BUG#37774513: Inconsistent conversion to_sql for cext vs pure python

This patch fixes the inconsistency of data type conversion support
between pure-python and c-extension based connector.

Change-Id: I829a2871e6dc2ebe782be74cbe01fd60c8c2be5b

Author: SubCoder1

CHANGES.txt

@@ -15,9 +15,10 @@ v9.4.0
 - WL#16963: Update the OpenTelemetry version
 - WL#16962: Update the Python Protobuf version
 - BUG#37868219: RPM packages have incorrect copyright year in their metadata
-- BUG#37820231: Text based django ORM filters doesn't work with Connector/Python
 - BUG#37859771: mysql/connector python version 9.3.0 has a regression which cannot persist binary data with percent signs in it
+- BUG#37820231: Text based django ORM filters doesn't work with Connector/Python
 - BUG#37806057: Rename extra option (when installing wheel package) to install webauthn functionality dependencies
+- BUG#37774513: Inconsistent conversion to_sql for cext vs pure python
 - BUG#37642447: The license type is missing from RPM package
 - BUG#37627508: mysql/connector python fetchmany() has an off by one bug when argument given as 1
 - BUG#37047789: Python connector does not support Django enum

mysql-connector-python/lib/mysql/connector/constants.py

@@ -31,6 +31,9 @@
 import warnings
 
 from abc import ABC, ABCMeta
+from datetime import date, datetime, time, timedelta
+from decimal import Decimal
+from time import struct_time
 from typing import Any, Dict, List, Optional, Sequence, Tuple, Union, ValuesView
 
 from .charsets import MYSQL_CHARACTER_SETS, MYSQL_CHARACTER_SETS_57
@@ -284,6 +287,26 @@
     "TLSv1.3": TLSV1_3_CIPHER_SUITES.values(),
 }
 
+NATIVE_SUPPORTED_CONVERSION_TYPES = {
+    int: "int",
+    float: "float",
+    str: "str",
+    bytes: "bytes",
+    bytearray: "bytearray",
+    bool: "bool",
+    type(None): "nonetype",
+    datetime: "datetime",
+    date: "date",
+    time: "time",
+    struct_time: "struct_time",
+    timedelta: "timedelta",
+    Decimal: "decimal",
+}
+"""Dictionary of the supported data types of the default MySQLConverter class
+and the corresponding tag names used to map against their respective methods
+'_{tag_name}_to_mysql(...)'. These converter methods are then used to convert
+the matched data type to mysql recognizable type."""
+
 
 def flag_is_set(flag: int, flags: int) -> bool:
     """Checks if the flag is set

mysql-connector-python/lib/mysql/connector/conversion.py

@@ -40,6 +40,7 @@
 
 from .constants import (
     MYSQL_VECTOR_TYPE_CODE,
+    NATIVE_SUPPORTED_CONVERSION_TYPES,
     CharacterSet,
     FieldFlag,
     FieldType,
@@ -236,13 +237,26 @@ def to_mysql(self, value: MySQLConvertibleType) -> MySQLProducedType:
         """Convert Python data type to MySQL"""
         if isinstance(value, Enum):
             value = value.value
-        type_name = value.__class__.__name__.lower()
+        # check if type of value object matches any one of the native supported conversion types
+        # most of the types will match the condition below
+        type_name: str = NATIVE_SUPPORTED_CONVERSION_TYPES.get(type(value), "")
+        if not type_name:
+            # check if the value object inherits from one of the native supported conversion types
+            type_name = next(
+                (
+                    name
+                    for data_type, name in NATIVE_SUPPORTED_CONVERSION_TYPES.items()
+                    if isinstance(value, data_type)
+                ),
+                value.__class__.__name__.lower(),
+            )
         try:
             converted: MySQLProducedType = getattr(self, f"_{type_name}_to_mysql")(
                 value
             )
             return converted
         except AttributeError:
+            # Value type is not a native one, nor a subclass of a native one
             if self.str_fallback:
                 return str(value).encode()
             raise TypeError(

mysql-connector-python/src/include/mysql_capi_conversion.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2024, Oracle and/or its affiliates.
+ * Copyright (c) 2014, 2025, Oracle and/or its affiliates.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License, version 2.0, as
@@ -33,6 +33,9 @@
 
 #include <Python.h>
 
+int
+is_decimal_instance(PyObject *obj);
+
 PyObject *
 pytomy_date(PyObject *obj);
 

mysql-connector-python/src/mysql_capi.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2024, Oracle and/or its affiliates.
+ * Copyright (c) 2014, 2025, Oracle and/or its affiliates.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License, version 2.0, as
@@ -2010,16 +2010,16 @@ MySQL_convert_to_mysql(MySQL *self, PyObject *args)
             // datetime is handled first
             new_value = pytomy_datetime(value);
         }
-        else if (PyDate_CheckExact(value)) {
+        else if (PyDate_Check(value)) {
             new_value = pytomy_date(value);
         }
         else if (PyTime_Check(value)) {
             new_value = pytomy_time(value);
         }
-        else if (PyDelta_CheckExact(value)) {
+        else if (PyDelta_Check(value)) {
             new_value = pytomy_timedelta(value);
         }
-        else if (strcmp((value)->ob_type->tp_name, "decimal.Decimal") == 0) {
+        else if (is_decimal_instance(value)) {
             new_value = pytomy_decimal(value);
         }
         else if (self->converter_str_fallback == Py_True) {
@@ -2194,7 +2194,7 @@ MySQL_query(MySQL *self, PyObject *args, PyObject *kwds)
                 continue;
             }
             /* DATE */
-            else if (PyDate_CheckExact(value)) {
+            else if (PyDate_Check(value)) {
                 MYSQL_TIME *date = &pbind->buffer.t;
                 date->year = PyDateTime_GET_YEAR(value);
                 date->month = PyDateTime_GET_MONTH(value);
@@ -2225,7 +2225,7 @@ MySQL_query(MySQL *self, PyObject *args, PyObject *kwds)
                 continue;
             }
             /* datetime.timedelta is TIME */
-            else if (PyDelta_CheckExact(value)) {
+            else if (PyDelta_Check(value)) {
                 MYSQL_TIME *time = &pbind->buffer.t;
                 time->hour = PyDateTime_TIME_GET_HOUR(value);
                 time->minute = PyDateTime_TIME_GET_MINUTE(value);
@@ -2244,7 +2244,7 @@ MySQL_query(MySQL *self, PyObject *args, PyObject *kwds)
                 continue;
             }
             /* DECIMAL */
-            else if (strcmp((value)->ob_type->tp_name, "decimal.Decimal") == 0) {
+            else if (is_decimal_instance(value)) {
                 pbind->str_value = pytomy_decimal(value);
                 mbind[i].buffer_type = MYSQL_TYPE_DECIMAL;
             }
@@ -3383,7 +3383,7 @@ MySQLPrepStmt_execute(MySQLPrepStmt *self, PyObject *args, PyObject *kwds)
             continue;
         }
         /* DATE */
-        else if (PyDate_CheckExact(value)) {
+        else if (PyDate_Check(value)) {
             MYSQL_TIME *date = &pbind->buffer.t;
             date->year = PyDateTime_GET_YEAR(value);
             date->month = PyDateTime_GET_MONTH(value);
@@ -3414,7 +3414,7 @@ MySQLPrepStmt_execute(MySQLPrepStmt *self, PyObject *args, PyObject *kwds)
             continue;
         }
         /* datetime.timedelta is TIME */
-        else if (PyDelta_CheckExact(value)) {
+        else if (PyDelta_Check(value)) {
             MYSQL_TIME *time = &pbind->buffer.t;
             time->hour = PyDateTime_TIME_GET_HOUR(value);
             time->minute = PyDateTime_TIME_GET_MINUTE(value);
@@ -3433,7 +3433,7 @@ MySQLPrepStmt_execute(MySQLPrepStmt *self, PyObject *args, PyObject *kwds)
             continue;
         }
         /* DECIMAL */
-        else if (strcmp((value)->ob_type->tp_name, "decimal.Decimal") == 0) {
+        else if (is_decimal_instance(value)) {
             pbind->str_value = pytomy_decimal(value);
             mbind[i].buffer_type = MYSQL_TYPE_DECIMAL;
         }

mysql-connector-python/src/mysql_capi_conversion.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2024, Oracle and/or its affiliates.
+ * Copyright (c) 2014, 2025, Oracle and/or its affiliates.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License, version 2.0, as
@@ -44,6 +44,34 @@
 #define MINYEAR 1
 #define MAXYEAR 9999
 
+
+// Decimal module needs to be loaded at runtime
+static PyObject *decimal_class = NULL;
+
+/**
+  Check whether the type of object is a decimal.
+
+  Check whether the object passed via parameter is an instance of decimal class.
+
+  @param    obj     the PyObject to be checked
+
+  @return   1 if obj is an instance of decimal class, 0 otherwise.
+    @retval 1   Instance of the decimal class
+    @retval 0   Not an instance of the decimal class
+*/
+int is_decimal_instance(PyObject *obj)
+{
+    if (!decimal_class) {
+        PyObject *decimal_module = PyImport_ImportModule("decimal");
+        if (decimal_module) {
+            decimal_class = PyObject_GetAttrString(decimal_module, "Decimal");
+        }
+    }
+    return (decimal_class)
+        ? PyObject_IsInstance(obj, decimal_class)
+        : strcmp((obj)->ob_type->tp_name, "decimal.Decimal") == 0;
+}
+
 /**
   Check whether a year is a leap year.