Dependency Workarounds

This document explains why certain packages are patched via yarn patch (.yarn/patches/). These patches exist because we need the @grafana/flamegraph component for business requirements and the package has incompatibilities with our stack that upstream has not yet resolved.

react-custom-scrollbars-2 — ESM entry point

Patch file: .yarn/patches/react-custom-scrollbars-2-npm-4.5.0-*.patch

Problem

react-custom-scrollbars-2 ships only a CommonJS build (lib/index.js). Rolldown (the bundler used by Vite 8) wraps CJS modules with __toESM, and Vite's optimizeDeps pre-bundler adds another layer on top of that. The net result is two levels of indirection: the default import resolves to the whole CJS exports object rather than the Scrollbars class itself.

import Scrollbars from 'react-custom-scrollbars-2';
// Without patch: Scrollbars = { default: <class>, Scrollbars: <class> }  ← wrong
// With patch:    Scrollbars = <class>  ← correct

@grafana/ui (a transitive dependency of @grafana/flamegraph) imports Scrollbars as the default export, so this breakage manifests as a runtime crash inside the flamegraph header's custom scrollbar.

Fix

The patch adds:

• lib/index.mjs — a native ESM re-export that handles both possible wrapping outcomes from __toESM defensively.
• exports and module fields to package.json — directs ESM-aware bundlers to lib/index.mjs, bypassing the CJS pre-bundling path entirely.

When to remove

Remove this patch if react-custom-scrollbars-2 ships a native ESM build (i.e., gains a module or exports.import field in its own package.json), or if it is replaced by a package that does.

@grafana/flamegraph — remove @grafana/assistant dependency

Patch file: .yarn/patches/@grafana-flamegraph-npm-12.4.2-*.patch

Problem

@grafana/flamegraph imports OpenAssistantButton from @grafana/assistant in its FlameGraphHeader component. @grafana/assistant is a Grafana Labs internal package for AI assistant integration. It is not published to the public npm registry in a form that works outside the Grafana application platform, so there is no viable version we can install.

// Before patch (in dist/esm/FlameGraphHeader.mjs):
import { OpenAssistantButton } from '@grafana/assistant';

The import causes a build error because the module cannot be resolved.

Fix

The patch replaces the @grafana/assistant import with an inline no-op:

const OpenAssistantButton = () => null;

The OpenAssistantButton is only rendered when assistantContext is non-empty, and we never populate assistantContext in our usage of FlameGraph. The no-op is therefore functionally invisible — no AI assistant button will appear, which is the correct behavior for our deployment.

When to remove

Remove this patch if @grafana/assistant becomes available as a public package or if @grafana/flamegraph makes the dependency optional/tree-shakeable such that the import is no longer emitted in the distributed build.