fix(projects): isolate legacy host identity

packages/server/src/server/project-group-key.test.ts

@@ -1,3 +1,5 @@
+import { mkdirSync, mkdtempSync, rmSync, symlinkSync } from "node:fs";
+import { tmpdir } from "node:os";
 import path from "node:path";
 import { describe, expect, test } from "vitest";
 import { deriveProjectGroupKey } from "./project-group-key.js";
@@ -82,4 +84,29 @@ describe("deriveProjectGroupKey", () => {
       }),
     ).toBe(path.join(mainRepoRoot, "packages", "app"));
   });
+
+  test.skipIf(process.platform === "win32")(
+    "preserves a selected subproject reached through a symlink",
+    () => {
+      const tempDir = mkdtempSync(path.join(tmpdir(), "project-group-key-"));
+      try {
+        const worktreeRoot = path.join(tempDir, "repo");
+        const selectedRoot = path.join(worktreeRoot, "packages", "app");
+        const linkedRoot = path.join(tempDir, "app-link");
+        mkdirSync(selectedRoot, { recursive: true });
+        symlinkSync(selectedRoot, linkedRoot, "dir");
+
+        expect(
+          deriveProjectGroupKey({
+            rootPath: linkedRoot,
+            remoteUrl: "git@github.com:getpaseo/paseo.git",
+            worktreeRoot,
+            mainRepoRoot: worktreeRoot,
+          }),
+        ).toBe("remote:github.com/getpaseo/paseo#subdir:packages/app");
+      } finally {
+        rmSync(tempDir, { recursive: true, force: true });
+      }
+    },
+  );
 });

packages/server/src/server/project-group-key.ts

@@ -1,4 +1,5 @@
-import { isAbsolute, relative, resolve, sep } from "node:path";
+import { resolve, sep } from "node:path";
+import { getRealpathAwareRelativePath } from "../utils/path.js";
 
 /**
  * Derives the persisted, opaque equivalence key used to group projects across hosts.
@@ -23,17 +24,7 @@ export function deriveProjectGroupKey(input: {
 
 function deriveSelectedPath(rootPath: string, worktreeRoot: string | null): string | null {
   if (!worktreeRoot) return null;
-  const selectedPath = relative(resolve(worktreeRoot), resolve(rootPath));
-  if (
-    !selectedPath ||
-    selectedPath === "." ||
-    selectedPath === ".." ||
-    selectedPath.startsWith(`..${sep}`) ||
-    isAbsolute(selectedPath)
-  ) {
-    return null;
-  }
-  return selectedPath;
+  return getRealpathAwareRelativePath(worktreeRoot, rootPath) || null;
 }
 
 function encodeSelectedPath(selectedPath: string): string {