Migrations\Shell\Task\MigrationDiffTask::getColumns PHP Method

    protected function getColumns()
    {
        foreach ($this->commonTables as $table => $currentSchema) {
            $currentColumns = $currentSchema->columns();
            $oldColumns = $this->dumpSchema[$table]->columns();
            // brand new columns
            $addedColumns = array_diff($currentColumns, $oldColumns);
            foreach ($addedColumns as $columnName) {
                $this->templateData[$table]['columns']['add'][$columnName] = $currentSchema->column($columnName);
            }
            // changes in columns meta-data
            foreach ($currentColumns as $columnName) {
                $column = $currentSchema->column($columnName);
                unset($column['collate']);
                $oldColumn = $this->dumpSchema[$table]->column($columnName);
                if (in_array($columnName, $oldColumns) && $column !== $oldColumn) {
                    $changedAttributes = array_diff($column, $oldColumn);
                    if (!isset($changedAttributes['type'])) {
                        $changedAttributes['type'] = $column['type'];
                    }
                    $this->templateData[$table]['columns']['changed'][$columnName] = $changedAttributes;
                }
            }
            // columns deletion
            if (!isset($this->templateData[$table]['columns']['remove'])) {
                $this->templateData[$table]['columns']['remove'] = [];
            }
            $removedColumns = array_diff($oldColumns, $currentColumns);
            if (!empty($removedColumns)) {
                foreach ($removedColumns as $column) {
                    $this->templateData[$table]['columns']['remove'][$column] = $this->dumpSchema[$table]->column($column);
                }
            }
        }
    }