From 944d4d327bcce7c10f1c886492af0a24c9770376 Mon Sep 17 00:00:00 2001
From: Yaroslav Bolyukin <iam@lach.pw>
Date: Thu, 23 Apr 2026 00:21:44 +0200
Subject: [PATCH 1/3] fix: keep ?fresh-partial an implementation detail

---
 packages/fresh/src/runtime/client/partials.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/fresh/src/runtime/client/partials.ts b/packages/fresh/src/runtime/client/partials.ts
index ab7cbb35bb4..b8cf487f3f2 100644
--- a/packages/fresh/src/runtime/client/partials.ts
+++ b/packages/fresh/src/runtime/client/partials.ts
@@ -361,6 +361,7 @@ async function fetchPartials(
       actualUrl = nextUrl;
     }
   }
+  actualUrl.searchParams.delete(PARTIAL_SEARCH_PARAM);
 
   try {
     await applyPartials(res);

From 91369f472377de35c6b5161c76b903df48db6486 Mon Sep 17 00:00:00 2001
From: Yaroslav Bolyukin <iam@lach.pw>
Date: Sun, 26 Apr 2026 04:18:10 +0200
Subject: [PATCH 2/3] fix: after redirect, should replace history instead of
 pushing it

---
 packages/fresh/src/runtime/client/partials.ts | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/packages/fresh/src/runtime/client/partials.ts b/packages/fresh/src/runtime/client/partials.ts
index b8cf487f3f2..008e23a9592 100644
--- a/packages/fresh/src/runtime/client/partials.ts
+++ b/packages/fresh/src/runtime/client/partials.ts
@@ -83,7 +83,7 @@ if (!history.state) {
   history.replaceState(state, document.title);
 }
 
-function maybeUpdateHistory(nextUrl: URL) {
+function maybePushHistory(nextUrl: URL) {
   // Only add history entry when URL is new. Still apply
   // the partials because sometimes users click a link to
   // "refresh" the current page.
@@ -106,6 +106,12 @@ function maybeUpdateHistory(nextUrl: URL) {
   }
 }
 
+function maybeReplaceHistory(nextUrl: URL) {
+  if (nextUrl.href !== globalThis.location.href) {
+    history.replaceState(history.state, "", nextUrl.href);
+  }
+}
+
 document.addEventListener("click", async (e) => {
   let el = e.target;
   if (el && (el instanceof HTMLElement || el instanceof SVGElement)) {
@@ -154,7 +160,7 @@ document.addEventListener("click", async (e) => {
 
       const nextUrl = new URL(el.href);
       try {
-        maybeUpdateHistory(nextUrl);
+        maybePushHistory(nextUrl);
 
         const partialUrl = new URL(
           partial ? partial : nextUrl.href,
@@ -376,7 +382,7 @@ async function fetchPartials(
   }
 
   if (shouldNavigate) {
-    maybeUpdateHistory(actualUrl);
+    maybeReplaceHistory(actualUrl);
   }
 }
 

From ff3683eb9ed47ecfaaa346d64d06b44c38155e67 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bartek=20Iwa=C5=84czuk?= <biwanczuk@gmail.com>
Date: Sun, 26 Apr 2026 10:14:42 +0200
Subject: [PATCH 3/3] test: add tests for redirect history behavior

- Redirect via link click should not create a back-button trap
  (back should go to the page before the redirect, not the redirect source)
- Redirect should not leak ?fresh-partial in the URL bar
---
 packages/fresh/tests/partials_test.tsx | 90 ++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)

diff --git a/packages/fresh/tests/partials_test.tsx b/packages/fresh/tests/partials_test.tsx
index 1ef3a78f5a8..9b4a17d510b 100644
--- a/packages/fresh/tests/partials_test.tsx
+++ b/packages/fresh/tests/partials_test.tsx
@@ -3498,3 +3498,93 @@ Deno.test({
     });
   },
 });
+
+Deno.test({
+  name: "partials - redirect does not create back-button trap",
+  fn: async () => {
+    const app = testApp()
+      .get("/target", (ctx) => {
+        return ctx.render(
+          <Doc>
+            <Partial name="foo">
+              <h1 class="done">target page</h1>
+            </Partial>
+          </Doc>,
+        );
+      })
+      .get("/redirect", (ctx) => ctx.redirect("/target"))
+      .get("/", (ctx) => {
+        return ctx.render(
+          <Doc>
+            <div f-client-nav>
+              <a href="/redirect" class="nav">go</a>
+              <Partial name="foo">
+                <h1 class="init">home</h1>
+              </Partial>
+            </div>
+          </Doc>,
+        );
+      });
+
+    await withBrowserApp(app, async (page, address) => {
+      await page.goto(address, { waitUntil: "load" });
+      await page.locator(".init").wait();
+
+      // Click link that redirects
+      await page.locator(".nav").click();
+      await page.locator(".done").wait();
+
+      // Should show the redirect target URL, not the intermediate
+      await page.waitForFunction(() => {
+        return window.location.pathname === "/target";
+      });
+
+      // Going back should return to home, not to /redirect
+      await page.evaluate(() => window.history.go(-1));
+      await page.locator(".init").wait();
+      await page.waitForFunction(() => {
+        return window.location.pathname === "/";
+      });
+    });
+  },
+});
+
+Deno.test({
+  name: "partials - redirect does not leak ?fresh-partial in URL",
+  fn: async () => {
+    const app = testApp()
+      .get("/target", (ctx) => {
+        return ctx.render(
+          <Doc>
+            <Partial name="foo">
+              <h1 class="done">target page</h1>
+            </Partial>
+          </Doc>,
+        );
+      })
+      .get("/redirect", (ctx) => ctx.redirect("/target"))
+      .get("/", (ctx) => {
+        return ctx.render(
+          <Doc>
+            <div f-client-nav>
+              <a href="/redirect" class="nav">go</a>
+              <Partial name="foo">
+                <h1 class="init">home</h1>
+              </Partial>
+            </div>
+          </Doc>,
+        );
+      });
+
+    await withBrowserApp(app, async (page, address) => {
+      await page.goto(address, { waitUntil: "load" });
+      await page.locator(".init").wait();
+
+      await page.locator(".nav").click();
+      await page.locator(".done").wait();
+
+      const url = await page.evaluate(() => window.location.href);
+      expect(url).not.toContain("fresh-partial");
+    });
+  },
+});