[camera_android_camerax] Add explicit concurrent-futures dependency

[dhc-tech]

camera_android_camerax's Gradle module does not explicitly declare a dependency on androidx.concurrent:concurrent-futures. Verified via androidx.camera:camera-core:1.6.1's own Gradle module metadata (.module file): camera-core declares androidx.concurrent:concurrent-futures only on its runtime variant (releaseVariantReleaseRuntimePublication), not its api/compile variant (releaseVariantReleaseApiPublication). So when a consumer compiles against camera-core, Gradle correctly does not put concurrent-futures on the compile classpath — that's not a resolution bug, it's what camera-core's own metadata declares.

However, camera-core's compiled SurfaceRequest.class carries a compile-time-retained jspecify @NonNull type annotation on a member typed androidx.concurrent.futures.CallbackToFutureAdapter. javac needs that class on the compile classpath to fully process the annotation metadata during compilation — even though no camera_android_camerax (or camera-core) source calls it directly. This is a mismatch in camera-core's own packaging (a type needed at compile time for annotation processing, but declared runtime-only), which the Flutter team can't fix upstream since camera-core is owned by the AndroidX/Jetpack team. Declaring the dependency explicitly in camera_android_camerax works around it.

Confirmed 100% reproducible on a completely stock, uncustomized flutter create app on current stable (3.44.8, default AGP 9.0.1, compileSdk 37):

flutter create camera_repro
cd camera_repro
flutter pub add camera
flutter build apk --debug

fails every time with:

error: Cannot attach type annotations @org.jspecify.annotations.NonNull to
SurfaceRequest.mSurfaceRecreationCompleter: class file for
androidx.concurrent.futures.CallbackToFutureAdapter not found

Minimal repro repo (steps + README with root cause): https://github.com/dhc-tech/camera-android-camerax-build-repro

List which issues are fixed by this PR:

Fixes flutter/flutter#190505

Pre-Review Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the AI contribution guidelines and understand my responsibilities. This PR was prepared with AI assistance (Claude Code); I reviewed the diagnosis and the diff, reproduced the failure myself on a clean project, and verified the root cause against camera-core's published Gradle module metadata before submitting.
• I read the Tree Hygiene page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter.
• I signed the CLA.
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [camera_android_camerax]
• I linked to at least one issue that this PR fixes in the description above.
• I followed the version and CHANGELOG instructions, using semantic versioning and the repository CHANGELOG style (bumped to 0.7.4+5, rebased to avoid colliding with the real 0.7.4+4 release).
• I updated/added any relevant documentation (doc comments with ///). N/A — no public API surface changed, only a build-file dependency.
• I added new tests to check the change I am making: ConcurrentFuturesDependencyTest.java asserts CallbackToFutureAdapter resolves on the classpath, so it fails if the dependency is ever dropped again.
• All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

[flutter-dashboard]

It looks like this pull request may not have tests. Please make sure to add tests or get an explicit test exemption before merging.

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing. If you believe this PR qualifies for a test exemption, contact "@test-exemption-reviewer" in the #hackers channel in Discord (don't just cc them here, they won't see it!). The test exemption team is a small volunteer group, so all reviewers should feel empowered to ask for tests, without delegating that responsibility entirely to the test exemption group.

[google-cla]

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View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[gemini-code-assist]

Code Review

This pull request adds an explicit dependency on androidx.concurrent:concurrent-futures to resolve compilation errors where CallbackToFutureAdapter annotations cannot be resolved. It also updates the package version to 0.7.4+4 and documents the change in the changelog. Feedback suggests using the stable version 1.2.0 of the dependency instead of 1.3.0 to prevent potential dependency resolution errors.

[dhc-tech]

Fixes flutter/flutter#190505

[dhc-tech]

/gemini review

@flutter-dashboard: a regression test has been added in 7efa210 (ConcurrentFuturesDependencyTest.java) that asserts androidx.concurrent.futures.CallbackToFutureAdapter resolves on the classpath, so this fix cannot be silently reverted without a test failure.

@gemini-code-assist: please re-review with the latest commit — the concurrent-futures version is pinned to the stable 1.2.0 per earlier feedback, and a test now covers the fix.

[gemini-code-assist]

Code Review

This pull request adds an explicit dependency on androidx.concurrent:concurrent-futures:1.2.0 in android/build.gradle.kts to resolve a compilation issue where CallbackToFutureAdapter was not found. It also introduces a regression test, ConcurrentFuturesDependencyTest, to verify that the class remains on the classpath, and updates the version to 0.7.4+4 in pubspec.yaml and CHANGELOG.md. There are no review comments, and I have no feedback to provide.

[digvijaysinh-cloudemy]

Hi team, I encountered the exact same Gradle transform error on my setup after updating plugins. I can confirm that the changes in this PR fixed the issue for me as well.

Could someone please review and merge this when possible? Thanks! @justinmc PTAL

[stuartmorgan-g]

@digvijaysinh-cloudemy Please do not ping people like that. We have a documented process for routing PRs to appropriate reviewers, and it does not involve immediately pinging random Flutter team members who don't even work on the relevant package to individually ask them for review.

[stuartmorgan-g]

Thank you for your contribution! Because of the volume of PRs we receive, we require that new contributors use our checklist to guide them through critical steps in creating a Flutter PR. This PR's description is not using our standard checklist, so it is being marked as a Draft.

Please edit the PR description to add the correct checklist, then ensure that you have completed all of the steps. Once you've done that, please mark the PR as ready for review.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

Also, as previously discussed, it's not clear why this PR would be necessary, and neither the PR description nor the issue actually explain that; that's going to be a necessary first step for this being reviewable. It says:

camera_android_camerax's Gradle module does not explicitly declare a
dependency on androidx.concurrent:concurrent-futures, relying on it being
pulled in transitively via androidx.camera:camera-core.

but no explanation is given for why you believe it is a bug that the plugin does not declare a direct dependency on a library that the plugin does not appear to directly use. If you believe camera_android_camerax plugin code is directly relying on this library, please provide a link to the specific relevant code in the PR description.

[dhc-tech]

Rebased onto current main (version is now 0.7.4+5 to avoid colliding with the real 0.7.4+4 that landed in the meantime) and added a minimal, verified reproduction:

• Minimal repro repo: https://github.com/dhc-tech/camera-android-camerax-build-repro
• Reproduces 100% on a completely stock flutter create app (no customization) on Flutter 3.44.8 stable, default AGP 9.0.1, compileSdk 37
• Root cause verified via camera-core's own Gradle module metadata: androidx.concurrent:concurrent-futures is declared only on camera-core's runtime variant, not its api/compile variant — but SurfaceRequest.class's compile-time jspecify @NonNull annotation needs that class on the compile classpath regardless.
• Also re-opened/commented on the linked issue ([camera_android_camerax] Build failure: class file for androidx.concurrent.futures.CallbackToFutureAdapter not found during Java compilation flutter#190505) with the same repro + full environment details, since it had been closed as "unable to reproduce."

/gemini review

[gemini-code-assist]

Code Review

This pull request adds an explicit dependency on androidx.concurrent:concurrent-futures:1.2.0 in build.gradle.kts to resolve compilation issues with CallbackToFutureAdapter annotations, along with a regression test to verify its presence on the classpath. Feedback suggests referencing CallbackToFutureAdapter.class statically in the test instead of using reflection (Class.forName) to ensure compile-time safety.

[gemini-code-assist]

Using reflection (Class.forName) to check for the presence of a class on the classpath defers the check to runtime. Referencing the class statically (e.g., androidx.concurrent.futures.CallbackToFutureAdapter.class) provides compile-time safety. If the dependency is accidentally removed, the build will fail during compilation, which is more robust and standard in Java than a runtime test failure.

    org.junit.Assert.assertNotNull(androidx.concurrent.futures.CallbackToFutureAdapter.class);

[gemini-code-assist]

Code Review

This pull request adds an explicit androidx.concurrent:concurrent-futures:1.2.0 dependency to the camera_android_camerax package's Android build configuration to resolve a compilation failure where CallbackToFutureAdapter is not found. It also introduces a regression test ConcurrentFuturesDependencyTest to verify the presence of this class on the classpath, and bumps the package version to 0.7.4+4 in pubspec.yaml and CHANGELOG.md. There are no review comments, and I have no feedback to provide.

[dhc-tech]

Closing in favor of a clean recreation with the same fix and all review feedback applied: #12373