fix(core): add migration to set useLegacyCache by default

packages/nx/migrations.json

@@ -57,6 +57,11 @@
       "version": "20.0.0-beta.7",
       "description": "Migration for v20.0.0-beta.7",
       "implementation": "./src/migrations/update-20-0-0/move-use-daemon-process"
+    },
+    "use-legacy-cache": {
+      "version": "20.0.1",
+      "description": "Set `useLegacyCache` to true for migrating workspaces",
+      "implementation": "./src/migrations/update-20-0-1/use-legacy-cache"
     }
   }
 }

packages/nx/src/migrations/update-20-0-1/use-legacy-cache.spec.ts

@@ -0,0 +1,59 @@
+import { createTreeWithEmptyWorkspace } from '../../generators/testing-utils/create-tree-with-empty-workspace';
+import { Tree } from '../../generators/tree';
+
+import update from './use-legacy-cache';
+import { readNxJson, updateNxJson } from '../../generators/utils/nx-json';
+
+describe('use legacy cache', () => {
+  let tree: Tree;
+
+  beforeEach(() => {
+    tree = createTreeWithEmptyWorkspace();
+  });
+
+  it('should add `useLegacyCache` on migrating workspaces that did not have `enableDbCache`', async () => {
+    await update(tree);
+
+    expect(readNxJson(tree)).toMatchInlineSnapshot(`
+      {
+        "affected": {
+          "defaultBase": "main",
+        },
+        "targetDefaults": {
+          "build": {
+            "cache": true,
+          },
+          "lint": {
+            "cache": true,
+          },
+        },
+        "useLegacyCache": true,
+      }
+    `);
+  });
+  it('should not add `useLegacyCache` on migrating workspaces that did have `enableDbCache`', async () => {
+    const nxJson = readNxJson(tree);
+    updateNxJson(tree, {
+      enableDbCache: true,
+      ...nxJson,
+    } as any);
+
+    await update(tree);
+
+    expect(readNxJson(tree)).toMatchInlineSnapshot(`
+      {
+        "affected": {
+          "defaultBase": "main",
+        },
+        "targetDefaults": {
+          "build": {
+            "cache": true,
+          },
+          "lint": {
+            "cache": true,
+          },
+        },
+      }
+    `);
+  });
+});

packages/nx/src/migrations/update-20-0-1/use-legacy-cache.ts

@@ -0,0 +1,19 @@
+import { Tree } from '../../generators/tree';
+import { formatChangedFilesWithPrettierIfAvailable } from '../../generators/internal-utils/format-changed-files-with-prettier-if-available';
+import { readNxJson, updateNxJson } from '../../generators/utils/nx-json';
+import { NxJsonConfiguration } from '../../config/nx-json';
+
+export default async function update(tree: Tree) {
+  const nxJson = readNxJson(tree) as NxJsonConfiguration;
+
+  // If workspaces  had `enableDbCache` we can just delete the property as the db cache is enabled by default in nx v20
+  if ((nxJson as any).enableDbCache) {
+    delete (nxJson as any).enableDbCache;
+  } else {
+    nxJson.useLegacyCache = true;
+  }
+
+  updateNxJson(tree, nxJson);
+
+  await formatChangedFilesWithPrettierIfAvailable(tree);
+}