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[GH-ISSUE #8298] analyze-javascript-application stalls at javascript_worker_static on a 222 KB Vite + React 19 production bundle (Windows) #6532

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opened 2026-11-01 21:12:00 +00:00 by bsakaguchi · 1 comment

bsakaguchi commented

2026-11-01 21:12:00 +00:00

Owner

Originally created by @bstBizEra on GitHub (Oct 31, 2026).
Original GitHub issue: https://github.com/morluto/rea/issues/8298

Version: rea-agents 6.8.0 (npm), via MCP (npx -y rea-agents@6.8.0 mcp) and via the CLI
OS: Windows 11 (10.0.26300.9711), Node v24.22.1

What happens

Running analyze-javascript-application on a small Vite production build never parses its one JavaScript file. Progress stops at the static pass and the analysis ends at its deadline with 0 syntax nodes visited.

MCP (analyze_javascript_application, default 300000 ms): returns partial Evidence and provider_timeout ("JavaScript source analysis reached its 300000ms per-source server/provider deadline"); parsed_javascript_files: 0, 1 skipped, coverage partial, 12 semantic unknowns.
CLI with --analysis-timeout-ms 120000: same stall, exit 1 with partial Evidence. Last progress lines:

{"rea_progress":{"phase":"parse_javascript_source", ... "Parsing and projecting assets/index-D5eaJq-h.js (1/2)"}}
{"rea_progress":{"phase":"javascript_worker_parse", ... "JavaScript worker parse: assets/index-D5eaJq-h.js"}}
{"rea_progress":{"phase":"javascript_worker_static", ... "JavaScript worker static: assets/index-D5eaJq-h.js"}}

CLI with --analysis-timeout-ms 900000: same stall for the full 15 minutes (15m 2.8s wall clock), exit 1, partial Evidence ev_aa3d26ff4f9b…, parsed_javascript_files: 0; no progress line after javascript_worker_static. So it never finishes rather than being slow.

Control

A hand-written 2-file app (one index.html, one 5-line app.js using localStorage, fetch, setTimeout) analyses in 3.5 s, exit 0, with all three relationships found. So the install and engine work; the stall is specific to this bundle.

The input

dist/assets/index-D5eaJq-h.js, 222,054 bytes, sha256 5bcc24d653ea2940d668da4bad7b4923d5cbbbe638e452e9a1035a10c2e135d5
Built by vite build (Vite 8.3.5, @vitejs/plugin-react 6.1.2) from a ~100-line React 19.3.1 todo app; no custom config. Happy to attach the bundle (it contains only React and the app code).

Steps

npm create vite@latest app -- --template react   # then a small component
npm run build
npx -y rea-agents@6.8.0 analyze-javascript-application <abs path>/dist --json --analysis-timeout-ms 120000

Expected

The bundle parses (or fails with a parse error) well within the deadline, and the Evidence lists the entry point and the localStorage use.

Originally created by @bstBizEra on GitHub (Oct 31, 2026). Original GitHub issue: https://github.com/morluto/rea/issues/8298 **Version:** `rea-agents` 6.8.0 (npm), via MCP (`npx -y rea-agents@6.8.0 mcp`) and via the CLI **OS:** Windows 11 (10.0.26300.9711), Node v24.22.1 ## What happens Running `analyze-javascript-application` on a small Vite production build never parses its one JavaScript file. Progress stops at the static pass and the analysis ends at its deadline with 0 syntax nodes visited. - **MCP** (`analyze_javascript_application`, default 300000 ms): returns partial Evidence and `provider_timeout` ("JavaScript source analysis reached its 300000ms per-source server/provider deadline"); `parsed_javascript_files: 0`, 1 skipped, coverage partial, 12 semantic unknowns. - **CLI** with `--analysis-timeout-ms 120000`: same stall, exit 1 with partial Evidence. Last progress lines: ``` {"rea_progress":{"phase":"parse_javascript_source", ... "Parsing and projecting assets/index-D5eaJq-h.js (1/2)"}} {"rea_progress":{"phase":"javascript_worker_parse", ... "JavaScript worker parse: assets/index-D5eaJq-h.js"}} {"rea_progress":{"phase":"javascript_worker_static", ... "JavaScript worker static: assets/index-D5eaJq-h.js"}} ``` - **CLI** with `--analysis-timeout-ms 900000`: same stall for the full 15 minutes (15m 2.8s wall clock), exit 1, partial Evidence `ev_aa3d26ff4f9b…`, `parsed_javascript_files: 0`; no progress line after `javascript_worker_static`. So it never finishes rather than being slow. ## Control A hand-written 2-file app (one `index.html`, one 5-line `app.js` using `localStorage`, `fetch`, `setTimeout`) analyses in 3.5 s, exit 0, with all three relationships found. So the install and engine work; the stall is specific to this bundle. ## The input - `dist/assets/index-D5eaJq-h.js`, 222,054 bytes, sha256 `5bcc24d653ea2940d668da4bad7b4923d5cbbbe638e452e9a1035a10c2e135d5` - Built by `vite build` (Vite 8.3.5, `@vitejs/plugin-react` 6.1.2) from a ~100-line React 19.3.1 todo app; no custom config. Happy to attach the bundle (it contains only React and the app code). ## Steps ``` npm create vite@latest app -- --template react # then a small component npm run build npx -y rea-agents@6.8.0 analyze-javascript-application <abs path>/dist --json --analysis-timeout-ms 120000 ``` ## Expected The bundle parses (or fails with a parse error) well within the deadline, and the Evidence lists the entry point and the `localStorage` use.

bsakaguchi commented

2026-11-03 22:45:05 +00:00

Author

Owner

@Plastic-time commented on GitHub (Nov 3, 2026):

Reproduced on main at c3647ade1 (Windows 11 x64, Node 24.22.1). This is not specific to Vite 8. All four inputs below end with parsed_javascript_files: 0 and "Owned JavaScript worker exhausted its 1024 MiB V8 old-space heap … during static":

react-dom's own cjs/react-dom-client.production.js, 19.2.7 and 19.3.1
a Vite 7.3.7 build of a 20-line React app
a Vite 8.3.5 build of the same app, with or without minification

On main the CLI now exits 0 after about 60 s with partial Evidence, instead of running into the deadline.

I ran only the static pass in-process (analyzeParsedJavaScriptStaticSourceSteps), on growing prefixes of react-dom-client.production.js 19.3.1:

Up to top-level statement 204, each prefix finishes in under 2.5 s.
From statement 205 on, each prefix runs past 40 s. Statement 205 is propagateContextChanges.
That 2.3 KB function alone takes 39 s and about 300 MiB.
A CPU profile puts 76 % of the samples under collectSemanticMemberMutationsSteps → markValue → markTarget → semanticProjectedSourceFactsAtRead.

This 1.3 KB reduction of that function still takes about 5 s and returns status: partial:

function propagateContextChanges(workInProgress, contexts, renderLanes, forcePropagateEntireTree) {
  var fiber = workInProgress.child;
  for (; null !== fiber; ) {
    var list = fiber.dependencies;
    if (null !== list) {
      var nextFiber = fiber.child;
    } else if (18 === fiber.tag) {
      nextFiber = fiber.return;
      nextFiber.lanes |= renderLanes;
      null !== list && (list.lanes |= renderLanes);
      nextFiber = null;
    } else
      13 === fiber.tag && null !== fiber.memoizedState && null === fiber.memoizedState.dehydrated
        ? ((fiber.lanes |= renderLanes),
          (nextFiber = fiber.alternate),
          null !== nextFiber && (nextFiber.lanes |= renderLanes),
          scheduleContextWorkOnParentPath(fiber.return, renderLanes, workInProgress),
          (nextFiber = fiber.child),
          (nextFiber = null !== nextFiber ? nextFiber.sibling : null))
        : (nextFiber = fiber.child);
    if (null !== nextFiber) nextFiber.return = fiber;
    else
      for (nextFiber = fiber; null !== nextFiber; ) {
        fiber = nextFiber.sibling;
        nextFiber = nextFiber.return;
      }
    fiber = nextFiber;
  }
}

Any one of these changes brings it under 0.3 s:

dropping the inner for (nextFiber = fiber; …) loop
dropping the nextFiber.return = fiber write
replacing the conditional with a plain nextFiber = fiber.child

@Plastic-time commented on GitHub (Nov 3, 2026): Reproduced on `main` at `c3647ade1` (Windows 11 x64, Node 24.22.1). This is not specific to Vite 8. All four inputs below end with `parsed_javascript_files: 0` and "Owned JavaScript worker exhausted its 1024 MiB V8 old-space heap … during static": - react-dom's own `cjs/react-dom-client.production.js`, 19.2.7 and 19.3.1 - a Vite 7.3.7 build of a 20-line React app - a Vite 8.3.5 build of the same app, with or without minification On `main` the CLI now exits 0 after about 60 s with partial Evidence, instead of running into the deadline. I ran only the static pass in-process (`analyzeParsedJavaScriptStaticSourceSteps`), on growing prefixes of `react-dom-client.production.js` 19.3.1: - Up to top-level statement 204, each prefix finishes in under 2.5 s. - From statement 205 on, each prefix runs past 40 s. Statement 205 is `propagateContextChanges`. - That 2.3 KB function alone takes 39 s and about 300 MiB. - A CPU profile puts 76 % of the samples under `collectSemanticMemberMutationsSteps` → `markValue` → `markTarget` → `semanticProjectedSourceFactsAtRead`. This 1.3 KB reduction of that function still takes about 5 s and returns `status: partial`: ```js function propagateContextChanges(workInProgress, contexts, renderLanes, forcePropagateEntireTree) { var fiber = workInProgress.child; for (; null !== fiber; ) { var list = fiber.dependencies; if (null !== list) { var nextFiber = fiber.child; } else if (18 === fiber.tag) { nextFiber = fiber.return; nextFiber.lanes |= renderLanes; null !== list && (list.lanes |= renderLanes); nextFiber = null; } else 13 === fiber.tag && null !== fiber.memoizedState && null === fiber.memoizedState.dehydrated ? ((fiber.lanes |= renderLanes), (nextFiber = fiber.alternate), null !== nextFiber && (nextFiber.lanes |= renderLanes), scheduleContextWorkOnParentPath(fiber.return, renderLanes, workInProgress), (nextFiber = fiber.child), (nextFiber = null !== nextFiber ? nextFiber.sibling : null)) : (nextFiber = fiber.child); if (null !== nextFiber) nextFiber.return = fiber; else for (nextFiber = fiber; null !== nextFiber; ) { fiber = nextFiber.sibling; nextFiber = nextFiber.return; } fiber = nextFiber; } } ``` Any one of these changes brings it under 0.3 s: - dropping the inner `for (nextFiber = fiber; …)` loop - dropping the `nextFiber.return = fiber` write - replacing the conditional with a plain `nextFiber = fiber.child`

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