fix: propagate registry-failure errors to avoid config validation warnings

We don’t want npmjs 5xx errors to cause config validation Issues in repositories.

Closes #1388

lib/config/presets.js

@@ -41,6 +41,11 @@ async function resolveConfigPresets(inputConfig, existingPresets = []) {
               error.validationError = `Preset package is missing a renovate-config entry (${preset})`;
             } else if (err.message === 'preset not found') {
               error.validationError = `Preset name not found within published preset config (${preset})`;
+            } else {
+              /* istanbul ignore next */ // eslint-disable-next-line
+              if (err.message === 'registry-failure') {
+                throw err;
+              }
             }
             logger.info('Throwing preset error');
             throw error;

lib/workers/repository/error.js

@@ -32,6 +32,10 @@ async function handleError(config, err) {
     logger.info({ error: err }, 'Repository has invalid config');
     await raiseConfigWarningIssue(config, err);
     return err.message;
+  } else if (err.message === 'registry-failure') {
+    logger.info('Registry error - skipping');
+    delete config.branchList; // eslint-disable-line no-param-reassign
+    return err.message;
   }
   // Swallow this error so that other repositories can be processed
   logger.error({ err }, `Repository has unknown error`);

test/workers/repository/error.spec.js

@@ -17,6 +17,7 @@ describe('workers/repository/error', () => {
       'no-package-files',
       'loops>5',
       'config-validation',
+      'registry-failure',
       'archived',
       'not-found',
     ];