include parsed col length field as integer from mysql index reflection

Added support to MySQL index reflection to correctly reflect the
``mysql_length`` dictionary, which previously was being ignored.

Fixes: #9047
Change-Id: I0a5e27123be68741e12af4464a0fa305052ec36e

2 files changed, 16 insertions, 3 deletions

diff --git a/lib/sqlalchemy/dialects/mysql/base.py b/lib/sqlalchemy/dialects/mysql/base.py
index fbd20a0ba..e89ebb09d 100644
--- a/lib/sqlalchemy/dialects/mysql/base.py
+++ b/lib/sqlalchemy/dialects/mysql/base.py
@@ -3075,14 +3075,22 @@ class MySQLDialect(default.DefaultDialect):
                 ]
 
             index_d = {}
-            if dialect_options:
-                index_d["dialect_options"] = dialect_options
 
             index_d["name"] = spec["name"]
             index_d["column_names"] = [s[0] for s in spec["columns"]]
+            mysql_length = {
+                s[0]: s[1] for s in spec["columns"] if s[1] is not None
+            }
+            if mysql_length:
+                dialect_options["%s_length" % self.name] = mysql_length
+
             index_d["unique"] = unique
             if flavor:
                 index_d["type"] = flavor
+
+            if dialect_options:
+                index_d["dialect_options"] = dialect_options
+
             indexes.append(index_d)
         indexes.sort(key=lambda d: d["name"] or "~")  # sort None as last
         return indexes if indexes else ReflectionDefaults.indexes()
diff --git a/lib/sqlalchemy/dialects/mysql/reflection.py b/lib/sqlalchemy/dialects/mysql/reflection.py
index fe92c733a..ec3f82a60 100644
--- a/lib/sqlalchemy/dialects/mysql/reflection.py
+++ b/lib/sqlalchemy/dialects/mysql/reflection.py
@@ -382,7 +382,12 @@ class MySQLTableDefinitionParser:
     def _parse_keyexprs(self, identifiers):
         """Unpack '"col"(2),"col" ASC'-ish strings into components."""
 
-        return self._re_keyexprs.findall(identifiers)
+        return [
+            (colname, int(length) if length else None, modifiers)
+            for colname, length, modifiers in self._re_keyexprs.findall(
+                identifiers
+            )
+        ]
 
     def _prep_regexes(self):
         """Pre-compile regular expressions."""