* Und viele andere Dinge ...

All dies, während Sie Codeverdoppelung minimieren.

## Erste Schritte { #first-steps }

Sehen wir uns ein sehr einfaches Beispiel an. Es ist so einfach, dass es vorerst nicht sehr nützlich ist.

Aber so können wir uns besser auf die Funktionsweise des **Dependency Injection** Systems konzentrieren.

     *
     * @param userProperties The mutable user properties, never {@code null}.
     * @see #contribute(ProtoSession)
     */
    default void contribute(Map<String, String> userProperties) {}

    /**
     * Invoked just before session is created with proto session instance. The proto session contains user and

   *
   * TODO(cpovirk): So make it part of the open-source build, albeit package-private there?
   *
   * So we use uncheckedCastNullableTToT here. This is a weird usage of that method: The method is
   * documented as being for use with type parameters that have parametric nullness. But Converter's
   * type parameters do not. Still, we use it here so that we can suppress a warning at a smaller

- Contains well-written, logical commits explaining *why* changes were made (e.g., “Add S3 bucket tagging support so that users can organize resources efficiently”).
- Is small, focused, and easy to review—ideally one commit, unless multiple commits better narrate complex work.

  - type: textarea
    id: related-proposals
    attributes:
      label: Has this idea, or one like it, been proposed before?
      description: If so, how does this proposal differ?
      placeholder: |
       Yes or No

       If yes, 
        1. Mention the related proposals 
        2. then describe how this proposal differs       
    validations:

      // the operation would be a no-op, so exceptions are allowed but not required
    }
    expectUnchanged();
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)
  public void testReplaceEntry_unsupportedAbsentKey() {
    try {
      getMap().replace(k3(), v3(), v4());
    } catch (UnsupportedOperationException tolerated) {
      // the operation would be a no-op, so exceptions are allowed but not required
    }

/// tip | Tipp

Für neuen Code und wann immer es möglich ist, verwenden Sie `Annotated` wie oben erklärt. Es gibt mehrere Vorteile (unten erläutert) und keine Nachteile. 🍰

///

Up to here, everything would work as normally.

But then, when you open the integrated docs UI (the frontend), it would expect to get the OpenAPI schema at `/openapi.json`, instead of `/api/v1/openapi.json`.

// UnmarshalJSON - decodes JSON data.
func (a *Args) UnmarshalJSON(data []byte) error {
	// subtype to avoid recursive call to UnmarshalJSON()
	type subArgs Args
	var so subArgs

	if err := json.Unmarshal(data, &so); err != nil {
		return err
	}

	oa := Args(so)
	if oa.URL == nil || oa.URL.String() == "" {
		*a = oa
		return nil
	}

	*a = oa
	return nil
}

/// tip

This section is useful only to a handful of people, team members with permissions to manage the repository. You can probably skip it. 😉

///

...so, you are a [team member of FastAPI](./fastapi-people.md#team){.internal-link target=_blank}? Wow, you are so cool! 😎