[flutter_tools] Provision Android NDK in the main Gradle invocation by kyungilcho · Pull Request #186337 · flutter/flutter

kyungilcho · 2026-05-11T06:50:00Z

Summary

move Android NDK provisioning into the main Gradle invocation
pass the sdkmanager path, Android SDK root, and validated installed NDK versions from flutter_tools to the Flutter Gradle Plugin
only fall back to the synthetic externalNativeBuild/CMake path when the main invocation cannot satisfy provisioning

Context

This is a draft to explore the single-invocation direction discussed after #183555 and #185439.

The goal here is to keep the cleaner shape of doing the NDK check where AGP has already resolved the actual ndkVersion, while also tightening the behavior around installation and fallback.

Design

AndroidGradleBuilder now receives AndroidSdk explicitly instead of reading it from globals
flutter_tools passes:
- flutter.androidSdkRoot
- flutter.installedNdkVersions
- flutter.sdkManagerPath when installation is actually possible
the plugin now:
- returns early when the resolved NDK is already installed
- installs the resolved NDK with sdkmanager --sdk_root=... when possible
- verifies source.properties after installation
- falls back to the synthetic CMake path only when the tool-provided path cannot handle the build

Validation

packages/flutter_tools/test/general.shard/android/android_gradle_builder_test.dart
packages/flutter_tools/gradle: FlutterPluginUtilsTest
local benchmarking still shows the same structural improvement as the earlier prototype:
- no extra printNdkVersion Gradle invocation
- no unexpected .cxx output in the fast path

Notes

This is still a draft because I want feedback on the shape before turning it into the replacement for the narrower flavored-only reland.

kyungilcho · 2026-05-15T02:41:33Z

@gmackall I pushed an updated draft in the direction you suggested.

The current shape keeps the single-invocation approach, passes the sdkmanager / SDK root / installed-NDK information through the main Gradle invocation, and tightens a few of the rougher edges from my first pass.

I reran analyze, android_gradle_builder_test.dart, FlutterPluginUtilsTest, and a source-level plain release build locally. On that plain build, the extra metadata invocation is gone, build/.cxx no longer gets created, and ./gradlew -q printNdkVersion is working again.

At this point I think the main build path is in a pretty good place, but there are still two scope questions I would like your take on before I keep pushing it further:

Should the same provisioning contract also be applied to non-build Gradle invocations like getBuildVariants / outputsAppLinkSettings, so they do not still have a path back to synthetic .cxx?
Is it acceptable to keep the synthetic externalNativeBuild path as a compatibility fallback when tool-driven provisioning cannot handle the build, or were you aiming for something stricter than that?

If the bar is "main build path is fixed and fallback remains for compatibility", I think this draft is getting close. If the bar is broader than that, I think there is still another step.

flutter-dashboard · 2026-05-15T17:11:56Z

This pull request is not mergeable in its current state, likely because of a merge conflict. Pre-submit CI jobs were not triggered. Pushing a new commit to this branch that resolves the issue will result in pre-submit jobs being scheduled.

gmackall · 2026-05-15T17:19:41Z

Should the same provisioning contract also be applied to non-build Gradle invocations like getBuildVariants / outputsAppLinkSettings, so they do not still have a path back to synthetic .cxx?

Hmm I would just follow the current pattern here. From glancing at it my understanding is that they simply don't rely on the ndk being present, and so are independent. Is that also your understanding? I believe we only use the ndk for the previously mentioned purpose of allowing AGP to take care of stripping debug symbols.

Is it acceptable to keep the synthetic externalNativeBuild path as a compatibility fallback when tool-driven provisioning cannot handle the build, or were you aiming for something stricter than that?

I was thinking of leaving the synthetic path as a fallback for now. I think abstractly we should be able to move to the strict path in the future, based on what we can ensure we have access to from the doctor step, but I also would want to do that in a follow up pr once I have a sense that people aren't hitting issues with the new main path.

gemini-code-assist

Code Review

This pull request introduces tool-side Android NDK provisioning, enabling the Flutter tool to detect and install required NDK versions using sdkmanager prior to Gradle's native build execution. The changes include a new printNdkVersion task, refactored NDK resolution logic, and the passing of SDK metadata through Gradle properties. Feedback recommends ensuring NDK installation respects Gradle's offline mode, refactoring file path construction for clarity, and utilizing the new NDK version helper to ensure compatibility across various Android Gradle Plugin versions.

gemini-code-assist · 2026-05-19T06:15:50Z

+        val sdkManagerPath = toolNdkProvisioningProperties.sdkManagerPath ?: return false
+        val execOps = gradleProject.serviceOf<ExecOperations>()


Running sdkmanager to install the NDK involves network access. This should respect Gradle's offline mode to avoid build failures when the user explicitly requests an offline build.

val sdkManagerPath = toolNdkProvisioningProperties.sdkManagerPath ?: return false if (gradleProject.gradle.startParameter.isOffline) { return false } val execOps = gradleProject.serviceOf<ExecOperations>()

gemini-code-assist · 2026-05-19T06:15:50Z

+        val installedNdkMarker =
+            File(
+                File(File(toolNdkProvisioningProperties.androidSdkRoot, "ndk"), configuredNdkVersion),
+                "source.properties"
+            )


The nested File constructor calls can be simplified for better readability by using the File(parent, child) constructor with a combined path string.

Suggested change

val installedNdkMarker =

File(

File(File(toolNdkProvisioningProperties.androidSdkRoot, "ndk"), configuredNdkVersion),

"source.properties"

)

val installedNdkMarker = File(toolNdkProvisioningProperties.androidSdkRoot, "ndk/$configuredNdkVersion/source.properties")

gemini-code-assist · 2026-05-19T06:15:50Z

+        val androidExtension = getAndroidApplicationExtension(project)
+        project.tasks.register(TASK_PRINT_NDK_VERSION) {
+            description = "Prints out the configured ndkVersion for this Android project"
+            doLast {
+                val configuredNdkVersion = androidExtension.ndkVersion
+                println("$NDK_VERSION_OUTPUT_PREFIX$configuredNdkVersion")
+            }
+        }


Using getConfiguredNdkVersion(project) is safer and more consistent than accessing androidExtension.ndkVersion directly. It handles both the modern ApplicationExtension and the legacy BaseExtension while using findByType to avoid potential exceptions on older AGP versions where the new extension might not be available.

project.tasks.register(TASK_PRINT_NDK_VERSION) { description = "Prints out the configured ndkVersion for this Android project" doLast { val configuredNdkVersion = getConfiguredNdkVersion(project) println("$NDK_VERSION_OUTPUT_PREFIX$configuredNdkVersion") } }

auto-submit · 2026-07-06T20:45:26Z

autosubmit label was removed for flutter/flutter/186337, because This PR has not met approval requirements for merging. The PR author is not a member of flutter-hackers and needs 1 more review(s) in order to merge this PR.

Merge guidelines: A PR needs at least one approved review if the author is already part of flutter-hackers or two member reviews if the author is not a member of flutter-hackers before re-applying the autosubmit label. Reviewers: If you left a comment approving, please use the "approve" review action instead.

…12169) Manual roll Flutter from 91939cc4db78 to dc2a8703e12b (50 revisions) Manual roll requested by [email protected] flutter/flutter@91939cc...dc2a870 2026-07-09 [email protected] [ios,macos] Update swiftc.py flags to match swiftc (flutter/flutter#189174) 2026-07-09 [email protected] [AGP 9] Update Warn Version to AGP 9+ (flutter/flutter#189109) 2026-07-09 [email protected] Sync CHANGELOG.md from stable (flutter/flutter#189203) 2026-07-09 [email protected] [web] Roll Chrome to 145 (framework) (flutter/flutter#182861) 2026-07-09 [email protected] Roll Packages from 52d84d6 to 20928d5 (6 revisions) (flutter/flutter#189194) 2026-07-09 [email protected] [web] Avoid absolute positioning for base CanvasKit canvas (flutter/flutter#188337) 2026-07-09 [email protected] Roll Dart SDK from cdb7217e65aa to a11fb7ed40a5 (6 revisions) (flutter/flutter#189195) 2026-07-09 [email protected] Fix dereference of nullptr in the moved-to-rect signal in the Linux embedder (flutter/flutter#189152) 2026-07-09 [email protected] Fix data for design packages (flutter/flutter#189140) 2026-07-09 [email protected] Roll Skia from 7b42d1251d54 to ab3a7b98c94d (2 revisions) (flutter/flutter#189181) 2026-07-09 [email protected] Roll Skia from 05d9d214e0b7 to 7b42d1251d54 (2 revisions) (flutter/flutter#189175) 2026-07-09 [email protected] Roll Skia from 542c8bdd7f4f to 05d9d214e0b7 (4 revisions) (flutter/flutter#189169) 2026-07-09 [email protected] UberSDF rect handling for thin (line-like) rectangles (flutter/flutter#188821) 2026-07-09 [email protected] Roll Skia from dd572c07f63c to 542c8bdd7f4f (4 revisions) (flutter/flutter#189160) 2026-07-09 [email protected] [flutter_tools] Fix hot restart for WASM web builds (flutter/flutter#187898) 2026-07-08 [email protected] Split FlViewRenderer into OpenGL and software backends (flutter/flutter#188824) 2026-07-08 [email protected] Promote android_hardware_smoke_tests out of bringup in CI (flutter/flutter#189081) 2026-07-08 [email protected] Roll Skia from 8df24be66531 to dd572c07f63c (4 revisions) (flutter/flutter#189150) 2026-07-08 [email protected] Expose LinuxWindowRegistrar on _window_linux.dart in order to better support out of tree LinuxWindowingOwners (flutter/flutter#188917) 2026-07-08 [email protected] Roll pub packages (flutter/flutter#189149) 2026-07-08 [email protected] fix(ci): harden some workflows (flutter/flutter#189087) 2026-07-08 [email protected] Roll Skia from 51a62da33da0 to 8df24be66531 (1 revision) (flutter/flutter#189139) 2026-07-08 [email protected] Roll Dart SDK to Dart 3.13 beta3 (flutter/flutter#189122) 2026-07-08 [email protected] [flutter_tools] Don't crash on non-UTF-8 plugin pubspec.yaml (flutter/flutter#188976) 2026-07-08 [email protected] [flutter_tools] Watch transitive #include headers for FragmentProgram hot reload (flutter/flutter#187945) 2026-07-08 [email protected] Roll Skia from 040d9f55de00 to 51a62da33da0 (1 revision) (flutter/flutter#189135) 2026-07-08 [email protected] Roll Packages from 92525f5 to 52d84d6 (7 revisions) (flutter/flutter#189134) 2026-07-08 [email protected] [flutter_tools] Forcefully kill hung subprocesses 5 seconds after timeout (flutter/flutter#187178) 2026-07-08 [email protected] Expose the app's build name and number as compile-time constants (flutter/flutter#187935) 2026-07-08 [email protected] Roll Skia from 1ff92f879815 to 040d9f55de00 (1 revision) (flutter/flutter#189131) 2026-07-08 [email protected] Roll Skia from 6137414bef5c to 1ff92f879815 (6 revisions) (flutter/flutter#189126) 2026-07-08 [email protected] [test cross imports] More test/rendering + flutter_test/test fixes (flutter/flutter#188954) 2026-07-08 [email protected] engine: explain why each candidate build was skipped in Flutter web loader (flutter/flutter#186254) 2026-07-08 [email protected] vscode: add missing unicode.h (flutter/flutter#189102) 2026-07-08 [email protected] Roll Fuchsia Linux SDK from 7RjQJBW3m-3Jl-7jr... to QcRFUtvCw2EobfJ8s... (flutter/flutter#189104) 2026-07-08 [email protected] Roll Skia from 075fbe4778d9 to 6137414bef5c (10 revisions) (flutter/flutter#189106) 2026-07-08 [email protected] engine: warn on WASM load failure when not crossOriginIsolated (flutter/flutter#186252) 2026-07-08 [email protected] Roll Dart SDK from c9bccc09e733 to db2155f56bf3 (2 revisions) (flutter/flutter#189105) 2026-07-08 [email protected] [flutter_tools] Prevent interactive device selection in machine mode (flutter/flutter#188267) 2026-07-08 [email protected] [flutter_tools] Fix wireless ADB device discovery when serial contains spaces (flutter/flutter#187943) 2026-07-07 [email protected] [web] Fix grouped autofill on iOS Chrome (flutter/flutter#187459) 2026-07-07 [email protected] Fix TextSelectionOverlay crash when layout is degenerate (flutter/flutter#188672) 2026-07-07 [email protected] [flutter_tools] Provision Android NDK in the main Gradle invocation (flutter/flutter#186337) 2026-07-07 [email protected] Android_hardware_smoke_test: Migrate to AGP 9 (flutter/flutter#189082) ...

kyungilcho added 5 commits April 24, 2026 18:55

[flutter_tools] Preprovision Android NDK only for flavored builds

176a120

[flutter_tools] Reuse project FlutterExtension for printNdkVersion

1e4bde9

[flutter_tools] Remove obvious local types in gradle builder tests

cd46bf4

[devicelab] Keep non-flavored fat APK .cxx expectation

7fffcf9

[flutter_tools] Provision Android NDK in the main Gradle invocation

1aaca5b

github-actions Bot added platform-android Android applications specifically tool Affects the "flutter" command-line tool. See also t: labels. team-android Owned by Android platform team labels May 11, 2026

[flutter_tools] Tighten main-invocation Android NDK provisioning

a3d5731

gmackall added the CICD Run CI/CD label May 15, 2026

Merge upstream master into Android NDK provisioning draft

d0218e2

github-actions Bot removed the CICD Run CI/CD label May 18, 2026

Use ExecOperations for NDK provisioning install

4414ab0

kyungilcho marked this pull request as ready for review May 19, 2026 06:13

kyungilcho requested a review from a team as a code owner May 19, 2026 06:13

kyungilcho requested review from reidbaker and removed request for a team May 19, 2026 06:13

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Address NDK provisioning review feedback

4c7a2d8

gmackall added the CICD Run CI/CD label May 19, 2026

Fix ktlint errors

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reidbaker added the CICD Run CI/CD label May 21, 2026

reidbaker requested a review from gmackall May 21, 2026 20:13

[flutter_tools] Update build_aar test for NDK provisioning args

3b5d388

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gmackall requested a review from reidbaker July 6, 2026 20:51

fix import order from merge

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[flutter_tools] Provision Android NDK in the main Gradle invocation#186337

[flutter_tools] Provision Android NDK in the main Gradle invocation#186337
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		val sdkManagerPath = toolNdkProvisioningProperties.sdkManagerPath ?: return false
		val execOps = gradleProject.serviceOf<ExecOperations>()

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kyungilcho commented May 11, 2026

Summary

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