Bump minimum MySQL version to 5.0.2; use all-numeric server version

MySQL dialect's server_version_info tuple is now all numeric.  String
tokens like "MariaDB" are no longer present so that numeric comparison
works in all cases.  The .is_mariadb flag on the dialect should be
consulted for whether or not mariadb was detected.   Additionally removed
structures meant to support extremely old MySQL versions 3.x and 4.x;
the minimum MySQL version supported is now version 5.0.2.

In addition, as the "MariaDB" name goes away from server version,
expand upon the change in I330815ebe572b6a9818377da56621397335fa702
to support the name "mariadb" throughout the dialect and test suite
when mariadb-only mode is used.    This changes the "name" field
on the MariaDB dialect to "mariadb", which then implies a change
throughout the testing requirements system as well as all the
dialect-specific DDL argument names such as "mysql_engine" is
now specified as "mariadb_engine", etc.   Make use of the
recent additions to test suite URL provisioning so that we can
force MariaDB databases to have a "mariadb-only" dialect which
allows us to test this name change fully.

Update documentation to refer to MySQL / MariaDB explicitly
as well as indicating the "mariadb_" prefix used for options.

It seems likely that MySQL and MariaDB version numbers are going to
start colliding at some point so having the "mariadb" name
be available as a totally separate dialect name should give us
some options in this regard.

Currently also includes a date related fix to a test for
the postgresql dialect that was implicitly assuming a
non-UTC timezone

Fixes: #4189
Change-Id: I00e76d00f62971e1f067bd61915fa6cc1cf64e5e

1 files changed, 27 insertions, 4 deletions

diff --git a/lib/sqlalchemy/dialects/mysql/provision.py b/lib/sqlalchemy/dialects/mysql/provision.py
index bf126464d..b86056da6 100644
--- a/lib/sqlalchemy/dialects/mysql/provision.py
+++ b/lib/sqlalchemy/dialects/mysql/provision.py
@@ -1,10 +1,33 @@
+import copy
+
+from ... import exc
 from ...testing.provision import configure_follower
 from ...testing.provision import create_db
 from ...testing.provision import drop_db
+from ...testing.provision import generate_driver_url
 from ...testing.provision import temp_table_keyword_args
 
 
-@create_db.for_db("mysql")
+@generate_driver_url.for_db("mysql", "mariadb")
+def generate_driver_url(url, driver):
+    backend = url.get_backend_name()
+
+    if backend == "mysql":
+        dialect_cls = url.get_dialect()
+        if dialect_cls._is_mariadb_from_url(url):
+            backend = "mariadb"
+
+    new_url = copy.copy(url)
+    new_url.drivername = "%s+%s" % (backend, driver)
+    try:
+        new_url.get_dialect()
+    except exc.NoSuchModuleError:
+        return None
+    else:
+        return new_url
+
+
+@create_db.for_db("mysql", "mariadb")
 def _mysql_create_db(cfg, eng, ident):
     with eng.connect() as conn:
         try:
@@ -23,13 +46,13 @@ def _mysql_create_db(cfg, eng, ident):
         )
 
 
-@configure_follower.for_db("mysql")
+@configure_follower.for_db("mysql", "mariadb")
 def _mysql_configure_follower(config, ident):
     config.test_schema = "%s_test_schema" % ident
     config.test_schema_2 = "%s_test_schema_2" % ident
 
 
-@drop_db.for_db("mysql")
+@drop_db.for_db("mysql", "mariadb")
 def _mysql_drop_db(cfg, eng, ident):
     with eng.connect() as conn:
         conn.exec_driver_sql("DROP DATABASE %s_test_schema" % ident)
@@ -37,6 +60,6 @@ def _mysql_drop_db(cfg, eng, ident):
         conn.exec_driver_sql("DROP DATABASE %s" % ident)
 
 
-@temp_table_keyword_args.for_db("mysql")
+@temp_table_keyword_args.for_db("mysql", "mariadb")
 def _mysql_temp_table_keyword_args(cfg, eng):
     return {"prefixes": ["TEMPORARY"]}