From c8d9f80d683d537a70e756538b450eb20b2dfacd Mon Sep 17 00:00:00 2001
From: sanath <sanathrshs@gmail.com>
Date: Wed, 9 Sep 2026 11:28:59 +0530
Subject: [PATCH] Keep subpath sitemap root entries consistent

---
 .changeset/tidy-sitemap-root.md               |  5 ++
 packages/nimbus-docs/src/integration.ts       | 15 ++++
 .../test/integration-sitemap.test.ts          | 79 +++++++++++++++++++
 3 files changed, 99 insertions(+)
 create mode 100644 .changeset/tidy-sitemap-root.md
 create mode 100644 packages/nimbus-docs/test/integration-sitemap.test.ts

diff --git a/.changeset/tidy-sitemap-root.md b/.changeset/tidy-sitemap-root.md
new file mode 100644
index 00000000..087fcef5
--- /dev/null
+++ b/.changeset/tidy-sitemap-root.md
@@ -0,0 +1,5 @@
+---
+"@cloudflare/nimbus-docs": patch
+---
+
+Avoid duplicate root sitemap entries in directory builds deployed under a base path without a trailing slash.
diff --git a/packages/nimbus-docs/src/integration.ts b/packages/nimbus-docs/src/integration.ts
index 706be073..84c22242 100644
--- a/packages/nimbus-docs/src/integration.ts
+++ b/packages/nimbus-docs/src/integration.ts
@@ -986,6 +986,21 @@ export function nimbus(
                 ),
             }),
           });
+          const configureSitemap = sitemapIntegration.hooks["astro:config:done"];
+          sitemapIntegration.hooks["astro:config:done"] = async (options) => {
+            const { config: astroConfig } = options;
+            // Sitemap joins the empty home-page path to base verbatim, but
+            // adds a slash for the same root's route in directory builds.
+            const base =
+              astroConfig.build.format === "directory" &&
+              astroConfig.trailingSlash !== "never"
+              ? `${astroConfig.base.replace(/\/$/, "")}/`
+              : astroConfig.base;
+            await configureSitemap?.({
+              ...options,
+              config: { ...astroConfig, base },
+            });
+          };
           integrationsToAdd.push(sitemapIntegration);
         }
 
diff --git a/packages/nimbus-docs/test/integration-sitemap.test.ts b/packages/nimbus-docs/test/integration-sitemap.test.ts
new file mode 100644
index 00000000..e1a97157
--- /dev/null
+++ b/packages/nimbus-docs/test/integration-sitemap.test.ts
@@ -0,0 +1,79 @@
+import assert from "node:assert/strict";
+import { mkdtemp, readFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import { pathToFileURL } from "node:url";
+import { test } from "node:test";
+import type { AstroIntegration } from "astro";
+import { nimbus } from "../src/integration.js";
+
+for (const base of ["/", "/my-project", "/my-project/"]) {
+  test(`sitemap emits one root entry with base ${base}`, async () => {
+    const root = await mkdtemp(path.join(tmpdir(), "nimbus-sitemap-"));
+    const directory = pathToFileURL(root + path.sep);
+    const logger = {
+      warn() {},
+      info() {},
+      error(message: string) {
+        throw new Error(message);
+      },
+    };
+    const config = {
+      root: directory,
+      srcDir: new URL("src/", directory),
+      cacheDir: new URL(".cache/", directory),
+      site: "https://example.test",
+      base,
+      trailingSlash: "ignore",
+      build: { format: "directory" },
+    };
+    let integrations: AstroIntegration[] = [];
+    const integration = nimbus(
+      { site: config.site, title: "Test" },
+      {
+        validateMdx: false,
+        admonitions: false,
+        markdown: { processor: {} as never },
+      },
+    );
+    await integration.hooks["astro:config:setup"]!({
+      config,
+      logger,
+      updateConfig(update: { integrations: AstroIntegration[] }) {
+        integrations = update.integrations;
+        return {};
+      },
+    } as never);
+    const sitemap = integrations.find(
+      (item) => item.name === "@astrojs/sitemap",
+    )!;
+    await sitemap.hooks["astro:config:done"]!({ config } as never);
+    assert.equal(config.base, base, "the app's base must remain unchanged");
+    await sitemap.hooks["astro:routes:resolved"]!({
+      routes: [
+        {
+          type: "page",
+          pathname: "/",
+          generate: () => "/",
+        },
+      ],
+    } as never);
+    await sitemap.hooks["astro:build:done"]!({
+      dir: directory,
+      pages: [{ pathname: "" }, { pathname: "guide/" }],
+      logger,
+    } as never);
+    const xml = await readFile(new URL("sitemap-0.xml", directory), "utf8");
+    const urls = [...xml.matchAll(/<loc>(.*?)<\/loc>/g)].map(
+      (match) => match[1],
+    );
+    const prefix = base.replace(/\/$/, "");
+    assert.deepEqual(
+      urls.sort(),
+      [
+        `https://example.test${prefix}/`,
+        `https://example.test${prefix}/guide/`,
+      ].sort(),
+    );
+  });
+}