fix: TypeScript workspaces bring in conflicting projen dependencies (#847)

This only opens up the possibility of multiple projen versions
across the monorepo, which is a source of bugs.

Author: rix0rrr

src/yarn/typescript-workspace.ts

@@ -247,6 +247,9 @@ export class TypeScriptWorkspace extends typescript.TypeScriptProject implements
 
     this.bundledDeps.push(...options.bundledDeps ?? []);
 
+    // Individual workspace packages shouldn't depend on "projen", it gets brought in at the monorepo root
+    this.deps.removeDependency('projen');
+
     options.parent.register(this);
   }
 

test/__snapshots__/cdklabs-monorepo.test.ts.snap

@@ -28,6 +28,19 @@ describe('CdkLabsMonorepo', () => {
       expect(outdir).toMatchSnapshot();
     });
 
+    test('workspaces dont have their own projen dependency', () => {
+      new yarn.TypeScriptWorkspace({
+        parent,
+        name: '@cdklabs/one',
+      });
+
+      const outdir = Testing.synth(parent);
+      const deps = outdir['packages/@cdklabs/one/.projen/deps.json'];
+      expect(deps.dependencies).not.toContain(expect.objectContaining({
+        name: 'projen',
+      }));
+    });
+
     test('bundled dependencies lead to a nohoist directive', () => {
       // GIVEN
       new yarn.TypeScriptWorkspace({