GH-15750 Pdo\Pgsql with ATTR_PREFETCH = 0: handle handle's internal queries

not only the statements, but the driver, love to make internal queries. We make sure no unfinished query still runs when having to pass an internal one.
by the way factorize the loops that consumed the preceding query's results

Author: outtersg

ext/pdo_pgsql/pgsql_driver.c

@@ -36,6 +36,7 @@
 #include "pgsql_driver_arginfo.h"
 
 static bool pgsql_handle_in_transaction(pdo_dbh_t *dbh);
+void pgsql_stmt_finish(pdo_pgsql_stmt *S, int fin_mode);
 
 static char * _pdo_pgsql_trim_message(const char *message, int persistent)
 {
@@ -109,6 +110,37 @@ int _pdo_pgsql_error(pdo_dbh_t *dbh, pdo_stmt_t *stmt, int errcode, const char *
 }
 /* }}} */
 
+static zend_always_inline void pgsql_finish_running_stmt(pdo_pgsql_db_handle *H)
+{
+	if (H->running_stmt) {
+		pgsql_stmt_finish(H->running_stmt, 0);
+	}
+}
+
+static zend_always_inline void pgsql_discard_running_stmt(pdo_pgsql_db_handle *H)
+{
+	if (H->running_stmt) {
+		pgsql_stmt_finish(H->running_stmt, FIN_DISCARD);
+	}
+
+	PGresult *pgsql_result;
+	bool first = true;
+	while ((pgsql_result = PQgetResult(H->server))) {
+		/* We should not arrive here, where libpq has a result to deliver without us
+		 * having registered a running statement:
+		 * every result discarding should go through the unified pgsql_stmt_finish,
+		 * but maybe there still is an internal query that we omitted to adapt.
+		 * So instead of asserting let's just emit an informational notice,
+		 * and consume anyway (results consumption is handle-wise, so we have no formal
+		 * need for the statement). */
+		if (first) {
+			php_error_docref("ref.pgsql", E_NOTICE, "Internal error: unable to link a libpq result to consume, to its origin statement");
+			first = false;
+		}
+		PQclear(pgsql_result);
+	}
+}
+
 static void _pdo_pgsql_notice(void *context, const char *message) /* {{{ */
 {
 	pdo_dbh_t * dbh = (pdo_dbh_t *)context;
@@ -355,6 +387,7 @@ static zend_long pgsql_handle_doer(pdo_dbh_t *dbh, const zend_string *sql)
 
 	bool in_trans = pgsql_handle_in_transaction(dbh);
 
+	pgsql_finish_running_stmt(H);
 	if (!(res = PQexec(H->server, ZSTR_VAL(sql)))) {
 		/* fatal error */
 		pdo_pgsql_error(dbh, PGRES_FATAL_ERROR, NULL);
@@ -430,6 +463,7 @@ static zend_string *pdo_pgsql_last_insert_id(pdo_dbh_t *dbh, const zend_string *
 	PGresult *res;
 	ExecStatusType status;
 
+	pgsql_finish_running_stmt(H);
 	if (name == NULL) {
 		res = PQexec(H->server, "SELECT LASTVAL()");
 	} else {
@@ -593,6 +627,7 @@ static bool pdo_pgsql_transaction_cmd(const char *cmd, pdo_dbh_t *dbh)
 	PGresult *res;
 	bool ret = true;
 
+	pgsql_finish_running_stmt(H);
 	res = PQexec(H->server, cmd);
 
 	if (PQresultStatus(res) != PGRES_COMMAND_OK) {
@@ -700,9 +735,8 @@ void pgsqlCopyFromArray_internal(INTERNAL_FUNCTION_PARAMETERS)
 	/* Obtain db Handle */
 	H = (pdo_pgsql_db_handle *)dbh->driver_data;
 
-	while ((pgsql_result = PQgetResult(H->server))) {
-		PQclear(pgsql_result);
-	}
+	pgsql_discard_running_stmt(H);
+
 	pgsql_result = PQexec(H->server, query);
 
 	efree(query);
@@ -824,9 +858,8 @@ void pgsqlCopyFromFile_internal(INTERNAL_FUNCTION_PARAMETERS)
 
 	H = (pdo_pgsql_db_handle *)dbh->driver_data;
 
-	while ((pgsql_result = PQgetResult(H->server))) {
-		PQclear(pgsql_result);
-	}
+	pgsql_discard_running_stmt(H);
+
 	pgsql_result = PQexec(H->server, query);
 
 	efree(query);
@@ -920,9 +953,7 @@ void pgsqlCopyToFile_internal(INTERNAL_FUNCTION_PARAMETERS)
 		RETURN_FALSE;
 	}
 
-	while ((pgsql_result = PQgetResult(H->server))) {
-		PQclear(pgsql_result);
-	}
+	pgsql_discard_running_stmt(H);
 
 	/* using pre-9.0 syntax as PDO_pgsql is 7.4+ compatible */
 	if (pg_fields) {
@@ -1011,9 +1042,7 @@ void pgsqlCopyToArray_internal(INTERNAL_FUNCTION_PARAMETERS)
 
 	H = (pdo_pgsql_db_handle *)dbh->driver_data;
 
-	while ((pgsql_result = PQgetResult(H->server))) {
-		PQclear(pgsql_result);
-	}
+	pgsql_discard_running_stmt(H);
 
 	/* using pre-9.0 syntax as PDO_pgsql is 7.4+ compatible */
 	if (pg_fields) {

ext/pdo_pgsql/pgsql_statement.c

@@ -56,14 +56,14 @@
 #define FLOAT8LABEL "float8"
 #define FLOAT8OID 701
 
-#define FIN_DISCARD 0x1
-#define FIN_CLOSE   0x2
-#define FIN_ABORT   0x4
 
 
-
-static void pgsql_stmt_finish(pdo_pgsql_stmt *S, int fin_mode)
+void pgsql_stmt_finish(pdo_pgsql_stmt *S, int fin_mode)
 {
+	if (!S) {
+		return;
+	}
+
 	pdo_pgsql_db_handle *H = S->H;
 
 	if (S->is_running_unbuffered && S->result && (fin_mode & FIN_ABORT)) {

ext/pdo_pgsql/php_pdo_pgsql_int.h

@@ -92,6 +92,12 @@ extern int _pdo_pgsql_error(pdo_dbh_t *dbh, pdo_stmt_t *stmt, int errcode, const
 
 extern const struct pdo_stmt_methods pgsql_stmt_methods;
 
+#define FIN_DISCARD 0x1
+#define FIN_CLOSE   0x2
+#define FIN_ABORT   0x4
+
+extern void pgsql_stmt_finish(pdo_pgsql_stmt *S, int fin_mode);
+
 #define pdo_pgsql_sqlstate(r) PQresultErrorField(r, PG_DIAG_SQLSTATE)
 
 enum {