Implemented request #69592: allow 0-column rowsets to be skipped automatically

This adds a new attribute PDO::DBLIB_ATTR_SKIP_EMPTY_ROWSETS to enable automatic
skipping of empty rowsets.

This happens with some SQL commands (like PRINT or SET): a rowset with 0 columns
is returned by the driver.

With this option enabled, 0 columns rowsets are automatically skipped, mirroring
the behavior of the deprecated mssql extension.

Credits go to MiRacLe-RPZ for developping and promoting this patch.

5 files changed, 84 insertions, 3 deletions

diff --git a/ext/pdo_dblib/dblib_driver.c b/ext/pdo_dblib/dblib_driver.c
index efc8dc1197..e8c010c563 100644
--- a/ext/pdo_dblib/dblib_driver.c
+++ b/ext/pdo_dblib/dblib_driver.c
@@ -287,6 +287,9 @@ static int dblib_set_attr(pdo_dbh_t *dbh, zend_long attr, zval *val)
 		case PDO_DBLIB_ATTR_STRINGIFY_UNIQUEIDENTIFIER:
 			H->stringify_uniqueidentifier = zval_get_long(val);
 			return 1;
+		case PDO_DBLIB_ATTR_SKIP_EMPTY_ROWSETS:
+			H->skip_empty_rowsets = zval_is_true(val);
+			return 1;
 		default:
 			return 0;
 	}
@@ -314,6 +317,10 @@ static int dblib_get_attribute(pdo_dbh_t *dbh, zend_long attr, zval *return_valu
 			ZVAL_STRING(return_value, dbversion());
 			break;
 
+		case PDO_DBLIB_ATTR_SKIP_EMPTY_ROWSETS:
+			ZVAL_BOOL(return_value, H->skip_empty_rowsets);
+			break;
+
 		default:
 			return 0;
 	}
@@ -387,6 +394,7 @@ static int pdo_dblib_handle_factory(pdo_dbh_t *dbh, zval *driver_options)
 	H->err.sqlstate = dbh->error_code;
 	H->assume_national_character_set_strings = 0;
 	H->stringify_uniqueidentifier = 0;
+	H->skip_empty_rowsets = 0;
 
 	if (!H->login) {
 		goto cleanup;
@@ -409,6 +417,7 @@ static int pdo_dblib_handle_factory(pdo_dbh_t *dbh, zval *driver_options)
 
 		H->assume_national_character_set_strings = pdo_attr_lval(driver_options, PDO_ATTR_DEFAULT_STR_PARAM, 0) == PDO_PARAM_STR_NATL ? 1 : 0;
 		H->stringify_uniqueidentifier = pdo_attr_lval(driver_options, PDO_DBLIB_ATTR_STRINGIFY_UNIQUEIDENTIFIER, 0);
+		H->skip_empty_rowsets = pdo_attr_lval(driver_options, PDO_DBLIB_ATTR_SKIP_EMPTY_ROWSETS, 0);
 	}
 
 	DBERRHANDLE(H->login, (EHANDLEFUNC) pdo_dblib_error_handler);
diff --git a/ext/pdo_dblib/dblib_stmt.c b/ext/pdo_dblib/dblib_stmt.c
index 6c8427da6b..469bd790de 100644
--- a/ext/pdo_dblib/dblib_stmt.c
+++ b/ext/pdo_dblib/dblib_stmt.c
@@ -124,20 +124,29 @@ static int pdo_dblib_stmt_next_rowset_no_cancel(pdo_stmt_t *stmt)
 	pdo_dblib_stmt *S = (pdo_dblib_stmt*)stmt->driver_data;
 	pdo_dblib_db_handle *H = S->H;
 	RETCODE ret;
+	int num_fields;
+
+	do {
+		ret = dbresults(H->link);
+		num_fields = dbnumcols(H->link);
+	} while (H->skip_empty_rowsets && num_fields <= 0 && ret == SUCCEED);
 
-	ret = dbresults(H->link);
 
 	if (FAIL == ret) {
 		pdo_raise_impl_error(stmt->dbh, stmt, "HY000", "PDO_DBLIB: dbresults() returned FAIL");
 		return 0;
 	}
 
-	if(NO_MORE_RESULTS == ret) {
+	if (NO_MORE_RESULTS == ret) {
+		return 0;
+	}
+
+	if (H->skip_empty_rowsets && num_fields <= 0) {
 		return 0;
 	}
 
 	stmt->row_count = DBCOUNT(H->link);
-	stmt->column_count = dbnumcols(H->link);
+	stmt->column_count = num_fields;
 
 	return 1;
 }
diff --git a/ext/pdo_dblib/pdo_dblib.c b/ext/pdo_dblib/pdo_dblib.c
index 1732cd75f9..d6a0eda07b 100644
--- a/ext/pdo_dblib/pdo_dblib.c
+++ b/ext/pdo_dblib/pdo_dblib.c
@@ -195,6 +195,7 @@ PHP_MINIT_FUNCTION(pdo_dblib)
 	REGISTER_PDO_CLASS_CONST_LONG("DBLIB_ATTR_QUERY_TIMEOUT", (long) PDO_DBLIB_ATTR_QUERY_TIMEOUT);
 	REGISTER_PDO_CLASS_CONST_LONG("DBLIB_ATTR_STRINGIFY_UNIQUEIDENTIFIER", (long) PDO_DBLIB_ATTR_STRINGIFY_UNIQUEIDENTIFIER);
 	REGISTER_PDO_CLASS_CONST_LONG("DBLIB_ATTR_VERSION", (long) PDO_DBLIB_ATTR_VERSION);
+	REGISTER_PDO_CLASS_CONST_LONG("DBLIB_ATTR_SKIP_EMPTY_ROWSETS", (long) PDO_DBLIB_ATTR_SKIP_EMPTY_ROWSETS);
 
 	if (FAIL == dbinit()) {
 		return FAILURE;
diff --git a/ext/pdo_dblib/php_pdo_dblib_int.h b/ext/pdo_dblib/php_pdo_dblib_int.h
index c40697680f..1b59dd3a38 100644
--- a/ext/pdo_dblib/php_pdo_dblib_int.h
+++ b/ext/pdo_dblib/php_pdo_dblib_int.h
@@ -118,6 +118,7 @@ typedef struct {
 	pdo_dblib_err err;
 	unsigned assume_national_character_set_strings:1;
 	unsigned stringify_uniqueidentifier:1;
+	unsigned skip_empty_rowsets:1;
 } pdo_dblib_db_handle;
 
 typedef struct {
@@ -150,6 +151,7 @@ enum {
 	PDO_DBLIB_ATTR_QUERY_TIMEOUT,
 	PDO_DBLIB_ATTR_STRINGIFY_UNIQUEIDENTIFIER,
 	PDO_DBLIB_ATTR_VERSION,
+	PDO_DBLIB_ATTR_SKIP_EMPTY_ROWSETS,
 };
 
 #endif
diff --git a/ext/pdo_dblib/tests/bug_69592.phpt b/ext/pdo_dblib/tests/bug_69592.phpt
new file mode 100644
index 0000000000..98936618d1
--- /dev/null
+++ b/ext/pdo_dblib/tests/bug_69592.phpt
@@ -0,0 +1,60 @@
+--TEST--
+PDO_DBLIB: PDO::DBLIB_ATTR_SKIP_EMPTY_ROWSETS for skip junk resultsets on SET NOCOUNT expression
+--SKIPIF--
+<?php
+if (!extension_loaded('pdo_dblib')) die('skip not loaded');
+require dirname(__FILE__) . '/config.inc';
+?>
+--FILE--
+<?php
+require dirname(__FILE__) . '/config.inc';
+
+$sql = '
+    SET NOCOUNT ON
+    SELECT 0 AS [result]
+';
+
+var_dump($db->getAttribute(PDO::DBLIB_ATTR_SKIP_EMPTY_ROWSETS));
+
+$stmt = $db->query($sql);
+var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));
+var_dump($stmt->nextRowset());
+var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));
+$stmt->closeCursor();
+
+
+$db->setAttribute(PDO::DBLIB_ATTR_SKIP_EMPTY_ROWSETS, true);
+var_dump($db->getAttribute(PDO::DBLIB_ATTR_SKIP_EMPTY_ROWSETS));
+
+$stmt = $db->query($sql);
+var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));
+var_dump($stmt->nextRowset());
+var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));
+$stmt->closeCursor();
+var_dump($db->getAttribute(PDO::DBLIB_ATTR_SKIP_EMPTY_ROWSETS));
+
+?>
+--EXPECT--
+bool(false)
+array(0) {
+}
+bool(true)
+array(1) {
+  [0]=>
+  array(1) {
+    ["result"]=>
+    int(0)
+  }
+}
+bool(true)
+array(1) {
+  [0]=>
+  array(1) {
+    ["result"]=>
+    int(0)
+  }
+}
+bool(false)
+array(0) {
+}
+bool(true)