fix(@angular-devkit/core): track workspace targets with no original collection

Fixes angular#15403

Author: clydin

packages/angular_devkit/core/src/workspace/definitions.ts

@@ -29,11 +29,12 @@ export interface TargetDefinition {
   builder: string;
 }
 
-export type DefinitionCollectionListener<V> = (
+export type DefinitionCollectionListener<V extends object> = (
   name: string,
   action: 'add' | 'remove' | 'replace',
   newValue: V | undefined,
   oldValue: V | undefined,
+  collection: DefinitionCollection<V>,
 ) => void;
 
 class DefinitionCollection<V extends object> implements ReadonlyMap<string, V> {
@@ -50,7 +51,7 @@ class DefinitionCollection<V extends object> implements ReadonlyMap<string, V> {
     const value = this._map.get(key);
     const result = this._map.delete(key);
     if (result && value !== undefined && this._listener) {
-      this._listener(key, 'remove', undefined, value);
+      this._listener(key, 'remove', undefined, value, this);
     }
 
     return result;
@@ -61,7 +62,7 @@ class DefinitionCollection<V extends object> implements ReadonlyMap<string, V> {
     this._map.set(key, value);
 
     if (this._listener) {
-      this._listener(key, existing !== undefined ? 'replace' : 'add', value, existing);
+      this._listener(key, existing !== undefined ? 'replace' : 'add', value, existing, this);
     }
 
     return this;

packages/angular_devkit/core/src/workspace/json/reader.ts

@@ -213,17 +213,35 @@ function parseProject(
   }
 
   let collectionListener: DefinitionCollectionListener<TargetDefinition> | undefined;
-  if (context.trackChanges && targetsNode) {
-    const parentNode = targetsNode;
-    collectionListener = (name, action, newValue) => {
-      jsonMetadata.addChange(
-        action,
-        `/projects/${projectName}/targets/${escapeKey(name)}`,
-        parentNode,
-        newValue,
-        'target',
-      );
-    };
+  if (context.trackChanges) {
+    if (targetsNode) {
+      const parentNode = targetsNode;
+      collectionListener = (name, action, newValue) => {
+        jsonMetadata.addChange(
+          action,
+          `/projects/${projectName}/targets/${escapeKey(name)}`,
+          parentNode,
+          newValue,
+          'target',
+        );
+      };
+    } else {
+      let added = false;
+      collectionListener = (_name, action, _new, _old, collection) => {
+        if (added || action !== 'add') {
+          return;
+        }
+
+        jsonMetadata.addChange(
+          'add',
+          `/projects/${projectName}/targets`,
+          projectNode,
+          collection,
+          'targetcollection',
+        );
+        added = true;
+      };
+    }
   }
 
   const base = {

packages/angular_devkit/core/src/workspace/json/reader_spec.ts

@@ -710,4 +710,53 @@ describe('JSON ProjectDefinition Tracks Project Changes', () => {
       expect(change.value).toBe('valueA');
     }
   });
+
+  it('tracks target additions with no original target collection', async () => {
+    const original = stripIndent`
+      {
+        "version": 1,
+        // Comment
+        "schematics": {
+          "@angular/schematics:component": {
+            "prefix": "abc"
+          }
+        },
+        "projects": {
+          "p1": {
+            "root": "p1-root"
+          }
+        },
+        "x-foo": {
+          "is": ["good", "great", "awesome"]
+        },
+        "x-bar": 5,
+      }
+    `;
+    const host = createTestHost(original);
+
+    const workspace = await readJsonWorkspace('', host);
+
+    const project = workspace.projects.get('p1');
+    expect(project).not.toBeUndefined();
+    if (!project) {
+      return;
+    }
+
+    project.targets.add({
+      name: 't1',
+      builder: 't1-builder',
+    });
+
+    const metadata = getMetadata(workspace);
+
+    expect(metadata.hasChanges).toBeTruthy();
+    expect(metadata.changeCount).toBe(1);
+
+    const change = metadata.findChangesForPath('/projects/p1/targets')[0];
+    expect(change).not.toBeUndefined();
+    if (change) {
+      expect(change.op).toBe('add');
+      expect(change.type).toBe('targetcollection');
+    }
+  });
 });