RFC: Runtime-aware App executables

[replghost]

RFC: Runtime-aware App executables

Tracking issue: #550

Summary

Introduces App executable manifest v2 with an explicit runtime. Web remains the mandatory App runtime; Products may additionally declare a PolkaVM runtime with versioned graphics, device-input, and audio requirements.

The proposal keeps App as the executable kind, treats PolkaVM as its runtime, and treats framebuffer, Tri2D, and WebGPU Raster as negotiated graphics profiles.

Checklist

• Added docs/rfcs/runtime-aware-app-executables.md without a number; CI assigns one after merge
• Filled Summary, Motivation, Detailed Design, Drawbacks, Alternatives, and Unresolved Questions
• Added the rfc label
• Updated Rust traits in rust/crates/truapi/ — not applicable: this RFC changes the Product Manifest Format rather than the TruAPI method surface

Motivation

App manifest v1 implicitly describes a web archive with an index.html entrypoint. It cannot distinguish that archive from a sandboxed PolkaVM program or let a Host preflight the program's graphics and input requirements. Extending v1 would let older Hosts misinterpret PolkaVM bytes as web content, so the proposal adds a fail-closed v2 manifest.

Interface changes

This is a manifest-format RFC and does not add or modify a TruAPI method. It therefore contains no changes under rust/crates/truapi/.

The current validate-rfc workflow assumes every RFC modifies that directory. The same check failed on the merged Product Manifest RFC (#206) and currently fails on the manifest-only Funding proposal (#458).

Validation

• git diff --check

[pgherveou]

for reference would be nice to know what host today, support what

[replghost]

The v2 manifest is supported by Epoca 0.2.0 and later.

It can also be tried from the feat/pvm-wasm branch of dotli-community.

Reproducible App manifest v2 examples for the framebuffer, Tri2D, and WebGPU Raster profiles are available in paritytech/product-runtime-examples.

iOS and Android currently support web Apps and do not yet implement the PolkaVM runtime.

I have kept these references out of the RFC because they describe implementation status rather than the portable contract.

[filvecchiato]

FYI this should be raised as an issue first to follow the new pipeline

[replghost]

@filvecchiato Tracking issue is #550. I linked RFC #507 and implementation PR #540, added the rfc label, and expanded the issue to track the runtime contracts, publisher support, examples, and Host adoption.