renovate/lib/config/utils.ts

import { instrument } from '../instrumentation/index.ts';
import { logger } from '../logger/index.ts';
import { clone } from '../util/clone.ts';
import { getHighestVulnerabilitySeverity } from '../util/vulnerability/utils.ts';
import * as options from './options/index.ts';
import type { RenovateConfig } from './types.ts';

export function mergeChildConfig<
  T extends Record<string, any>,
  TChild extends Record<string, any> | undefined,
>(parent: T, child: TChild): T & TChild {
  return instrument('mergeChildConfig', () => {
    logger.trace({ parent, child }, `mergeChildConfig`);
    if (!child) {
      return parent as never;
    }
    const parentConfig = clone(parent);
    const childConfig = clone(child);
    const config: Record<string, any> = { ...parentConfig, ...childConfig };

    // Ensure highest severity survives parent / child merge
    if (
      config.isVulnerabilityAlert &&
      (parent.vulnerabilitySeverity !== undefined ||
        child.vulnerabilitySeverity !== undefined)
    ) {
      config.vulnerabilitySeverity = getHighestVulnerabilitySeverity(
        parent,
        child,
      );
    }

    for (const option of options.getOptions()) {
      if (
        option.mergeable &&
        childConfig[option.name] &&
        parentConfig[option.name]
      ) {
        logger.trace(`mergeable option: ${option.name}`);

        if (option.name === 'constraints') {
          config[option.name] = {
            ...parentConfig[option.name],
            ...childConfig[option.name],
          };
        } else if (option.type === 'array') {
          config[option.name] = (parentConfig[option.name] as unknown[]).concat(
            config[option.name],
          );
        } else {
          config[option.name] = mergeChildConfig(
            parentConfig[option.name] as RenovateConfig,
            childConfig[option.name] as RenovateConfig,
          );
        }
        logger.trace(
          { result: config[option.name] },
          `Merged config.${option.name}`,
        );
      }
    }
    return { ...config, ...config.force };
  });
}