wasi: make returnOnExit true by default

Refs: nodejs#46923

Signed-off-by: Michael Dawson <mdawson@devrus.com>

doc/api/wasi.md

@@ -118,6 +118,9 @@ added:
  - v13.3.0
  - v12.16.0
 changes:
+ - version: REPLACEME
+   pr-url: https://github.com/nodejs/node/pull/47390
+   description: default for returnOnExit changed to true.
  - version: v19.8.0
    pr-url: https://github.com/nodejs/node/pull/46469
    description: version field added to options.
@@ -133,10 +136,11 @@ changes:
     sandbox directory structure. The string keys of `preopens` are treated as
     directories within the sandbox. The corresponding values in `preopens` are
     the real paths to those directories on the host machine.
-  * `returnOnExit` {boolean} By default, WASI applications terminate the Node.js
-    process via the `__wasi_proc_exit()` function. Setting this option to `true`
-    causes `wasi.start()` to return the exit code rather than terminate the
-    process. **Default:** `false`.
+  * `returnOnExit` {boolean} By default, when WASI applications call
+    `__wasi_proc_exit()`  `wasi.start()` will returns with the exit code
+    specified rather than terminatng the process. Setting this option to
+    `false` will cause the Node.js process to exit with the specified
+    exit code instead.  **Default:** `true`.
   * `stdin` {integer} The file descriptor used as standard input in the
     WebAssembly application. **Default:** `0`.
   * `stdout` {integer} The file descriptor used as standard output in the

lib/wasi.js

@@ -109,11 +109,13 @@ class WASI {
       wrap[prop] = FunctionPrototypeBind(wrap[prop], wrap);
     }
 
+    let returnOnExit = true;
     if (options.returnOnExit !== undefined) {
-      validateBoolean(options.returnOnExit, 'options.returnOnExit');
-      if (options.returnOnExit)
-        wrap.proc_exit = FunctionPrototypeBind(wasiReturnOnProcExit, this);
+      returnOnExit = options.returnOnExit;
+      validateBoolean(returnOnExit, 'options.returnOnExit');
     }
+    if (returnOnExit === true)
+      wrap.proc_exit = FunctionPrototypeBind(wasiReturnOnProcExit, this);
 
     this[kSetMemory] = wrap._setMemory;
     delete wrap._setMemory;

test/wasi/test-wasi.js

@@ -1,6 +1,14 @@
 'use strict';
 const common = require('../common');
 
+function returnOnExitEnvToValue(env) {
+  const envValue = env.RETURN_ON_EXIT;
+  if (envValue !== undefined)
+    return envValue === 'true';
+
+  return undefined;
+}
+
 if (process.argv[2] === 'wasi-child-default') {
   // test default case
   const fixtures = require('../common/fixtures');
@@ -21,6 +29,7 @@ if (process.argv[2] === 'wasi-child-default') {
       '/sandbox': fixtures.path('wasi'),
       '/tmp': tmpdir.path,
     },
+    returnOnExit: returnOnExitEnvToValue(process.env),
   });
   const importObject = { wasi_snapshot_preview1: wasi.wasiImport };
   const modulePath = path.join(wasmDir, `${process.argv[3]}.wasm`);
@@ -53,6 +62,7 @@ if (process.argv[2] === 'wasi-child-default') {
       '/sandbox': fixtures.path('wasi'),
       '/tmp': tmpdir.path,
     },
+    returnOnExit: returnOnExitEnvToValue(process.env),
   });
 
   // Validate the getImportObject helper
@@ -86,6 +96,9 @@ if (process.argv[2] === 'wasi-child-default') {
     if (options.stdin !== undefined)
       opts.input = options.stdin;
 
+    if (options.returnOnExit === false)
+      opts.env.RETURN_ON_EXIT = 'false';
+
     const child = cp.spawnSync(process.execPath, [
       ...args,
       __filename,
@@ -110,7 +123,9 @@ if (process.argv[2] === 'wasi-child-default') {
   if (!common.isIBMi) {
     runWASI({ test: 'clock_getres' });
   }
-  runWASI({ test: 'exitcode', exitCode: 120 });
+  runWASI({ test: 'exitcode' });
+  runWASI({ test: 'exitcode', returnOnExit: true });
+  runWASI({ test: 'exitcode', exitCode: 120, returnOnExit: false });
   runWASI({ test: 'fd_prestat_get_refresh' });
   runWASI({ test: 'freopen', stdout: `hello from input2.txt${checkoutEOL}` });
   runWASI({ test: 'ftruncate' });