Components with dependencies attach extra components... | aframevr/aframe

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Description:

A-Frame components with dependencies add additional components to entities even when that type of component is already attached to the entity. It appears that the extra attachment happens when the entity has the component using an ID (e.g., foo__1) but does not have an attached component using just the base component name (e.g., foo).

Expected: Components using the ID should be recognized as satifying the dependency so that extra components are not attached.

Note: The animation component is used as an example, but the same thing happens with other components.

A-Frame Version: 1.0.0-1.6.0
Platform / Device: Windows / Chromium Browsers
Reproducible Code Snippet or URL: Glitch | aframe-extra-component-attach

Test scene:

<html>
  <head>
    <script src="https://aframe.io/releases/1.6.0/aframe.min.js"></script>
    <script>
      AFRAME.registerComponent("test-component-with-dependency", {
        dependencies: ["animation"],
        init: function () {
          console.log("components:", this.el.id, this.el.components);
        },
      });
    </script>
    <script>
      AFRAME.registerComponent("test-component-without-dependency", {
        init: function () {
          console.log("components:", this.el.id, this.el.components);
        },
      });
    </script>
  </head>
  <body>
    <!-- Will attach additional animation component to entity even though
    animation components are already attached. -->
    <a-entity
      id="with-dependency"
      test-component-with-dependency
      animation__0
      animation__1
    ></a-entity>
    <!-- Will not attach additional animation component to entity. -->
    <a-entity
      id="without-dependency"
      test-component-without-dependency
      animation__0
      animation__1
    ></a-entity>
    <a-scene>
      <a-box position="-1 0.5 -3" rotation="0 45 0" color="#4CC3D9"></a-box>
      <a-sphere position="0 1.25 -5" radius="1.25" color="#EF2D5E"></a-sphere>
      <a-cylinder
        position="1 0.75 -3"
        radius="0.5"
        height="1.5"
        color="#FFC65D"
      ></a-cylinder>
      <a-plane
        position="0 0 -4"
        rotation="-90 0 0"
        width="4"
        height="4"
        color="#7BC8A4"
      ></a-plane>
      <a-sky color="#ECECEC"></a-sky>
    </a-scene>
  </body>
</html>

Resulting console output demonstrating extra animation component attached:

components: with-dependency 
  Object
    animation: n {el: a-entity#with-dependency, id: undefined, attrName: 'animation', evtDetail: {…}, initialized: true, …}
    animation__0: n {el: a-entity#with-dependency, id: '0', attrName: 'animation__0', evtDetail: {…}, initialized: true, …}
    animation__1: n {el: a-entity#with-dependency, id: '1', attrName: 'animation__1', evtDetail: {…}, initialized: true, …}
    test-component-with-dependency: n {el: a-entity#with-dependency, id: undefined, attrName: 'test-component-with-dependency', evtDetail: {…}, initialized: true, …}
    [[Prototype]]: Object 

components: without-dependency 
  Object
    animation__0: n {el: a-entity#without-dependency, id: '0', attrName: 'animation__0', evtDetail: {…}, initialized: true, …}
    animation__1: n {el: a-entity#without-dependency, id: '1', attrName: 'animation__1', evtDetail: {…}, initialized: true, …}
    test-component-without-dependency: n {el: a-entity#without-dependency, id: undefined, attrName: 'test-component-without-dependency', evtDetail: {…}, initialized: true, …}
    [[Prototype]]: Object

Start with the linked Glitch reproduction and the test scene showing animation__0 and animation__1 alongside a dependency on animation. Trace A-Frame's component dependency attachment path and verify that ID-suffixed components satisfy the dependency without adding an unsuffixed component. Done when the reproduced entity no longer receives the extra animation component and existing behavior remains intact.

Written by the indexing model from the issue text.

Components with dependencies attach extra components to entities even when component of same type is attached.

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