From b4cd145b574f8ac29bd63bdfb00a3cd5fd62bbee Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Mon, 9 Jan 2023 22:52:19 +0100
Subject: [PATCH] cli: added package-exports migration command

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 .changeset/long-nails-pump.md                 |  5 ++
 packages/cli/src/commands/index.ts            |  7 ++
 .../src/commands/migrate/packageExports.ts    | 83 +++++++++++++++++++
 packages/cli/src/lib/monorepo/PackageGraph.ts |  4 +
 4 files changed, 99 insertions(+)
 create mode 100644 .changeset/long-nails-pump.md
 create mode 100644 packages/cli/src/commands/migrate/packageExports.ts

diff --git a/.changeset/long-nails-pump.md b/.changeset/long-nails-pump.md
new file mode 100644
index 0000000000..d9eefc0249
--- /dev/null
+++ b/.changeset/long-nails-pump.md
@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Added a new `migrate package-exports` command that synchronizes package exports fields in all `package.json`s.
diff --git a/packages/cli/src/commands/index.ts b/packages/cli/src/commands/index.ts
index 628e46df85..2fdd2442d4 100644
--- a/packages/cli/src/commands/index.ts
+++ b/packages/cli/src/commands/index.ts
@@ -191,6 +191,13 @@ export function registerMigrateCommand(program: Command) {
       lazy(() => import('./migrate/packageScripts').then(m => m.command)),
     );
 
+  command
+    .command('package-exports')
+    .description('Synchronize package sub-path export definitions')
+    .action(
+      lazy(() => import('./migrate/packageExports').then(m => m.command)),
+    );
+
   command
     .command('package-lint-configs')
     .description(
diff --git a/packages/cli/src/commands/migrate/packageExports.ts b/packages/cli/src/commands/migrate/packageExports.ts
new file mode 100644
index 0000000000..3a59c02375
--- /dev/null
+++ b/packages/cli/src/commands/migrate/packageExports.ts
@@ -0,0 +1,83 @@
+/*
+ * Copyright 2020 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import fs from 'fs-extra';
+import { resolve as resolvePath } from 'path';
+import { PackageGraph } from '../../lib/monorepo';
+
+function trimRelative(path: string): string {
+  if (path.startsWith('./')) {
+    return path.slice(2);
+  }
+  return path;
+}
+
+export async function command() {
+  const packages = await PackageGraph.listTargetPackages();
+
+  await Promise.all(
+    packages.map(async ({ dir, packageJson }) => {
+      const { exports: exp } = packageJson;
+      if (!exp || typeof exp !== 'object' || Array.isArray(exp)) {
+        return;
+      }
+
+      const existingTypesVersions = JSON.stringify(packageJson.typesVersions);
+
+      const typeEntries: Record<string, [string]> = {};
+
+      for (const [path, value] of Object.entries(exp)) {
+        const newPath = path === '.' ? '*' : trimRelative(path);
+
+        if (typeof value === 'string') {
+          typeEntries[newPath] = [trimRelative(value)];
+        } else if (
+          value &&
+          typeof value === 'object' &&
+          !Array.isArray(value)
+        ) {
+          if (typeof value.types === 'string') {
+            typeEntries[newPath] = [trimRelative(value.types)];
+          } else if (typeof value.default === 'string') {
+            typeEntries[newPath] = [trimRelative(value.default)];
+          }
+        }
+      }
+
+      const typesVersions = { '*': typeEntries };
+
+      if (existingTypesVersions !== JSON.stringify(typesVersions)) {
+        console.log(`Synchronizing exports in ${packageJson.name}`);
+        const newPkgEntries = Object.entries(packageJson).filter(
+          ([name]) => name !== 'typesVersions',
+        );
+        newPkgEntries.splice(
+          newPkgEntries.findIndex(([name]) => name === 'exports') + 1,
+          0,
+          ['typesVersions', typesVersions],
+        );
+
+        await fs.writeJson(
+          resolvePath(dir, 'package.json'),
+          Object.fromEntries(newPkgEntries),
+          {
+            spaces: 2,
+          },
+        );
+      }
+    }),
+  );
+}
diff --git a/packages/cli/src/lib/monorepo/PackageGraph.ts b/packages/cli/src/lib/monorepo/PackageGraph.ts
index a1fc95e669..d34ede41ae 100644
--- a/packages/cli/src/lib/monorepo/PackageGraph.ts
+++ b/packages/cli/src/lib/monorepo/PackageGraph.ts
@@ -20,6 +20,7 @@ import { paths } from '../paths';
 import { PackageRole } from '../role';
 import { listChangedFiles, readFileAtRef } from '../git';
 import { Lockfile } from '../versioning';
+import { JsonValue } from '@backstage/types';
 
 type PackageJSON = Package['packageJson'];
 
@@ -34,6 +35,9 @@ export interface ExtendedPackageJSON extends PackageJSON {
   backstage?: {
     role?: PackageRole;
   };
+
+  exports?: JsonValue;
+  typesVersions?: Record<string, Record<string, string[]>>;
 }
 
 export type ExtendedPackage = {