feat(packs): candidate typescript 5 to 6 pack, judged by the target compiler (UPT-56)

[lucasbraum]

Pack

typescript >=5 <6 → >=6 <7 (default 6.0.3), for UPT-56. Candidate, by choice: under today's gate the run measures verified (7 public repositories, 0 breaking false positives). The stricter gate (UPT-48) is landing separately, so verification.json keeps its candidate record until this branch is rebased on UPT-48 and re-scored with --write.

The upgraded package is the compiler itself, so this also changes the engine. How check resolves the compiler for this upgrade:

• Installed side: the repository's own node_modules/typescript, the nearest one from the workspace up.
• Target side: the typescript copy check fetched at the target, the release fix installs, loaded from that directory.
• Never the bundled compiler (ts-morph's 6.0.2). With no TypeScript installed, the compile is skipped and the report says why. A target with no JavaScript API (TypeScript 7) is skipped and named the same way.
• What is compiled: every project of the workspace (its tsconfig, its references, every nested tsconfig.json), all files, not only importers of typescript. The coverage line names both compilers: "compiled 13 of 13 files … with the repo's TypeScript 5.9.3 and 6.0.3".
• tsconfig diagnostics (TS5101/TS5107/TS5011) are pack findings from the inventory, reported in the file that sets the option, not compile findings. So the UPT-49 project scope (fix(check): respect TypeScript project compile scope (UPT-49) #138) does not drop them. packs/typescript/check.test.ts pins this with a tsconfig outside every include.

Engine changes, in their own commit:

• compileCompilerUpgrade in adapters/typescript/compile.ts.
• loadCompiler drops Node's cached module when the version on disk changed, and the compiler cache is keyed by version. Without this, fix would verify a TypeScript 6 install with the 5.x module loaded earlier from the same path.
• A workspace that imports nothing is still checked when a named pack's inventory matches.
• companionsOf reports a peer conflict even when list does not group the peer with the lead. Before, @typescript-eslint/parser 8.56.0 (typescript <6.0.0) was planned as a conflict and then dropped from the report; it is now listed as possible impact and left where it is.
• packs:truth:
  • reads tsconfig*.json in the upgrade diff and lists tsconfig option errors;
  • anchors insertions in JSON;
  • loads the linked target compiler by its real path. Node's cached resolution kept handing back the installed 5.x, so the first drafts silently compiled 5.x twice.

Sources

Read 2026-10-14, pinned in RESEARCH.md: the TypeScript 6.0 release notes (TypeScript-Website 119f931), Announcing TypeScript 6.0 (2026-03-23), Announcing TypeScript 7.0 (2026-07-08), and tags v5.9.3 / v6.0.3. Every diagnostic code was read from 6.0.3 itself.

Range decision: two packs. 6.0 deprecates (errors unless ignoreDeprecations: "6.0" is set) what 7.0 removes. packs/queue.json gets 5 → 6 (candidate) and 6 → 7, blocked: typescript@7.0.2 exports no compiler API (a new one is planned for 7.1).

Rules and behavior notes

Mechanical, each with an exact replacement from the notes and unchanged behavior:

• downlevel-iteration: removes the line. Declined with an ES3/ES5 target, with ignoreDeprecations set, or when the property shares its line.
• module-keyword: TS1540, module Foo { → namespace Foo {. Declined for a quoted ambient module.
• import-assertions: TS2880, assert { → with {. Declined unless { or : follows.

Assisted, reported where set, with a guide:

• base-url: the paths rewrite is exact, but bare-import lookup and bundlers that read baseUrl can change.
• module-resolution-node10, module-resolution-classic: bundler vs nodenext is the owner's call.
• target-es5, module-format-removed, out-file, interop-false, always-strict-false: each changes emit.
• root-dir: TS5011 at outDir when include is one directory and rootDir is unset.

Behavior note changed-defaults (a decision): lists, per tsconfig, the 6.0 defaults it leaves unset through in-repo extends (strict, types, noUncheckedSideEffectImports). The owner pins or keeps each. Defaults are not pinned by rule: a static pin would hit every tsconfig that leaves them unset, and most of those compile cleanly. The code errors those defaults cause are the compiler's findings.

requiresBuild: true. The instructions forbid any, @ts-ignore/@ts-expect-error/@ts-nocheck, ignoreDeprecations, skipLibCheck and loosening strictness.

Ground-truth repositories

Committed in 2699e8c, the first commit of this branch, before the first scoring run; nothing was changed after scoring. Drafted with pnpm packs:truth (6.0.3 on every tsconfig.json, plus the upgrade diff), then assigned by hand.

Repository	Before	Upgrade	Expected
m-lyon/recipe (client/)	f6e44b5 (5.6.2)	pull request 113 (merged)	1
robrechtme/recipes	0853747	pull request 7 (merged)	2
JosephMaynard/dependency-radar	1920eb3	pull request 46 (merged)	116
CroffZ/github-release-notifier	d9353f2	pull request 5 (merged)	12
SignalK/signalk-derived-data	02f635e	pull request 239 (merged)	418
shogo82148/typescript-action	0f03405	pull request 487 (merged)	3
Borewit/music-metadata	783509b	pull request 2661 (merged)	851

Most expected sites are generic compiler sites, which mostly come from the types: [] and strict defaults.

uptide pack test output

uptide pack test typescript · verified, recorded candidate
fixtures      7 cases, 14 sites · pass
ground truth
  m-lyon/recipe@f6e44b530c4d                   typescript 5.6.2 → 6.0.3  predicted 1, expected 1, false positives 0, false negatives 0
  robrechtme/recipes@0853747427b7              typescript 5.9.3 → 6.0.3  predicted 2, expected 2, false positives 0, false negatives 0
  JosephMaynard/dependency-radar@1920eb3217b7  typescript 5.9.3 → 6.0.3  predicted 115, expected 116, false positives 0, false negatives 1
  CroffZ/github-release-notifier@d9353f2471c5  typescript 5.9.3 → 6.0.3  predicted 11, expected 12, false positives 0, false negatives 1
  SignalK/signalk-derived-data@02f635e8232a    typescript 5.9.3 → 6.0.3  predicted 417, expected 418, false positives 0, false negatives 1
  shogo82148/typescript-action@0f03405c7267    typescript 5.9.3 → 6.0.3  predicted 2, expected 3, false positives 0, false negatives 1
  Borewit/music-metadata@783509b27bac          typescript 5.9.3 → 6.0.3  predicted 831, expected 851, false positives 0, false negatives 20

  rule                         precision  recall    tp   fp   fn
  base-url                          100%    100%     4    0    0
  changed-defaults                   n/a      0%     0    0    4
  generic                           100%     99%  1371    0   18
  module-resolution-node10          100%     67%     2    0    1
  root-dir                          100%     50%     1    0    1
  target-es5                        100%    100%     1    0    0
  overall (sites)                   100%     98%  1379    0   24
  behavior notes (sites)             n/a      0%     0    0    4
  breaking (sites)                  100%     99%  1379    0   20

It exits 1 only because verification.json still holds the candidate record, which is the point. The 24 false negatives are explained in RESEARCH.md:

• 18 second-round Borewit lines (17 tightened test lines and a TS6385 deprecation);
• 2 same-change tsconfig lines no rule predicts;
• 4 changed-defaults decision sites, which are behavior-only, not missed breaks.

Under UPT-48 as specified:

• 7 repositories and 1,399 expected breaking sites: both meet the minimums.
• Real-world true positives per rule: base-url 4, module-resolution-node10 2, target-es5 1, root-dir 1.
• The three mechanical rewrites met no real site. They become unexercised and run as assisted; their only evidence is the fixtures.

Checklist

• Every rule and note comes from a source listed in meta.sources
• Every rule that rewrites or detects has a fixture case, with a site it must leave alone (keep): 7 cases, 14 sites
• Ground truth: public repositories at the commit before their upgrade; expected findings read from their own upgrade commit and the compiler, never copied from Uptide's output
• At least two public repositories for verified: 7, held at candidate until UPT-48
• verification.json written with --write: deliberately not yet, after the rebase on UPT-48
• pnpm lint && pnpm typecheck && pnpm test pass locally (1,731 core and 454 CLI tests)
• Changeset added
• No private code, names or paths: fixtures are synthetic, ground truth is public

To check before merge:

• Pack CI's record check fails until --write. That is expected while this is a draft.
• fix(check): respect TypeScript project compile scope (UPT-49) #138 (UPT-49) also edits compile.ts. Whichever lands second rebases, and compileCompilerUpgrade could then take its project list from fix(check): respect TypeScript project compile scope (UPT-49) #138's projectScope.
• Known limits:
  • extends to a package config is not read;
  • root-dir reads one file;
  • errors that appear only after the first fixes are not predicted.

🤖 Generated with Claude Code

[lucasbraum]

Rebased on main after #138 (UPT-49). Both behaviors kept:

• compileCompilerUpgrade now takes its projects from fix(check): respect TypeScript project compile scope (UPT-49) #138's projectScope, and a compiler diagnostic counts only in a file a project covers.
• Pack findings in tsconfig files are never scoped. The new check test pins an extended base config outside every include, in an excluded directory, still reported. The network test pins an uncovered file's compiler error dropped.
• The target compiler is still loaded by real path in loadCompiler and packs:truth.

Focused tests pass (69, including #138's scope tests and the 6.0.3 network test), as does typecheck.

Left as draft on purpose: the re-score now has 14 false positives, all in shogo82148/typescript-action __tests__/. #138's scope also compiles tsconfig.eslint.json, and packs:truth only reads tsconfig.json. The errors are real 6.0 errors (jest globals under types: []); that repo's upgrade added types: ["jest", "node"] there. Fixing the ground-truth method after scoring is a maintainer call, so it is recorded in RESEARCH.md, not done. verification.json stays candidate.

[lucasbraum]

Pack test failure after the #138 rebase (run 38690803983, pack-test.json):

• Failing pack: typescript, the only failure.
• Not an overclaim (recorded candidate) and not with/blocker (problems: []).
• Score: 14 breaking false positives in shogo82148/typescript-action __tests__/.

#138's scope compiles tsconfig.eslint.json. packs:truth only read tsconfig.json, so the truth missed real 6.0 errors there: ts-jest type-checks the tests with that config, and the repo's upgrade added types: ["jest", "node"] to it.

Fixed in this PR (d0e6092): packs:truth now drafts on projectScope, the same projects check compiles. All seven repos were redrafted before re-scoring; only shogo gains sites (those 14). Re-score: PASS, 0 FP, breaking recall 99% (1393/1413). It measures verified; the record stays candidate by choice.

[lucasbraum]

Reverted the ground-truth redraft (f07cdaa): ground-truth.json is back to the original commit d128198. The packs:truth scope change stays, for future packs only.

Engine fix (26d4be7):

• The typescript pack's new foldFindings hook folds errors from the 6.0 types: [] default into one changed-defaults finding at the covering tsconfig that leaves types unset, as fix(check): fold implicit-any errors inside a removed option into its pack finding #136 does for TS7006 cascades.
• Folded: TS2580–2593 "install type definitions" errors, and TS2304/TS2503 for a global declared by an @types package that 5.x included automatically.
• Tested on the shogo shape (14 test errors → one finding at tsconfig.eslint.json) and the Borewit shape.

Re-score on the original truth: PASS, 0 breaking FP. Two trade-offs, in RESEARCH.md:

• The anchor uses the note's severity (deprecated). A breaking anchor would be a breaking FP where the truth has no site for that edit, e.g. dependency-radar.
• Breaking recall drops to 17%: 1,159 truth lines (one per error) are now evidence of one tsconfig finding each. There are also 8 non-breaking changed-defaults FPs, because the anchor line (the config's root {) differs from the diff-shaped truth lines.

[lucasbraum]

Rebased on main after #155 (force-pushed with lease from 26d4be7). The only conflict was the generated README table: I took main's README and regenerated the table with pnpm docs:packs. The registry already matched renderRegistry, so it is unchanged. 8b91752 writes the typescript record from a fresh pack test: class breaking, 1,399 real breaking sites, 4 behavior-note sites, and downlevel-iteration, import-assertions, module-keyword unexercised (assisted). It stays candidate by choice, although the run measures verified (0 breaking false positives, recall 17%). Focused tests pass, apart from the local-only scaffold.test formatted check.