Scripts: exit error code 1 when status value is null (#42396)

* handle case when status is null

this commit is done to fix pipeline exit in case of failure. status value
is `null` in case of failure

* fix OR condition

* fix process.exit condition if status is `null`

* Update CHANGELOG.md

Co-authored-by: Greg Ziółkowski <grzegorz@gziolo.pl>

packages/scripts/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Bug Fix
+
+-   Fix the incorrect exit error code when status missing in `webpack` call for `build` and `start` commands ([#42396](https://github.com/WordPress/gutenberg/pull/42396)).
+
 ## 23.3.0 (2022-06-15)
 
 ### Enhancements

packages/scripts/scripts/build.js

@@ -8,6 +8,7 @@ const { sync: resolveBin } = require( 'resolve-bin' );
  * Internal dependencies
  */
 const { getWebpackArgs, hasArgInCLI, getArgFromCLI } = require( '../utils' );
+const EXIT_ERROR_CODE = 1;
 
 process.env.NODE_ENV = process.env.NODE_ENV || 'production';
 
@@ -30,4 +31,4 @@ process.env.WP_SRC_DIRECTORY = hasArgInCLI( '--webpack-src-dir' )
 const { status } = spawn( resolveBin( 'webpack' ), getWebpackArgs(), {
 	stdio: 'inherit',
 } );
-process.exit( status );
+process.exit( status === null ? EXIT_ERROR_CODE : status );

packages/scripts/scripts/start.js

@@ -8,6 +8,7 @@ const { sync: resolveBin } = require( 'resolve-bin' );
  * Internal dependencies
  */
 const { getArgFromCLI, getWebpackArgs, hasArgInCLI } = require( '../utils' );
+const EXIT_ERROR_CODE = 1;
 
 if ( hasArgInCLI( '--webpack-no-externals' ) ) {
 	process.env.WP_NO_EXTERNALS = true;
@@ -36,4 +37,4 @@ const { status } = spawn(
 		stdio: 'inherit',
 	}
 );
-process.exit( status );
+process.exit( status === null ? EXIT_ERROR_CODE : status );