fix(aborist): handle missing link targets in load-virtual.js

workspaces/arborist/lib/arborist/load-virtual.js

@@ -200,6 +200,12 @@ module.exports = cls => class VirtualLoader extends cls {
       const targetPath = resolve(this.path, meta.resolved)
       const targetLoc = relpath(this.path, targetPath)
       const target = nodes.get(targetLoc)
+      // Skip loading the target if it doesn't exist
+      // This can happen if the edge to it has error MISSING
+      // For example, where a workspace has a broken link dependency
+      if (!target) {
+        continue
+      }
       const link = this.#loadLink(location, targetLoc, target, meta)
       nodes.set(location, link)
       nodes.set(targetLoc, link.target)

workspaces/arborist/test/arborist/load-virtual.js

@@ -245,3 +245,37 @@ t.test('do not bundle the entire universe', async t => {
     'yaml',
   ].sort())
 })
+
+t.test('load-virtual does not fail if a link target does not exist', async t => {
+  // Create a mock Shrinkwrap with a link to a non-existent target
+  const mockPath = t.testdir({
+    'package.json': JSON.stringify({
+      name: 'test-package',
+      version: '1.0.0',
+    }),
+    'package-lock.json': JSON.stringify({
+      name: 'test-package',
+      version: '1.0.0',
+      lockfileVersion: 2,
+      requires: true,
+      packages: {
+        '': {
+          name: 'test-package',
+          version: '1.0.0',
+          dependencies: {
+            'missing-pkg': 'file:./missing-pkg',
+          },
+        },
+        'node_modules/missing-pkg': {
+          link: true,
+          resolved: './missing-pkg',
+        },
+      },
+    }),
+  })
+
+  // This should not throw an error because the #resolveLinks method
+  // should skip loading the target if it doesn't exist
+  const tree = await loadVirtual(mockPath)
+  t.ok(tree, 'tree loaded successfully despite missing target')
+})