Merge "New lint detector for flow usage" into main (d6c34259) · Commits · e / os / android_frameworks_base

packages/SystemUI/Android.bp

+1 −0

Original line number	Diff line number	Diff line
		@@ -191,6 +191,7 @@ android_library {
		lint: {
		extra_check_modules: ["SystemUILintChecker"],
		warning_checks: ["MissingApacheLicenseDetector"],
		baseline_filename: "lint-baseline.xml",
		},
		}

packages/SystemUI/checks/Android.bp

+1 −0

Original line number	Diff line number	Diff line
		@@ -40,6 +40,7 @@ java_test_host {
		data: [
		":framework",
		":androidx.annotation_annotation-nodeps",
		":kotlinx-coroutines-core",
		],
		static_libs: [
		"SystemUILintChecker",

packages/SystemUI/checks/src/com/android/internal/systemui/lint/FlowDetector.kt

0 → 100644

+112 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2024 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*
		*/

		package com.android.internal.systemui.lint

		import com.android.tools.lint.detector.api.Category
		import com.android.tools.lint.detector.api.Detector
		import com.android.tools.lint.detector.api.Implementation
		import com.android.tools.lint.detector.api.Issue
		import com.android.tools.lint.detector.api.JavaContext
		import com.android.tools.lint.detector.api.Scope
		import com.android.tools.lint.detector.api.Severity
		import com.android.tools.lint.detector.api.SourceCodeScanner
		import com.intellij.psi.PsiClassType
		import com.intellij.psi.PsiMethod
		import com.intellij.psi.PsiParameter
		import org.jetbrains.kotlin.psi.psiUtil.isTopLevelKtOrJavaMember
		import org.jetbrains.uast.UCallExpression

		/** Detects bad usages of Kotlin Flows */
		class FlowDetector : Detector(), SourceCodeScanner {

		override fun getApplicableMethodNames(): List<String> =
		listOf(
		FUN_MUTABLE_SHARED_FLOW,
		FUN_SHARE_IN,
		)

		override fun visitMethodCall(context: JavaContext, node: UCallExpression, method: PsiMethod) {
		if (
		method.name == FUN_MUTABLE_SHARED_FLOW &&
		method.parent.isTopLevelKtOrJavaMember() &&
		context.evaluator.getPackage(method)?.qualifiedName == PACKAGE_FLOW
		) {
		context.report(
		issue = SHARED_FLOW_CREATION,
		location = context.getNameLocation(node),
		message =
		"`MutableSharedFlow()` creates a new shared flow, which has poor performance " +
		"characteristics"
		)
		}
		if (
		method.name == FUN_SHARE_IN &&
		getTypeOfExtensionMethod(method)?.resolve()?.qualifiedName == CLASS_FLOW
		) {
		context.report(
		issue = SHARED_FLOW_CREATION,
		location = context.getNameLocation(node),
		message =
		"`shareIn()` creates a new shared flow, which has poor performance " +
		"characteristics"
		)
		}
		}

		companion object {
		@JvmStatic
		val SHARED_FLOW_CREATION =
		Issue.create(
		id = "SharedFlowCreation",
		briefDescription = "Shared flow creation",
		explanation =
		"""
		Shared flows scale poorly with the number of collectors in use due to
		their internal buffering mechanism and reliance on thread
		synchronization. They can also cause memory leaks when used incorrectly.
		If possible, use `StateFlow` instead.
		""",
		moreInfo = "http://go//sysui-shared-flow",
		category = Category.PERFORMANCE,
		priority = 8,
		severity = Severity.ERROR,
		implementation =
		Implementation(
		FlowDetector::class.java,
		Scope.JAVA_FILE_SCOPE,
		),
		)

		fun getTypeOfExtensionMethod(method: PsiMethod): PsiClassType? {
		// If this is an extension method whose return type matches receiver
		val parameterList = method.parameterList
		if (parameterList.parametersCount > 0) {
		val firstParameter = parameterList.getParameter(0)
		if (firstParameter is PsiParameter && firstParameter.name.startsWith("\$this\$")) {
		return firstParameter.type as? PsiClassType
		}
		}
		return null
		}
		}
		}

		private const val PACKAGE_FLOW = "kotlinx.coroutines.flow"
		private const val FUN_MUTABLE_SHARED_FLOW = "MutableSharedFlow"
		private const val FUN_SHARE_IN = "shareIn"
		private const val CLASS_FLOW = "$PACKAGE_FLOW.Flow"

packages/SystemUI/checks/src/com/android/internal/systemui/lint/MissingApacheLicenseDetector.kt

+7 −3

Original line number	Diff line number	Diff line
		@@ -25,7 +25,6 @@ import com.android.tools.lint.detector.api.Issue
		import com.android.tools.lint.detector.api.JavaContext
		import com.android.tools.lint.detector.api.Location
		import com.android.tools.lint.detector.api.Scope
		import com.android.tools.lint.detector.api.Severity
		import com.android.tools.lint.detector.api.SourceCodeScanner
		import java.time.Year
		import org.jetbrains.uast.UComment
		@@ -117,8 +116,13 @@ class MissingApacheLicenseDetector : Detector(), SourceCodeScanner {
		attached at the beginning.""",
		category = Category.COMPLIANCE,
		priority = 8,
		// ignored by default and then explicitly overridden in SysUI's soong configuration
		severity = Severity.IGNORE,
		// This check is disabled by default so that it is not accidentally used by internal
		// modules that have different silencing. This check can be enabled in Soong using
		// the following configuration:
		// lint: {
		// warning_checks: ["MissingApacheLicenseDetector"],
		// }
		enabledByDefault = false,
		implementation =
		Implementation(MissingApacheLicenseDetector::class.java, Scope.JAVA_FILE_SCOPE),
		)

packages/SystemUI/checks/src/com/android/internal/systemui/lint/SystemUIIssueRegistry.kt

+1 −0

Original line number	Diff line number	Diff line
		@@ -33,6 +33,7 @@ class SystemUIIssueRegistry : IssueRegistry() {
		BroadcastSentViaContextDetector.ISSUE,
		CleanArchitectureDependencyViolationDetector.ISSUE,
		DumpableNotRegisteredDetector.ISSUE,
		FlowDetector.SHARED_FLOW_CREATION,
		SlowUserQueryDetector.ISSUE_SLOW_USER_ID_QUERY,
		SlowUserQueryDetector.ISSUE_SLOW_USER_INFO_QUERY,
		NonInjectedMainThreadDetector.ISSUE,