Clean up serial column detection.

Use more postgres catalog data to correctly identify serial columns.
This also means we can remove additional hacky code around guessing
serial columns.

Refs #7871

src/Database/Schema/PostgresSchema.php

@@ -37,17 +37,20 @@ class PostgresSchema extends BaseSchema
      */
     public function describeColumnSql($tableName, $config)
     {
-        $sql =
-        'SELECT DISTINCT table_schema AS schema, column_name AS name, data_type AS type,
+        $sql = 'SELECT DISTINCT table_schema AS schema,
+            column_name AS name,
+            data_type AS type,
             is_nullable AS null, column_default AS default,
             character_maximum_length AS char_length,
             d.description as comment,
-            ordinal_position
+            ordinal_position,
+            pg_get_serial_sequence(attr.attrelid::regclass::text, attr.attname) IS NOT NULL AS has_serial
         FROM information_schema.columns c
         INNER JOIN pg_catalog.pg_namespace ns ON (ns.nspname = table_schema)
         INNER JOIN pg_catalog.pg_class cl ON (cl.relnamespace = ns.oid AND cl.relname = table_name)
         LEFT JOIN pg_catalog.pg_index i ON (i.indrelid = cl.oid AND i.indkey[0] = c.ordinal_position)
         LEFT JOIN pg_catalog.pg_description d on (cl.oid = d.objoid AND d.objsubid = c.ordinal_position)
+        LEFT JOIN pg_catalog.pg_attribute attr ON (cl.oid = attr.attrelid AND column_name = attr.attname)
         WHERE table_name = ? AND table_schema = ? AND table_catalog = ?
         ORDER BY ordinal_position';
 
@@ -144,8 +147,7 @@ class PostgresSchema extends BaseSchema
                 $row['default'] = 0;
             }
         }
-        // Sniff out serial types.
-        if (in_array($field['type'], ['integer', 'biginteger']) && strpos($row['default'], 'nextval(') === 0) {
+        if (!empty($row['has_serial'])) {
             $field['autoIncrement'] = true;
         }
         $field += [
@@ -193,9 +195,7 @@ class PostgresSchema extends BaseSchema
             c2.relname,
             a.attname,
             i.indisprimary,
-            i.indisunique,
-            i.indisvalid,
-            pg_catalog.pg_get_indexdef(i.indexrelid, 0, true) AS statement
+            i.indisunique
         FROM pg_catalog.pg_class AS c,
             pg_catalog.pg_class AS c2,
             pg_catalog.pg_index AS i,
@@ -268,19 +268,6 @@ class PostgresSchema extends BaseSchema
         }
         $constraint['columns'][] = $row['attname'];
         $table->addConstraint($name, $constraint);
-
-        // If there is only one column in the primary key and it is integery,
-        // make it autoincrement.
-        $columns = $constraint['columns'];
-        $columnDef = $table->column($columns[0]);
-
-        if ($type === Table::CONSTRAINT_PRIMARY &&
-            count($columns) === 1 &&
-            in_array($columnDef['type'], ['integer', 'biginteger'])
-        ) {
-            $columnDef['autoIncrement'] = true;
-            $table->addColumn($columns[0], $columnDef);
-        }
     }
 
     /**

tests/TestCase/Database/Schema/PostgresSchemaTest.php

@@ -288,7 +288,7 @@ SQL;
                 'precision' => null,
                 'unsigned' => null,
                 'comment' => null,
-                'autoIncrement' => true,
+                'autoIncrement' => false,
             ],
             'title' => [
                 'type' => 'string',
@@ -381,8 +381,8 @@ SQL;
         $connection->execute('DROP TABLE schema_composite');
 
         $this->assertEquals(['id', 'site_id'], $result->primaryKey());
-        $this->assertNull($result->column('site_id')['autoIncrement'], 'site_id should not be autoincrement');
         $this->assertTrue($result->column('id')['autoIncrement'], 'id should be autoincrement');
+        $this->assertNull($result->column('site_id')['autoIncrement'], 'site_id should not be autoincrement');
     }
 
     /**