child_process: exit spawnSync with null on signal

This commit sets the spawnSync() exit code to null when the
child is killed via signal. This brings the behavior more in
sync with spawn().

Fixes: #11284
PR-URL: #11288
Reviewed-By: Santiago Gimeno <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Evan Lucas <[email protected]>

Author: cjihrig

src/spawn_sync.cc

@@ -645,12 +645,17 @@ Local<Object> SyncProcessRunner::BuildResultObject() {
                    Integer::New(env()->isolate(), GetError()));
   }
 
-  if (exit_status_ >= 0)
-    js_result->Set(env()->status_string(),
-        Number::New(env()->isolate(), static_cast<double>(exit_status_)));
-  else
+  if (exit_status_ >= 0) {
+    if (term_signal_ > 0) {
+      js_result->Set(env()->status_string(), Null(env()->isolate()));
+    } else {
+      js_result->Set(env()->status_string(),
+          Number::New(env()->isolate(), static_cast<double>(exit_status_)));
+    }
+  } else {
     // If exit_status_ < 0 the process was never started because of some error.
     js_result->Set(env()->status_string(), Null(env()->isolate()));
+  }
 
   if (term_signal_ > 0)
     js_result->Set(env()->signal_string(),

test/parallel/test-child-process-spawnsync-kill-signal.js

@@ -1,20 +1,19 @@
 'use strict';
-const common = require('../common');
+require('../common');
 const assert = require('assert');
 const cp = require('child_process');
 
 if (process.argv[2] === 'child') {
   setInterval(() => {}, 1000);
 } else {
-  const exitCode = common.isWindows ? 1 : 0;
   const { SIGKILL } = process.binding('constants').os.signals;
 
   function spawn(killSignal) {
     const child = cp.spawnSync(process.execPath,
                                [__filename, 'child'],
                                {killSignal, timeout: 100});
 
-    assert.strictEqual(child.status, exitCode);
+    assert.strictEqual(child.status, null);
     assert.strictEqual(child.error.code, 'ETIMEDOUT');
     return child;
   }