrind
       displayName: 'Install valgrind'

package.xml

@@ -44,6 +44,9 @@
  <license uri="https://github.com/igbinary/igbinary/blob/master/COPYING">BSD-3-Clause</license>
  <notes>
 * Improve memory efficiency when unserializing packed arrays (e.g. lists) - certain checks are no longer needed.
+* Emit a deprecation notice when serializing resources.
+  PHP itself is converting many resources to objects that throw an Error on serialization attempts.
+  Continue to represent resources as null in the serialized data.
  </notes>
  <contents>
   <dir name="/">

src/php7/igbinary.c

@@ -1818,6 +1818,17 @@ inline static int igbinary_serialize_object(struct igbinary_serialize_data *igsd
 	}
 }
 /* }}} */
+/* {{{ igbinary_warn_serialize_resource */
+static ZEND_COLD int igbinary_warn_serialize_resource(zval *z) {
+	const char *resource_type;
+	resource_type = zend_rsrc_list_get_rsrc_type(Z_RES_P(z));
+	if (!resource_type) {
+		resource_type = "Unknown";
+	}
+	php_error_docref(NULL, E_DEPRECATED, "Cannot serialize resource(%s) and resources may be converted to objects that cannot be serialized in future php releases. Serializing the value as null instead", resource_type);
+	return EG(exception) != NULL;
+}
+/* }}} */
 /* {{{ igbinary_serialize_zval */
 /** Serialize zval. */
 static int igbinary_serialize_zval(struct igbinary_serialize_data *igsd, zval *z) {
@@ -1843,6 +1854,9 @@ static int igbinary_serialize_zval(struct igbinary_serialize_data *igsd, zval *z
 	}
 	switch (Z_TYPE_P(z)) {
 		case IS_RESOURCE:
+			if (igbinary_warn_serialize_resource(z)) {
+				return 1;
+			}
 			return igbinary_serialize_null(igsd);
 		case IS_OBJECT:
 			return igbinary_serialize_object(igsd, z);

src/php7/igbinary.h

@@ -18,7 +18,7 @@ struct zval;
 /** Binary protocol version of igbinary. */
 #define IGBINARY_FORMAT_VERSION 0x00000002
 
-#define PHP_IGBINARY_VERSION "3.1.7dev"
+#define PHP_IGBINARY_VERSION "3.2.0dev"
 
 /* Macros */
 

tests/igbinary_023.phpt

@@ -22,7 +22,15 @@ test('resource', $res, false);
 
 fclose($res);
 
---EXPECT--
+test('resource', $res, false);
+
+--EXPECTF--
+Deprecated: igbinary_serialize(): Cannot serialize resource(stream) and resources may be converted to objects that cannot be serialized in future php releases. Serializing the value as null instead in %sigbinary_023.php on line 4
+resource
+00
+OK
+
+Deprecated: igbinary_serialize(): Cannot serialize resource(Unknown) and resources may be converted to objects that cannot be serialized in future php releases. Serializing the value as null instead in %sigbinary_023.php on line 4
 resource
 00
 OK