From 5af8ece7ac8f5248bb8acd2635e684fe7661d492 Mon Sep 17 00:00:00 2001
From: INADA Naoki <methane@users.noreply.github.com>
Date: Tue, 4 Dec 2018 21:54:14 +0900
Subject: [PATCH] Remove automatic warning check (#296)

---
 MySQLdb/cursors.py                 | 46 ------------------------------
 tests/test_MySQLdb_capabilities.py | 22 --------------
 2 files changed, 68 deletions(-)

diff --git a/MySQLdb/cursors.py b/MySQLdb/cursors.py
index f503b71..9790824 100644
--- a/MySQLdb/cursors.py
+++ b/MySQLdb/cursors.py
@@ -61,7 +61,6 @@ class BaseCursor(object):
         InternalError, ProgrammingError, NotSupportedError,
     )
 
-    _defer_warnings = False
     connection = None
 
     def __init__(self, connection):
@@ -126,40 +125,6 @@ class BaseCursor(object):
         if not self._executed:
             raise ProgrammingError("execute() first")
 
-    def _warning_check(self):
-        from warnings import warn
-        db = self._get_db()
-
-        # None => warnings not interrogated for current query yet
-        # 0 => no warnings exists or have been handled already for this query
-        if self._warnings is None:
-            self._warnings = db.warning_count()
-        if self._warnings:
-            # Only propagate warnings for current query once
-            warning_count = self._warnings
-            self._warnings = 0
-            # When there is next result, fetching warnings cause "command
-            # out of sync" error.
-            if self._result and self._result.has_next:
-                msg = "There are %d MySQL warnings." % (warning_count,)
-                self.messages.append(msg)
-                warn(self.Warning(0, msg), stacklevel=3)
-                return
-
-            warnings = db.show_warnings()
-            if warnings:
-                # This is done in two loops in case
-                # Warnings are set to raise exceptions.
-                for w in warnings:
-                    self.messages.append((self.Warning, w))
-                for w in warnings:
-                    warn(self.Warning(*w[1:3]), stacklevel=3)
-            else:
-                info = db.info()
-                if info:
-                    self.messages.append((self.Warning, info))
-                    warn(self.Warning(0, info), stacklevel=3)
-
     def nextset(self):
         """Advance to the next result set.
 
@@ -175,7 +140,6 @@ class BaseCursor(object):
             return None
         self._do_get_result(db)
         self._post_get_result()
-        self._warning_check()
         return 1
 
     def _do_get_result(self, db):
@@ -248,8 +212,6 @@ class BaseCursor(object):
             query = query.encode(db.encoding, 'surrogateescape')
 
         res = self._query(query)
-        if not self._defer_warnings:
-            self._warning_check()
         return res
 
     def executemany(self, query, args):
@@ -363,8 +325,6 @@ class BaseCursor(object):
         if isinstance(q, unicode):
             q = q.encode(db.encoding, 'surrogateescape')
         self._query(q)
-        if not self._defer_warnings:
-            self._warning_check()
         return args
 
     def _query(self, q):
@@ -470,8 +430,6 @@ class CursorUseResultMixIn(object):
     close() the cursor before additional queries can be performed on
     the connection."""
 
-    _defer_warnings = True
-
     def _get_result(self):
         return self._get_db().use_result()
 
@@ -480,7 +438,6 @@ class CursorUseResultMixIn(object):
         self._check_executed()
         r = self._fetch_row(1)
         if not r:
-            self._warning_check()
             return None
         self.rownumber = self.rownumber + 1
         return r[0]
@@ -491,8 +448,6 @@ class CursorUseResultMixIn(object):
         self._check_executed()
         r = self._fetch_row(size or self.arraysize)
         self.rownumber = self.rownumber + len(r)
-        if not r:
-            self._warning_check()
         return r
 
     def fetchall(self):
@@ -500,7 +455,6 @@ class CursorUseResultMixIn(object):
         self._check_executed()
         r = self._fetch_row(0)
         self.rownumber = self.rownumber + len(r)
-        self._warning_check()
         return r
 
     def __iter__(self):
diff --git a/tests/test_MySQLdb_capabilities.py b/tests/test_MySQLdb_capabilities.py
index 0427ed7..e9b0e2a 100644
--- a/tests/test_MySQLdb_capabilities.py
+++ b/tests/test_MySQLdb_capabilities.py
@@ -160,28 +160,6 @@ class test_MySQLdb(capabilities.DatabaseTest):
             return
         self.fail("Should raise ProgrammingError")
 
-    def test_warning_propagation(self):
-        with warnings.catch_warnings():
-            # Ignore all warnings other than MySQLdb generated ones
-            warnings.simplefilter("ignore")
-            warnings.simplefilter("error", category=MySQLdb.Warning)
-
-            # verify for both buffered and unbuffered cursor types
-            for cursor_class in (cursors.Cursor, cursors.SSCursor):
-                c = self.connection.cursor(cursor_class)
-                try:
-                    c.execute("SELECT CAST('124b' AS SIGNED)")
-                    c.fetchall()
-                except MySQLdb.Warning as e:
-                    # Warnings should have errorcode and string message, just like exceptions
-                    self.assertEqual(len(e.args), 2)
-                    self.assertEqual(e.args[0], 1292)
-                    self.assertTrue(isinstance(e.args[1], unicode))
-                else:
-                    self.fail("Should raise Warning")
-                finally:
-                    c.close()
-
     def test_binary_prefix(self):
         # verify prefix behaviour when enabled, disabled and for default (disabled)
         for binary_prefix in (True, False, None):