fix: keep forked child process alive via SIGTERM s-panferov#287

When exporting an array of configs from webpack.config.js, atl crashes.
The error message is "channel closed", indicating that a forked child
process is dying too soon. This commit changes the Checker class such
that it's kill method sends a SIGTERM to the child process rather
than a SIGKILL. The child process intercepts this signal and
ignores it to ensure it is kept alive.

Closes s-panferov#287

Author: zspecza

src/checker/checker.ts

@@ -136,7 +136,7 @@ export class Checker {
     }
 
     kill() {
-        this.checker.kill('SIGKILL');
+        this.checker.kill('SIGTERM');
     }
 }
 

src/checker/runtime.ts

@@ -7,6 +7,11 @@ process.on('disconnect', function() {
     process.exit();
 });
 
+// HACK keepalive for concurrent webpack config
+process.on('SIGTERM', function () {
+    // do nothing
+});
+
 import * as path from 'path';
 import * as colors from 'colors';
 import { findResultFor } from '../helpers';
@@ -231,7 +236,6 @@ function processInit({seq, payload}: Init.Request) {
         });
     }
 
-
     replyOk(seq, null);
 }