Kotlin support 2.4.0 and drop 1.x test mode by andersfugmann · Pull Request #21970 · github/codeql

andersfugmann · 2026-06-11T07:34:38Z

Drop Kotlin 1.x test mode to 2.0, add Kotlin 2.4.0 extractor compatibility, and keep only required expected file updates. Known K2 mixed Java/Kotlin differences are tracked in https://github.com/github/codeql-kotlin-team/issues/196.

andersfugmann · 2026-06-11T07:34:48Z

Result-loss analysis: all changed failing tests were reproduced in Kotlin 2.0 mode, avoidable losses were addressed, and remaining differences are the pre-existing K2 mixed Java/Kotlin callable-binding issue tracked at https://github.com/github/codeql-kotlin-team/issues/196 and discussed in prior thread.

andersfugmann · 2026-06-11T07:34:48Z

/qlucie

Copilot

Pull request overview

This pull request updates the Java/Kotlin extractor and its test infrastructure to support Kotlin 2.4.0, while dropping Kotlin 1.x support (minimum Kotlin version becomes 2.0.0) and updating baselines/docs accordingly.

Changes:

Add Kotlin 2.4.0 compiler/stdlib dependencies and extractor compatibility shims for Kotlin IR API changes in 2.4.0.
Switch Kotlin integration tests that previously used Kotlin 1.x language mode to use -language-version 2.0, and update expected outputs.
Update docs and change notes to reflect the new supported Kotlin version range and deprecation of Kotlin < 2.0.

Show a summary per file

File	Description
MODULE.bazel	Adds Bazel repos for Kotlin 2.4.0 compiler/embeddable/stdlib artifacts.
java/ql/test/query-tests/security/CWE-312/android/CleartextStorage/DB-CHECK.expected	Updated test baseline output (dbcheck).
java/ql/test/query-tests/security/CWE-312/android/CleartextStorage/CleartextStorageSharedPrefsTest.expected	Updated test baseline output.
java/ql/test/library-tests/pathsanitizer/test.expected	Updated test baseline output.
java/ql/test/library-tests/pathsanitizer/DB-CHECK.expected	Updated test baseline output (dbcheck).
java/ql/lib/change-notes/2026-06-08-kotlin-drop-1x.md	Adds change note deprecating Kotlin < 2.0.
java/ql/lib/change-notes/2026-06-04-kotlin-2.4.0.md	Adds change note for Kotlin 2.4.0 support.
java/ql/integration-tests/kotlin/all-platforms/kotlin_java_lowering_wildcards/test.py	Moves test compilation to `-language-version 2.0`.
java/ql/integration-tests/kotlin/all-platforms/kotlin_java_lowering_wildcards/test.expected	Updates expected output for wildcard lowering changes.
java/ql/integration-tests/kotlin/all-platforms/kotlin_java_lowering_wildcards/DB-CHECK.expected	Updated test baseline output (dbcheck).
java/ql/integration-tests/kotlin/all-platforms/java-interface-redeclares-tostring/test.py	Moves test compilation to `-language-version 2.0`.
java/ql/integration-tests/kotlin/all-platforms/java-interface-redeclares-tostring/test.expected	Updates expected output for interface `toString` redeclare scenario.
java/ql/integration-tests/kotlin/all-platforms/file_classes/test.py	Moves test compilation to `-language-version 2.0`.
java/ql/integration-tests/kotlin/all-platforms/file_classes/classes.expected	Updates expected class extraction output.
java/ql/integration-tests/kotlin/all-platforms/extractor_information_kotlin1/test.py	Moves test compilation to `-language-version 2.0`.
java/ql/integration-tests/kotlin/all-platforms/extractor_information_kotlin1/ExtractorInformation.expected	Updates expected extractor info (Uses Kotlin 2 flag).
java/ql/integration-tests/kotlin/all-platforms/external-property-overloads/test.py	Moves test compilation to `-language-version 2.0`.
java/ql/integration-tests/kotlin/all-platforms/external-property-overloads/test.expected	Updates expected external binary location formatting.
java/ql/integration-tests/kotlin/all-platforms/enhanced-nullability/test.py	Moves test compilation to `-language-version 2.0`.
java/ql/integration-tests/kotlin/all-platforms/enhanced-nullability/test.expected	Updates expected output for enhanced nullability extraction.
java/ql/integration-tests/kotlin/all-platforms/enhanced-nullability/DB-CHECK.expected	Updated test baseline output (dbcheck).
java/ql/integration-tests/kotlin/all-platforms/diagnostics/kotlin-version-too-new/diagnostics.expected	Updates max-supported-version diagnostic message.
java/kotlin-extractor/versions.bzl	Adds 2.4.0 to supported versions list; adjusts language-version mapping.
java/kotlin-extractor/src/main/resources/META-INF/services/org.jetbrains.kotlin.compiler.plugin.CompilerPluginRegistrar	Adds service registration for Kotlin 2.4+ compiler plugin registrar.
java/kotlin-extractor/src/main/kotlin/utils/versions/v_2_4_0/parameterIndexExcludingReceivers.kt	Adds Kotlin 2.4.0-specific parameter indexing logic (handles new receiver kinds).
java/kotlin-extractor/src/main/kotlin/utils/versions/v_2_4_0/Kotlin2ComponentRegistrar.kt	Introduces Kotlin 2.4.0 `CompilerPluginRegistrar`-based registration path.
java/kotlin-extractor/src/main/kotlin/utils/versions/v_2_4_0/IrCompat.kt	Adds Kotlin 2.4.0 IR compatibility accessors for removed APIs.
java/kotlin-extractor/src/main/kotlin/utils/versions/v_1_9_0-Beta/Kotlin2ComponentRegistrar.kt	Refactors older registrar to route through `doRegisterExtensions` and centralize extension registration.
java/kotlin-extractor/src/main/kotlin/utils/versions/v_1_8_0/Kotlin2ComponentRegistrar.kt	Refactors older registrar to route through `doRegisterExtensions`.
java/kotlin-extractor/src/main/kotlin/utils/versions/v_1_8_0/IrCompat.kt	Adds pre-2.4.0 IR compatibility wrappers matching the new shim API.
java/kotlin-extractor/src/main/kotlin/utils/TypeSubstitution.kt	Switches annotation handling to compatibility wrappers (`codeQlAddAnnotations` / `codeQlAnnotationFromSymbolOwner`).
java/kotlin-extractor/src/main/kotlin/utils/JvmNames.kt	Switches annotation argument access to compatibility wrappers.
java/kotlin-extractor/src/main/kotlin/TrapWriter.kt	Switches extension receiver access to compatibility wrapper.
java/kotlin-extractor/src/main/kotlin/MetaAnnotationSupport.kt	Switches IR annotation construction/mutation to compatibility wrappers.
java/kotlin-extractor/src/main/kotlin/KotlinUsesExtractor.kt	Switches parameter/receiver access to compatibility wrappers.
java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt	Switches multiple IR access patterns to compatibility wrappers; updates related comment/docs.
java/kotlin-extractor/src/main/kotlin/KotlinExtractorComponentRegistrar.kt	Refactors registrar to use `doRegisterExtensions` and centralized extension registration.
java/kotlin-extractor/src/main/kotlin/comments/CommentExtractor.kt	Switches extension receiver detection to compatibility wrapper.
java/kotlin-extractor/dev/wrapper.py	Bumps default wrapper Kotlin version to 2.4.0.
java/kotlin-extractor/deps/kotlin-stdlib-2.4.0.jar	Adds Kotlin 2.4.0 stdlib (LFS pointer).
java/kotlin-extractor/deps/kotlin-compiler-embeddable-2.4.0.jar	Adds Kotlin 2.4.0 embeddable compiler (LFS pointer).
java/kotlin-extractor/deps/kotlin-compiler-2.4.0.jar	Adds Kotlin 2.4.0 compiler (LFS pointer).
java/kotlin-extractor/BUILD.bazel	Conditionally packages `CompilerPluginRegistrar` service file for Kotlin >= 2.4.0.
docs/codeql/reusables/supported-versions-compilers.rst	Updates documented supported Kotlin version range to 2.0.0–2.4.x.

Copilot's findings

Files reviewed: 44/44 changed files
Comments generated: 4

             *       this.dispatchReceiver = dispatchReceiver
-             *       this.extensionReceiver = extensionReceiver
+             *       this.codeQlExtensionReceiver = extensionReceiver
             *   }


    "2.2.20-Beta2",
    "2.3.0",
    "2.3.20",
+    "2.4.0",
 ]


andersfugmann · 2026-06-11T08:11:51Z

Current red Qlucie checks are caused by semmle-code workflow jobs still invoking just kotlin language-tests-1 (which runs test-kotlin1 with -language-version 1.9, now unsupported by Kotlin 2.4).\n\nI have the corresponding workflow updates in semmle-code PR https://github.com/github/semmle-code/pull/55714 (extras jobs only run language-tests-2). After that dependency lands, rerunning /qlucie on this PR should clear these failures.

andersfugmann · 2026-06-11T11:35:35Z

/qlucie

andersfugmann · 2026-06-11T11:35:45Z

Addressed review feedback in commit e50e0b5. Updated the Kotlin 2.4 registrar plugin id to kotlin-extractor, removed unused registrar state, fixed the FunctionReference explanatory comment to use extensionReceiver, and removed Kotlin 1.x entries from java/kotlin-extractor/versions.bzl (with MODULE.bazel regenerated via bazel mod tidy). Local validation: tools/bazel build target many and the enhanced-nullability Kotlin integration test pass.

andersfugmann · 2026-06-16T10:00:46Z

Why the Java/Kotlin checks are red here (and why that is expected)

TL;DR: the red Java/Kotlin checks on this PR are a cross-repo coordination artefact, not a defect in these changes. They run the ql branch against semmle-code main, which does not yet contain the coordinated semmle-code-side changes. Those changes live in the paired semmle-code PR github/semmle-code#55714, where the full Java/Kotlin suite (64 checks) is green. These checks will go green once #55714 reaches semmle-code main.

What is happening

The heavy Java/Kotlin checks reported here (Language Tests, Integration tests, Kotlin internal queries) are dispatched by the internal CI against semmle-code. For this PR they paired the ql branch with semmle-code main (branch=main), which does not have the workflow and pytest changes this work depends on.

The failure is the exact signature those semmle-code changes resolve:

codeql-extractor: target/intree/codeql-java/...   (single-version pack)
-language-version 1.9
error: language version 1.9 is no longer supported; use version 2.0 or greater instead.

In other words: on main the test harness extracts the Kotlin1 tests with -language-version 1.9 against the single-version codeql-java pack, whose bundled extractor is now Kotlin 2.4. kotlinc 2.4 rejects -language-version 1.9, so extraction fails.

Why this PR cannot fix it on its own

The fix is on the semmle-code side and is not expressible in this repository:

Build and run the Kotlin1 language-test phase against the full multi-version dist (codeql-java-full), pinning kotlinc to a pre-2.4 version (2.3.20) so the matching extractor is available.
The same two-phase split (Kotlin1 on the pinned compiler, Kotlin2 on the default 2.4) for the integration tests.

These live in github/semmle-code#55714. The ql changes here are validated in integration through that PR: it points at this branch and runs the complete Java/Kotlin suite green (Language Tests including the extras lane, all RTJO lanes, Kotlin internal queries, Bazel Format, and Integration tests on Linux, Ubuntu, Windows, Windows 2022, and macOS).

Resolution

No action is required on this PR to address the red checks. They resolve when #55714 merges to semmle-code main (or if the internal CI is asked to pair the two same-named branches). I will keep the two PRs in sync.

Add the Kotlin 2.4.0 compiler plugin variant (component registrar, IR compatibility shims, and version-specific utilities), bundle the 2.4.0 compiler dependencies, and update the build wiring, supported version metadata and the too-new diagnostic bound. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Mark the integration tests that require a Kotlin 1.x language version with @pytest.mark.kotlin1 so CI can run them on a pinned pre-2.4 compiler (Kotlin 2.4 no longer accepts -language-version 1.9). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings June 11, 2026 07:34

andersfugmann requested review from a team as code owners June 11, 2026 07:34

Copilot started reviewing on behalf of andersfugmann June 11, 2026 07:34 View session

github-actions Bot added documentation Java Kotlin labels Jun 11, 2026

Copilot AI reviewed Jun 11, 2026

View reviewed changes

andersfugmann force-pushed the andersfugmann/kotlin-2.4-v2 branch 2 times, most recently from 30b0a30 to 547c78f Compare June 12, 2026 09:53

andersfugmann marked this pull request as draft June 12, 2026 14:09

hfhbd mentioned this pull request Jun 13, 2026

Support Kotlin 2.4.0 #21938

Open

andersfugmann and others added 2 commits June 16, 2026 16:24

andersfugmann force-pushed the andersfugmann/kotlin-2.4-v2 branch from 79437b8 to 1b785a8 Compare June 16, 2026 14:25

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Kotlin support 2.4.0 and drop 1.x test mode#21970

Kotlin support 2.4.0 and drop 1.x test mode#21970
andersfugmann wants to merge 2 commits into
mainfrom
andersfugmann/kotlin-2.4-v2

andersfugmann commented Jun 11, 2026

Uh oh!

andersfugmann commented Jun 11, 2026

Uh oh!

andersfugmann commented Jun 11, 2026

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

Uh oh!

andersfugmann commented Jun 11, 2026

Uh oh!

andersfugmann commented Jun 11, 2026

Uh oh!

andersfugmann commented Jun 11, 2026

Uh oh!

andersfugmann commented Jun 16, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Conversation

andersfugmann commented Jun 11, 2026

Uh oh!

andersfugmann commented Jun 11, 2026

Uh oh!

andersfugmann commented Jun 11, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Copilot's findings

Uh oh!

Uh oh!

Uh oh!

andersfugmann commented Jun 11, 2026

Uh oh!

andersfugmann commented Jun 11, 2026

Uh oh!

andersfugmann commented Jun 11, 2026

Uh oh!

andersfugmann commented Jun 16, 2026

Why the Java/Kotlin checks are red here (and why that is expected)

What is happening

Why this PR cannot fix it on its own

Resolution

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants