Merge "Introduce linter to prevent runBlocking from being injected" into main

3 files changed, 189 insertions, 0 deletions

diff --git a/packages/SystemUI/checks/src/com/android/internal/systemui/lint/RunBlockingDetector.kt b/packages/SystemUI/checks/src/com/android/internal/systemui/lint/RunBlockingDetector.kt
new file mode 100644
index 000000000000..fce536a60b84
--- /dev/null
+++ b/packages/SystemUI/checks/src/com/android/internal/systemui/lint/RunBlockingDetector.kt
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2025 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.client.api.UElementHandler
+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 org.jetbrains.uast.UElement
+import org.jetbrains.uast.UFile
+import org.jetbrains.uast.UImportStatement
+
+/** Detects whether [runBlocking] is being imported. */
+class RunBlockingDetector : Detector(), SourceCodeScanner {
+
+    override fun getApplicableUastTypes(): List<Class<out UElement>> {
+        return listOf(UFile::class.java)
+    }
+
+    override fun createUastHandler(context: JavaContext): UElementHandler {
+        return object : UElementHandler() {
+            override fun visitFile(node: UFile) {
+                for (importStatement in node.imports) {
+                    visitImportStatement(context, importStatement)
+                }
+            }
+        }
+    }
+
+    private fun visitImportStatement(context: JavaContext, importStatement: UImportStatement) {
+        val importName = importStatement.importReference?.asSourceString()
+        if (FORBIDDEN_IMPORTS.contains(importName)) {
+            context.report(
+                ISSUE,
+                importStatement as UElement,
+                context.getLocation(importStatement),
+                "Importing $importName is not allowed.",
+            )
+        }
+    }
+
+    companion object {
+        @JvmField
+        val ISSUE =
+            Issue.create(
+                id = "RunBlockingUsage",
+                briefDescription = "Discouraged runBlocking call",
+                explanation =
+                    """
+                    Using `runBlocking` is generally discouraged in Android
+                    development as it can lead to UI freezes and ANRs.
+                    Consider using `launch` or `async` with coroutine scope
+                    instead. If needed from java, consider introducing a method
+                    with a callback instead from kotlin.
+                    """,
+                category = Category.PERFORMANCE,
+                priority = 8,
+                severity = Severity.WARNING,
+                implementation =
+                    Implementation(RunBlockingDetector::class.java, Scope.JAVA_FILE_SCOPE),
+            )
+
+        val FORBIDDEN_IMPORTS = listOf("kotlinx.coroutines.runBlocking")
+    }
+}
diff --git a/packages/SystemUI/checks/src/com/android/internal/systemui/lint/SystemUIIssueRegistry.kt b/packages/SystemUI/checks/src/com/android/internal/systemui/lint/SystemUIIssueRegistry.kt
index adb311610587..b455c0021517 100644
--- a/packages/SystemUI/checks/src/com/android/internal/systemui/lint/SystemUIIssueRegistry.kt
+++ b/packages/SystemUI/checks/src/com/android/internal/systemui/lint/SystemUIIssueRegistry.kt
@@ -50,6 +50,7 @@ class SystemUIIssueRegistry : IssueRegistry() {
                 ShadeDisplayAwareDialogDetector.ISSUE,
                 RegisterContentObserverSyncViaSettingsProxyDetector.SYNC_WARNING,
                 RegisterContentObserverViaContentResolverDetector.CONTENT_RESOLVER_ERROR,
+                RunBlockingDetector.ISSUE,
             )
 
     override val api: Int
diff --git a/packages/SystemUI/checks/tests/com/android/internal/systemui/lint/RunBlockingDetectorTest.kt b/packages/SystemUI/checks/tests/com/android/internal/systemui/lint/RunBlockingDetectorTest.kt
new file mode 100644
index 000000000000..4ae429d204aa
--- /dev/null
+++ b/packages/SystemUI/checks/tests/com/android/internal/systemui/lint/RunBlockingDetectorTest.kt
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2025 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.Detector
+import com.android.tools.lint.detector.api.Issue
+import org.junit.Test
+
+class RunBlockingDetectorTest : SystemUILintDetectorTest() {
+
+    override fun getDetector(): Detector = RunBlockingDetector()
+
+    override fun getIssues(): List<Issue> = listOf(RunBlockingDetector.ISSUE)
+
+    @Test
+    fun testViolation() {
+        lint()
+            .files(
+                kotlin(
+                    """
+                    package com.example
+
+                    import kotlinx.coroutines.runBlocking
+
+                    class MyClass {
+                        fun myMethod() {
+                            runBlocking {
+                                // Some code here
+                            }
+                        }
+                    }
+                    """
+                ),
+                RUN_BLOCKING_DEFINITION,
+            )
+            .issues(RunBlockingDetector.ISSUE)
+            .run()
+            .expect(
+                """
+src/com/example/MyClass.kt:4: Warning: Importing kotlinx.coroutines.runBlocking is not allowed. [RunBlockingUsage]
+                    import kotlinx.coroutines.runBlocking
+                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+0 errors, 1 warnings
+"""
+                    .trimIndent()
+            )
+    }
+
+    // Verifies that the lint check does *not* flag calls to other methods.
+    @Test
+    fun testNotViolation() {
+        lint()
+            .detector(RunBlockingDetector())
+            .issues(RunBlockingDetector.ISSUE)
+            .files(
+                kotlin(
+                    """
+                    package com.example
+
+                    class MyClass {
+                        fun myMethod() {
+                            myOtherMethod {
+                            }
+                        }
+
+                        fun myOtherMethod(block: () -> Unit) {
+                            block()
+                        }
+                    }
+                    """
+                )
+            )
+            .run()
+            .expectClean()
+    }
+
+    private companion object {
+        val RUN_BLOCKING_DEFINITION =
+            kotlin(
+                """
+                    package kotlinx.coroutines
+
+                    fun runBlocking(block: suspend () -> Unit) {
+                        // Implementation details don't matter for this test.
+                    }
+                    """
+            )
+    }
+}