fix(arborist): honor allow-remote=root for root-direct remote tarballs

workspaces/arborist/lib/arborist/isolated-reifier.js

@@ -43,6 +43,7 @@ module.exports = cls => class IsolatedReifier extends cls {
       isInStore,
       inBundle,
       isRegistryDependency: node.isRegistryDependency,
+      isRootDependency: node.isRootDependency,
       location,
       name: node.packageName || node.name,
       optional: node.optional,
@@ -157,6 +158,10 @@ module.exports = cls => class IsolatedReifier extends cls {
     // Carry the source node's registry-dependency flag so the store node retains it.
     // IsolatedNode has no edges to recompute it from, and reify's registry-tarball allow-remote exemption depends on it.
     result.isRegistryDependency = node.isRegistryDependency
+    // Same reasoning for allow-remote=root: the store node has no edgesIn, so capture from the source node whether it satisfies a valid edge from the project root or a workspace.
+    result.isRootDependency = [...node.edgesIn].some(e =>
+      e.valid && (e.from?.isProjectRoot || e.from?.isWorkspace)
+    )
     return result
   }
 

workspaces/arborist/lib/arborist/reify.js

@@ -707,7 +707,8 @@ module.exports = cls => class Reifier extends cls {
         integrity: node.integrity,
         // A node counts as "root" for allow-* enforcement if it satisfies at least one valid dependency edge declared by the project root or a workspace.
         // node.parent is unsafe here: after hoisting, transitive packages can have the project root as their tree parent.
-        _isRoot: [...node.edgesIn].some(e =>
+        // In the linked strategy the store node has no edgesIn, so isolated-reifier precomputes isRootDependency from the source node's edges.
+        _isRoot: node.isRootDependency || [...node.edgesIn].some(e =>
           e.valid && (e.from?.isProjectRoot || e.from?.isWorkspace)
         ),
         // pacote's npa re-parses our `name@URL` spec as type=remote, so allowRemote would mis-fire on registry tarballs.

workspaces/arborist/lib/isolated-classes.js

@@ -21,6 +21,7 @@ class IsolatedNode {
   isInStore = false
   inBundle = false
   isRegistryDependency = false
+  isRootDependency = false
   linksIn = new Set()
   meta = { loadedFromDisk: false }
   optional = false
@@ -54,6 +55,9 @@ class IsolatedNode {
     if (options.isRegistryDependency) {
       this.isRegistryDependency = true
     }
+    if (options.isRootDependency) {
+      this.isRootDependency = true
+    }
     if (options.optional) {
       this.optional = true
     }

workspaces/arborist/test/arborist/reify.js

@@ -3904,6 +3904,36 @@ t.test('should preserve exact ranges, missing actual tree', async (t) => {
     await t.resolves(arb.reify(), 'registry tarball is allowed under linked strategy')
   })
 
+  t.test('allowRemote=root allows root-direct remote tarball under linked install strategy', async t => {
+    // The linked strategy extracts store nodes as IsolatedNode, which has no edgesIn to recompute root-ness from.
+    // isRootDependency must be carried from the source tree node, otherwise allow-remote=root mis-fires on a genuine remote tarball that is a direct dep of the project root.
+    const testdir = t.testdir({
+      project: {
+        'package.json': JSON.stringify({
+          name: 'myproject',
+          version: '1.0.0',
+          dependencies: {
+            abbrev: 'https://remote.example.com/abbrev-1.1.1.tgz',
+          },
+        }),
+      },
+    })
+
+    tnock(t, 'https://remote.example.com')
+      .get('/abbrev-1.1.1.tgz')
+      .reply(200, abbrevTGZ)
+
+    const arb = new Arborist({
+      path: resolve(testdir, 'project'),
+      registry: 'https://registry.example.com',
+      cache: resolve(testdir, 'cache'),
+      allowRemote: 'root',
+      installStrategy: 'linked',
+    })
+
+    await t.resolves(arb.reify(), 'root-direct remote tarball is allowed under linked strategy with allow-remote=root')
+  })
+
   t.test('registry with different protocol should swap protocol', async (t) => {
     const abbrevPackument4 = JSON.stringify({
       _id: 'abbrev',