openclaw - 💡(How to fix) Fix Module-level `controllers` array is never cleared, accumulating stale entries on re-hydration [1 comments, 2 participants]

Severity: low / Confidence: medium / Category: bug Triage: risk Detected against: openclaw v2026.5.18 (latest stable at time of scan, 2026-05-18) Tooling: clawpatch 0.3.0 + acpx/claude-sonnet-4-5 via Brad Mills protocol

Evidence

• extensions/diffs/src/viewer-client.ts:22-22 (controllers)

const controllers: DiffController[] = [];

• extensions/diffs/src/viewer-client.ts:307-307 (hydrateViewer)

controllers.push(controller);

Reasoning

controllers is a module-level mutable array. hydrateViewer() only appends to it and never resets it before iterating cards. In a normal single-load browser context this is harmless, but in environments where the module is re-evaluated (bundler HMR, Vitest's module isolation, or programmatic re-import) a second invocation of hydrateViewer() doubles the controller list. Thereafter every syncAllControllers() call (triggered by any toolbar button click) will call applyState() on stale, already-detached FileDiff instances, producing errors and leaking event listeners and DOM references.

Reproduction

In Vitest with vi.resetModules() between two imports of viewer-client.ts, call main() twice in the same jsdom document. After the second call, controllers.length will be twice the number of cards.

Recommendation

Reset controllers at the start of hydrateViewer() (e.g., controllers.length = 0) or scope it to the function and expose it via a closure only to syncAllControllers. If live replacement is needed, also call .destroy() on evicted FileDiff instances if the @pierre/diffs API provides one.

Why existing tests miss this

No test exercises the viewer-client hydration lifecycle directly. The runtime bundle is only smoke-checked for string presence in config.test.ts.

Suggested regression test

Unit test that calls hydrateViewer twice and asserts controllers contains exactly as many entries as the number of diff cards in the DOM, not twice that many.

Minimum fix scope

Add controllers.length = 0; (or controllers.splice(0)) as the first statement inside hydrateViewer.

Standardized clawpatch finding. Persistent in v2026.5.18 (not resolved by upgrading from v2026.5.12). Finding ID: fnd_sig-feat-cli-command-1f351e9797-_a7eac11fd0.