From 6068f3e4cbbd985b0dc309030ec9f8d3c1cf7a96 Mon Sep 17 00:00:00 2001
From: Malcolm Tredinnick <malcolm.tredinnick@gmail.com>
Date: Wed, 27 Sep 2006 02:42:31 +0000
Subject: [PATCH] Reintroduced the changes from [3855] with more flexible
 handling of version strings. Refs #2188, #2827.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@3872 bcc190cf-cafb-0310-a4f2-bffc1f526a37
---
 AUTHORS                          |  1 +
 django/core/management.py        |  9 ++++++++-
 django/db/backends/mysql/base.py | 18 ++++++++++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/AUTHORS b/AUTHORS
index 3f256aad096..5ff4bc4da02 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -119,6 +119,7 @@ answer newbie questions, and generally made Django that much better:
     Eric Moritz <http://eric.themoritzfamily.com/>
     Robin Munn <http://www.geekforgod.com/>
     Nebojša Dorđević
+    Fraser Nevett <mail@nevett.org>
     Sam Newman <http://www.magpiebrain.com/>
     Neal Norwitz <nnorwitz@google.com>
     oggie rob <oz.robharvey@gmail.com>
diff --git a/django/core/management.py b/django/core/management.py
index bcfcd60617e..4fa40b58074 100644
--- a/django/core/management.py
+++ b/django/core/management.py
@@ -820,7 +820,8 @@ def get_validation_errors(outfile, app=None):
     validates all models of all installed apps. Writes errors, if any, to outfile.
     Returns number of errors.
     """
-    from django.db import models
+    from django.conf import settings
+    from django.db import models, connection
     from django.db.models.loading import get_app_errors
     from django.db.models.fields.related import RelatedObject
 
@@ -862,6 +863,12 @@ def get_validation_errors(outfile, app=None):
             if f.db_index not in (None, True, False):
                 e.add(opts, '"%s": "db_index" should be either None, True or False.' % f.name)
 
+            # Check that maxlength <= 255 if using older MySQL versions.
+            if settings.DATABASE_ENGINE == 'mysql':
+                db_version = connection.get_server_version()
+                if db_version < (5, 0, 3) and isinstance(f, (models.CharField, models.CommaSeparatedIntegerField, models.SlugField)) and f.maxlength > 255:
+                    e.add(opts, '"%s": %s cannot have a "maxlength" greater than 255 when you are using a version of MySQL prior to 5.0.3 (you are using %s).' % (f.name, f.__class__.__name__, '.'.join(str(n) for n in db_version[:3])))
+
             # Check to see if the related field will clash with any
             # existing fields, m2m fields, m2m related objects or related objects
             if f.rel:
diff --git a/django/db/backends/mysql/base.py b/django/db/backends/mysql/base.py
index 23ea76316f0..45118697280 100644
--- a/django/db/backends/mysql/base.py
+++ b/django/db/backends/mysql/base.py
@@ -13,6 +13,7 @@ except ImportError, e:
 from MySQLdb.converters import conversions
 from MySQLdb.constants import FIELD_TYPE
 import types
+import re
 
 DatabaseError = Database.DatabaseError
 
@@ -24,6 +25,12 @@ django_conversions.update({
     FIELD_TYPE.TIME: util.typecast_time,
 })
 
+# This should match the numerical portion of the version numbers (we can treat
+# versions like 5.0.24 and 5.0.24a as the same). Based on the list of version
+# at http://dev.mysql.com/doc/refman/4.1/en/news.html and
+# http://dev.mysql.com/doc/refman/5.0/en/news.html .
+server_version_re = re.compile(r'(\d{1,2})\.(\d{1,2})\.(\d{1,2})')
+
 # This is an extra debug layer over MySQL queries, to display warnings.
 # It's only used when DEBUG=True.
 class MysqlDebugWrapper:
@@ -61,6 +68,7 @@ class DatabaseWrapper(local):
     def __init__(self):
         self.connection = None
         self.queries = []
+        self.server_version = None
 
     def _valid_connection(self):
         if self.connection is not None:
@@ -110,6 +118,16 @@ class DatabaseWrapper(local):
             self.connection.close()
             self.connection = None
 
+    def get_server_version(self):
+        if not self.server_version:
+            if not self._valid_connection():
+                self.cursor()
+            m = server_version_re.match(self.connection.get_server_info())
+            if not m:
+                raise Exception('Unable to determine MySQL version from version string %r' % self.connection.get_server_info())
+            self.server_version = m.groups()
+        return self.server_version
+
 supports_constraints = True
 
 def quote_name(name):