From 7fc67497c4cd61733e4a6da63cf874373e694071 Mon Sep 17 00:00:00 2001 From: giles Date: Tue, 30 Jun 2026 15:38:47 +0000 Subject: [PATCH] note: WASM kernel uses deprecated 'try' instruction + sync XHR (follow-up) Real browser console on blog.rose-ash.com shows the WASM kernel (Jun-29 artifact, built with an older wasm_of_ocaml) emits the legacy 'try' exception instruction (deprecated; use try_table) + loadManifest does a sync XHR. Not breaking yet (SPA boots; the day's symptom was a stale cached loader, cleared by hard refresh) but will break when browsers drop 'try'. Fix = rebuild the kernel with the current 6.3.2 toolchain (may emit try_table) + verify in a real browser + make loadManifest async. hosts/ocaml/browser toolchain; schedule when the box is quiet with a rollback path, don't rush. Co-Authored-By: Claude Opus 4.8 --- plans/NOTE-wasm-try-deprecation.md | 40 ++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 plans/NOTE-wasm-try-deprecation.md diff --git a/plans/NOTE-wasm-try-deprecation.md b/plans/NOTE-wasm-try-deprecation.md new file mode 100644 index 00000000..bdba7664 --- /dev/null +++ b/plans/NOTE-wasm-try-deprecation.md @@ -0,0 +1,40 @@ +# Follow-up: WASM kernel uses deprecated `try` exception instruction (+ sync XHR) + +**Found:** 2026-06-30, from a real browser console on `blog.rose-ash.com` (modern Chrome/Firefox). +**Severity:** not yet breaking — *deprecation warnings*. The SPA still boots (a hard refresh +cleared a stale cached loader, which was the day's actual symptom). But when browsers **remove** +the legacy `try` instruction, the WASM kernel will fail to instantiate → "SxKernel not found +after 5s" → no SPA (server-rendered pages + native-form writes still work; only SPA nav + the +interactive picker need the kernel). + +## The two warnings + +1. **`WebAssembly exception handling 'try' instruction is deprecated … use 'try_table' instead`** + (×6). The kernel `shared/static/wasm/sx_browser.bc.wasm.assets/*.wasm` was compiled (Jun-29 + artifact) with the legacy exception-handling encoding. wasm_of_ocaml standardized on + `try_table`; current toolchain is **6.3.2**. +2. **`Synchronous XMLHttpRequest on the main thread is deprecated`** — `sx-platform.js:575`, + `loadManifest()` does `xhr.open("GET", …module-manifest.sx…, false)` (sync). Browsers + increasingly restrict sync XHR. + +## Fix + +1. **Rebuild the kernel with the current toolchain.** `bash hosts/ocaml/browser/build-all.sh` + (dune builds `browser/sx_browser.bc.wasm.js`), then `bundle.sh` syncs to + `shared/static/wasm/`. Modern wasm_of_ocaml 6.x *may* emit `try_table` by default → a fresh + rebuild alone could fix #1. **Verify:** disassemble a `.wasm` unit (`wasm-tools print` / grep + for `try_table` vs `try`), then boot it in a REAL up-to-date browser (not just the older + Playwright chromium, which still accepts `try`) and confirm no deprecation warning + SxKernel + registers. If 6.3.2 still emits legacy `try`, check for a wasm_of_ocaml flag or bump the + compiler. +2. **`loadManifest` → async.** Change to an async fetch and restructure the boot so the manifest + is awaited before module loading (it's currently consumed synchronously). Contained to + `hosts/ocaml/browser/sx-platform.js` + its copy in `shared/static/wasm/`. + +## Scope / ownership + +`hosts/ocaml/browser/` is the OCaml→WASM toolchain — generally out of the host loop's lane, though +the host loop has committed there for the blog SPA (b21ae05e, 689dae7d). A kernel rebuild affects +the LIVE SPA, so do it when the box is quiet, with real-browser verification, and a quick rollback +path (the Jun-29 `.assets` are the known-good artifact — keep a copy before overwriting). Not +urgent; schedule rather than rush.