Expose Cursor.warning_count

Nothing4You · Nothing4You · commit 958eec6ea530 · 2022-07-11T01:53:23.000+02:00
After the removal of automatic warnings in #774 this provides a way to check for existence of warnings without having to perform an additional query over the network.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,6 +7,7 @@ Release date: TBD
 * Dropped support of end of life MySQL version 5.6
 * Dropped support of end of life MariaDB versions below 10.3
 * Dropped support of end of life Python version 3.6
+* Exposed `Cursor.warning_count` to check for warnings without additional query (#1056)
 
 
 ## v1.0.2
diff --git a/pymysql/cursors.py b/pymysql/cursors.py
@@ -32,6 +32,7 @@ class Cursor:
 
     def __init__(self, connection):
         self.connection = connection
+        self.warning_count = -1
         self.description = None
         self.rownumber = 0
         self.rowcount = -1
@@ -331,6 +332,7 @@ def _clear_result(self):
         self._result = None
 
         self.rowcount = 0
+        self.warning_count = -1
         self.description = None
         self.lastrowid = None
         self._rows = None
@@ -341,6 +343,7 @@ def _do_get_result(self):
         self._result = result = conn._result
 
         self.rowcount = result.affected_rows
+        self.warning_count = result.warning_count
         self.description = result.description
         self.lastrowid = result.insert_id
         self._rows = result.rows
@@ -442,6 +445,7 @@ def fetchone(self):
         self._check_executed()
         row = self.read_next()
         if row is None:
+            self.warning_count = self._result.warning_count
             return None
         self.rownumber += 1
         return row
@@ -475,6 +479,7 @@ def fetchmany(self, size=None):
         for i in range(size):
             row = self.read_next()
             if row is None:
+                self.warning_count = self._result.warning_count
                 break
             rows.append(row)
             self.rownumber += 1
diff --git a/pymysql/tests/test_SSCursor.py b/pymysql/tests/test_SSCursor.py
@@ -3,13 +3,13 @@
 try:
     from pymysql.tests import base
     import pymysql.cursors
-    from pymysql.constants import CLIENT
+    from pymysql.constants import CLIENT, ER
 except Exception:
     # For local testing from top-level directory, without installing
     sys.path.append("../pymysql")
     from pymysql.tests import base
     import pymysql.cursors
-    from pymysql.constants import CLIENT
+    from pymysql.constants import CLIENT, ER
 
 
 class TestSSCursor(base.PyMySQLTestCase):
@@ -122,6 +122,35 @@ def test_SSCursor(self):
         cursor.execute("DROP TABLE IF EXISTS tz_data")
         cursor.close()
 
+    def test_warnings(self):
+        con = self.connect()
+        cur = con.cursor(pymysql.cursors.SSCursor)
+        cur.execute("DROP TABLE IF EXISTS `no_exists_table`")
+        self.assertEqual(cur.warning_count, 1)
+
+        cur.execute("SHOW WARNINGS")
+        w = cur.fetchone()
+        self.assertEqual(w[1], ER.BAD_TABLE_ERROR)
+        self.assertIn(
+            "no_exists_table",
+            w[2],
+        )
+
+        # ensure unbuffered result is finished
+        self.assertIsNone(cur.fetchone())
+
+        cur.execute("SELECT 1")
+        self.assertEqual(cur.fetchone(), (1,))
+        self.assertIsNone(cur.fetchone())
+
+        self.assertEqual(cur.warning_count, 0)
+
+        cur.execute("SELECT CAST('abc' AS SIGNED)")
+        # this ensures fully retrieving the unbuffered result
+        rows = cur.fetchmany(2)
+        self.assertEqual(len(rows), 1)
+        self.assertEqual(cur.warning_count, 1)
+
 
 __all__ = ["TestSSCursor"]
 
diff --git a/pymysql/tests/test_cursor.py b/pymysql/tests/test_cursor.py
@@ -1,5 +1,4 @@
-import warnings
-
+from pymysql.constants import ER
 from pymysql.tests import base
 import pymysql.cursors
 
@@ -129,3 +128,20 @@ def test_executemany(self):
             )
         finally:
             cursor.execute("DROP TABLE IF EXISTS percent_test")
+
+    def test_warnings(self):
+        con = self.connect()
+        cur = con.cursor()
+        cur.execute("DROP TABLE IF EXISTS `no_exists_table`")
+        self.assertEqual(cur.warning_count, 1)
+
+        cur.execute("SHOW WARNINGS")
+        w = cur.fetchone()
+        self.assertEqual(w[1], ER.BAD_TABLE_ERROR)
+        self.assertIn(
+            "no_exists_table",
+            w[2],
+        )
+
+        cur.execute("SELECT 1")
+        self.assertEqual(cur.warning_count, 0)
diff --git a/pymysql/tests/test_load_local.py b/pymysql/tests/test_load_local.py
@@ -1,4 +1,5 @@
 from pymysql import cursors, OperationalError, Warning
+from pymysql.constants import ER
 from pymysql.tests import base
 
 import os
@@ -63,6 +64,37 @@ def test_unbuffered_load_file(self):
             c = conn.cursor()
             c.execute("DROP TABLE test_load_local")
 
+    def test_load_warnings(self):
+        """Test load local infile produces the appropriate warnings"""
+        conn = self.connect()
+        c = conn.cursor()
+        c.execute("CREATE TABLE test_load_local (a INTEGER, b INTEGER)")
+        filename = os.path.join(
+            os.path.dirname(os.path.realpath(__file__)),
+            "data",
+            "load_local_warn_data.txt",
+        )
+        try:
+            c.execute(
+                (
+                    "LOAD DATA LOCAL INFILE '{0}' INTO TABLE "
+                    + "test_load_local FIELDS TERMINATED BY ','"
+                ).format(filename)
+            )
+            self.assertEqual(1, c.warning_count)
+
+            c.execute("SHOW WARNINGS")
+            w = c.fetchone()
+
+            self.assertEqual(ER.TRUNCATED_WRONG_VALUE_FOR_FIELD, w[1])
+            self.assertIn(
+                "incorrect integer value",
+                w[2].lower(),
+            )
+        finally:
+            c.execute("DROP TABLE test_load_local")
+            c.close()
+
 
 if __name__ == "__main__":
     import unittest
