fix(arborist): dependencies from registries with a peerDependency on a workspace (#6193)

* fix(arborist): support dependencies from registries with a peer dependency on a workspace

Author: ixalon

workspaces/arborist/lib/arborist/build-ideal-tree.js

@@ -1243,7 +1243,7 @@ This is a one-time fix-up, please be patient...
     if (isWorkspace) {
       const existingNode = this.idealTree.edgesOut.get(spec.name).to
       if (existingNode && existingNode.isWorkspace && existingNode.satisfies(edge)) {
-        return edge.to
+        return existingNode
       }
     }
 

workspaces/arborist/tap-snapshots/test/arborist/build-ideal-tree.js.test.cjs

@@ -159849,6 +159849,94 @@ ArboristNode {
 }
 `
 
+exports[`test/arborist/build-ideal-tree.js TAP workspaces should allow cyclic peer dependencies between workspaces and packages from a repository > must match snapshot 1`] = `
+ArboristNode {
+  "children": Map {
+    "foo" => ArboristNode {
+      "edgesIn": Set {
+        EdgeIn {
+          "from": "workspace-a",
+          "name": "foo",
+          "spec": ">=1.0.0",
+          "type": "prod",
+        },
+      },
+      "edgesOut": Map {
+        "workspace-a" => EdgeOut {
+          "name": "workspace-a",
+          "spec": "1.0.0",
+          "to": "node_modules/workspace-a",
+          "type": "peer",
+        },
+      },
+      "location": "node_modules/foo",
+      "name": "foo",
+      "path": "{CWD}/test/arborist/tap-testdir-build-ideal-tree-workspaces-should-allow-cyclic-peer-dependencies-between-workspaces-and-packages-from-a-repository/node_modules/foo",
+      "version": "1.0.0",
+    },
+    "workspace-a" => ArboristLink {
+      "edgesIn": Set {
+        EdgeIn {
+          "from": "",
+          "name": "workspace-a",
+          "spec": "file:{CWD}/test/arborist/tap-testdir-build-ideal-tree-workspaces-should-allow-cyclic-peer-dependencies-between-workspaces-and-packages-from-a-repository/workspace-a",
+          "type": "workspace",
+        },
+        EdgeIn {
+          "from": "node_modules/foo",
+          "name": "workspace-a",
+          "spec": "1.0.0",
+          "type": "peer",
+        },
+      },
+      "isWorkspace": true,
+      "location": "node_modules/workspace-a",
+      "name": "workspace-a",
+      "path": "{CWD}/test/arborist/tap-testdir-build-ideal-tree-workspaces-should-allow-cyclic-peer-dependencies-between-workspaces-and-packages-from-a-repository/node_modules/workspace-a",
+      "realpath": "{CWD}/test/arborist/tap-testdir-build-ideal-tree-workspaces-should-allow-cyclic-peer-dependencies-between-workspaces-and-packages-from-a-repository/workspace-a",
+      "resolved": "file:../workspace-a",
+      "target": ArboristNode {
+        "location": "workspace-a",
+      },
+      "version": "1.0.0",
+    },
+  },
+  "edgesOut": Map {
+    "workspace-a" => EdgeOut {
+      "name": "workspace-a",
+      "spec": "file:{CWD}/test/arborist/tap-testdir-build-ideal-tree-workspaces-should-allow-cyclic-peer-dependencies-between-workspaces-and-packages-from-a-repository/workspace-a",
+      "to": "node_modules/workspace-a",
+      "type": "workspace",
+    },
+  },
+  "fsChildren": Set {
+    ArboristNode {
+      "edgesOut": Map {
+        "foo" => EdgeOut {
+          "name": "foo",
+          "spec": ">=1.0.0",
+          "to": "node_modules/foo",
+          "type": "prod",
+        },
+      },
+      "isWorkspace": true,
+      "location": "workspace-a",
+      "name": "workspace-a",
+      "path": "{CWD}/test/arborist/tap-testdir-build-ideal-tree-workspaces-should-allow-cyclic-peer-dependencies-between-workspaces-and-packages-from-a-repository/workspace-a",
+      "version": "1.0.0",
+    },
+  },
+  "isProjectRoot": true,
+  "location": "",
+  "name": "tap-testdir-build-ideal-tree-workspaces-should-allow-cyclic-peer-dependencies-between-workspaces-and-packages-from-a-repository",
+  "packageName": "root",
+  "path": "{CWD}/test/arborist/tap-testdir-build-ideal-tree-workspaces-should-allow-cyclic-peer-dependencies-between-workspaces-and-packages-from-a-repository",
+  "workspaces": Map {
+    "workspace-a" => "workspace-a",
+  },
+}
+`
+
 exports[`test/arborist/build-ideal-tree.js TAP workspaces should ignore nested node_modules folders > expect resolving Promise 1`] = `
 ArboristNode {
   "children": Map {

workspaces/arborist/test/arborist/build-ideal-tree.js

@@ -877,6 +877,52 @@ t.test('workspaces', t => {
     t.matchSnapshot(printTree(await tree))
   })
 
+  t.test('should allow cyclic peer dependencies between workspaces and packages from a repository', async t => {
+    generateNocks(t, {
+      foo: {
+        versions: ['1.0.0'],
+        peerDependencies: ['workspace-a'],
+      },
+    })
+    const path = t.testdir({
+      'package.json': JSON.stringify({
+        name: 'root',
+        dependencies: {
+          'workspace-a': '*',
+        },
+        workspaces: ['workspace-a'],
+      }),
+      'workspace-a': {
+        'package.json': JSON.stringify({
+          name: 'workspace-a',
+          version: '1.0.0',
+          dependencies: {
+            foo: '>=1.0.0',
+          },
+        }),
+      },
+    })
+
+    const arb = new Arborist({
+      ...OPT,
+      path,
+      workspaces: ['workspace-a'],
+    })
+
+    const tree = arb.buildIdealTree({
+      path,
+      add: [
+        'foo',
+      ],
+    })
+
+    // just assert that the buildIdealTree call resolves, if there's a
+    // problem here it will reject because of nock disabling requests
+    await t.resolves(tree)
+
+    t.matchSnapshot(printTree(await tree))
+  })
+
   t.test('workspace nodes are used instead of fetching manifests when they are valid', async t => {
     // turn off networking, this should never make a registry request
     nock.disableNetConnect()