Temp commit

 <?xml version="1.0" encoding="UTF-8"?>
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
 <project version="4">
   <component name="CompilerConfiguration">
   <component name="CompilerConfiguration">
-    <bytecodeTargetLevel target="11" />
+    <bytecodeTargetLevel target="1.8">
+      <module name="livekit-android.livekit-android-sdk" target="11" />
+      <module name="livekit-android.sample-app" target="11" />
+    </bytecodeTargetLevel>
   </component>
   </component>
 </project>
 </project>

@@ -12,7 +12,7 @@ buildscript {
     }
     }
     dependencies {
     dependencies {
         classpath 'com.android.tools.build:gradle:7.0.1'
         classpath 'com.android.tools.build:gradle:7.0.1'
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.30"
         classpath "org.jetbrains.kotlin:kotlin-serialization:$kotlin_version"
         classpath "org.jetbrains.kotlin:kotlin-serialization:$kotlin_version"
         classpath "org.jetbrains.dokka:dokka-gradle-plugin:$dokka_version"
         classpath "org.jetbrains.dokka:dokka-gradle-plugin:$dokka_version"
         classpath 'com.google.protobuf:protobuf-gradle-plugin:0.8.15'
         classpath 'com.google.protobuf:protobuf-gradle-plugin:0.8.15'
@@ -52,12 +52,25 @@ ext {
             androidx_lifecycle: "2.3.1",
             androidx_lifecycle: "2.3.1",
             dagger            : "2.27",
             dagger            : "2.27",
             groupie           : "2.9.0",
             groupie           : "2.9.0",
+            junit             : "4.13.2",
+            junitJupiter      : "5.5.0",
+            lint              : "30.0.1",
             protobuf          : "3.15.1",
             protobuf          : "3.15.1",
     ]
     ]
     generated = [
     generated = [
             protoSrc: "$projectDir/../protocol",
             protoSrc: "$projectDir/../protocol",
     ]
     ]
     deps = [
     deps = [
+            // lint
+            lint              : "com.android.tools.lint:lint:${versions.lint}",
+            lintApi           : "com.android.tools.lint:lint-api:${versions.lint}",
+            lintChecks        : "com.android.tools.lint:lint-checks:${versions.lint}",
+            lintTests         : "com.android.tools.lint:lint-tests:${versions.lint}",
+
+            // tests
+            junit             : "junit:junit:${versions.junit}",
+            junitJupiterApi   : "org.junit.jupiter:junit-jupiter-api:${versions.junitJupiter}",
+            junitJupiterEngine: "org.junit.jupiter:junit-jupiter-engine:${versions.junitJupiter}",
     ]
     ]
     annotations = [
     annotations = [
     ]
     ]

+/build

+plugins {
+    id 'java-library'
+    id 'kotlin'
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_1_8
+    targetCompatibility = JavaVersion.VERSION_1_8
+}
+
+dependencies {
+    // used for lint rules
+    compileOnly deps.lintApi
+    compileOnly deps.lintChecks
+    compileOnly deps.lintTests
+
+    // test lint
+    testImplementation deps.lintTests
+
+    // test runners
+    testImplementation deps.junitJupiterApi
+    testRuntimeOnly deps.junitJupiterEngine
+}

+package io.livekit.lint
+
+import com.android.tools.lint.client.api.IssueRegistry
+import com.android.tools.lint.detector.api.CURRENT_API
+import com.android.tools.lint.detector.api.Issue
+
+class IssueRegistry : IssueRegistry() {
+
+    override val api: Int = CURRENT_API
+
+    override val issues: List<Issue>
+        get() = listOf(MediaTrackEquals.ISSUE)
+}

+/*
+ * Copyright (C) 2018 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 io.livekit.lint
+
+import com.android.tools.lint.checks.DiffUtilDetector
+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.android.tools.lint.detector.api.isKotlin
+import com.intellij.psi.CommonClassNames.JAVA_LANG_OBJECT
+import com.intellij.psi.PsiClassType
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiMethod
+import org.jetbrains.uast.UBinaryExpression
+import org.jetbrains.uast.UBinaryExpressionWithType
+import org.jetbrains.uast.UCallExpression
+import org.jetbrains.uast.UClass
+import org.jetbrains.uast.UElement
+import org.jetbrains.uast.UExpression
+import org.jetbrains.uast.UIfExpression
+import org.jetbrains.uast.UMethod
+import org.jetbrains.uast.UParenthesizedExpression
+import org.jetbrains.uast.UPolyadicExpression
+import org.jetbrains.uast.UQualifiedReferenceExpression
+import org.jetbrains.uast.UastBinaryOperator
+import org.jetbrains.uast.getParentOfType
+import org.jetbrains.uast.skipParenthesizedExprUp
+import org.jetbrains.uast.tryResolve
+import org.jetbrains.uast.visitor.AbstractUastVisitor
+
+/** Checks related to DiffUtil computation. */
+class MediaTrackEquals : Detector(), SourceCodeScanner {
+
+    override fun visitClass(context: JavaContext, declaration: UClass) {
+        for (method in declaration.methods) {
+            checkMethod(context, method)
+        }
+    }
+
+    private fun checkMethod(
+        context: JavaContext,
+        declaration: UMethod
+    ) {
+        declaration.accept(object : AbstractUastVisitor() {
+            override fun visitBinaryExpression(node: UBinaryExpression): Boolean {
+                checkExpression(context, node)
+                return super.visitBinaryExpression(node)
+            }
+
+            override fun visitCallExpression(node: UCallExpression): Boolean {
+                checkCall(context, node)
+                return super.visitCallExpression(node)
+            }
+        })
+    }
+
+    private fun defaultEquals(context: JavaContext, node: UElement): Boolean {
+        val resolved: PsiMethod?
+
+        when (node) {
+            is UBinaryExpression -> {
+                resolved = node.resolveOperator()
+                if (resolved == null) {
+                    val left = node.leftOperand.getExpressionType() as? PsiClassType
+                    return defaultEquals(context, left)
+                }
+            }
+            is UCallExpression -> {
+                resolved = node.resolve()
+            }
+            is UParenthesizedExpression -> {
+                return defaultEquals(context, node.expression)
+            }
+            else -> {
+                // We don't know any better
+                return false
+            }
+        }
+
+        return resolved?.containingClass?.qualifiedName == JAVA_LANG_OBJECT
+    }
+
+    private fun defaultEquals(
+        context: JavaContext,
+        type: PsiClassType?
+    ): Boolean {
+        val cls = type?.resolve() ?: return false
+
+        if (isKotlin(cls) && (context.evaluator.isSealed(cls) || context.evaluator.isData(cls))) {
+            // Sealed class doesn't guarantee that it defines equals/hashCode
+            // but it's likely (we'd need to go look at each inner class)
+            return false
+        }
+
+        for (m in cls.findMethodsByName("equals", true)) {
+            if (m is PsiMethod) {
+                val parameters = m.parameterList.parameters
+                if (parameters.size == 1 &&
+                    parameters[0].type.canonicalText == JAVA_LANG_OBJECT
+                ) {
+                    return m.containingClass?.qualifiedName == JAVA_LANG_OBJECT
+                }
+            }
+        }
+
+        return false
+    }
+
+    private fun checkCall(context: JavaContext, node: UCallExpression) {
+        if (defaultEquals(context, node)) {
+            // Within cast or instanceof check which implies a more specific type
+            // which provides an equals implementation?
+            if (withinCastWithEquals(context, node)) {
+                return
+            }
+
+            val targetType = node.receiverType?.canonicalText ?: "target"
+            val message = "Suspicious equality check: `equals()` is not implemented in $targetType"
+            val location = context.getCallLocation(node, false, true)
+            context.report(ISSUE, node, location, message)
+        }
+    }
+
+    /**
+     * Is this .equals() call within another if check which checks
+     * instanceof on a more specific type than we're calling equals on?
+     * If so, does that more specific type define its own equals?
+     *
+     * Also handle an implicit check via short circuit evaluation; e.g.
+     * something like "return a is A && b is B && a.equals(b)".
+     */
+    private fun withinCastWithEquals(context: JavaContext, node: UExpression): Boolean {
+        var parent = skipParenthesizedExprUp(node.uastParent)
+        if (parent is UQualifiedReferenceExpression) {
+            parent = skipParenthesizedExprUp(parent.uastParent)
+        }
+        val target: PsiElement? = when (node) {
+            is UCallExpression -> node.receiver?.tryResolve()
+            is UBinaryExpression -> node.leftOperand.tryResolve()
+            else -> null
+        }
+
+        if (parent is UPolyadicExpression && parent.operator == UastBinaryOperator.LOGICAL_AND) {
+            val operands = parent.operands
+            for (operand in operands) {
+                if (operand === node) {
+                    break
+                }
+                if (isCastWithEquals(context, operand, target)) {
+                    return true
+                }
+            }
+        }
+        val ifStatement = node.getParentOfType<UElement>(UIfExpression::class.java, false, UMethod::class.java)
+                as? UIfExpression ?: return false
+        val condition = ifStatement.condition
+        return isCastWithEquals(context, condition, target)
+    }
+
+    private fun isCastWithEquals(context: JavaContext, node: UExpression, target: PsiElement?): Boolean {
+        when {
+            node is UBinaryExpressionWithType -> {
+                if (target != null) {
+                    val resolved = node.operand.tryResolve()
+                    // Unfortunately in some scenarios isEquivalentTo returns false for equal instances
+                    //noinspection LintImplPsiEquals
+                    if (resolved != null && !(target == resolved || target.isEquivalentTo(resolved))) {
+                        return false
+                    }
+                }
+                return !defaultEquals(context, node.type as? PsiClassType)
+            }
+            node is UPolyadicExpression && node.operator == UastBinaryOperator.LOGICAL_AND -> {
+                for (operand in node.operands) {
+                    if (isCastWithEquals(context, operand, target)) {
+                        return true
+                    }
+                }
+            }
+            node is UParenthesizedExpression -> {
+                return isCastWithEquals(context, node.expression, target)
+            }
+        }
+        return false
+    }
+
+    private fun checkExpression(context: JavaContext, node: UBinaryExpression) {
+        if (node.operator == UastBinaryOperator.IDENTITY_EQUALS ||
+            node.operator == UastBinaryOperator.EQUALS
+        ) {
+            val left = node.leftOperand.getExpressionType() ?: return
+            val right = node.rightOperand.getExpressionType() ?: return
+            if (left is PsiClassType && right is PsiClassType) {
+                if (node.operator == UastBinaryOperator.EQUALS) {
+                    if (defaultEquals(context, node)) {
+                        if (withinCastWithEquals(context, node)) {
+                            return
+                        }
+
+                        val message =
+                            "Suspicious equality check: `equals()` is not implemented in ${left.className}"
+                        val location = node.operatorIdentifier?.let {
+                            context.getLocation(it)
+                        } ?: context.getLocation(node)
+                        context.report(ISSUE, node, location, message)
+                    }
+                } else {
+                    val message = if (isKotlin(node.sourcePsi))
+                        "Suspicious equality check: Did you mean `==` instead of `===` ?"
+                    else
+                        "Suspicious equality check: Did you mean `.equals()` instead of `==` ?"
+                    val location = node.operatorIdentifier?.let {
+                        context.getLocation(it)
+                    } ?: context.getLocation(node)
+                    context.report(ISSUE, node, location, message)
+                }
+            }
+        }
+    }
+
+    companion object {
+        private val IMPLEMENTATION =
+            Implementation(DiffUtilDetector::class.java, Scope.JAVA_FILE_SCOPE)
+
+        @JvmField
+        val ISSUE = Issue.create(
+            id = "DiffUtilEquals",
+            briefDescription = "Suspicious DiffUtil Equality",
+            explanation = """
+                `areContentsTheSame` is used by `DiffUtil` to produce diffs. If the \
+                method is implemented incorrectly, such as using identity equals \
+                instead of equals, or calling equals on a class that has not implemented \
+                it, weird visual artifacts can occur.
+                """,
+            category = Category.CORRECTNESS,
+            priority = 4,
+            androidSpecific = true,
+            moreInfo = "https://issuetracker.google.com/116789824",
+            severity = Severity.ERROR,
+            implementation = IMPLEMENTATION
+        )
+    }
+}

@@ -6,3 +6,4 @@ pluginManagement {
 }
 }
 include ':sample-app', ':livekit-android-sdk'
 include ':sample-app', ':livekit-android-sdk'
 rootProject.name='livekit-android'
 rootProject.name='livekit-android'
+include ':livekit-lint'