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[js_interop_gen] Split union/intersection AST types and extract TypeTransformer - #580

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kevmoo merged 26 commits into
slice-transform-typefrom
split-types-and-transformer
Sep 30, 2026
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[js_interop_gen] Split union/intersection AST types and extract TypeTransformer#580
kevmoo merged 26 commits into
slice-transform-typefrom
split-types-and-transformer

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@kevmoo kevmoo commented Sep 20, 2026 •
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Splits the two oversized files in js_interop_gen identified by dart run cognitive_complexity:file_split (> 800 lines):

  1. lib/src/ast/types.dart (1,302 -> 665 lines, -48.9%):

    • Extracts the cohesive union/intersection AST cluster (UnionOrIntersectionType, UnionType, IntersectionType, HomogenousEnumType, _UnionOrIntersectionDeclaration, _IntersectionDeclaration, _UnionDeclaration, _typeNameForGetter, _intersectTypes, and _sanitizeIdentifier) into lib/src/ast/union_intersection_types.dart (648 lines).
    • Updates call sites to import union_intersection_types.dart directly (0 private member widenings).

  2. lib/src/interop_gen/transform/transformer.dart (2,561 -> 1,841 lines, -28.1%):

    • Extracts TypeTransformer into lib/src/interop_gen/transform/type_transformer.dart (763 lines), following the existing TypeResolver(Transformer) companion class pattern in type_resolver.dart.

🤖 Tool Provenance & File Split Delta

Identified and verified using:

File Before (Lines) After (Lines) Delta <= 800 Ceiling
lib/src/ast/types.dart 1,302 665 -637 (-48.9%) ✅ Pass
lib/src/ast/union_intersection_types.dart (new) — 648 +648 ✅ Pass
lib/src/interop_gen/transform/transformer.dart 2,561 1,841 -720 (-28.1%) Reduced by 720 lines
lib/src/interop_gen/transform/type_transformer.dart (new) — 763 +763 ✅ Pass

Reproduction Commands

dart run cognitive_complexity:file_split js_interop_gen

@kevmoo
[js_interop_gen] Require code_builder: ^4.12.0 and update golden he…
e346a44 
…aders

`package:code_builder` `4.12.0` fixed dart-lang/tools#2404
by emitting scoped lint ignores (`no_leading_underscores_for_library_prefixes`)
directly in the sorted top-of-file `// ignore_for_file:` block before library
annotations and directives.

- Bump `code_builder` dependency constraint to `^4.12.0` (compatible with
  `sdk: ^3.10.0`, preserving `js_interop_gen`'s `sdk: ^3.12.0` constraint).
- Remove the now-obsolete `replaceFirstMapped` regex workaround for
  `dart-lang/tools#2404` in `lib/src/interop_gen/transform.dart`.
- Regenerate the expected test golden headers across `test/`.
@kevmoo
[js_interop_gen] Remove unused JS interop extension types and bindings
8514324 
Stacked on #576.

Remove 13 unreferenced declarations identified by `pkg:undead`
(`--extra-roots=lib/src/dart_main.dart`):
- `createSourceFile` in `lib/src/js/typescript.dart`
- `InterfacelikeExtension` in `lib/src/js/webidl_api.dart`
- 11 unused TypeScript AST extension types in
  `lib/src/js/typescript.types.dart` (`TSTypePredicateNode`,
  `TSNamedTupleMember`, `TSFunctionTypeNode`, `TSConstructorTypeNode`,
  `TSPropertyAccessExpression`, `TSNamespaceExport`, `TSExportAssignment`,
  `TSClassDeclaration`, `TSInterfaceDeclaration`, `TSPropertyDeclaration`,
  `TSMethodDeclaration`)
@kevmoo
[js_interop_gen] Deduplicate UnionType and IntersectionType via `…
b7691b6 
…UnionOrIntersectionType`

Stacked on #577.

- Extract `sealed class UnionOrIntersectionType extends DeclarationType` in
  `lib/src/ast/types.dart` (mirroring `_UnionOrIntersectionDeclaration`) to
  share `types`, `isNullable`, `declarationName`, `id`, `emit()`, `hashCode`,
  and `operator ==` across `UnionType` and `IntersectionType` (`pkg:dedupe`
  `cluster-47`).
- Fix `UnionType.==` and `IntersectionType.==`, which previously checked
  `other is TupleType` due to copy-paste.
- Consolidate `UnionType` / `IntersectionType` pattern cases in
  `lib/src/ast/helpers.dart` and
  `lib/src/interop_gen/transform/dependency_walker.dart`.
- Write `dart_main.js` via an atomic temporary file rename in
  `compileDartMain()` (`lib/src/cli.dart`) so parallel `dart test` isolates in
  the same VM process cannot truncate `dart_main.js` while `node main.mjs` is
  loading it.
@kevmoo
[js_interop_gen] Decompose Transformer._transformType and deduplica…
6648c9b 
…te type caching

Stacked on #578.

- Extract `_transformConditionalType`, `_transformTypeLiteral`,
  `_transformClosureType`, `_transformUnionType`,
  `_transformIntersectionType`, and `_transformIndexedAccessType` from
  `Transformer._transformType` in
  `lib/src/interop_gen/transform/transformer.dart`, reducing
  `Transformer._transformType` cognitive complexity from `190` to `59` (-68.9%).
- Extract `_filterNonNullableTypeNodes` and `_getOrCreateCachedType` helpers on
  `Transformer`, eliminating duplicate union/intersection filtering and
  `typeMap` caching blocks (`pkg:dedupe` `cluster-45`, `cluster-51`, and
  `cluster-52`).
@kevmoo
Enforce symmetric equality and length check in UnionOrIntersectionTyp…
22bd431 
…e.==
@kevmoo
Merge branch 'dedupe-union-intersection-ast' into slice-transform-type
afe422f
@kevmoo
[js_interop_gen] Split union/intersection AST types and extract TypeT…
a336d95 
…ransformer
gemini-code-assist[bot]
gemini-code-assist Bot reviewed Sep 20, 2026
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Code Review

This pull request refactors the AST and type transformation logic in js_interop_gen. Specifically, it extracts union and intersection types and declarations from types.dart into a new file union_intersection_types.dart. It also extracts the type transformation logic from Transformer into a new TypeTransformer class in type_transformer.dart. The reviewer provided feedback regarding an unused import of dart:js_interop in type_transformer.dart and raised a concern about mutating the isNullable property of shared/cached AST type instances in-place, which could leak nullability changes to unrelated references.

Comment thread js_interop_gen/lib/src/interop_gen/transform/type_transformer.dart Resolved
Comment thread js_interop_gen/lib/src/interop_gen/transform/type_transformer.dart Resolved
@kevmoo
kevmoo requested a review from srujzs September 20, 2026 05:31
@kevmoo
kevmoo added this pull request to stack #581 September 20, 2026 16:40
@kevmoo
kevmoo removed this pull request from stack #581 September 20, 2026 17:34
@kevmoo
kevmoo added this pull request to stack #583 September 20, 2026 17:35
@kevmoo
Merge remote-tracking branch 'origin/slice-transform-type' into split…
c83f7a2 
…-types-and-transformer

# Conflicts:
#	js_interop_gen/lib/src/ast/types.dart
#	js_interop_gen/lib/src/cli.dart
#	js_interop_gen/lib/src/interop_gen/transform/transformer.dart
#	js_interop_gen/lib/src/js_type_supertypes.dart
@kevmoo
kevmoo merged commit 8dc8f75 into main Sep 30, 2026
21 checks passed
@kevmoo
kevmoo deleted the split-types-and-transformer branch September 30, 2026 15:12
copybara-service Bot pushed a commit to dart-lang/sdk that referenced this pull request Oct 7, 2026
@natebosch dart-scoped@luci-project-accounts.iam.gserviceaccount.com
[deps] rev core, dartdoc, http, native, shelf, test, tools, web
1d6b42b 
Revisions updated by `dart tools/rev_sdk_deps.dart`.

core (https://github.com/dart-lang/core/compare/08e4022..4d80610):
  4d80610a  Thu Oct 1 22:03:38 2026 +0000  dependabot[bot]  Bump the github-actions group with 5 updates (dart-lang/core#1005)

dartdoc (https://github.com/dart-lang/dartdoc/compare/2a040a8..5eb0f2c):
  5eb0f2c7  Thu Oct 1 19:03:48 2026 +0000  dependabot[bot]  Bump github/codeql-action/upload-sarif from 4.37.9 to 4.38.2 in the github-actions group (dart-lang/dartdoc#4291)

http (https://github.com/dart-lang/http/compare/d8e8e9c..585d433):
  585d433  Mon Oct 5 16:12:54 2026 -0700  Brian Quinlan  fix(cupertino_http): fix a websocket memory leak (dart-lang/http#1991)
  337adf3  Mon Oct 5 16:03:25 2026 -0700  Brian Quinlan  fix(cupertino_http): add `autoReleasePool` use to `CupertinoClient` (dart-lang/http#1990)
  47c57df  Tue Sep 29 14:07:01 2026 -0700  Brian Quinlan  fix(ok_http): fix `NetworkOnMainThreadException` (dart-lang/http#1995)
  d8cde5d  Tue Sep 29 14:06:44 2026 -0700  Brian Quinlan  fix test (dart-lang/http#1996)
  31056fe  Tue Sep 29 13:57:20 2026 -0700  Brian Quinlan  chore(cronet_http): prepare to release 1.10.0 (dart-lang/http#1993)
  9bc3a91  Tue Sep 29 13:53:25 2026 -0700  Brian Quinlan  fix(cronet_http): one global reference per `onReadCompleted` (dart-lang/http#1992)
  49ecd36  Mon Sep 28 14:20:26 2026 -0700  Brian Quinlan  fix(conformance): `supportsAbort` not considered in response (dart-lang/http#1994)

native (https://github.com/dart-lang/native/compare/27f7678..a2a6179):
  a2a617910  Tue Oct 6 13:53:17 2026 +0200  Daco Harkes  [jni_flutter] Bump version for publishing (dart-lang/native#3730)
  d3a99d66b  Tue Oct 6 19:46:34 2026 +1100  Liam Appelbe  [infra] Fix ffigen and jni_flutter (dart-lang/native#3724)
  b66d0815a  Tue Oct 6 04:28:35 2026 +0300  Manar Elhabbal  [ffigen] add Support passing C++ classes by value  (dart-lang/native#3677)
  f7ffe9667  Fri Oct 2 11:33:49 2026 +0200  Moritz  [native_toolchain_c] Don't pass /INCLUDE per symbol with a generated .def on Windows (dart-lang/native#3718)
  77a5e4169  Thu Oct 1 10:56:45 2026 +0300  Hassnaa Mohamed  [ffigen] Fix cpp method filtering (dart-lang/native#3696)
  cca065ca6  Thu Oct 1 10:17:12 2026 +1000  Liam Appelbe  [infra] Prepare to publish everything (dart-lang/native#3716)
  f13623ee3  Thu Oct 1 10:16:39 2026 +1000  Liam Appelbe  [jnigen] API docs (dart-lang/native#3715)
  be618790c  Thu Oct 1 10:05:26 2026 +1000  Liam Appelbe  [objective_c] API docs (dart-lang/native#3708)
  a18dd1148  Thu Oct 1 10:04:38 2026 +1000  Liam Appelbe  [ffigen] API docs (dart-lang/native#3707)
  6fd87c3b2  Tue Sep 29 19:01:11 2026 -0700  Brian Quinlan  [jni] Clarify `JBuffer.asUint8List` behavior (dart-lang/native#3704)
  6d5bbcfad  Wed Sep 30 09:35:47 2026 +1000  Liam Appelbe  [jni] API documentation (dart-lang/native#3706)
  fbcbc894b  Wed Sep 30 09:35:34 2026 +1000  Liam Appelbe  [ffigen] Document autorelease issues (dart-lang/native#3705)
  f99449ec9  Tue Sep 29 09:39:27 2026 +1000  Liam Appelbe  [infra] Add swift2objc to the workspace (dart-lang/native#3700)
  31494fa08  Tue Sep 29 09:38:59 2026 +1000  Liam Appelbe  [infra] Add jni_util to the workspace (dart-lang/native#3698)

shelf (https://github.com/dart-lang/shelf/compare/e5c8dc6..b2cb503):
  b2cb503  Wed Sep 30 22:53:07 2026 -0700  Kevin Moore  Resolve shelf.io.connection_info lazily (dart-lang/shelf#542)
  b70fafa  Tue Sep 29 13:37:08 2026 -0700  Kevin Moore  Match parameterless shelf_router routes without running a regex (dart-lang/shelf#544)

test (https://github.com/dart-lang/test/compare/4f92d53..d749b10):
  d749b104  Mon Oct 5 15:42:46 2026 -0700  Nate Bosch  Fail isolate suites when the test isolate exits (dart-lang/test#2775)
  da2157e9  Mon Oct 5 11:12:43 2026 -0700  Nate Bosch  Wait longer for the Chrome test tab to appear (dart-lang/test#2771)
  00bd0c99  Mon Oct 5 18:50:03 2026 +0300  Yusuf İhsan Görgel  Fix broken links in architecture.md (dart-lang/test#2774)
  3be2f547  Thu Oct 1 03:46:29 2026 +0000  dependabot[bot]  Bump the github-actions group with 4 updates (dart-lang/test#2773)
  40a5ad90  Tue Sep 29 12:07:31 2026 -0700  Nate Bosch  Delete compilation artifacts once they are no longer needed (dart-lang/test#2764)
  171ad0e5  Mon Sep 28 17:29:48 2026 -0700  Jacob MacDonald  export additional types from package:test_api/backend.dart (dart-lang/test#2745)
  52b45064  Mon Sep 28 15:04:08 2026 -0700  Nate Bosch  Tag browser and node tests, relax flaky timeouts (dart-lang/test#2770)

tools (https://github.com/dart-lang/tools/compare/d87eaf7..a66d517):
  a66d517d  Tue Oct 6 09:41:32 2026 -0700  Phil Quitslund  [analytics] `DASH__SUPPRESS_ANALYTICS` env handling (dart-lang/tools#2641)
  00c6e4ad  Fri Oct 2 17:17:49 2026 +0530  shivytyahoo  Fix VersionConstraint.intersection throwing on disjoint ranges (dart-lang/tools#2622)
  d523e1f8  Thu Oct 1 11:09:16 2026 +0200  Morgan :)  [unified_analytics] Append to the log file instead of rewriting it (dart-lang/tools#2613)
  6993cbad  Wed Sep 30 14:09:32 2026 +0300  Yusuf İhsan Görgel  [yaml] Improve error messages when mixing list and key-value syntax (dart-lang/tools#2610)
  068119b4  Tue Sep 29 23:21:03 2026 +0200  Lukas Klingsbo  [pubspec_parse] Support tag_pattern for git dependencies (dart-lang/tools#2565)
  7d859ed5  Mon Sep 28 20:28:23 2026 -0700  Kevin Moore  [api_summary] Add expectApiSummaryClean and --write/--check CLI flags (dart-lang/tools#2603)

web (https://github.com/dart-lang/web/compare/ec71a4c..63e6662):
  63e6662  Sat Oct 3 00:23:21 2026 +0000  Natalie Weizenbaum  Add a JSPair type (dart-lang/web#586)
  2d68d90  Fri Oct 2 20:26:48 2026 +0000  Natalie Weizenbaum  Use `js_interop` APIs in `js_interop_gen` (dart-lang/web#585)
  037823c  Thu Oct 1 21:59:21 2026 +0000  Natalie Weizenbaum  Add JSMap, JSSet, and JSSetLike types (dart-lang/web#571)
  b2d1d6b  Thu Oct 1 06:57:03 2026 +0000  dependabot[bot]  Bump the github-actions group with 3 updates (dart-lang/web#584)
  8dc8f75  Wed Sep 30 08:12:18 2026 -0700  Kevin Moore  [js_interop_gen] Split union/intersection AST types and extract TypeTransformer (dart-lang/web#580)
  751ccdf  Wed Sep 30 08:12:18 2026 -0700  Kevin Moore  [js_interop_gen] Decompose `Transformer._transformType` and deduplicate type caching (dart-lang/web#579)
  6f3dd4e  Wed Sep 30 08:12:17 2026 -0700  Kevin Moore  [js_interop_gen] Deduplicate `UnionType` and `IntersectionType` via `UnionOrIntersectionType` (dart-lang/web#578)
  d9f095e  Tue Sep 29 12:17:29 2026 -0700  Kevin Moore  [js_interop_gen] Remove unused JS interop extension types and bindings (dart-lang/web#577)
  07111ee  Tue Sep 29 09:51:36 2026 -0700  Kevin Moore  fix(js_interop_gen): update js_type_supertypes for Dart 3.12 (dart-lang/web#582)

Change-Id: I4532049c45561fe8f8c57713ac8ec2153096fd9a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/560660
Commit-Queue: Nate Bosch <[email protected]>
Reviewed-by: Brian Quinlan <[email protected]>
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@srujzs srujzs srujzs approved these changes
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