feat(firefox): add JSPI live terminal stdin

README.md

@@ -6,7 +6,7 @@ An in-browser **C++20 IDE** delivered as a Chrome / Chromium extension.
 |---------|--------|
 | Editor | Monaco Editor (the engine behind VS Code) |
 | Compiler | WASM-native Clang (runs entirely in the browser, offline) |
-| Terminal | xterm.js with a bash-like shell (`g++`, `./a.out`, `ls`, `mkdir`, `touch`, `cat`, …) |
+| Terminal | xterm.js with a bash-like shell and live line input on Chromium and Firefox 153+ |
 | File access | File System Access API on Chromium, fallback open/save/folder flows on Firefox |
 | File I/O | `fstream` / `ifstream` / `ofstream` – read and write workspace files at runtime |
 | Standards | C++14 · C++17 · **C++20** (selectable in the toolbar) |
@@ -219,8 +219,9 @@ Firefox desktop is also a supported release target, but its support contract is
 different:
 
 - compile/run, Monaco, and extension-runtime flows are supported
-- programs that read `std::cin` use pre-supplied buffered stdin (up to 256 KiB);
-  live prompt-by-prompt stdin remains available on Chromium-family builds
+- Firefox 153+ uses WebAssembly JSPI for live, line-buffered `std::cin`,
+  `std::getline`, and `scanf` input; Firefox 140–152 (or a runtime without
+  JSPI) retains the pre-supplied buffered stdin fallback (up to 256 KiB)
 - file open/save and folder import use fallback browser flows rather than
   Chromium File System Access APIs
 - persistent folder write-back and directory-handle session restore may be
@@ -235,6 +236,7 @@ Full parity requires:
   `showSaveFilePicker`)
 - Web Workers and WebAssembly
 - `SharedArrayBuffer` and `Atomics.waitAsync` for Chromium live interactive stdin
+- `WebAssembly.Suspending` and `WebAssembly.promising` for Firefox 153+ live stdin
 - Managed browser policies that allow local file read/write prompts
 
 ### Release-blocking checks
@@ -462,7 +464,8 @@ manual/GitHub-distributed channel.
    signed artifact under `release/firefox-unlisted/`.
 5. Install the signed XPI in Firefox and complete the manual QA checklist
    in `docs/firefox-stdin-runtime-acceptance.md`, paying special attention to
-   buffered stdin and the documented workspace-persistence limitations.
+   JSPI live stdin, its buffered fallback, and the documented
+   workspace-persistence limitations.
 
 ### Manual release QA checklist
 
@@ -526,9 +529,10 @@ Copy the resulting `clang.js` and `clang.wasm` into `dist/clang/`.
   script" dialog.  The compiler runs in a dedicated Web Worker to avoid blocking
   the UI.
 - **Browser scope**: Full parity targets desktop Chrome, Edge, Brave, and
-  Chromium. Firefox is a compatible release target with buffered stdin and
-  workspace-persistence limitations; Safari is outside the current release
-  target.
+  Chromium. Firefox 153+ supports live canonical (line-buffered) stdin through
+  JSPI; older supported Firefox versions use buffered stdin. This is not a raw
+  POSIX PTY, and Firefox workspace-persistence limitations remain. Safari is
+  outside the current release target.
 - **Managed browsers**: Enterprise policies that block File System Access prompts
   prevent full local workspace read/write support.
 

docs/firefox-stdin-runtime-acceptance.md

@@ -1,8 +1,13 @@
-# Firefox buffered stdin runtime acceptance
+# Firefox stdin runtime acceptance
 
-Use this procedure to prove GitHub issue #53 is fixed in a real Firefox
-extension context. `npm run test:browser:firefox` validates packaging and
-manifest compatibility, but it does not execute a compiled program in Firefox.
+Use this procedure to validate live JSPI terminal input from GitHub issue #55
+in a real Firefox extension context. `npm run test:browser:firefox` validates
+packaging and manifest compatibility, but does not execute a compiled program.
+
+Firefox 153+ should use live, canonical (line-buffered) input. Firefox 140–152,
+or a runtime where JSPI is unavailable, should keep the pre-supplied buffered
+fallback. Persistent folder write-back is outside this test and retains its
+documented Firefox limitations.
 
 ## Setup
 
@@ -17,13 +22,14 @@ manifest compatibility, but it does not execute a compiled program in Firefox.
 3. Choose **Load Temporary Add-on** and select `dist-firefox/manifest.json`.
    For release validation, repeat with the signed XPI under
    `release/firefox-unlisted/`.
-4. Open browser.cpp from the extension toolbar action.
+4. Open browser.cpp from the extension toolbar action and open the Browser
+   Console for error inspection.
 
-Record the Firefox version and the unpacked directory or signed XPI path used.
+Record the exact Firefox version and unpacked directory or signed XPI path.
 
-## Test program
+## Live-input test for Firefox 153+
 
-Replace the editor contents with exactly:
+Replace the editor contents with:
 
 ```cpp
 #include <iostream>
@@ -33,56 +39,74 @@ int main() {
     std::string name;
     int age = 0;
 
-    std::cout << "Name? ";
-    std::cin >> name;
-    std::cout << "Age? ";
+    std::cout << "Name? " << std::flush;
+    std::getline(std::cin, name);
+    std::cout << "Age? " << std::flush;
     std::cin >> age;
 
     if (!std::cin) {
         std::cerr << "input failed\n";
         return 2;
     }
 
-    std::cout << "\nHello " << name << ", next year " << (age + 1) << "\n";
-    return 0;
+    std::cout << "Hello " << name << ", next year " << (age + 1) << "\n";
 }
 ```
 
-Choose **Compile and Run**. In the **Pre-supplied stdin** dialog, enter exactly:
+1. Choose **Compile and Run**.
+2. Confirm `Name? ` appears before entering anything and that the
+   **Pre-supplied stdin** dialog does not open.
+3. Type `Ada`, press Enter, and confirm `Age? ` appears afterward.
+4. Type `41` and press Enter.
+5. Confirm the final line is `Hello Ada, next year 42` and the process exits
+   with code `0` without stderr.
 
-```text
-Ada
-41
-```
+This validates two independent suspend/resume cycles and prompt ordering.
 
-Keep the final newline after `41`, then choose **Run program**.
+## EOF, interruption, and clean-session tests
 
-## Expected result
+1. Run the program again. At the empty `Name? ` prompt, press Ctrl+D. Confirm
+   stdin reaches EOF and the program exits with `input failed` and code `2`.
+2. Run again. At `Name? `, press Ctrl+C. Confirm browser.cpp reports
+   `Process interrupted.` and returns to its shell prompt.
+3. Run once more and complete both inputs successfully. Confirm no input from
+   either prior run appears in the new process.
 
-The process exits with code `0`, stderr is empty, and stdout is exactly:
+## Buffered fallback test
 
-```text
-Name? Age?␠
-Hello Ada, next year 42
-```
+Repeat in Firefox 140–152, or in a controlled environment where the worker does
+not expose both `WebAssembly.Suspending` and `WebAssembly.promising`.
+
+1. Choose **Compile and Run**.
+2. Confirm the **Pre-supplied stdin** dialog opens.
+3. Enter `Ada`, a newline, `41`, and a final newline; then choose **Run
+   program**.
+4. Confirm the same successful final output.
+
+The fallback must not attempt message-interactive stdin merely from the Firefox
+version string or main-window capabilities.
 
-The `␠` marker represents the single trailing ASCII space emitted after
-`Age?`.
+## Error exclusions
 
-The terminal and browser console must not contain any of these strings:
+The terminal and Browser Console must not contain unexpected instances of:
 
 ```text
 Interactive stdin requires SharedArrayBuffer
 Cross-Origin-Opener-Policy
 Cross-Origin-Embedder-Policy
+JSPI is unavailable
+Ignored stdin message for an inactive session
+Unhandled promise rejection
 ```
 
 ## PR evidence
 
-Paste the following into the pull request:
+Record the following in the pull request or follow-up release evidence:
 
-- Firefox version
-- tested artifact path
-- observed stdout
-- confirmation that stderr was empty
-- confirmation that none of the old SharedArrayBuffer/COOP/COEP errors appeared
+- Firefox version and tested artifact path
+- exact observed prompt/output ordering
+- confirmation that each input was entered only after its prompt appeared
+- Ctrl+D, Ctrl+C, and clean-rerun results
+- confirmation that the buffered dialog was absent on Firefox 153+ JSPI and
+  present in the no-JSPI fallback test
+- confirmation that stderr and the Browser Console had no unexpected errors

docs/release-playbook.md

@@ -87,8 +87,9 @@ real Firefox desktop build:
 2. Confirm Monaco renders and the default sample appears without blocking
    console/runtime errors.
 3. Compile and run the default sample program.
-4. Complete `docs/firefox-stdin-runtime-acceptance.md` and confirm pre-supplied
-   buffered stdin works without the old SharedArrayBuffer/COOP/COEP error.
+4. Complete `docs/firefox-stdin-runtime-acceptance.md`: confirm Firefox 153+
+   JSPI live stdin and the older/no-JSPI buffered fallback both work without
+   SharedArrayBuffer/COOP/COEP errors.
 5. Open a local source file with Firefox's fallback picker and save changes.
 6. Import a folder, compile a multi-file project, and confirm diagnostics appear
    in the expected file.

package.json

@@ -10,7 +10,7 @@
     "lint": "eslint .",
     "build": "npm run build:webpack && npm run build:targets",
     "build:firefox": "npm run build",
-    "test:e2e": "node --experimental-detect-module --test scripts/e2e-session-persistence.test.mjs scripts/e2e-session-restore-choice.test.mjs scripts/e2e-multifile-build.test.mjs scripts/e2e-workspace-file-tracking.test.mjs scripts/e2e-terminal-mkdir.test.mjs scripts/e2e-terminal-stop.test.mjs scripts/e2e-terminal-git-removal.test.mjs scripts/e2e-terminal-stop-icon.test.mjs scripts/e2e-buffered-stdin-ui.test.mjs scripts/e2e-browser-compatibility.test.mjs scripts/e2e-firefox-compatibility.test.mjs scripts/e2e-wasi-shim.test.mjs scripts/e2e-run-request.test.mjs scripts/e2e-release-packaging.test.mjs",
+    "test:e2e": "node --experimental-detect-module --test scripts/e2e-session-persistence.test.mjs scripts/e2e-session-restore-choice.test.mjs scripts/e2e-multifile-build.test.mjs scripts/e2e-workspace-file-tracking.test.mjs scripts/e2e-terminal-mkdir.test.mjs scripts/e2e-terminal-stop.test.mjs scripts/e2e-terminal-git-removal.test.mjs scripts/e2e-terminal-stop-icon.test.mjs scripts/e2e-buffered-stdin-ui.test.mjs scripts/e2e-browser-compatibility.test.mjs scripts/e2e-firefox-compatibility.test.mjs scripts/e2e-firefox-jspi-stdin.test.mjs scripts/e2e-wasi-shim.test.mjs scripts/e2e-run-request.test.mjs scripts/e2e-release-packaging.test.mjs",
     "test:preflight-clang": "node scripts/preflight-clang-artifacts.js",
     "test:browser:chrome": "npm run test:preflight-clang && node scripts/smoke-browser.mjs chrome",
     "test:browser:edge": "npm run test:preflight-clang && node scripts/smoke-browser.mjs edge",