fix(pr): prevent links opening projects on the wrong host

src/lib/pr-url.test.ts

@@ -1,6 +1,12 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
 
-import { _resetPrLinkIndex, parsePrUrl, publishPrLinkIndex } from "./pr-url";
+import {
+  _resetPrLinkIndex,
+  parsePrUrl,
+  publishPrLinkIndex,
+  resolvePrLink,
+  resolvePrRoot,
+} from "./pr-url";
 import type { PrRow } from "./pr-overview";
 
 const openUrl = vi.hoisted(() => vi.fn(() => Promise.resolve()));
@@ -88,6 +94,45 @@ describe("parsePrUrl", () => {
   });
 });
 
+describe("repository matching", () => {
+  const parsed = {
+    kind: "github" as const,
+    host: "github.com",
+    slug: "example/codemux",
+    number: 285,
+  };
+  const otherHostRow = row({
+    url: "https://git.acme.internal/example/codemux/pull/285",
+    projectRoot: "/home/dev/projects/enterprise-codemux",
+  });
+
+  it("matches both host and repository for an indexed pull request", () => {
+    expect(resolvePrLink(parsed, [otherHostRow, row()])).toEqual(row());
+    expect(resolvePrLink(parsed, [otherHostRow])).toBeNull();
+  });
+
+  it("checks the host when falling back to another pull request in the repository", () => {
+    expect(resolvePrRoot({ ...parsed, number: 353 }, [otherHostRow])).toBeNull();
+  });
+
+  it("checks the host when falling back to a workspace URL", () => {
+    expect(resolvePrRoot(parsed, [], [{
+      url: otherHostRow.url,
+      projectRoot: otherHostRow.projectRoot,
+    }])).toBeNull();
+    expect(resolvePrRoot(parsed, [], [{
+      url: row().url,
+      projectRoot: row().projectRoot,
+    }])).toBe(row().projectRoot);
+  });
+
+  it("accepts the www alias supported by URL parsing", () => {
+    expect(resolvePrLink(parsed, [row({
+      url: "https://www.github.com/example/codemux/pull/285",
+    })])).not.toBeNull();
+  });
+});
+
 describe("openExternalUrl", () => {
   beforeEach(() => {
     vi.clearAllMocks();
@@ -135,6 +180,16 @@ describe("openExternalUrl", () => {
     });
   });
 
+  it("opens a same-named repository on another host in the browser", async () => {
+    setCustomHosts({ "git.acme.internal": "github" });
+    publishPrLinkIndex([row()]);
+
+    const url = "https://git.acme.internal/example/codemux/pull/285";
+    expect(await openExternalUrl(url)).toBe("browser");
+    expect(openUrl).toHaveBeenCalledWith(url);
+    expect(useUIStore.getState().showPullRequests).toBe(false);
+  });
+
   it("shift-click keeps the browser", async () => {
     publishPrLinkIndex([row()]);
 

src/lib/pr-url.ts

@@ -119,18 +119,28 @@ export function _resetPrLinkIndex(): void {
   indexedRows = [];
 }
 
+function matchesHost(host: string, url: string): boolean {
+  try {
+    // URL parsing recognises www aliases, so repository matching must too.
+    return new URL(url).hostname.toLowerCase().replace(/^www\./, "") ===
+      host.toLowerCase().replace(/^www\./, "");
+  } catch {
+    return false;
+  }
+}
+
 /**
  * The open row this URL names, if any.
  *
- * Matched on repository slug *and* number: a number alone is only unique
- * within one repository, and two open projects can easily both have a
- * `#12`.
+ * Matched on host, repository slug and number: separate servers can host
+ * repositories with the same slug and pull-request numbers.
  */
 export function resolvePrLink(parsed: ParsedPrUrl, rows: PrRow[] = indexedRows): PrRow | null {
   const slug = parsed.slug.toLowerCase();
   return (
     rows.find(
-      (row) => row.number === parsed.number && (row.repo ?? "").toLowerCase() === slug,
+      (row) => row.number === parsed.number &&
+        (row.repo ?? "").toLowerCase() === slug && matchesHost(parsed.host, row.url),
     ) ?? null
   );
 }
@@ -152,7 +162,11 @@ export function resolvePrRoot(
   const exact = resolvePrLink(parsed, rows);
   if (exact) return exact.projectRoot;
   const slug = parsed.slug.toLowerCase();
-  const sameRepo = rows.find((row) => (row.repo ?? "").toLowerCase() === slug);
+  const sameRepo = rows.find((row) =>
+    (row.repo ?? "").toLowerCase() === slug && matchesHost(parsed.host, row.url),
+  );
   if (sameRepo) return sameRepo.projectRoot;
-  return known.find((k) => repoSlugFromUrl(k.url)?.toLowerCase() === slug)?.projectRoot ?? null;
+  return known.find((k) =>
+    repoSlugFromUrl(k.url)?.toLowerCase() === slug && matchesHost(parsed.host, k.url),
+  )?.projectRoot ?? null;
 }