What the /__mighty__ dev base prefix is for

[aminevg]

Part of #29

Question

In dev the Hono adapter sets Vite base to /__mighty__ and proxies /__mighty__* and /__open-in-editor into the Vite connect middleware (packages/hono/src/dev.ts, packages/hono/src/utils/runConnectMiddleware.ts, renamed in #21). Amine recalls concluding the prefix should change but has no notes; start from scratch.

Establish: why the prefix exists (asset URL collision with backend routes? HMR client path? Vite's base semantics in middleware mode), how Astro 7's dev server derives asset and HMR URLs, whether the prefix is still required when the Hono adapter proxies in-process, and whether it is required at all when the sidecar serves assets from its own origin (Laravel case, Vite-with-Laravel style with a separate origin and CORS). Resolve with the options and their trade-offs; the decision is a separate grilling ticket.

[aminevg]

Resolution

Development asset base research report, checked against Astro 7.3.2 and Vite 8.0.13. Preserved on research/dev-base-prefix.

The prefix reserves a path namespace for Vite assets on the backend origin. It is an adapter routing choice, not a requirement of running Astro in another process. The historical rename records no wider design rationale.

• In-process Hono needs an explicit policy for separating backend routes and Vite asset requests. A dedicated prefix is one option; removing it requires replacing the current routing policy.
• The current prefix is coupled to Vite configuration, HTTP dispatch, and the render request's asset address. Changing only vite.base leaves the other two inconsistent.
• The HTTP Connect wrapper does not forward WebSocket upgrades. Vite 8 normally uses a separate HMR listener on port 24678 in middleware mode; lack of upgrade forwarding does not itself prove HMR is broken. Asset URLs and the HMR connection need separate configuration and verification.
• A separate-origin sidecar can use / as its asset base, but it still needs consistent generated URLs, CORS for the backend origin, and a working HMR endpoint. Moving it to another origin alone does not complete that integration.

An isolated Vite 8 HTTP probe verified base normalization, prefixed module imports, asset-origin generation, and middleware behavior outside the base. WebSockets were disabled in that probe. The report records options and trade-offs. The final choice remains with Dev asset base prefix decision. Sidecar endpoint, hot-file and error behavior remain with Sidecar design; this research needs no additional ticket.

Verification on the current lockfile: pnpm build and pnpm run typecheck passed; pnpm test passed all 12 files / 50 tests. pnpm run ci:biome failed because .context worktrees contain nested root configurations. Biome restricted to Git-tracked paths passed (107 files). These checks do not establish Astro 7 browser/HMR compatibility. No product code changed.