fix(config): fix backslash regression

After the Adaptive Icon refactor, cordova-res started writing file paths
with backslashes on Windows to the config file. This has now been fixed.

fixes ionic-team/ionic-cli#4062

src/__tests__/config.ts

@@ -0,0 +1,64 @@
+import * as et from 'elementtree';
+
+import { runResource } from '../config';
+import { ResourceKey, ResourceType } from '../resources';
+import { GeneratedResource, Platform } from '../platform';
+
+describe('cordova-res', () => {
+
+  describe('config', () => {
+
+    describe('runResource', () => {
+
+      const resource: GeneratedResource = {
+        [ResourceKey.SRC]: '/path/to/resources/icon.png',
+        type: ResourceType.ICON,
+        srckey: ResourceKey.SRC,
+        platform: Platform.ANDROID,
+        nodeName: 'icon',
+        nodeAttributes: [ResourceKey.SRC],
+      };
+
+      it('should insert node for empty container', async () => {
+        const src = 'resources/icon.png';
+        const container = et.Element('platform');
+
+        runResource('/path/to/config.xml', resource, container);
+
+        const children = container.findall('icon');
+        expect(children.length).toEqual(1);
+        expect(children[0].tag).toEqual(resource.nodeName);
+        expect(children[0].get('src')).toEqual(src);
+      });
+
+      it('should not change node if found in container', async () => {
+        const src = 'resources/icon.png';
+        const container = et.Element('platform');
+        et.SubElement(container, 'icon', { src });
+
+        runResource('/path/to/config.xml', resource, container);
+
+        const children = container.findall('icon');
+        expect(children.length).toEqual(1);
+        expect(children[0].tag).toEqual(resource.nodeName);
+        expect(children[0].get('src')).toEqual(src);
+      });
+
+      it('should update node with win32 paths', async () => {
+        const src = 'resources/icon.png';
+        const container = et.Element('platform');
+        et.SubElement(container, 'icon', { src: 'resources\\icon.png' });
+
+        runResource('/path/to/config.xml', resource, container);
+
+        const children = container.findall('icon');
+        expect(children.length).toEqual(1);
+        expect(children[0].tag).toEqual(resource.nodeName);
+        expect(children[0].get('src')).toEqual(src);
+      });
+
+    });
+
+  });
+
+});

src/config.ts

@@ -111,13 +111,17 @@ export function runResource(configPath: string, resource: GeneratedResource, con
 
   // We force the use of forward slashes here to provide cross-platform
   // compatibility for paths.
-  const value = pathlib.relative(pathlib.dirname(configPath), src).replace(/\\/g, '/');
-  const imgElement = resolveResourceElement(container, resource.nodeName, resource.srckey, value);
+  const dest = pathlib.relative(pathlib.dirname(configPath), src).replace(/\\/g, '/');
+  const imgElement = resolveResourceElement(container, resource.nodeName, resource.srckey, dest);
 
   for (const attr of resource.nodeAttributes) {
-    const v = resource[attr];
+    let v = resource[attr];
 
     if (v) {
+      if (attr === resource.srckey) {
+        v = dest;
+      }
+
       imgElement.set(attr, v.toString());
     }
   }