fix(deps): revert typescript 7.0.2 -> 6.0.3 to fix broken ESLint by aithal007 · Pull Request #3773 · fosrl/pangolin

aithal007 · 2026-09-16T08:50:24Z

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AI Disclosure

Claude Code (Anthropic) was used to trace the failure through the CI logs, git history, and typescript-eslint's own source to find the exact root cause, and to build and verify this fix. I directed the investigation and verified every claim myself, including bisecting the commit history, reproducing the crash locally, and confirming the fix with a clean ESLint/tsc run against the actual codebase.

Description

Summary

ESLint currently fails on every PR against main (and on main itself). The failure isn't a lint violation — it's a hard crash before any file is linted:

Error: typescript-eslint does not support TS 7.0.
    at Object.<anonymous> (node_modules/typescript-eslint/dist/index.js:52:11)

This is a runtime version guard inside typescript-eslint itself, distinct from npm's peer-dependency resolution, and it fires on every npx eslint invocation given the currently pinned versions.

Root cause (bisected via git history)

c62fb6cbe ("Bump the npm-dependencies group... with 29 updates") bumped typescript 6.0.3 → 7.0.2 and typescript-eslint 8.68.0 → 8.70.0 in the same dependency-group update. typescript-eslint@8.70.0 doesn't support TS 7.0 yet — its own error message says to run it against the TS 6 API, and links the upstream issue tracking TS ≥7.1 support.
9d5dd526b ("Pin typescript"), 17 minutes later, reverted typescript back to 6.0.3 — this fixed it.
7ed646c02 ("Resolve eslint old ts issues and revert tanstack table") re-bumped typescript back to 7.0.2, alongside adding .npmrc's legacy-peer-deps=true with the comment "it works fine against it in practice." That re-introduced the crash.

The .npmrc addition doesn't (and can't) fix this: legacy-peer-deps only tells npm install to skip enforcing declared peer-dependency ranges (silencing an ERESOLVE warning at install time). It has no effect on typescript-eslint's own internal check, which runs later, at lint time, when the package loads and inspects the installed typescript version directly.

What changed

package.json: typescript 7.0.2 → 6.0.3 (the version already proven compatible by 9d5dd526b).
package-lock.json: regenerated for just this one package via npm install typescript@6.0.3 --package-lock-only. The entire diff is the removal of TypeScript 7's native per-platform compiler packages (@typescript/typescript-<platform>, new in TS 7, not present in 6.x) and their transitive deps — nothing else in the dependency tree changes.

.npmrc's legacy-peer-deps=true is left as-is; it isn't wrong on its own and removing it is out of scope for this fix.

Verification

npx eslint . --ext .js,.jsx,.ts,.tsx — was crashing before this change; now runs clean: 0 errors (4 pre-existing prefer-const warnings in unrelated files, untouched by this PR).
npx tsc --noEmit — passes with 0 errors on typescript@6.0.3, confirming nothing in the codebase relies on TS 7-only syntax or type-checker behavior.
Full OSS .test.ts suite — all pass except server/lib/traefik/traefikConfig.test.ts, which I confirmed fails identically on unmodified main (a pre-existing config-singleton initialization issue when that file is run standalone via tsx, unrelated to the TypeScript version — reproduced with this change stashed out).

How to test?

npm install (picks up typescript@6.0.3 from the updated lockfile)
npx eslint . --ext .js,.jsx,.ts,.tsx — should complete with 0 errors
npx tsc --noEmit — should complete with 0 errors

🤖 Generated with Claude Code

`npx eslint . --ext .js,.jsx,.ts,.tsx` currently crashes on `main`: Error: typescript-eslint does not support TS 7.0. at Object.<anonymous> (node_modules/typescript-eslint/dist/index.js:52:11) That's a hard runtime guard inside typescript-eslint@8.70.0 itself, thrown when it loads and inspects the installed typescript version - it's a separate check from npm's peer-dependency resolution. Root cause: commit c62fb6c bumped both `typescript` (6.0.3 -> 7.0.2) and `typescript-eslint` (8.68.0 -> 8.70.0) together. `typescript-eslint@8.70.0` does not yet support TS 7.0 (its own error message points to running against TS 6, and to the upstream issue tracking TS >=7.1 support). A same-day follow-up (9d5dd52, "Pin typescript") reverted `typescript` back to 6.0.3 and fixed it, but a later commit (7ed646c, "Resolve eslint old ts issues") re-bumped it back to 7.0.2 alongside an unrelated `.npmrc` change (`legacy-peer-deps=true`), reintroducing the crash. That `.npmrc` addition only silences `npm install`'s peer-dependency ERESOLVE warning; it cannot suppress typescript-eslint's own internal version check, so it didn't (and can't) fix this. This reverts the `typescript` pin to 6.0.3, the last version confirmed compatible with `typescript-eslint@8.70.0`, matching what 9d5dd52 already established. `package-lock.json` is regenerated for just this one package via `npm install typescript@6.0.3 --package-lock-only`; the diff is exactly the removal of TS7's native per-platform compiler packages (`@typescript/typescript-<platform>`, new in TS7, absent from 6.x), nothing else changes. Verified: `npx eslint . --ext .js,.jsx,.ts,.tsx` now runs clean (0 errors, 4 pre-existing unrelated warnings). `npx tsc --noEmit` also passes with no errors, confirming nothing in this codebase relies on TS 7-only syntax. Ran the full OSS `.test.ts` suite; all pass except one (`server/lib/traefik/traefikConfig.test.ts`) that fails identically on unmodified `main` - confirmed unrelated (a pre-existing config-initialization issue when that file is run standalone, unrelated to TypeScript's version). `.npmrc`'s `legacy-peer-deps=true` is left in place; it's not incorrect on its own; and removing it is out of scope for this fix. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Copilot

🟡 Changes recommended

The lockfile has a critical native-package selection regression, and TypeScript remains unbounded in both manifests.

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Pull request overview

Reverts TypeScript to 6.0.3 to restore compatibility with typescript-eslint@8.70.0 and fix ESLint crashes.

Changes:

Updates the TypeScript dependency declaration.
Regenerates the lockfile and removes TypeScript 7 platform packages.

File summaries

File	Summary	Findings
`package.json`	Changes TypeScript to the 6.0.3 line.	Moderate: use exact `6.0.3` instead of `^6.0.3` (3 votes).
`package-lock.json`	Resolves TypeScript 6.0.3 and updates dependency metadata.	Critical: preserve sharp’s `libc` selectors (2 votes). Moderate: pin the root TypeScript specifier to `6.0.3` (1 vote).

Review details

Files reviewed: 1/2 changed files
Comments generated: 1
Review effort level: Lite

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aithal007 · 2026-09-16T08:59:21Z

        "tsc-alias": "1.9.5",
        "tsx": "4.23.13",
-        "typescript": "7.0.2",
+        "typescript": "^6.0.3",


Good catch, thanks — you're right, and this wasn't intentional. npm install typescript@6.0.3 --package-lock-only applied npm's default save-prefix behind the scenes, so both package.json and the lockfile's root spec ended up as ^6.0.3 instead of the exact 6.0.3 I meant to pin. Since typescript-eslint@8.70.0's own peer range is <6.1.0, that range would have let a future install silently drift to an incompatible 6.1.x+ and reintroduce this exact crash.

Fixed in d0dbe8c — re-ran with --save-exact, so both package.json and the lockfile's root spec now pin exactly 6.0.3. Re-verified npx eslint . --ext .js,.jsx,.ts,.tsx still runs with 0 errors.

`npm install typescript@6.0.3 --package-lock-only` (used in the previous commit) applies npm's default save-prefix, which wrote `^6.0.3` to both package.json and the lockfile's root spec instead of an exact `6.0.3`. That range permits any future 6.x (including 6.1.0+), but typescript-eslint@8.70.0's own declared peer range is `<6.1.0` (package-lock.json's typescript-eslint entry) - so a future fresh install or lockfile refresh could silently resolve a 6.1.0+ typescript and reintroduce the exact crash this fix addresses. Re-ran with --save-exact to pin exactly 6.0.3 in both manifests, matching what's actually resolved and tested. Re-verified: `npx eslint . --ext .js,.jsx,.ts,.tsx` still 0 errors. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Copilot AI lite review requested due to automatic review settings September 16, 2026 08:50

aithal007 requested review from miloschwartz and oschwartz10612 as code owners September 16, 2026 08:50

Copilot started reviewing on behalf of aithal007 September 16, 2026 08:50 View session

Copilot AI reviewed Sep 16, 2026

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Tyagiquamar mentioned this pull request Sep 17, 2026

fix(sqlite): tag per-migration database backups with version and prevent collisions #3785

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fix(deps): revert typescript 7.0.2 -> 6.0.3 to fix broken ESLint - #3773

fix(deps): revert typescript 7.0.2 -> 6.0.3 to fix broken ESLint#3773
aithal007 wants to merge 2 commits into
fosrl:mainfrom
aithal007:fix/typescript-eslint-ts7-incompatibility

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aithal007 commented Sep 16, 2026

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Description

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Root cause (bisected via git history)

What changed

Verification

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