Introduction

• The engine-cdi module and the Quarkus extension make use of the RuntimeContainerDelegate implementation.
• This allows to register multiple process engines and even replace the default engine for users.
• Some tests ensure unregistering the default engine and replace it with another default engine or a custom engine.
  • These tests are successful on the Weld and Quarkus.

Problem

• The engine-cdi module seems to allow registering and using multiple engines in parallel.
  • However, there are no tests that ensure proper functionality.
• For Quarkus, the current product scope is single-engine support only.

Solution

1. Explicitly document that we only support the single-engine scenario with Quarkus.
2. Solution #1 + artificially prevent registering multiple engines or replacing the default engine.
3. Add tests for registering multiple engines and replacing the default engine in Quarkus without documenting the limitation.

Decision

The main use case of the extension is bootstrapping and using a single-engine per application. Multi-engine support can be achieved by creating multiple applications. This was already decided and defined by the product requirements. Solution #3 and #2 would mean additional unplanned effort. Let's document clearly that the extension only supports the single-engine scenario.