fix(server): PR watch wakes no longer split an emoji in a long comment

apps/server/src/orchestration-v2/pullRequestWatch.test.ts

@@ -8,6 +8,7 @@ import { assert, describe, it } from "@effect/vitest";
 import {
   PULL_REQUEST_WATCH_WAKE_LIMIT,
   evaluatePullRequestWatch as evaluate,
+  pullRequestWatchMessage,
 } from "./pullRequestWatch.ts";
 
 // These cases read the head once or at one moment, so the no-checks notice never comes due.
@@ -335,6 +336,22 @@ describe("evaluatePullRequestWatch", () => {
     assert.deepEqual(evaluatePullRequestWatch(report.next, detail(), comments).changes, []);
   });
 
+  it("cuts a long remark in the wake message without splitting an emoji", () => {
+    const body = `${"x".repeat(196)}🚀 and more`;
+    const report = evaluatePullRequestWatch(watch(), detail(), [
+      remark("reviewer", "2026-10-02T12:06:00Z", body),
+    ]);
+    const { text } = pullRequestWatchMessage({
+      number: 1,
+      url: "https://github.com/o/r/pull/1",
+      baseBranch: "main",
+      headSha: null,
+      report,
+    });
+    assert.isTrue(text.isWellFormed());
+    assert.include(text, `"${"x".repeat(196)}..."`);
+  });
+
   it("reports a conflict once, until the branch is clean again", () => {
     const conflicting = detail({ mergeability: "conflicting" });
     const first = evaluatePullRequestWatch(watch(), conflicting, noRemarks);

apps/server/src/orchestration-v2/pullRequestWatch.ts

@@ -160,7 +160,11 @@ function snippet(body: string): string {
     .replaceAll(/<!--[\s\S]*?-->/g, " ")
     .replaceAll(/\s+/g, " ")
     .trim();
-  return text.length <= SNIPPET_LENGTH ? text : `${text.slice(0, SNIPPET_LENGTH - 3)}...`;
+  if (text.length <= SNIPPET_LENGTH) return text;
+  // Half an emoji serializes to a lone surrogate escape, which provider JSON parsers reject.
+  const last = text.charCodeAt(SNIPPET_LENGTH - 4);
+  const end = last >= 0xd800 && last <= 0xdbff ? SNIPPET_LENGTH - 4 : SNIPPET_LENGTH - 3;
+  return `${text.slice(0, end)}...`;
 }
 
 function listed<T>(items: ReadonlyArray<T>, line: (item: T) => string): Array<string> {