test: cover sync-hive-docs path-traversal guard via exported resolveSyncTarget

scripts/sync-hive-docs.test.ts

@@ -1,5 +1,9 @@
 import { describe, it, expect } from "vitest";
-import { rewriteLinkTarget, rewriteLinks } from "./sync-hive-docs";
+import {
+  resolveSyncTarget,
+  rewriteLinkTarget,
+  rewriteLinks,
+} from "./sync-hive-docs";
 
 // The source file being synced, expressed as its real repo path. Links inside
 // the content are resolved relative to this file's directory.
@@ -203,3 +207,40 @@ describe("sync-hive-docs.ts — sync-root prefix drift guard", () => {
     expect(SOURCE).not.toContain("v2/docs");
   });
 });
+
+describe("resolveSyncTarget", () => {
+  const root = "/site/docs/content/hive";
+
+  it("joins a plain target under the root", () => {
+    expect(resolveSyncTarget(root, "architecture.md")).toBe(
+      "/site/docs/content/hive/architecture.md"
+    );
+  });
+
+  it("joins a nested target under the root", () => {
+    expect(resolveSyncTarget(root, "adr/0001.md")).toBe(
+      "/site/docs/content/hive/adr/0001.md"
+    );
+  });
+
+  it.each(["../escape.md", "adr/../../escape.md"])(
+    "refuses %s, which escapes the root",
+    target => {
+      expect(() => resolveSyncTarget(root, target)).toThrow(
+        `refusing to write outside Hive docs root: ${target}`
+      );
+    }
+  );
+
+  it("refuses a sibling directory that shares the root prefix", () => {
+    expect(() => resolveSyncTarget(root, "../hive-evil/x.md")).toThrow(
+      "refusing to write outside Hive docs root: ../hive-evil/x.md"
+    );
+  });
+
+  it.each(["", "."])("refuses the root itself (%j)", target => {
+    expect(() => resolveSyncTarget(root, target)).toThrow(
+      "refusing to write outside Hive docs root"
+    );
+  });
+});

scripts/sync-hive-docs.ts

@@ -220,14 +220,20 @@ async function fetchText(url: string): Promise<string> {
   return response.text();
 }
 
+/** Resolve a sync target under docsRoot, refusing anything that escapes it. */
+export function resolveSyncTarget(root: string, target: string): string {
+  const targetPath = path.join(root, target);
+  if (!targetPath.startsWith(root + path.sep)) {
+    throw new Error(`refusing to write outside Hive docs root: ${target}`);
+  }
+  return targetPath;
+}
+
 async function main() {
   for (const file of files) {
     const target = file.target || file.source;
     const sourceURL = `${rawBase}/${file.source}`;
-    const targetPath = path.join(docsRoot, target);
-    if (!targetPath.startsWith(docsRoot + path.sep)) {
-      throw new Error(`refusing to write outside Hive docs root: ${target}`);
-    }
+    const targetPath = resolveSyncTarget(docsRoot, target);
     const content = await fetchText(sourceURL);
     // Rewrite GitHub-relative links so they resolve on the docs site.
     const overlaid = applyLocalHiveOverlays(content, file.source);