cli: Log warning if unable to parse yarn.lock

Signed-off-by: Mustansar Anwar ul Samad <mustansar.samad@gmail.com>

.changeset/witty-lizards-nail.md

@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Log warning if unable to parse yarn.lock

packages/cli/src/commands/app/serve.ts

@@ -25,31 +25,56 @@ import { Lockfile } from '../../lib/versioning';
 import { forbiddenDuplicatesFilter, includedFilter } from '../versions/lint';
 
 export default async (cmd: Command) => {
-  const lockfile = await Lockfile.load(paths.resolveTargetRoot('yarn.lock'));
-  const result = lockfile.analyze({
-    filter: includedFilter,
-  });
-  const problemPackages = [...result.newVersions, ...result.newRanges]
-    .map(({ name }) => name)
-    .filter(name => forbiddenDuplicatesFilter(name));
+  const lockFilePath = paths.resolveTargetRoot('yarn.lock');
+  if (fs.existsSync(lockFilePath)) {
+    try {
+      const lockfile = await Lockfile.load(lockFilePath);
+      const result = lockfile.analyze({
+        filter: includedFilter,
+      });
+      const problemPackages = [...result.newVersions, ...result.newRanges]
+        .map(({ name }) => name)
+        .filter(name => forbiddenDuplicatesFilter(name));
 
-  if (problemPackages.length > 0) {
+      if (problemPackages.length > 0) {
+        console.log(
+          chalk.yellow(
+            `⚠️ Some of the following packages may be outdated or have duplicate installations:
+
+              ${uniq(problemPackages).join(', ')}
+            `,
+          ),
+        );
+        console.log(
+          chalk.yellow(
+            `⚠️ The following command may fix the issue, but it could also be an issue within one of your dependencies:
+
+              yarn backstage-cli versions:check --fix
+            `,
+          ),
+        );
+      }
+    } catch (error) {
+      console.log(
+        chalk.yellow(
+          `⚠️ Unable to parse yarn.lock file properly:
+
+            ${error}
+
+            skipping analyzer for outdated or duplicate installations
+          `,
+        ),
+      );
+    }
+  } else {
     console.log(
       chalk.yellow(
-        `⚠️ Some of the following packages may be outdated or have duplicate installations:
+        `⚠️ Unable to find yarn.lock file:
 
-          ${uniq(problemPackages).join(', ')}
+          skipping analyzer for outdated or duplicate installations
         `,
       ),
     );
-    console.log(
-      chalk.yellow(
-        `⚠️ The following command may fix the issue, but it could also be an issue within one of your dependencies:
-
-          yarn backstage-cli versions:check --fix
-      `,
-      ),
-    );
   }
 
   const { name } = await fs.readJson(paths.resolveTarget('package.json'));