fix(stream): drop @ts-expect-error via intersection-cast (forward-compat with @types/node 25.7.0) by oorabona · Pull Request #155 · oorabona/node-liblzma

oorabona · 2026-05-14T13:45:37Z

Summary

Unblocks the daily Refresh Lockfile workflow, which has been producing one "build failed" PR per day since 2026-05-06 (#143-#145, #149-#152 — 7 stale PRs).

Root cause

@types/node@25.7.0 added cancel?: TransformerCancelCallback to the Transformer interface in stream/web.d.ts. The catalog spec ^25.5.0 accepts it during unfrozen install, so:

Committed pnpm-lock.yaml pins @types/node@25.6.0 (no cancel) → the @ts-expect-error directives in src/wasm/stream.ts are necessary and silent.
Refresh-lockfile workflow runs pnpm install --no-frozen-lockfile → resolves to 25.7.0 (has cancel) → directives become unused → TS2578 → build step fails → workflow opens a "build failed" PR every day.

The same regression will hit master CI the next time @types/node lands at >= 25.7.0 in the lockfile (Dependabot bump, manual upgrade, etc.).

Fix

Drop the directives entirely. Cast the inline Transformer literal as Transformer<Uint8Array, Uint8Array> & { cancel?: (reason: unknown) => void | PromiseLike<void> } at both new TransformStream({...}) construction sites in src/wasm/stream.ts. The intersection adds the missing cancel?: on @types/node@25.6.0 (where the base Transformer has no cancel) and is structurally compatible on 25.7.0+ (where the base has the typed cancel?:). The cast signature mirrors the Streams spec / TransformerCancelCallback so the call contract stays visible.

Net result: zero @ts-expect-error / @ts-ignore / biome-ignore in the file. Biome's lint/suspicious/noTsIgnore rule has nothing to act on. The pre-commit hook is a no-op for this file.

Typings state	Before this PR (`@ts-expect-error`)	After this PR (intersection cast)
`cancel` absent (25.6.0)	suppresses error	structurally adds the property
`cancel` present (25.7.0+)	TS2578 fails build	structurally compatible — no friction

Why not switch to `@ts-ignore`?

The intuitive fix — swap @ts-expect-error → @ts-ignore — fails silently. The project's pre-commit hook (simple-git-hooks → pnpm exec nano-staged) runs biome check --write on staged .ts files. Biome v2's lint/suspicious/noTsIgnore rule has a safe fix (auto-applied with --write) that rewrites @ts-ignore → @ts-expect-error as a text replace — even when the directive is suppressed by a biome-ignore pragma on the line above. Three earlier rounds of this PR tried the swap and watched the rewrite undo it between git add and git commit. The intersection-cast sidesteps the rule entirely.

Regression guard

Adds test/wasm/stream-directive-hygiene.test.ts. The test reads src/wasm/stream.ts and asserts that no // @ts-expect-error or // @ts-ignore directive is present. If a future change re-introduces either, the test fails on every PR — not only on the next lockfile refresh.

Verification

pnpm type-check clean against both @types/node@25.6.0 (lockfile pin) and @types/node@25.7.0 (refresh-lockfile resolution).
biome check src/wasm/stream.ts clean (with and without --write).
New hygiene test passes locally.

Test plan

CI passes on this PR with @types/node@25.6.0
Next Refresh Lockfile cron commits the refreshed lockfile directly to master (no more "build failed" PR)
The 7 stale PRs (chore(deps): refresh lockfile (build failed) #143-145, chore(deps): refresh lockfile (build failed) #149-152) can be closed without action

Follow-ups (not blocking)

Closing chore(deps): refresh lockfile (build failed) #143-145 / chore(deps): refresh lockfile (build failed) #149-152 explicitly once this merges.
(L) The hygiene test only covers src/wasm/stream.ts. If similar drift hits other files, the test can be generalised — currently scoped narrowly because that file is the only known affected surface.

@types/node 25.7.0 added `cancel?: TransformerCancelCallback` to the `Transformer` interface in stream/web.d.ts. On the older 25.6.0 that ships with the committed pnpm-lock.yaml the property is absent, so `@ts-expect-error` was suppressing a real error. On the daily refresh-lockfile workflow's regenerated lockfile (which picks 25.7.0 within the catalog `^25.5.0` range) the directive becomes unused and trips TS2578, blocking the workflow's build step and causing 9 stale "chore(deps): refresh lockfile (build failed)" PRs (#143-#145, #149-#152). Switch to `@ts-ignore`: - Old typings (cancel absent): suppresses the assignment error (same behavior as before). - New typings (cancel present): no-op, no warning. Forward-compatible with future @types/node releases. Reproduction: pnpm add -D -E @types/node@25.7.0 && pnpm build # passes pnpm add -D -E @types/node@25.6.0 && pnpm build # passes

Copilot

Pull request overview

The PR intends to unblock the daily Refresh Lockfile workflow that started failing after @types/node@25.7.0 added cancel?: TransformerCancelCallback to Transformer, which makes the existing @ts-expect-error directives in src/wasm/stream.ts unused (TS2578). The stated fix is to swap those two directives for @ts-ignore so they remain harmless on both old and new typings, and to expand the inline rationale comment.

Changes:

Expand the comment above the cancel handler in createXz() to explain the typings situation.
Cross-reference that explanation from the comment above the cancel handler in createUnxz().
(Per description) switch the two @ts-expect-error directives to @ts-ignore — not actually present in the diff.

Comments suppressed due to low confidence (2)

src/wasm/stream.ts:132

Same issue as line 72: directive is still @ts-expect-error rather than @ts-ignore as the PR description claims, so this will produce TS2578 once @types/node 25.7.0+ is resolved.

    // @ts-expect-error cancel is a valid Transformer method per Streams spec

src/wasm/stream.ts:131

"rationale on @ts-expect-error vs @ts-expect-error" compares the directive to itself. This should reference @ts-ignore vs @ts-expect-error to match the intended fix described in the PR.

    /* cancel() frees WASM resources when the readable side is cancelled.
       See createXz() for the rationale on @ts-expect-error vs @ts-expect-error. */

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@ts-expect-error

…rior commit) Prior commit 50eea34 updated the rationale comments but left the directives unchanged, so @types/node 25.7.0 would still trip TS2578. - src/wasm/stream.ts L72, L132: directive @ts-expect-error → @ts-ignore - comments: replaced nonsensical "@ts-expect-error (not @ts-expect-error)" self-comparison with "@ts-ignore (not @ts-expect-error)"

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Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (2)

src/wasm/stream.ts:132

Same issue as on line 72: this directive is still @ts-expect-error rather than @ts-ignore, contradicting both the PR description and the new comment at line 130-131 which references the (non-existent) switch. On @types/node@25.7.0+, where cancel is now declared on Transformer, this directive becomes unused and triggers TS2578, failing the build.

    // @ts-expect-error cancel is a valid Transformer method per Streams spec

src/wasm/stream.ts:131

Same self-referential mistake as in the createXz comment: "rationale on @ts-expect-error vs @ts-expect-error" compares the directive to itself. This should read @ts-ignore vs @ts-expect-error per the PR description.

    /* cancel() frees WASM resources when the readable side is cancelled.
       See createXz() for the rationale on `@ts-expect-error` vs `@ts-expect-error`. */

…rewrite Rounds 1 and 2 silently regressed because Biome's recommended `suspicious/noTsIgnore` rule, run via `biome check --write` from the nano-staged pre-commit hook, auto-rewrites `@ts-ignore` back to `@ts-expect-error`. Net result: the directive swap never reached HEAD even though local edits applied correctly. Adds `// biome-ignore lint/suspicious/noTsIgnore: ...` pragma above each `// @ts-ignore` directive so the hook leaves them untouched. The `@ts-ignore` choice is deliberate — `@ts-expect-error` would fire TS2578 the moment `@types/node` 25.7.0 (which adds `Transformer.cancel`) lands in the lockfile, exactly the breakage the daily Refresh Lockfile workflow keeps surfacing. Verified: `pnpm type-check` clean (current lockfile), `biome check src/wasm/stream.ts` clean (via rtk proxy to bypass RTK rewrite).

…ward-compat) `@types/node@25.7.0` added `cancel?: TransformerCancelCallback` to the `Transformer` interface in `node:stream/web`. The previous `@ts-expect-error` directives suppressing the missing-`cancel` error on older typings would become "unused" (TS2578) on 25.7.0+, which is exactly what the daily `Refresh Lockfile` workflow has been opening "build failed" PRs about since 2026-05-06. Switching the directive to `@ts-ignore` is not viable: the pre-commit hook runs `biome check --write`, and Biome v2's `lint/suspicious/noTsIgnore` safe-fix rewrites `@ts-ignore` back to `@ts-expect-error` as a text replace — even inside `biome-ignore` suppression pragmas. Verified empirically. Instead, cast the inline `Transformer` literal as `Transformer<Uint8Array, Uint8Array> & { cancel?: (reason: unknown) => void | PromiseLike<void> }`. The intersection adds `cancel?:` on `@types/node@25.6.0` (where it's absent) and is structurally compatible on 25.7.0+ (where it's present). Zero `@ts-ignore`/`@ts-expect-error`/`biome-ignore` directives in the file. The `cancel` signature matches the Streams spec (`reason: unknown => void | PromiseLike<void>`), so the call contract stays visible. Adds `test/wasm/stream-directive-hygiene.test.ts` as a deterministic regression detector: if a future change re-introduces either directive in `src/wasm/stream.ts`, the test fails on every PR — not just on the next lockfile refresh. Verified locally against both `@types/node@25.6.0` (lockfile) and `@types/node@25.7.0`: `tsc --noEmit` clean both ways, biome check clean (with and without `--write`), new test passes.

Copilot

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

Copilot AI review requested due to automatic review settings May 14, 2026 13:45

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oorabona requested a review from Copilot May 14, 2026 14:06

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oorabona added 2 commits May 14, 2026 16:13

oorabona requested a review from Copilot May 14, 2026 14:33

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Comment thread src/wasm/stream.ts

oorabona changed the title ~~fix(stream): tolerate @types/node Transformer.cancel availability~~ fix(stream): drop @ts-expect-error via intersection-cast (forward-compat with @types/node 25.7.0) May 14, 2026

oorabona merged commit bc0bf0f into master May 14, 2026
23 checks passed

oorabona deleted the fix/ts-expect-error-stream-cancel branch May 14, 2026 14:47

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fix(stream): drop @ts-expect-error via intersection-cast (forward-compat with @types/node 25.7.0)#155

fix(stream): drop @ts-expect-error via intersection-cast (forward-compat with @types/node 25.7.0)#155
oorabona merged 4 commits into
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fix/ts-expect-error-stream-cancel

oorabona commented May 14, 2026 •

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oorabona commented May 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

Root cause

Fix

Why not switch to @ts-ignore?

Regression guard

Verification

Test plan

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oorabona commented May 14, 2026 •

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Why not switch to `@ts-ignore`?