AngularJS module loading error: missing dependency during bootstrap

Problem statement

During a recent deployment of an AngularJS 1.x application, the console logs show an injector error: Module 'missingModule' is not available! The app never bootstraps, and no directives or services run.

Goal

Identify why the deployment fails and determine if the error can be mitigated or if the missing module is truly required.

Constraints & Uncertainty

• The error originates from angular.module('app', ['missingModule']) or from script load order.
• AngularJS 1.x offers no fallback for missing dependencies; bootstrap halts.
• The deployment environment may differ from local dev, possibly missing a script tag.

Specific Questions

1. Is there a documented configuration or pattern that allows AngularJS to skip or defer missing modules during bootstrap?
2. What are the documented differences, if any, between minor releases (e.g., 1.6 vs 1.8) regarding the handling of missing module dependencies?
3. Can a custom bootstrap trap or error handler be introduced to provide graceful degradation when a module is missing, and is this approach documented?