[Bug]: Cursor Origin caches mergeability for a base commit the API did not evaluate #35901

#!/bin/sh
set -u
repo=$(cd "$1" && pwd) || { echo 'RESULT: inconclusive'; exit 2; }
scratch=$(mktemp -d) || { echo 'RESULT: inconclusive'; exit 2; }
trap 'rm -rf "$scratch"' EXIT HUP INT TERM
export HOME="$scratch/home" TMPDIR="$scratch/tmp"
export XDG_CONFIG_HOME="$scratch/config" XDG_DATA_HOME="$scratch/data" XDG_STATE_HOME="$scratch/state" T3CODE_HOME="$scratch/t3"
export GIT_CONFIG_NOSYSTEM=1 GIT_CONFIG_GLOBAL=/dev/null
mkdir -p "$HOME" "$TMPDIR" "$XDG_CONFIG_HOME" "$XDG_DATA_HOME" "$XDG_STATE_HOME" "$T3CODE_HOME"
node --version
npm --version
if ! npm install --prefix "$scratch" --ignore-scripts --no-audit --no-fund --no-package-lock --save-exact effect@4.1.3 @effect/platform-node@4.1.2 >"$scratch/install.log" 2>&1; then
  cat "$scratch/install.log"
  echo 'RESULT: inconclusive'
  exit 2
fi
node -e 'for (const n of ["effect", "@effect/platform-node"]) console.log(n + " " + require(process.argv[1] + "/node_modules/" + n + "/package.json").version)' "$scratch"
cat >"$scratch/probe.mjs" <<'JS'
import { registerHooks, createRequire } from 'node:module';
import { readFileSync } from 'node:fs';
import { resolve } from 'node:path';
import { pathToFileURL } from 'node:url';
const repo = resolve(process.argv[2]);
const runtime = import.meta.url;
registerHooks({ resolve(specifier, context, nextResolve) {
  if (specifier.startsWith('@t3tools/')) {
    const [name, ...rest] = specifier.slice('@t3tools/'.length).split('/');
    const folder = `${repo}/packages/${name}`;
    const manifest = JSON.parse(readFileSync(`${folder}/package.json`, 'utf8'));
    const key = rest.length ? `./${rest.join('/')}` : '.';
    const target = manifest.exports[key];
    return nextResolve(pathToFileURL(resolve(folder, typeof target === 'string' ? target : target.import)).href, context);
  }
  if (specifier === 'effect' || specifier.startsWith('effect/') || specifier.startsWith('@effect/')) return nextResolve(specifier, {...context, parentURL: runtime});
  return nextResolve(specifier, context);
}});
const Effect = await import('effect/Effect');
const Schema = await import('effect/Schema');
const { make } = await import(pathToFileURL(`${repo}/packages/source-control-cursor-origin/src/server/OriginPullRequestProvider.ts`).href);
const { OriginCli } = await import(pathToFileURL(`${repo}/packages/source-control-cursor-origin/src/server/OriginCli.ts`).href);
const Clock = await import('effect/Clock');
const head = 'a'.repeat(40), baseB = 'b'.repeat(40), baseC = 'c'.repeat(40), oldBase = 'd'.repeat(40);
async function scenario(racing) {
 let millis = 10000, phase = 0, calls = 0;
 const clock = {
  currentTimeMillisUnsafe:()=>millis, currentTimeMillis:Effect.sync(()=>millis),
  currentTimeNanosUnsafe:()=>BigInt(millis)*1000000n, currentTimeNanos:Effect.sync(()=>BigInt(millis)*1000000n),
  monotonicTimeNanosUnsafe:()=>BigInt(millis)*1000000n, monotonicTimeNanos:Effect.sync(()=>BigInt(millis)*1000000n),
  sleep:()=>Effect.never,
 };
 const cli = OriginCli.of({
  api:(input,schema)=>Effect.suspend(()=>{
   let data;
   if(input.operation==='getPullRequest') data={number:1,state:'open',title:'Fixture',webUrl:'https://cursor.com/codebase/fixture/repo/pull/1',head:{ref:'feature',sha:head},base:{ref:'main',sha:oldBase},version:{headSha:head,baseSha:oldBase,potentialMergeCommit:{state:'prepared',baseSha:oldBase}}};
   else if(input.operation==='getRepository') data={name:'repo'};
   else if(input.operation==='listChecks') data={checkRuns:[]};
   else if(input.operation==='getBaseTip') data={object:{sha:baseB}};
   else if(input.operation==='getMergeability') {
    calls++;
    const moved = racing && phase===0;
    data={verdict:moved?'blocked':'mergeable',headSha:head,baseRef:'main',baseSha:moved?baseC:baseB,blockers:moved?[{kind:'merge_conflict'}]:[]};
   } else return Effect.die(new Error(`unexpected operation ${input.operation}`));
   return Schema.decodeUnknownEffect(schema)(data);
  }),
  execute:()=>Effect.succeed('{}'),viewer:()=>Effect.succeed('fixture'),personalNamespace:()=>Effect.succeed('fixture'),resolveRepository:()=>Effect.succeed('fixture/repo'),
 });
 return Effect.runPromise(Effect.scoped(Effect.gen(function*(){
  const provider=yield* make;
  const input={cwd:process.cwd(),repository:'fixture/repo',number:1};
  const first=yield* provider.getChangeRequest(input);
  phase=1; millis+=3000;
  const second=yield* provider.getChangeRequest(input);
  return {first:first.mergeability,second:second.mergeability,calls};
 }).pipe(Effect.provideService(OriginCli,cli),Effect.provideService(Clock.Clock,clock))));
}
try {
 const control=await scenario(false), race=await scenario(true);
 console.log(`stable-base control: ${JSON.stringify(control)}`);
 console.log(`base changed B -> C during evaluation, then reset to B: ${JSON.stringify(race)}`);
 if(control.first!=='mergeable'||control.second!=='mergeable'||control.calls!==1) {console.log('RESULT: inconclusive');process.exitCode=2;}
 else if(race.second==='conflicting'&&race.calls===1) {console.log('RESULT: defect reproduced');process.exitCode=1;}
 else if(race.second==='mergeable') {console.log('RESULT: expected behavior');process.exitCode=0;}
 else {console.log('RESULT: inconclusive');process.exitCode=2;}
} catch(error) {console.error(error);console.log('RESULT: inconclusive');process.exitCode=2;}

JS
node "$scratch/probe.mjs" "$repo"
status=$?
if [ "$status" -ne 0 ] && [ "$status" -ne 1 ]; then
  echo 'RESULT: inconclusive'
  exit 2
fi
exit "$status"