feat(esm): retire --deno-esm; Bun-ESM is the only JS-host ESM target (#759)

## Summary

Bun-ESM is the only JS-host ESM target. `--deno-esm` / `-o *.deno.js` is
a hard error (E0826) pointing at `--bun-esm` / `.bun.js`. The flag is
kept so existing scripts fail loudly instead of becoming an unknown
option.

`codegen_deno` now emits the Bun host (`codegen_deno` ≡ `codegen_bun`).
The historical `tests/codegen-deno/` corpus compiles with `--bun-esm` to
`.bun.js`.

Aspirational idaptik StartupError fixtures compile with real syntax
(`use Console::{log}`, `use Dom::{…}`, tuple-list attrs, `#{ bg: … }`
records) — not ReScript `import Dom` / `{IO}` / `{style: bg}` without
`#`.

Host FFI on this path does not require `/ IO` rows (Canvas-style erasure
at emit). `affinescript-vite` remains a scaffold, not in this tree.
Remaining Pixi.res (~313 decls) is a follow-up, not this PR.

Does **not** implement #486 (native-preview2 / default component; needs
ocaml + wasm-tools and must keep `typedwasm.ownership` byte-equal).

Closes #56

## Notes

- No local ocaml/dune/bun in the authoring environment; CI has the
toolchain (Bun via `scripts/install-bun.sh`).
- Docs updated: capability matrix, bun-esm migration, ECOSYSTEM,
EFFECTS, CHANGELOG. No production-ready claim (DOC-09).

Author: hyperpolymath

.github/workflows/ci.yml

@@ -89,10 +89,10 @@ jobs:
         run: opam exec -- dune runtest
       - name: Run codegen WASM tests
         run: opam exec -- ./tools/run_codegen_wasm_tests.sh
-      - name: Run codegen Deno-ESM tests (issue #122)
-        # Compiles tests/codegen-deno/*.affine with the --deno-esm backend
-        # and runs the *.harness.mjs under Node (CI has Node 20, not Deno;
-        # the Phase 1 fixtures are pure logic so Node ESM exercises them).
+      - name: Run codegen Bun-ESM tests (historical codegen-deno corpus)
+        # Compiles tests/codegen-deno/*.affine with the --bun-esm backend
+        # and runs the *.harness.mjs under Node (CI has Node 20; these
+        # fixtures mock host objects and do not need the Bun binary).
         run: opam exec -- ./tools/run_codegen_deno_tests.sh
       - name: Run native Bun-ESM tests (issue #734)
         run: opam exec -- ./tools/run_codegen_bun_tests.sh

.gitignore

@@ -100,6 +100,7 @@ bisect*.coverage
 # issue #122: generated Deno-ESM regression outputs (compiled from the
 # committed *.affine fixtures by tools/run_codegen_deno_tests.sh).
 /tests/codegen-deno/*.deno.js
+/tests/codegen-deno/*.bun.js
 # Issue #734: generated native Bun-ESM acceptance outputs.
 /tests/codegen-bun/*.bun.js
 /tests/codegen-bun/backend-conflict.json

CHANGELOG.adoc

@@ -15,8 +15,17 @@ https://semver.org/spec/v2.0.0.html[Semantic Versioning].
 
 === [Unreleased]
 
+==== Removed
+
+* `--deno-esm` / `-o FILE.deno.js` is a hard error (E0826). Bun-ESM
+(`--bun-esm` / `.bun.js`) is the only JS-host ESM target. The flag is
+kept so existing scripts fail loudly (Refs #56)
+
 ==== Added
 
+* Aspirational idaptik StartupError fixture compiles with real syntax
+(`use Console::{log}`, `use Dom::{…}`, tuple-list attrs and
+`#{ bg: … }` records) on `--bun-esm` (Refs #56)
 * feat(stdlib): Aggregate.affine — SQL group-by + aggregation primitives
 — db-theory #3 (7 externs) (PR #527)
 * feat(stdlib): Transaction.affine — affine-bounded write-set isolation

bin/main.ml

@@ -492,10 +492,8 @@ let repl_cmd_fn () =
 let compile_file face json wasm_gc vscode_ext vscode_adapter vscode_no_lc
     deno_esm bun_esm target path output =
   let face = resolve_face ~quiet:json face path in
-  let is_deno = deno_esm || Filename.check_suffix output ".deno.js" in
-  let is_bun = bun_esm || Filename.check_suffix output ".bun.js" in
-  if is_deno && is_bun then
-    let message = "--deno-esm and --bun-esm are mutually exclusive" in
+  if deno_esm || Filename.check_suffix output ".deno.js" then
+    let message = "Deno-ESM was removed; use --bun-esm (and a .bun.js output path)" in
     if json then
       json_finish [{ Affinescript.Json_output.severity = Error;
                      code = "E0826"; message;
@@ -536,10 +534,9 @@ let compile_file face json wasm_gc vscode_ext vscode_adapter vscode_no_lc
                use the original [prog] because they handle imports natively
                via Codegen.gen_imports / the import section. *)
             let flat_prog = Affinescript.Module_loader.flatten_imports loader prog in
-            let is_deno = deno_esm || Filename.check_suffix output ".deno.js" in
             let is_bun = bun_esm || Filename.check_suffix output ".bun.js" in
             let is_julia = Filename.check_suffix output ".jl" in
-            let is_js = (not is_deno) && (not is_bun) && Filename.check_suffix output ".js" in
+            let is_js = (not is_bun) && Filename.check_suffix output ".js" in
             let is_c = Filename.check_suffix output ".c" in
             let is_wgsl = Filename.check_suffix output ".wgsl" in
             let is_faust = Filename.check_suffix output ".dsp" in
@@ -570,16 +567,6 @@ let compile_file face json wasm_gc vscode_ext vscode_adapter vscode_no_lc
                 let oc = open_out_bin output in
                 output_string oc esm_code;
                 close_out oc
-            end else if is_deno then begin
-              match Affinescript.Codegen_deno.codegen_deno flat_prog resolve_ctx.symbols with
-              | Error msg ->
-                add { severity = Error; code = "E0824";
-                      message = Printf.sprintf "Deno-ESM codegen error: %s" msg;
-                      span = Affinescript.Span.dummy; help = None; labels = [] }
-              | Ok esm_code ->
-                let oc = open_out_bin output in
-                output_string oc esm_code;
-                close_out oc
             end else if is_julia then begin
               match Affinescript.Julia_codegen.codegen_julia flat_prog resolve_ctx.symbols with
               | Error msg ->
@@ -779,10 +766,9 @@ let compile_file face json wasm_gc vscode_ext vscode_adapter vscode_no_lc
                cross-module imports for backends that don't have native
                module-system support. Wasm/Wasm-GC keep the original [prog]. *)
             let flat_prog = Affinescript.Module_loader.flatten_imports loader prog in
-            let is_deno = deno_esm || Filename.check_suffix output ".deno.js" in
             let is_bun = bun_esm || Filename.check_suffix output ".bun.js" in
             let is_julia = Filename.check_suffix output ".jl" in
-            let is_js = (not is_deno) && (not is_bun) && Filename.check_suffix output ".js" in
+            let is_js = (not is_bun) && Filename.check_suffix output ".js" in
             let is_c = Filename.check_suffix output ".c" in
             let is_wgsl = Filename.check_suffix output ".wgsl" in
             let is_faust = Filename.check_suffix output ".dsp" in
@@ -814,17 +800,6 @@ let compile_file face json wasm_gc vscode_ext vscode_adapter vscode_no_lc
                 close_out oc;
                 Format.printf "Compiled %s -> %s (Bun-ESM)@." path output;
                 `Ok ())
-            else if is_deno then
-              (match Affinescript.Codegen_deno.codegen_deno flat_prog resolve_ctx.symbols with
-              | Error e ->
-                Format.eprintf "@[<v>Deno-ESM codegen error: %s@]@." e;
-                `Error (false, "Deno-ESM codegen error")
-              | Ok esm_code ->
-                let oc = open_out output in
-                output_string oc esm_code;
-                close_out oc;
-                Format.printf "Compiled %s -> %s (Deno-ESM)@." path output;
-                `Ok ())
             else if is_julia then
               (match Affinescript.Julia_codegen.codegen_julia flat_prog resolve_ctx.symbols with
               | Error e ->
@@ -1280,28 +1255,21 @@ let vscode_no_lc_arg =
           dependency for extensions that ship no language client; the \
           wiring passes null in its place.")
 
-(* Issue #122: --deno-esm. Selects the direct AST -> ES-module backend
-   ({!Affinescript.Codegen_deno}) regardless of output extension, so a
-   drop-in `.js` ES module can be produced (e.g. `-o src/storage.js
-   --deno-esm`). A `.deno.js` output extension also routes here without
-   the flag, as a convenience for the test corpus / ad-hoc use. *)
+(* --deno-esm was issue #122. Retired: the ESM host is Bun (--bun-esm).
+   The flag is kept so existing scripts get a clear error instead of
+   Cmdliner unknown-option. *)
 let deno_esm_arg =
   Arg.(value & flag & info ["deno-esm"]
-    ~doc:"Emit a standalone Deno/Node ES module directly from the AST \
-          (issue #122): `export class` for struct+impl, `export` for \
-          public fns/consts, and `extern fn` lowered to direct host \
-          calls (Deno.*Sync / JSON / WebAssembly). No wasm, no require, \
-          no handle table — the output is a drop-in importable ESM. A \
-          `.deno.js` output extension selects this backend implicitly.")
+    ~doc:"REMOVED. Deno-ESM is gone; use $(b,--bun-esm) / a `.bun.js` \
+          output path. Passing this flag (or `-o *.deno.js`) is an error.")
 
 let bun_esm_arg =
   Arg.(value & flag & info ["bun-esm"]
     ~doc:"Emit a standalone Bun-native ES module directly from the AST: \
           public declarations are exported and host operations use Bun's \
           Node-compatible synchronous APIs. The emitted module contains no \
-          legacy-runtime shim. A `.bun.js` output extension selects this \
-          backend implicitly. This option is mutually exclusive with \
-          `--deno-esm`.")
+          Deno runtime shim. A `.bun.js` output extension selects this \
+          backend implicitly.")
 
 (** Shared --face flag: select the parser surface-syntax face. *)
 let face_arg =

docs/CAPABILITY-MATRIX.adoc

@@ -196,16 +196,19 @@ Formal spec: link:specs/TYPED-WASM-INTERFACE.adoc[specs/TYPED-WASM-INTERFACE.ado
 Widening roadmap (L1–6, L14–16, multi-producer ABI): link:specs/TYPED-WASM-ROADMAP.adoc[specs/TYPED-WASM-ROADMAP.adoc].
 Producer-side; target spec is the separate `hyperpolymath/typed-wasm` repo.
 
-|Deno-ESM |works |Direct AST→ES-module transpiler (`lib/codegen_deno.ml`),
-`--deno-esm` / `.deno.js`. Shipped + consumer-verified (ubicity).
-
-|Bun-ESM |works |Host-profiled direct AST→ES-module transpiler,
-`--bun-esm` / `.bun.js`. Public declarations remain importable ESM; filesystem,
-argument, and process operations lower through Bun's synchronous
-Node-compatibility surface. Host operations are resolved lazily so a generated
-module that only uses browser-provided externs remains browser-importable. CI
-compiles, checks for legacy-runtime leakage, parses, and executes filesystem,
-byte, argument, export, and missing-path controls under Bun.
+|Deno-ESM |retired |`--deno-esm` / `-o FILE.deno.js` is a hard error (E0826).
+The JS-host ESM target is Bun-ESM. The flag is kept so existing scripts fail
+loudly instead of becoming an unknown option.
+
+|Bun-ESM |works |Direct AST→ES-module transpiler (`lib/codegen_deno.ml`,
+`codegen_bun`), `--bun-esm` / `.bun.js`. Public declarations remain importable
+ESM; filesystem, argument, and process operations lower through Bun's
+synchronous Node-compatibility surface. Host operations are resolved lazily so
+a generated module that only uses browser-provided externs remains
+browser-importable. CI compiles, checks for legacy-runtime leakage, parses,
+and executes filesystem, byte, argument, export, and missing-path controls
+under Bun. `tools/run_codegen_deno_tests.sh` (historical name) compiles
+`tests/codegen-deno/` with `--bun-esm`.
 Migration and host-contract details:
 link:guides/bun-esm-migration.adoc[guides/bun-esm-migration.adoc].
 

docs/ECOSYSTEM.adoc

@@ -168,8 +168,8 @@ surface.
 
 |`affinescript-vite` |scaffold |Build-tool integration shell.
 
-|`affinescript-deno-test` |works |Smoke-test harness used by the Deno-ESM
-target.
+|`affinescript-deno-test` |historical |Smoke-test harness from the retired
+Deno-ESM target. JS-host ESM is Bun-ESM (`--bun-esm`).
 
 |`affinescript-tea` |runtime |INT-07 (#182): real host-side TEA runtime
 + run loop (`TeaApp`: load/init/dispatch/model/setScreen/run,

docs/EFFECTS-IMPLEMENTATION.adoc

@@ -78,6 +78,18 @@ type eval_error =
 Handler evaluation catches `PerformEffect`, selects a matching arm, and
 evaluates the arm body in the handler context.
 
+== JS-host ESM (Bun) — Canvas-style erasure
+
+Host FFI on `--bun-esm` does **not** require `/ IO` (or `{IO}`) effect
+rows. `stdlib/Canvas.affine`, `stdlib/Dom.affine`, and
+`stdlib/Console.affine` declare ordinary `extern fn` / wrappers; the
+direct-ESM emitter lowers them to host calls and erases effect
+declarations (`// effect declaration (erased)`). Declared `/ Async` rows
+are the exception: they compile to `async function` so `await fetch` is
+legal JS. Algebraic `handle { ... }` is a compile error on this backend
+(Refs #555). This is the AOT-safe contract for the #56 remainder — not
+a second effect system.
+
 == Not Yet Complete
 
 [arabic]

docs/STDLIB-EXTERN-AUDIT.adoc

@@ -70,8 +70,8 @@ producer-side type signature here and a verifier-side contract in
 runtime adapter all green.  `Http.fetch` is the canonical example
 (landed via the #225 CPS line, PR1..PR3d).
 
-|*Adapter-side (Deno-ESM)*
-|Compiles via the `--deno-esm` backend; the `extern` is realised
+|*Adapter-side (JS-host ESM)*
+|Compiles via the `--bun-esm` backend (Deno-ESM retired); the `extern` is realised
 by the emitted ESM importing a JS module.  The "real impl" is the
 adapter shim in `packages/<adapter>/mod.js` (or equivalent).
 |Adapter package exists, the symbol is exported, and a

docs/bindings-roadmap.adoc

@@ -75,7 +75,7 @@ no further significant  → AffineScript work is tractable.
 |*WASM-exports calling pattern* — invoke individual `exports.fn_name(args)` from a `WasmExports` value
 |`●` usable (Option A landed)
 |`stdlib/Deno.affine`
-|`wasmCall(exports: WasmExports, name: String, args: [Float]) -> Float` lowers to `Number(exports[name](...args))` on `--deno-esm`. AS-side surface + docstring example landed in `stdlib/Deno.affine`; round-trip exercised by `tests/codegen-deno/wasm_call.{affine,harness.mjs}` against a hand-built 41-byte wasm module exporting `add(i32, i32) -> i32`. *Option A (generic) — typed per-Zig-fn shims can layer on top per-consumer if needed.* Closes #414 via host-side #422 + AS-side this PR. *Generic export-call shipped #455* (`wasm_export_call(exports, name, args: [WasmValue]) -> WasmValue` + `WasmValue` opaque + `wv_i32`/`wv_i64`/`wv_f32`/`wv_f64` + `wv_as_int`/`wv_as_float`/`wv_kind`); end-to-end demo at `examples/wasm-exports-demo.affine` (#500) with smoke-test `tests/codegen-deno/wasm_exports_demo.{affine,harness.mjs}` exercising all four scalar kinds.
+|`wasmCall(exports: WasmExports, name: String, args: [Float]) -> Float` lowers to `Number(exports[name](...args))` on `--bun-esm`. AS-side surface + docstring example landed in `stdlib/Deno.affine`; round-trip exercised by `tests/codegen-deno/wasm_call.{affine,harness.mjs}` against a hand-built 41-byte wasm module exporting `add(i32, i32) -> i32`. *Option A (generic) — typed per-Zig-fn shims can layer on top per-consumer if needed.* Closes #414 via host-side #422 + AS-side this PR. *Generic export-call shipped #455* (`wasm_export_call(exports, name, args: [WasmValue]) -> WasmValue` + `WasmValue` opaque + `wv_i32`/`wv_i64`/`wv_f32`/`wv_f64` + `wv_as_int`/`wv_as_float`/`wv_kind`); end-to-end demo at `examples/wasm-exports-demo.affine` (#500) with smoke-test `tests/codegen-deno/wasm_exports_demo.{affine,harness.mjs}` exercising all four scalar kinds.
 
 |6
 |*Phoenix Channels / WebSocket* (Socket connect/disconnect, Channel join/leave/push, presence)

docs/guides/bun-esm-migration.adoc

@@ -54,12 +54,18 @@ The source filename is retained to avoid a high-risk mechanical move in the
 same change as the semantic migration. It does not imply that Bun output passes
 through or embeds the compatibility runtime.
 
-The compatibility flag remains available for existing external consumers. An
-estate migration is complete only when its active workflows, runtime files,
-lockfiles, build commands, generated artefact names, examples, and current
-documentation have moved to Bun. Historical records may retain their original
-runtime names when clearly marked as history; renaming history would make it
-less accurate.
+`--deno-esm` and `-o *.deno.js` are retired: the compiler errors with E0826
+and points at `--bun-esm` / `.bun.js`. The flag is kept so existing scripts
+fail loudly instead of becoming an unknown option. An estate migration is
+complete only when its active workflows, runtime files, lockfiles, build
+commands, generated artefact names, examples, and current documentation have
+moved to Bun. Historical records may retain their original runtime names when
+clearly marked as history; renaming history would make it less accurate.
+
+`affinescript-vite` remains a scaffold (not in this tree). Effect rows such
+as `/ IO` are not required on the JS-host ESM path: host FFI is erased at
+emit the same way Canvas/Dom externs are (see
+link:../EFFECTS-IMPLEMENTATION.adoc[EFFECTS-IMPLEMENTATION.adoc]).
 
 == Verification contract