Add `--[no-]enable-hcpp` build flag and pipe through via Gradle manifest transformation by gmackall · Pull Request #189955 · flutter/flutter

gmackall · 2026-07-23T22:36:56Z

Adds --[no-]enable-hcpp to flutter build apk and flutter build appbundle.
Not added to build aar: a value injected into a module's library manifest can
fail an add-to-app host's build in the manifest merger when the host selects the
opposite value, so the host application's manifest stays the source of truth.
Passes -Penable-hcpp=<bool> (the tool's default) and -Pexplicit-enable-hcpp=<bool>
(set only when the developer passed the flag) to Gradle.
Registers EnableHcppManifestTask in the Flutter Gradle Plugin, a transform of the
application project's merged manifest. Precedence is
--[no-]enable-hcpp > AndroidManifest.xml > the tool's default:
an explicit flag is written into the merged manifest over whatever is there and
reported at lifecycle level; without the flag, the default is only injected when the
manifest does not set EnableHcpp at all.
Known tradeoff: when the transform modifies the manifest it re-serializes it, which
drops XML comments including the manifest merger's provenance annotations. This is
invisible to aapt2 and is covered by a test.
Adds Kotlin Gradle task and Dart tool unit/integration test coverage.

- Adds --[no-]enable-hcpp CLI flag to build apk/appbundle/aar commands. - Passes -Penable-hcpp=<bool> and -Pexplicit-enable-hcpp=<bool> to Gradle. - Registers EnableHcppManifestTask in the Flutter Gradle Plugin to inject EnableHcpp metadata into application merged manifests when requested and warn on merged manifest conflicts. - Adds Kotlin Gradle task and Dart tool unit/integration test coverage.

…hurn

- computeHcppEnabled now takes an ifAbsent value, so `flutter build apk/appbundle --enable-hcpp` against a manifest that does not set EnableHcpp reports what actually gets packaged instead of always reporting false. - Only send -Pexplicit-enable-hcpp from commands that produce a final artifact. run/test/drive apply --enable-hcpp at launch, where it does override the manifest, so the gradle "does not affect this artifact" warning was wrong for them. - Correct the flag help text: --no-enable-hcpp does not currently override a manifest value at launch, only --enable-hcpp does. - Drop the RunCommandBase.enableHcpp override, which is now identical to the FlutterCommand implementation.

- Remove the addEnableHcppMetadataIfAbsent "legacy wrapper", which was never a legacy anything and had no callers outside tests, and make requestedEnableHcpp a required argument so nothing silently defaults to enabling hcpp. - The FlutterPluginUtilsTest registration tests only asserted that getByType had been called. Drive onVariants and assert the task name and the values it is configured with. - Cover the requested=false, metadata absent path, and pin the fact that re-serializing the manifest drops XML comments. - Note in the task doc that the conflict warning is not repeated on up-to-date or cached builds.

…er#189937

gemini-code-assist

Code Review

This pull request introduces the EnableHcppManifestTask to inject io.flutter.embedding.android.EnableHcpp metadata into the merged Android manifest of application projects. It adds the --[no-]enable-hcpp CLI flag to build commands, updates BuildInfo and FlutterCommand to pass these properties to Gradle, and includes corresponding tests. Feedback on the changes highlights a critical compilation error in project.dart due to an undefined defaultValue reference in a catch block, and suggests simplifying property checks in FlutterPluginUtils.kt and avoiding unsafe null assertions in flutter_command.dart.

gemini-code-assist · 2026-07-29T01:03:19Z

+    return _computeManifestMetadataBoolValueOrNull(metadataKey) ?? defaultValue;
+  }
+
+  bool? _computeManifestMetadataBoolValueOrNull(String metadataKey) {


The helper method _computeManifestMetadataBoolValueOrNull does not define a defaultValue parameter, but the unchanged catch block inside the try statement (which is not shown in this diff but is part of the method body) still attempts to return defaultValue when an XmlException is caught. This will result in a compilation error (Undefined name 'defaultValue').\n\nTo fix this, the catch block should be updated to return null instead of defaultValue. Since the catch block is not part of the modified lines in this diff, please manually update it in project.dart:\n\ndart\n } on XmlException {\n return null;\n }\n

gemini-code-assist · 2026-07-29T01:03:19Z

+        val explicitEnableHcpp: Boolean? =
+            if (project.hasProperty(PROP_EXPLICIT_ENABLE_HCPP)) {
+                project.findProperty(PROP_EXPLICIT_ENABLE_HCPP)?.toString()?.toBoolean()
+            } else {
+                null
+            }


The redundant hasProperty check can be simplified. project.findProperty already returns null if the property is not present, so you can directly retrieve and convert the property in a single expression.

val explicitEnableHcpp: Boolean? =\n project.findProperty(PROP_EXPLICIT_ENABLE_HCPP)?.toString()?.toBoolean()

gemini-code-assist · 2026-07-29T01:03:20Z

+  bool? get explicitEnableHcpp =>
+      (argResults?.options.contains('enable-hcpp') ?? false) && argResults!.wasParsed('enable-hcpp')
+      ? boolArg('enable-hcpp')
+      : null;


This expression can be simplified to avoid the unsafe null assertion operator (!) on argResults and improve readability.

bool? get explicitEnableHcpp {\n final ArgResults? results = argResults;\n if (results == null || !results.options.contains('enable-hcpp') || !results.wasParsed('enable-hcpp')) {\n return null;\n }\n return boolArg('enable-hcpp');\n }

- Drop the redundant hasProperty check; findProperty already returns null when the property is absent. - Give explicitEnableHcpp a block body so the argResults null check is explicit instead of relying on && short circuiting before a `!`.

reidbaker · 2026-07-31T18:27:02Z

+package com.flutter.gradle.tasks
+
+import groovy.util.Node
+import groovy.xml.XmlNodePrinter


non blocking. There are a couple of these xml parsing classes. Can you double check which one that people are supposed to use and make sure this does not add tech debt.

reidbaker · 2026-07-31T18:28:13Z

+                }
+
+            if (explicitEnableHcpp != null && (existingValueBool == null || explicitEnableHcpp != existingValueBool)) {
+                val flagName = if (explicitEnableHcpp) "--enable-hcpp" else "--no-enable-hcpp"


could you pull the flag names out into constants at the top of the file.

reidbaker · 2026-07-31T18:32:13Z

+
+            if (explicitEnableHcpp != null && (existingValueBool == null || explicitEnableHcpp != existingValueBool)) {
+                val flagName = if (explicitEnableHcpp) "--enable-hcpp" else "--no-enable-hcpp"
+                logger?.warn(


I think this is backwards from what most developers expect. Specifically gradle has a different order of defaults. https://docs.gradle.org/current/userguide/build_environment.html

Fair, changed to have cli win in all cases

Per review. The tests assert on the flag name in the warning, so make them internal and reference them there instead of repeating the literals.

Per review. A flag passed at invocation time now takes priority over the EnableHcpp metadata in AndroidManifest.xml, instead of being ignored with a warning. This matches how gradle orders -P properties ahead of gradle.properties, and drops the asymmetry where the same flag overrode the manifest at launch for run/test/drive but not for a built artifact. The precedence is now --[no-]enable-hcpp > AndroidManifest.xml > the tool's default, for every command. - The task writes an explicit value into the merged manifest, replacing what is there. Nothing conflicts in the merger because this is a transform of MERGED_MANIFEST, which already ran. - Without the flag, the requested value is still only injected when the manifest says nothing, so the manifest keeps winning over a default. - The warning becomes a lifecycle message reporting the override, and warnOnHcppManifestConflict is gone, since there is no longer a command for which the flag is inert. - Analytics report the explicit value rather than the source manifest.

args_test flags "[a-z].[A-Z]" as a probable missing space after a sentence, and io.flutter.embedding.android.EnableHcpp trips it on "android.EnableHcpp". The bare name reads fine in context.

auto-submit · 2026-08-04T21:34:18Z

autosubmit label was removed for flutter/flutter/189955, because The base commit of the PR is older than 7 days and can not be merged. Please merge the latest changes from the main into this branch and resubmit the PR.

auto-submit · 2026-08-04T22:24:49Z

autosubmit label was removed for flutter/flutter/189955, because - The status or check suite Dashboard Checks has failed. Please fix the issues identified (or deflake) before re-applying this label.

auto-submit · 2026-08-04T23:12:02Z

autosubmit label was removed for flutter/flutter/189955, because - The status or check suite Dashboard Checks has failed. Please fix the issues identified (or deflake) before re-applying this label.

auto-submit · 2026-08-05T01:45:16Z

autosubmit label was removed for flutter/flutter/189955, because - The status or check suite Dashboard Checks has failed. Please fix the issues identified (or deflake) before re-applying this label.

auto-submit · 2026-08-05T02:15:14Z

autosubmit label was removed for flutter/flutter/189955, because - The status or check suite Dashboard Checks has failed. Please fix the issues identified (or deflake) before re-applying this label.

…ter#190623) AI pr description which is correct (I checked 🙂 ) - Enables the `enable-hcpp` feature flag by default on the `master` and `beta` channels (remains default off on `stable`). - Pipes the feature flag default through `FlutterCommand.enableHcpp` into `BuildInfo.androidEnableHcpp`, allowing Gradle's `EnableHcppManifestTask` (landed in flutter#189955) to inject `io.flutter.embedding.android.EnableHcpp = true` into the merged manifest when the app's manifest is silent. - Preserves the established precedence: explicit `--[no-]enable-hcpp` CLI flag > `AndroidManifest.xml` > feature flag default. - Ensures `DebuggingOptions.enableHcpp` is treated as a nullable `bool?`, only passing launch overrides (`--enable-hcpp-and-surface-control=$enableHcpp` / `--ez enable-hcpp-and-surface-control $enableHcpp`) when explicitly provided on the CLI, allowing the installed artifact's manifest to decide by default. - Updates unit and command test suites across `flutter_tools`. > **Note for reviewers**: iOS reviewers were auto-requested because `build_swift_package_test.dart` was updated to implement `isHcppEnabled` in its `FakeFeatureFlags` (queried by `FlutterCommand.getBuildInfo()`). No iOS or Swift Package Manager logic is changed. --------- Co-authored-by: Gray Mackall <[email protected]> Co-authored-by: Camille Simon <[email protected]>

github-actions Bot added platform-android Android applications specifically tool Affects the "flutter" command-line tool. See also t: labels. labels Jul 23, 2026

gmackall added the CICD Run CI/CD label Jul 23, 2026

gmackall and others added 10 commits July 23, 2026 16:04

Remove stale hcpp feature flag references and revert unrelated test c…

b653771

…hurn

test update

c96625e

Fix parameter count in hermetic build_aar_test

2a56e35

Fix upgrade_test flake by setting Cache.flutterRoot in setUp

1c9dbc5

Fix ktlint blank line before closing brace

becc8be

Merge branch 'master' into hcpp-build-flag-manifest

82c9f35

Drop redundant upgrade_test flutterRoot fix, master fixed it in flutt…

e6d116c

…er#189937

Merge branch 'master' into hcpp-build-flag-manifest

e21a9a3

gmackall marked this pull request as ready for review July 29, 2026 01:01

gmackall requested a review from a team as a code owner July 29, 2026 01:01

gmackall requested review from reidbaker and removed request for a team July 29, 2026 01:01

gemini-code-assist Bot reviewed Jul 29, 2026

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reidbaker reviewed Jul 31, 2026

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gmackall added 3 commits August 3, 2026 14:19

Pull the hcpp flag names out into constants

01f6d60

Per review. The tests assert on the flag name in the warning, so make them internal and reference them there instead of repeating the literals.

Drop the qualified metadata name from the enable-hcpp help

d36323c

args_test flags "[a-z].[A-Z]" as a probable missing space after a sentence, and io.flutter.embedding.android.EnableHcpp trips it on "android.EnableHcpp". The bare name reads fine in context.

reidbaker approved these changes Aug 4, 2026

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Merge branch 'master' into hcpp-build-flag-manifest

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Merge branch 'master' into hcpp-build-flag-manifest

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Merge branch 'master' into hcpp-build-flag-manifest

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This was referenced Aug 19, 2026

Add HCPP feature flag, and turn it on by default in beta/master #190623

Merged

Allow --enable-hcpp to be passed into build commands #189672

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