# Prometheus complete test parsing

CodeMirror gives editor-state creation a 20 ms synchronous parsing budget.
The shared `createEditorState()` test helper can therefore return an
incomplete syntax tree when the process is descheduled. The completion and
vector-matching tests immediately inspect that tree.

## Scope and behavior

`complete-test-parsing.patch` changes only
`module/codemirror-promql/src/test/utils-test.ts` inside `web/ui`. It completes
the small test expression with `ensureSyntaxTree(..., Infinity)` and publishes
the completed parse through an empty transaction so `syntaxTree(state)` sees
it. Failure to obtain a tree raises an error.

The original assertions remain enabled, including `autocomplete topk params 2`
and `foo * on(test,blub) bar`. The unlimited budget applies to the test helper;
production editor parsing budgets are unchanged.

## Reproduction and focused checks

Use a disposable Prometheus 3.14.0 checkout. The patch root is `web/ui`, matching
the Nix assets derivation. From this directory:

```sh
patch --fuzz=0 -d /path/to/prometheus/web/ui -p1 < complete-test-parsing.patch
cd /path/to/prometheus/web/ui
pnpm install --frozen-lockfile
pnpm --filter @prometheus-io/lezer-promql build
pnpm --filter @prometheus-io/codemirror-promql test
```

To force the scheduling condition, temporarily append this clock to
`module/codemirror-promql/setupJest.cjs` in the disposable checkout:

```js
let parseClock = 0;
Date.now = () => (parseClock += 25);
```

Each clock read crosses the editor's initial parsing budget. Against the
original helper, the hybrid and vector suites have 186 failures, including
both locally excluded cases. With the patch, all 386 CodeMirror tests pass
under that same clock. Remove the injected clock before normal builds.

## Upstream status

This is a standalone test-helper patch for Prometheus 3.14.0. No upstream
submission was made during this work. Recheck the helper when updating
Prometheus or CodeMirror, including how an ensured parse becomes visible
through the editor state.

## Local NixOS integration and build results

[`../default.nix`](../default.nix) loads `default.nix`, which patches the
separate assets derivation. It updates both `passthru.assets` and the main
Prometheus build's reference to those assets. From the repository root:

```sh
nix build --no-link -L .#nixosConfigurations.jeeves.pkgs.prometheus.assets
```

The full x86-64-v3 assets build passed with the normal clock, including the
CodeMirror and UI suites. Host-flake evaluation confirmed that the main
Prometheus derivation refers to these patched assets. The Go server package
was not rebuilt for this test-helper change.