Reflect ASC/DESC in MySQL index columns

Fixed bug in index reflection where on MySQL 8.0 an index that includes
ASC or DESC in an indexed column specfication would not be correctly
reflected, as MySQL 8.0 introduces support for returning this information
in a table definition string.

Change-Id: I21f64984ade690aac8c87dbe3aad0c1ee8e9727f
Fixes: #4293

diff --git a/doc/build/changelog/unreleased_12/4293.rst b/doc/build/changelog/unreleased_12/4293.rst
new file mode 100644 (file)
index 0000000..51fac20
--- /dev/null
+++ b/doc/build/changelog/unreleased_12/4293.rst
@@ -0,0 +1,8 @@
+.. change::
+    :tags: bug, mysql
+    :tickets: 4293
+
+    Fixed bug in index reflection where on MySQL 8.0 an index that includes
+    ASC or DESC in an indexed column specfication would not be correctly
+    reflected, as MySQL 8.0 introduces support for returning this information
+    in a table definition string.

diff --git a/lib/sqlalchemy/dialects/mysql/reflection.py b/lib/sqlalchemy/dialects/mysql/reflection.py
index e152110443c59846b0bfe77b39254b547c4b06bd..e88bc3f42fbae16c8ace1ae30a891620ac0ddbe9 100644 (file)
--- a/lib/sqlalchemy/dialects/mysql/reflection.py
+++ b/lib/sqlalchemy/dialects/mysql/reflection.py
@@ -76,6 +76,8 @@ class MySQLTableDefinitionParser(object):
         if m:
             spec = m.groupdict()
             # convert columns into name, length pairs
+            # NOTE: we may want to consider SHOW INDEX as the
+            # format of indexes in MySQL becomes more complex
             spec['columns'] = self._parse_keyexprs(spec['columns'])
             if spec['version_sql']:
                 m2 = self._re_key_version_sql.match(spec['version_sql'])
@@ -317,11 +319,10 @@ class MySQLTableDefinitionParser(object):
 
         # `col`,`col2`(32),`col3`(15) DESC
         #
-        # Note: ASC and DESC aren't reflected, so we'll punt...
         self._re_keyexprs = _re_compile(
             r'(?:'
             r'(?:%(iq)s((?:%(esc_fq)s|[^%(fq)s])+)%(fq)s)'
-            r'(?:\((\d+)\))?(?=\,|$))+' % quotes)
+            r'(?:\((\d+)\))?(?: +(ASC|DESC))?(?=\,|$))+' % quotes)
 
         # 'foo' or 'foo','bar' or 'fo,o','ba''a''r'
         self._re_csv_str = _re_compile(r'\x27(?:\x27\x27|[^\x27])*\x27')

diff --git a/test/dialect/mysql/test_reflection.py b/test/dialect/mysql/test_reflection.py
index 76b6954aedfb1ff92a2ee21c09ad1ffe7c5c3232..c244ba97274cb693caf7df36f4ae72285c29a5e0 100644 (file)
--- a/test/dialect/mysql/test_reflection.py
+++ b/test/dialect/mysql/test_reflection.py
@@ -633,6 +633,20 @@ class ReflectionTest(fixtures.TestBase, AssertsCompiledSQL):
             "(textdata) WITH PARSER ngram"
         )
 
+    @testing.provide_metadata
+    def test_non_column_index(self):
+        m1 = self.metadata
+        t1 = Table(
+            'add_ix', m1, Column('x', String(50)), mysql_engine='InnoDB')
+        Index('foo_idx', t1.c.x.desc())
+        m1.create_all()
+
+        insp = inspect(testing.db)
+        eq_(
+            insp.get_indexes("add_ix"),
+            [{'name': 'foo_idx', 'column_names': ['x'], 'unique': False}]
+        )
+
 
 class RawReflectionTest(fixtures.TestBase):
     __backend__ = True
@@ -678,6 +692,55 @@ class RawReflectionTest(fixtures.TestBase):
             "/*!50100 WITH PARSER `ngram` */ "
         )
 
+    def test_key_reflection_columns(self):
+        regex = self.parser._re_key
+        exprs = self.parser._re_keyexprs
+        m = regex.match(
+            "  KEY (`id`) USING BTREE COMMENT '''comment'")
+        eq_(m.group("columns"), '`id`')
+
+        m = regex.match(
+            "  KEY (`x`, `y`) USING BTREE")
+        eq_(m.group("columns"), '`x`, `y`')
+
+        eq_(
+            exprs.findall(m.group("columns")),
+            [("x", "", ""), ("y", "", "")]
+        )
+
+        m = regex.match(
+            "  KEY (`x`(25), `y`(15)) USING BTREE")
+        eq_(m.group("columns"), '`x`(25), `y`(15)')
+        eq_(
+            exprs.findall(m.group("columns")),
+            [("x", "25", ""), ("y", "15", "")]
+        )
+
+        m = regex.match(
+            "  KEY (`x`(25) DESC, `y`(15) ASC) USING BTREE")
+        eq_(m.group("columns"), '`x`(25) DESC, `y`(15) ASC')
+        eq_(
+            exprs.findall(m.group("columns")),
+            [("x", "25", "DESC"), ("y", "15", "ASC")]
+        )
+
+        m = regex.match(
+            "  KEY `foo_idx` (`x` DESC)")
+        eq_(m.group("columns"), '`x` DESC')
+        eq_(
+            exprs.findall(m.group("columns")),
+            [("x", "", "DESC")]
+        )
+
+        eq_(
+            exprs.findall(m.group("columns")),
+            [("x", "", "DESC")]
+        )
+
+        m = regex.match(
+            "  KEY `foo_idx` (`x` DESC, `y` ASC)")
+        eq_(m.group("columns"), '`x` DESC, `y` ASC')
+
     def test_fk_reflection(self):
         regex = self.parser._re_fk_constraint