[flutter_tools] Lazily initialize AndroidStudio validation and optimize candidate selection by bkonyi · Pull Request #191968 · flutter/flutter

bkonyi · 2026-08-28T16:57:09Z

Description

This PR optimizes Android toolchain initialization by deferring expensive synchronous operations, candidate discovery, and SDK location scans out of tool startup.

Why this is needed now

As part of the modular dependency injection migration (#190724), context objects like AndroidContext are created upfront during ToolDependencies.bootstrap / runner initialization rather than via the old global ambient context (AppContext).

Previously, AndroidStudio and AndroidSdk were initialized lazily only when a command or service queried globals.androidStudio or context.get<AndroidStudio>(). With upfront AndroidContext creation, AndroidStudio.latestValid() and AndroidSdk.locateAndroidSdk() ran on tool startup for every command. Because the constructors and locators performed synchronous filesystem scans and executed java -version (a JVM cold start), this introduced unnecessary latency to tool startup, including commands completely unrelated to Android (such as flutter config or iOS-specific workflows).

Changes

Defers synchronous Java validation (_initAndValidate()) out of the AndroidStudio constructor so that object instantiation is fast and side-effect free.
isValid, javaPath, and validationMessages are evaluated lazily on first access.
In AndroidStudio.latestValid(), candidate installations are sorted in descending order of version prior to validation, allowing candidate discovery to short-circuit upon encountering the first valid installation without executing Java checks against older, unneeded candidates.
AndroidContext accepts lazy builder closures (required AndroidSdk? Function() androidSdkBuilder, required AndroidStudio? Function() androidStudioBuilder, required GradleUtils Function() gradleUtilsBuilder, and required Java? Function() javaBuilder) so commands that do not use Android do not pay any startup initialization cost.
Java.find accepts required AndroidStudio? Function() androidStudioBuilder builder closure so that creating the Java object does not eagerly trigger AndroidStudio.latestValid().

Related Issues

Part of #47161 (flutter_tools modular dependency injection migration).

Tests

Updated packages/flutter_tools/test/general.shard/android/android_studio_test.dart to remove obsolete FakeCommand expectations for unneeded java -version executions.
Added unit tests verifying:
- Constructor instantiation does not execute validation or touch the process manager.
- isValid, javaPath, and validationMessages evaluate lazily on first access across independent instances.
- latestValid() short-circuits candidate validation once a valid installation is found.
- latestValid() falls back to older candidate installations when a newer installation is invalid.
Updated packages/flutter_tools/test/general.shard/context/dependency_injection_test.dart to verify:
- AndroidContext lazily evaluates and memoizes androidSdk, androidStudio, gradleUtils, and java.
- AndroidContext memoizes null results without re-evaluating builder closures.
- ToolDependencies.bootstrap shares the same AndroidStudio instance across AndroidContext and Java.
- ToolDependencies.bootstrap lazily evaluates androidSdk on first access rather than on startup.
Updated packages/flutter_tools/test/general.shard/android/java_test.dart to verify:
- Java.find does not invoke the androidStudioBuilder factory if jdk-dir is configured.

…ze candidate selection Defers synchronous Java validation (`_initAndValidate()`) out of the `AndroidStudio` constructor so that object instantiation is fast and side-effect free. Access to `isValid`, `javaPath`, and `validationMessages` now evaluates validation lazily on first read. Additionally, `AndroidStudio.latestValid()` now sorts discovered candidates in descending order of version before testing validity, allowing candidate discovery to short-circuit on the newest valid installation without executing Java version checks against older, unneeded candidate installations.

…tudio_constructor_initialization

gemini-code-assist

Code Review

This pull request introduces lazy validation for AndroidStudio instances, deferring initialization until properties like javaPath, isValid, or validationMessages are accessed. This allows the latestValid method to short-circuit validation once a valid installation is found. The tests are updated to verify this lazy behavior and short-circuiting logic. The review feedback suggests copying the studios list before sorting it in latestValid to prevent potential runtime errors or side effects from in-place sorting.

I am having trouble creating individual review comments. Click here to see my feedback.

packages/flutter_tools/lib/src/android/android_studio.dart (269-275)

Sorting the studios list in-place can lead to unexpected side effects if the list returned by allInstalled() is cached, shared, or unmodifiable (which would cause a runtime UnsupportedError).

To prevent this, copy the list before sorting it.

    final List<AndroidStudio> sortedStudios = studios.toList()..sort(_compareCandidates);

    for (final studio in sortedStudios) {
      if (studio.isValid) {
        return studio;
      }
    }

jason-simmons · 2026-08-28T17:41:04Z

With this PR, commands that do not need AndroidStudio are still paying the cost of its initialization because globals.androidStudio and ToolDependencies are calling AndroidStudio.latestValid.

latestValid will still need to do the _initAndValidate work for at least one AndroidStudio instance even if it is never used afterward.

…ntext Accepts lazy factory closures in AndroidContext so that AndroidStudio and Java discovery are not executed on CLI startup. Uses late final variables in ToolDependencies and AndroidContext to memoize discovery on first access and share instances without duplicate disk scans.

Updates Java.find to take an AndroidStudio factory closure instead of an instance so that AndroidStudio discovery is not eagerly triggered when resolving Java.

Renames androidStudio and java initializers to androidStudioBuilder and javaBuilder to clearly distinguish factory closures from resolved properties.

…es in ToolDependencies Defines androidStudioBuilder and javaBuilder directly as closure functions in ToolDependencies.init rather than local late final variables.

Accepts androidSdkBuilder in AndroidContext so that AndroidSdk.locateAndroidSdk is not eagerly executed on CLI startup. Evaluates and memoizes androidSdk on first access.

Accepts gradleUtilsBuilder in AndroidContext so that all AndroidContext properties are lazily initialized on demand via builder closures.

…initialization

…dio_constructor_initialization

…endencies

bkonyi · 2026-09-09T13:51:48Z

Good catch! The eager execution was originating from ToolDependencies.bootstrap initializing EmulatorManager, which was eagerly reading finalAndroidContext.java. Reading that getter evaluated Java.find(...) and invoked androidStudioBuilder() / AndroidStudio.latestValid on startup.

EmulatorManager has now been updated to accept a Java? Function()? javaBuilder closure and evaluate _java lazily. ToolDependencies wires javaBuilder: () => finalAndroidContext.java into EmulatorManager. This ensures neither Java nor AndroidStudio.latestValid is evaluated on startup or basic command execution unless explicitly accessed.

…io in ToolDependencies

mboetger · 2026-09-11T19:15:58Z

Good catch! The eager execution was originating from ToolDependencies.bootstrap initializing EmulatorManager, which was eagerly reading finalAndroidContext.java. Reading that getter evaluated Java.find(...) and invoked androidStudioBuilder() / AndroidStudio.latestValid on startup.

EmulatorManager has now been updated to accept a Java? Function()? javaBuilder closure and evaluate _java lazily. ToolDependencies wires javaBuilder: () => finalAndroidContext.java into EmulatorManager. This ensures neither Java nor AndroidStudio.latestValid is evaluated on startup or basic command execution unless explicitly accessed.

Is it just the EmulatorManager - or does it happen when we just pass the params to bootstrap?

final ToolDependencies toolDeps = await ToolDependencies.bootstrap(                  
      androidSdk: globals.androidSdk,       // -> AndroidSdk.locateAndroidSdk()                                                                     
      androidStudio: globals.androidStudio, // -> AndroidStudio.latestValid()                                                                  
...                                      
    );

…structor_initialization

…dio_constructor_initialization

…_comments # Conflicts: # packages/flutter_tools/lib/src/context/tool_dependencies.dart

…and command registration

…meters where G3Fix is unnecessary

bkonyi · 2026-10-07T20:34:27Z

Is it just the EmulatorManager - or does it happen when we just pass the params to bootstrap?

final ToolDependencies toolDeps = await ToolDependencies.bootstrap(                  
      androidSdk: globals.androidSdk,       // -> AndroidSdk.locateAndroidSdk()                                                                     
      androidStudio: globals.androidStudio, // -> AndroidStudio.latestValid()                                                                  
...                                      
    );

Sorry, not sure how I missed this reply.

Yes, this also happens when we pass the params to bootstrap as well. Fixed!

…_comments # Conflicts: # packages/flutter_tools/test/general.shard/context/dependency_injection_test.dart

Roll Flutter from 4249ccbc18a3 to 426be968b5eb (44 revisions) flutter/flutter@4249ccb...426be96 2026-10-14 [email protected] Allow color delta tolerance in in-memory fuzzy image comparator (flutter/flutter#193937) 2026-10-14 [email protected] [web] Drop stale composing range after text is replaced mid-composition (flutter/flutter#194096) 2026-10-14 [email protected] Roll Skia from 2a2bbea66844 to acde3755d2e2 (1 revision) (flutter/flutter#194376) 2026-10-14 [email protected] Roll Skia from 128c983b12de to 2a2bbea66844 (1 revision) (flutter/flutter#194371) 2026-10-14 [email protected] Roll Skia from 48a294ed4955 to 128c983b12de (3 revisions) (flutter/flutter#194353) 2026-10-14 [email protected] feat(flutter_tools): extract WebDebugConfig from DebuggingOptions (flutter/flutter#194312) 2026-10-14 [email protected] Roll Skia from ea6781c5b6d1 to 48a294ed4955 (2 revisions) (flutter/flutter#194349) 2026-10-14 [email protected] Include <vector> in Android proc_table.h. (flutter/flutter#194325) 2026-10-14 [email protected] Roll Dart SDK from 5933cb486b4a to 6b50116630d0 (28 revisions) (flutter/flutter#194341) 2026-10-14 [email protected] Move GLES3 instancing API entry points to FOR_EACH_IMPELLER_GLES3_PROC (flutter/flutter#194319) 2026-10-14 [email protected] feat(flutter_tools): extract AndroidGradleConfig and move toGradleConfig to AndroidBuildInfo (flutter/flutter#194016) 2026-10-14 [email protected] Roll Skia from ae297bec6012 to ea6781c5b6d1 (8 revisions) (flutter/flutter#194331) 2026-10-14 [email protected] [flutter_tools] Migrate gradle_errors and deferred_components_prebuild_validator away from globals (flutter/flutter#193649) 2026-10-14 [email protected] [Impeller] Cache GLES sampler configuration in RenderPassStateCache (flutter/flutter#193922) 2026-10-14 [email protected] Roll pub packages (flutter/flutter#194332) 2026-10-13 [email protected] [tool] Migrate RunCommand to modular dependency injection (flutter/flutter#190791) 2026-10-13 [email protected] Include `engine/src/flutter/.ci.yaml` in quarterly `goldctl` checklist (flutter/flutter#194316) 2026-10-13 [email protected] [flutter_tools] Remove the last AMD module system support (flutter/flutter#193607) 2026-10-13 [email protected] Roll Skia from 8b3394a60654 to ae297bec6012 (5 revisions) (flutter/flutter#194310) 2026-10-13 [email protected] [web] Remove the a11y placeholder only after the gesture ends (flutter/flutter#194109) 2026-10-13 [email protected] Upgrade goldctl to the latest version (flutter/flutter#193932) 2026-10-13 [email protected] [flutter_tools] Lazily initialize AndroidStudio validation and optimize candidate selection (flutter/flutter#191968) 2026-10-13 [email protected] [flutter_tools] Clean up outdated widget preview TODOs and refactor static state (flutter/flutter#189437) 2026-10-13 [email protected] Roll Skia from e5b5db6d0d6f to 8b3394a60654 (2 revisions) (flutter/flutter#194306) 2026-10-13 [email protected] Redistribute TESTOWNERS for Android team (flutter/flutter#193861) 2026-10-13 [email protected] feat(flutter_tools): introduce Test and Drive specification objects (flutter/flutter#194017) 2026-10-13 [email protected] [Impeller] Keep the aspect ratio when shrinking images to the max texture size (flutter/flutter#194010) 2026-10-13 [email protected] [flutter tool] preserve inherited `DASH__SUPPRESS_ANALYTICS=true` for sub-tools (flutter/flutter#194261) 2026-10-13 [email protected] Roll Packages from d8d9e97 to a1ed23c (9 revisions) (flutter/flutter#194302) 2026-10-13 [email protected] Use PE/COFF AOT snapshots for Windows x64 (flutter/flutter#187594) 2026-10-13 [email protected] Fix Expansible crash when PageStorage holds a non-bool value (flutter/flutter#192195) 2026-10-13 [email protected] Roll Skia from ffeccb3ca58a to e5b5db6d0d6f (1 revision) (flutter/flutter#194297) 2026-10-13 [email protected] Explain why initState() is too early to depend on an inherited widget (flutter/flutter#192727) 2026-10-13 [email protected] Refactor TestPlatformDispatcher (flutter/flutter#192747) 2026-10-13 [email protected] Roll Skia from 3de0984208ec to ffeccb3ca58a (2 revisions) (flutter/flutter#194291) 2026-10-13 [email protected] Roll Skia from 0580c2b780f6 to 3de0984208ec (2 revisions) (flutter/flutter#194281) 2026-10-13 [email protected] Roll Skia from f641d55e07a8 to 0580c2b780f6 (3 revisions) (flutter/flutter#194275) 2026-10-13 [email protected] Roll Skia from 0e5d8d1be81b to f641d55e07a8 (1 revision) (flutter/flutter#194266) 2026-10-13 [email protected] Scaffold view metrics overrides (flutter/flutter#192764) 2026-10-13 [email protected] [web] Add SemanticsRole.listBox and SemanticsRole.option (flutter/flutter#192971) 2026-10-13 [email protected] Pin mac_unopt to macOS 15 (flutter/flutter#194254) 2026-10-13 [email protected] Roll pub packages (flutter/flutter#194257) 2026-10-12 [email protected] Roll Skia from 17f6986c226c to 0e5d8d1be81b (4 revisions) (flutter/flutter#194249) 2026-10-12 [email protected] Make DisplayLists' use of DlPaint, SkPaint, and impeller::Paint agree on the default isAntiAlias (flutter/flutter#193939) If this roll has caused a breakage, revert this CL and set the roller ...

…ze candidate selection (flutter#191968) ## Description This PR optimizes Android toolchain initialization by deferring expensive synchronous operations, candidate discovery, and SDK location scans out of tool startup. ### Why this is needed now As part of the modular dependency injection migration ([flutter#190724](flutter#190724)), context objects like `AndroidContext` are created upfront during `ToolDependencies.bootstrap` / runner initialization rather than via the old global ambient context (`AppContext`). Previously, `AndroidStudio` and `AndroidSdk` were initialized lazily only when a command or service queried `globals.androidStudio` or `context.get<AndroidStudio>()`. With upfront `AndroidContext` creation, `AndroidStudio.latestValid()` and `AndroidSdk.locateAndroidSdk()` ran on tool startup for every command. Because the constructors and locators performed synchronous filesystem scans and executed `java -version` (a JVM cold start), this introduced unnecessary latency to tool startup, including commands completely unrelated to Android (such as `flutter config` or iOS-specific workflows). ### Changes - Defers synchronous Java validation (`_initAndValidate()`) out of the `AndroidStudio` constructor so that object instantiation is fast and side-effect free. - `isValid`, `javaPath`, and `validationMessages` are evaluated lazily on first access. - In `AndroidStudio.latestValid()`, candidate installations are sorted in descending order of version prior to validation, allowing candidate discovery to short-circuit upon encountering the first valid installation without executing Java checks against older, unneeded candidates. - `AndroidContext` accepts lazy builder closures (`required AndroidSdk? Function() androidSdkBuilder`, `required AndroidStudio? Function() androidStudioBuilder`, `required GradleUtils Function() gradleUtilsBuilder`, and `required Java? Function() javaBuilder`) so commands that do not use Android do not pay any startup initialization cost. - `Java.find` accepts `required AndroidStudio? Function() androidStudioBuilder` builder closure so that creating the `Java` object does not eagerly trigger `AndroidStudio.latestValid()`. ## Related Issues Part of [flutter#47161](flutter#47161) (flutter_tools modular dependency injection migration). ## Tests - Updated `packages/flutter_tools/test/general.shard/android/android_studio_test.dart` to remove obsolete `FakeCommand` expectations for unneeded `java -version` executions. - Added unit tests verifying: - Constructor instantiation does not execute validation or touch the process manager. - `isValid`, `javaPath`, and `validationMessages` evaluate lazily on first access across independent instances. - `latestValid()` short-circuits candidate validation once a valid installation is found. - `latestValid()` falls back to older candidate installations when a newer installation is invalid. - Updated `packages/flutter_tools/test/general.shard/context/dependency_injection_test.dart` to verify: - `AndroidContext` lazily evaluates and memoizes `androidSdk`, `androidStudio`, `gradleUtils`, and `java`. - `AndroidContext` memoizes `null` results without re-evaluating builder closures. - `ToolDependencies.bootstrap` shares the same `AndroidStudio` instance across `AndroidContext` and `Java`. - `ToolDependencies.bootstrap` lazily evaluates `androidSdk` on first access rather than on startup. - Updated `packages/flutter_tools/test/general.shard/android/java_test.dart` to verify: - `Java.find` does not invoke the `androidStudioBuilder` factory if `jdk-dir` is configured.

bkonyi requested a review from a team as a code owner August 28, 2026 16:57

bkonyi requested review from mboetger and removed request for a team August 28, 2026 16:57

flutter-dashboard Bot added the CICD Run CI/CD label Aug 28, 2026

Merge remote-tracking branch 'upstream/master' into optimize_androids…

56ce3f7

…tudio_constructor_initialization

gemini-code-assist Bot reviewed Aug 28, 2026

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bkonyi requested a review from jason-simmons August 28, 2026 17:04

github-actions Bot added tool Affects the "flutter" command-line tool. See also t: labels. team-android Owned by Android platform team labels Aug 28, 2026

bkonyi added 9 commits August 28, 2026 18:39

[flutter_tools] Accept factory closure for androidStudio in Java.find

39e83d8

Updates Java.find to take an AndroidStudio factory closure instead of an instance so that AndroidStudio discovery is not eagerly triggered when resolving Java.

[flutter_tools] Rename lazy initializers to Builders

1c03081

Renames androidStudio and java initializers to androidStudioBuilder and javaBuilder to clearly distinguish factory closures from resolved properties.

[flutter_tools] Define androidStudioBuilder and javaBuilder as closur…

9fa24e1

…es in ToolDependencies Defines androidStudioBuilder and javaBuilder directly as closure functions in ToolDependencies.init rather than local late final variables.

[flutter_tools] Lazily initialize AndroidSdk in AndroidContext

60a6c8b

Accepts androidSdkBuilder in AndroidContext so that AndroidSdk.locateAndroidSdk is not eagerly executed on CLI startup. Evaluates and memoizes androidSdk on first access.

[flutter_tools] Lazily initialize GradleUtils in AndroidContext

ee103b6

Accepts gradleUtilsBuilder in AndroidContext so that all AndroidContext properties are lazily initialized on demand via builder closures.

[tool] Merge upstream master into optimize_androidstudio_constructor_…

ef4c4fe

…initialization

Merge remote-tracking branch 'origin/master' into optimize_androidstu…

7978cae

…dio_constructor_initialization

[flutter_tools] Lazily initialize Java in EmulatorManager and ToolDep…

147cee3

…endencies

[flutter_tools] Memoize Java in EmulatorManager and share AndroidStud…

98a786f

…io in ToolDependencies

bkonyi added 6 commits September 12, 2026 17:21

[flutter_tools] Merge upstream master into optimize_androidstudio_con…

4d943ea

…structor_initialization

Merge remote-tracking branch 'origin/master' into optimize_androidstu…

4114d90

…dio_constructor_initialization

[flutter_tools] Ensure androidSdk lazy evaluation in AndroidContext

63f9881

Merge remote-tracking branch 'upstream/master' into address_pr_191968…

5b9db38

…_comments # Conflicts: # packages/flutter_tools/lib/src/context/tool_dependencies.dart

[flutter_tools] Defer Android dependency evaluation across bootstrap …

f14150d

…and command registration

[flutter_tools] Remove duplicate androidSdk and java constructor para…

a1b68de

…meters where G3Fix is unnecessary

mboetger previously approved these changes Oct 12, 2026

View reviewed changes

Merge remote-tracking branch 'upstream/master' into address_pr_191968…

5b83187

…_comments # Conflicts: # packages/flutter_tools/test/general.shard/context/dependency_injection_test.dart

bkonyi dismissed mboetger’s stale review via 5b83187 October 13, 2026 15:47

mboetger approved these changes Oct 13, 2026

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bkonyi added the autosubmit Merge PR when tree becomes green via auto submit App label Oct 13, 2026

auto-submit Bot added this pull request to the merge queue Oct 13, 2026

Merged via the queue into flutter:master with commit debf408 Oct 13, 2026
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flutter-dashboard Bot removed the autosubmit Merge PR when tree becomes green via auto submit App label Oct 13, 2026

This was referenced Oct 14, 2026

Roll Flutter from d03768eef055 to a4896bac0e8f (201 revisions) flutter/packages#13254

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Roll Flutter from 4249ccbc18a3 to 426be968b5eb (44 revisions) flutter/packages#13256

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[flutter_tools] Lazily initialize AndroidStudio validation and optimize candidate selection - #191968

[flutter_tools] Lazily initialize AndroidStudio validation and optimize candidate selection#191968
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Description

Why this is needed now

Changes

Related Issues

Tests

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packages/flutter_tools/lib/src/android/android_studio.dart (269-275)

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