fix relative hrefs inside groups (#900)

backport of expo/expo#25111

packages/expo-router/src/__tests__/navigation.test.tsx

@@ -331,3 +331,107 @@ it("can push & replace with nested Slots", async () => {
   expect(screen).toHavePathname("/");
   expect(screen.getByTestId("index")).toBeOnTheScreen();
 });
+
+it("can navigation to a relative route without losing path params", async () => {
+  renderRouter(
+    {
+      _layout: () => <Slot />,
+      "(group)/[value]/one": () => <Text testID="one" />,
+      "(group)/[value]/two": () => <Text testID="two" />,
+      "(group)/[...value]/three": () => <Text testID="three" />,
+      "(group)/[...value]/four": () => <Text testID="four" />,
+    },
+    {
+      initialUrl: "/test/one",
+    }
+  );
+
+  expect(screen).toHavePathname("/test/one");
+  expect(screen.getByTestId("one")).toBeOnTheScreen();
+
+  act(() => router.push("./two"));
+  expect(screen).toHavePathname("/test/two");
+  expect(screen.getByTestId("two")).toBeOnTheScreen();
+
+  act(() => router.push("../apple/one?orange=1"));
+  expect(screen).toHavePathname("/apple/one");
+  expect(screen.getByTestId("one")).toBeOnTheScreen();
+
+  act(() => router.push("./two"));
+  expect(screen).toHavePathname("/apple/two");
+  expect(screen.getByTestId("two")).toBeOnTheScreen();
+
+  act(() => router.push("./three"));
+  expect(screen).toHavePathname("/apple/three");
+  expect(screen.getByTestId("three")).toBeOnTheScreen();
+
+  act(() => router.push("./banana/four"));
+  expect(screen).toHavePathname("/apple/banana/four");
+  expect(screen.getByTestId("four")).toBeOnTheScreen();
+
+  act(() => router.push("./three"));
+  expect(screen).toHavePathname("/apple/banana/three");
+  expect(screen.getByTestId("three")).toBeOnTheScreen();
+});
+
+describe("shared routes with tabs", () => {
+  function renderSharedTabs() {
+    renderRouter({
+      "(one,two)/_layout": () => <Stack />,
+      "(one,two)/one": () => <Text />,
+      "(one,two)/post": () => <Text />,
+      "(two)/two": () => <Text />,
+      _layout: () => <Tabs />,
+      index: () => <Redirect href="/one" />,
+    });
+
+    expect(screen).toHavePathname("/one");
+  }
+
+  describe("tab one (default)", () => {
+    it("pushes post in tab one using absolute /post", async () => {
+      renderSharedTabs();
+      act(() => router.push("/post"));
+      expect(screen).toHavePathname("/post");
+      expect(screen).toHaveSegments(["(one)", "post"]);
+    });
+    it("pushes post in tab one using absolute /(tabs)/(one)/post", async () => {
+      renderSharedTabs();
+      act(() => router.push("/(one)/post"));
+      expect(screen).toHavePathname("/post");
+      expect(screen).toHaveSegments(["(one)", "post"]);
+    });
+    it("pushes post in tab one using relative ./post", async () => {
+      renderSharedTabs();
+      act(() => router.push("./post"));
+      expect(screen).toHavePathname("/post");
+      expect(screen).toHaveSegments(["(one)", "post"]);
+    });
+  });
+  describe("tab two", () => {
+    // Navigate to tab two before each case here.
+    beforeEach(() => {
+      renderSharedTabs();
+      act(() => router.push("/two"));
+      expect(screen).toHavePathname("/two");
+      expect(screen).toHaveSegments(["(two)", "two"]);
+    });
+
+    it("pushes post in tab two with absolute `/post` goes to default tab", async () => {
+      act(() => router.push("/post"));
+      expect(screen).toHavePathname("/post");
+      expect(screen).toHaveSegments(["(one)", "post"]);
+    });
+    it("pushes post in tab two using absolute /(tabs)/(two)/post", async () => {
+      act(() => router.push("/(two)/post"));
+      expect(screen).toHavePathname("/post");
+      expect(screen).toHaveSegments(["(two)", "post"]);
+    });
+    it("pushes post in tab two using relative ./post", async () => {
+      // Pushing `./post` should preserve the relative position in tab two and NOT swap to the default tab one variation of the `/post` route.
+      act(() => router.push("./post"));
+      expect(screen).toHavePathname("/post");
+      expect(screen).toHaveSegments(["(two)", "post"]);
+    });
+  });
+});

packages/expo-router/src/global-state/routing.ts

@@ -78,16 +78,28 @@ export function linkTo(this: RouterStore, href: string, event?: string) {
   const rootState = navigationRef.getRootState();
 
   if (href.startsWith(".")) {
-    let base =
-      this.linking.getPathFromState?.(rootState, {
-        screens: [],
-        preserveGroups: true,
-      }) ?? "";
-
-    if (base && !base.endsWith("/")) {
-      base += "/..";
-    }
-    href = resolve(base, href);
+    const base =
+      this.routeInfo?.segments
+        ?.map((segment) => {
+          if (!segment.startsWith("[")) return segment;
+
+          if (segment.startsWith("[...")) {
+            segment = segment.slice(4, -1);
+            const params = this.routeInfo?.params?.[segment];
+            if (Array.isArray(params)) {
+              return params.join("/");
+            } else {
+              return params?.split(",")?.join("/") ?? "";
+            }
+          } else {
+            segment = segment.slice(1, -1);
+            return this.routeInfo?.params?.[segment];
+          }
+        })
+        .filter(Boolean)
+        .join("/") ?? "/";
+
+    href = resolve(base + "/..", href);
   }
 
   const state = this.linking.getStateFromPath!(href, this.linking.config);