Asset v2: Asset path serialization fix

[Neo-Zhixing]

Objective

• Silence Failed to send DropEvent for StrongHandle "SendError(..)" errors when StrongHandle were dropped during application shutdown.
• Re-export BoxedFuture considering that it's used everywhere in bevy_asset
• Fixed an issue introduced by Copy on Write AssetPaths #9729.

  Asset 'final_gather.rgen' encountered an error in dust_render::shader::spirv::SpirvLoader: Failed to deserialize asset meta: SpannedError { code: InvalidValueForType { expected: "string AssetPath", found: "a sequence" }, position: Position { line: 9, col: 24 } }
  

  Basically, for processed assets with dependencies, bevy will serialize the metafile as follows:

  (
    meta_format_version: "1.0",
    processed_info: Some((
        hash: (203, 239, 108, 156, 180, 23, 157, 217, 159, 36, 158, 193, 185, 253, 242, 156),
        full_hash: (77, 58, 30, 200, 21, 180, 221, 133, 151, 83, 247, 47, 193, 70, 228, 97),
        process_dependencies: [
            (
                full_hash: (56, 46, 55, 118, 3, 6, 213, 250, 124, 26, 153, 87, 15, 85, 4, 89),
                path: ("standard.glsl"), # <<---------- See here
            ),
        ],
    )),
    asset: Load(
        loader: "dust_render::shader::spirv::SpirvLoader",
        settings: (),
    ),
  )
  

  AssetPath gets serialized as ("standard.glsl") which was then deserialized as a sequence instead of our AssetPath.

Solution

• Serialize AssetPath directly as a string instead. The above metafile would be serialized as follows:

 (
   meta_format_version: "1.0",
   processed_info: Some((
       hash: (203, 239, 108, 156, 180, 23, 157, 217, 159, 36, 158, 193, 185, 253, 242, 156),
       full_hash: (77, 58, 30, 200, 21, 180, 221, 133, 151, 83, 247, 47, 193, 70, 228, 97),
       process_dependencies: [
           (
               full_hash: (56, 46, 55, 118, 3, 6, 213, 250, 124, 26, 153, 87, 15, 85, 4, 89),
               path: "standard.glsl", # <<------- No longer a tuple struct
           ),
       ],
   )),
   asset: Load(
       loader: "dust_render::shader::spirv::SpirvLoader",
       settings: (),
   ),
 )

---

[Neo-Zhixing]

Side note: We might wanna serialize the hash into something more compact, like a hex string.

[cart]

Good calls!

We might wanna serialize the hash into something more compact, like a hex string.

Agreed on this too!