fix(core): handle self referencing workspaces field

.yarn/versions/4b66efea.yml

@@ -0,0 +1,34 @@
+releases:
+  "@yarnpkg/cli": patch
+  "@yarnpkg/core": patch
+
+declined:
+  - "@yarnpkg/plugin-compat"
+  - "@yarnpkg/plugin-constraints"
+  - "@yarnpkg/plugin-dlx"
+  - "@yarnpkg/plugin-essentials"
+  - "@yarnpkg/plugin-exec"
+  - "@yarnpkg/plugin-file"
+  - "@yarnpkg/plugin-git"
+  - "@yarnpkg/plugin-github"
+  - "@yarnpkg/plugin-http"
+  - "@yarnpkg/plugin-init"
+  - "@yarnpkg/plugin-interactive-tools"
+  - "@yarnpkg/plugin-link"
+  - "@yarnpkg/plugin-nm"
+  - "@yarnpkg/plugin-npm"
+  - "@yarnpkg/plugin-npm-cli"
+  - "@yarnpkg/plugin-pack"
+  - "@yarnpkg/plugin-patch"
+  - "@yarnpkg/plugin-pnp"
+  - "@yarnpkg/plugin-pnpm"
+  - "@yarnpkg/plugin-stage"
+  - "@yarnpkg/plugin-typescript"
+  - "@yarnpkg/plugin-version"
+  - "@yarnpkg/plugin-workspace-tools"
+  - "@yarnpkg/builder"
+  - "@yarnpkg/doctor"
+  - "@yarnpkg/extensions"
+  - "@yarnpkg/nm"
+  - "@yarnpkg/pnpify"
+  - "@yarnpkg/sdks"

packages/acceptance-tests/pkg-tests-specs/sources/commands/workspaces/__snapshots__/foreach.test.js.snap

@@ -289,9 +289,9 @@ exports[`Commands workspace foreach should run on current and descendant workspa
   "stderr": "",
   "stdout": "Test Workspace C
 Test Workspace D
-Test Workspace E
 Test Workspace F
 Test Workspace G
+Test Workspace E
 Done
 ",
 }

packages/acceptance-tests/pkg-tests-specs/sources/commands/workspaces/foreach.test.js

@@ -108,6 +108,27 @@ describe(`Commands`, () => {
       ),
     );
 
+    test(
+      `should support self referencing workspaces field`,
+      makeTemporaryEnv(
+        {
+          private: true,
+          workspaces: [`.`],
+        },
+        async ({path, run}) => {
+          await run(`install`);
+
+          await expect(run(`workspaces`, `foreach`, `--worktree`, `exec`, `echo`, `42`)).resolves.toMatchObject(
+            {
+              code: 0,
+              stdout: `42\nDone\n`,
+              stderr: ``,
+            },
+          );
+        },
+      ),
+    );
+
     test(
       `should execute 'node' command`,
       makeTemporaryEnv(

packages/yarnpkg-core/sources/Workspace.ts

@@ -197,17 +197,21 @@ export class Workspace {
    * @returns all the child workspaces
    */
   getRecursiveWorkspaceChildren() {
-    const workspaceList: Array<Workspace> = [];
+    const workspaceSet = new Set<Workspace>([this]);
 
-    for (const childWorkspaceCwd of this.workspacesCwds) {
-      const childWorkspace = this.project.workspacesByCwd.get(childWorkspaceCwd);
+    for (const workspace of workspaceSet) {
+      for (const childWorkspaceCwd of workspace.workspacesCwds) {
+        const childWorkspace = this.project.workspacesByCwd.get(childWorkspaceCwd);
 
-      if (childWorkspace) {
-        workspaceList.push(childWorkspace, ...childWorkspace.getRecursiveWorkspaceChildren());
+        if (childWorkspace) {
+          workspaceSet.add(childWorkspace);
+        }
       }
     }
 
-    return workspaceList;
+    workspaceSet.delete(this);
+
+    return Array.from(workspaceSet);
   }
 
   async persistManifest() {