Fix TEXT column variants not round-tripping correctly (#1032)

When using migration_diff, TEXT column variants (TINYTEXT, MEDIUMTEXT,
LONGTEXT) were not being properly mapped back from the database. The
BLOB type handling already used rawType to distinguish BLOB variants,
but TEXT variants were missing equivalent handling.

This adds similar rawType-based mapping for TEXT columns in
mapColumnType() and includes round-trip tests.

Fixes #1029

Author: dereuromark

src/Db/Adapter/MysqlAdapter.php

@@ -594,6 +594,20 @@ protected function mapColumnType(array $columnData): array
                 }
             }
             // else: keep as binary or varbinary (actual BINARY/VARBINARY column)
+        } elseif ($type === TableSchema::TYPE_TEXT) {
+            // CakePHP returns TEXT columns as 'text' with specific lengths
+            // Check the raw MySQL type to distinguish TEXT variants
+            $rawType = $columnData['rawType'] ?? '';
+            if (str_contains($rawType, 'tinytext')) {
+                $length = static::TEXT_TINY;
+            } elseif (str_contains($rawType, 'mediumtext')) {
+                $length = static::TEXT_MEDIUM;
+            } elseif (str_contains($rawType, 'longtext')) {
+                $length = static::TEXT_LONG;
+            } else {
+                // Regular TEXT - use null to indicate default TEXT type
+                $length = null;
+            }
         }
 
         return [$type, $length];

tests/TestCase/Db/Adapter/MysqlAdapterTest.php

@@ -1369,6 +1369,37 @@ public function testBlobRoundTrip(string $type, ?int $limit, string $expectedTyp
         $this->adapter->dropTable('blob_round_trip_test');
     }
 
+    public static function textRoundTripData()
+    {
+        return [
+            // type, limit, expected type after round-trip, expected limit after round-trip
+            ['text', null, 'text', null],
+            ['text', MysqlAdapter::TEXT_TINY, 'text', MysqlAdapter::TEXT_TINY],
+            ['text', MysqlAdapter::TEXT_MEDIUM, 'text', MysqlAdapter::TEXT_MEDIUM],
+            ['text', MysqlAdapter::TEXT_LONG, 'text', MysqlAdapter::TEXT_LONG],
+        ];
+    }
+
+    #[DataProvider('textRoundTripData')]
+    public function testTextRoundTrip(string $type, ?int $limit, string $expectedType, ?int $expectedLimit)
+    {
+        // Create a table with a TEXT column
+        $table = new Table('text_round_trip_test', [], $this->adapter);
+        $table->addColumn('text_col', $type, ['limit' => $limit])
+              ->save();
+
+        // Read the column back from the database
+        $columns = $this->adapter->getColumns('text_round_trip_test');
+
+        $textColumn = $columns[1];
+        $this->assertNotNull($textColumn, 'TEXT column not found');
+        $this->assertSame($expectedType, $textColumn->getType(), 'Type mismatch after round-trip');
+        $this->assertSame($expectedLimit, $textColumn->getLimit(), 'Limit mismatch after round-trip');
+
+        // Clean up
+        $this->adapter->dropTable('text_round_trip_test');
+    }
+
     public function testTimestampInvalidLimit()
     {
         $this->adapter->connect();