Add EXACTLY_ONCE contract to functions that call their lambda parameter once

KT-35972

libraries/kotlin.test/common/src/main/kotlin/kotlin/test/Assertions.kt

@@ -29,7 +29,10 @@ val asserter: Asserter
 internal var _asserter: Asserter? = null
 
 /** Asserts that the given [block] returns `true`. */
-fun assertTrue(message: String? = null, block: () -> Boolean): Unit = assertTrue(block(), message)
+fun assertTrue(message: String? = null, block: () -> Boolean) {
+    contract { callsInPlace(block, InvocationKind.EXACTLY_ONCE) }
+    assertTrue(block(), message)
+}
 
 /** Asserts that the expression is `true` with an optional [message]. */
 fun assertTrue(actual: Boolean, message: String? = null) {
@@ -38,7 +41,10 @@ fun assertTrue(actual: Boolean, message: String? = null) {
 }
 
 /** Asserts that the given [block] returns `false`. */
-fun assertFalse(message: String? = null, block: () -> Boolean): Unit = assertFalse(block(), message)
+fun assertFalse(message: String? = null, block: () -> Boolean) {
+    contract { callsInPlace(block, InvocationKind.EXACTLY_ONCE) }
+    assertFalse(block(), message)
+}
 
 /** Asserts that the expression is `false` with an optional [message]. */
 fun assertFalse(actual: Boolean, message: String? = null) {
@@ -105,11 +111,13 @@ fun fail(message: String? = null, cause: Throwable? = null): Nothing {
 
 /** Asserts that given function [block] returns the given [expected] value. */
 fun <@OnlyInputTypes T> expect(expected: T, block: () -> T) {
+    contract { callsInPlace(block, InvocationKind.EXACTLY_ONCE) }
     assertEquals(expected, block())
 }
 
 /** Asserts that given function [block] returns the given [expected] value and use the given [message] if it fails. */
 fun <@OnlyInputTypes T> expect(expected: T, message: String?, block: () -> T) {
+    contract { callsInPlace(block, InvocationKind.EXACTLY_ONCE) }
     assertEquals(expected, block(), message)
 }
 

libraries/stdlib/js/src/kotlinx/dom/Builders.kt

@@ -6,19 +6,25 @@
 package kotlinx.dom
 
 import org.w3c.dom.*
+import kotlin.contracts.*
 
 /**
  * Creates a new element with the specified [name].
  *
  * The element is initialized with the specified [init] function.
  */
-public fun Document.createElement(name: String, init: Element.() -> Unit): Element = createElement(name).apply(init)
+public fun Document.createElement(name: String, init: Element.() -> Unit): Element {
+    contract { callsInPlace(init, InvocationKind.EXACTLY_ONCE) }
+    return createElement(name).apply(init)
+}
 
 /**
  * Appends a newly created element with the specified [name] to this element.
  *
  * The element is initialized with the specified [init] function.
  */
-public fun Element.appendElement(name: String, init: Element.() -> Unit): Element =
+public fun Element.appendElement(name: String, init: Element.() -> Unit): Element {
-    ownerDocument!!.createElement(name, init).also { appendChild(it) }
+    contract { callsInPlace(init, InvocationKind.EXACTLY_ONCE) }
+    return ownerDocument!!.createElement(name, init).also { appendChild(it) }
+}
 

libraries/stdlib/jvm/src/kotlin/concurrent/Locks.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
@@ -8,7 +8,7 @@ package kotlin.concurrent
 
 import java.util.concurrent.locks.Lock
 import java.util.concurrent.locks.ReentrantReadWriteLock
-import java.util.concurrent.CountDownLatch
+import kotlin.contracts.*
 
 /**
  * Executes the given [action] under this lock.
@@ -16,6 +16,7 @@ import java.util.concurrent.CountDownLatch
  */
 @kotlin.internal.InlineOnly
 public inline fun <T> Lock.withLock(action: () -> T): T {
+    contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
     lock()
     try {
         return action()
@@ -30,6 +31,7 @@ public inline fun <T> Lock.withLock(action: () -> T): T {
  */
 @kotlin.internal.InlineOnly
 public inline fun <T> ReentrantReadWriteLock.read(action: () -> T): T {
+    contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
     val rl = readLock()
     rl.lock()
     try {
@@ -54,6 +56,7 @@ public inline fun <T> ReentrantReadWriteLock.read(action: () -> T): T {
  */
 @kotlin.internal.InlineOnly
 public inline fun <T> ReentrantReadWriteLock.write(action: () -> T): T {
+    contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
     val rl = readLock()
 
     val readCount = if (writeHoldCount == 0) readHoldCount else 0

libraries/stdlib/src/kotlin/text/StringBuilder.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
@@ -8,6 +8,8 @@
 
 package kotlin.text
 
+import kotlin.contracts.*
+
 /**
  * A mutable sequence of characters.
  *
@@ -399,8 +401,10 @@ public inline fun StringBuilder.append(obj: Any?): StringBuilder = this.append(o
  * and then converting it to [String].
  */
 @kotlin.internal.InlineOnly
-public inline fun buildString(builderAction: StringBuilder.() -> Unit): String =
+public inline fun buildString(builderAction: StringBuilder.() -> Unit): String {
-    StringBuilder().apply(builderAction).toString()
+    contract { callsInPlace(builderAction, InvocationKind.EXACTLY_ONCE) }
+    return StringBuilder().apply(builderAction).toString()
+}
 
 /**
  * Builds new string by populating newly created [StringBuilder] initialized with the given [capacity]
@@ -408,8 +412,10 @@ public inline fun buildString(builderAction: StringBuilder.() -> Unit): String =
  */
 @SinceKotlin("1.1")
 @kotlin.internal.InlineOnly
-public inline fun buildString(capacity: Int, builderAction: StringBuilder.() -> Unit): String =
+public inline fun buildString(capacity: Int, builderAction: StringBuilder.() -> Unit): String {
-    StringBuilder(capacity).apply(builderAction).toString()
+    contract { callsInPlace(builderAction, InvocationKind.EXACTLY_ONCE) }
+    return StringBuilder(capacity).apply(builderAction).toString()
+}
 
 /**
  * Appends all arguments to the given StringBuilder.

libraries/stdlib/src/kotlin/time/Duration.kt

@@ -1,10 +1,11 @@
 /*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
 package kotlin.time
 
+import kotlin.contracts.*
 import kotlin.math.abs
 
 @OptIn(ExperimentalTime::class)
@@ -104,8 +105,10 @@ public inline class Duration internal constructor(internal val value: Double) :
      *   If the value doesn't fit in [Int] range, i.e. it's greater than [Int.MAX_VALUE] or less than [Int.MIN_VALUE],
      *   it is coerced into that range.
      */
-    public inline fun <T> toComponents(action: (days: Int, hours: Int, minutes: Int, seconds: Int, nanoseconds: Int) -> T): T =
+    public inline fun <T> toComponents(action: (days: Int, hours: Int, minutes: Int, seconds: Int, nanoseconds: Int) -> T): T {
-        action(inDays.toInt(), hoursComponent, minutesComponent, secondsComponent, nanosecondsComponent)
+        contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
+        return action(inDays.toInt(), hoursComponent, minutesComponent, secondsComponent, nanosecondsComponent)
+    }
 
     /**
      * Splits this duration into hours, minutes, seconds, and nanoseconds and executes the given [action] with these components.
@@ -118,8 +121,10 @@ public inline class Duration internal constructor(internal val value: Double) :
      *   If the value doesn't fit in [Int] range, i.e. it's greater than [Int.MAX_VALUE] or less than [Int.MIN_VALUE],
      *   it is coerced into that range.
      */
-    public inline fun <T> toComponents(action: (hours: Int, minutes: Int, seconds: Int, nanoseconds: Int) -> T): T =
+    public inline fun <T> toComponents(action: (hours: Int, minutes: Int, seconds: Int, nanoseconds: Int) -> T): T {
-        action(inHours.toInt(), minutesComponent, secondsComponent, nanosecondsComponent)
+        contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
+        return action(inHours.toInt(), minutesComponent, secondsComponent, nanosecondsComponent)
+    }
 
     /**
      * Splits this duration into minutes, seconds, and nanoseconds and executes the given [action] with these components.
@@ -131,8 +136,10 @@ public inline class Duration internal constructor(internal val value: Double) :
      *   If the value doesn't fit in [Int] range, i.e. it's greater than [Int.MAX_VALUE] or less than [Int.MIN_VALUE],
      *   it is coerced into that range.
      */
-    public inline fun <T> toComponents(action: (minutes: Int, seconds: Int, nanoseconds: Int) -> T): T =
+    public inline fun <T> toComponents(action: (minutes: Int, seconds: Int, nanoseconds: Int) -> T): T {
-        action(inMinutes.toInt(), secondsComponent, nanosecondsComponent)
+        contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
+        return action(inMinutes.toInt(), secondsComponent, nanosecondsComponent)
+    }
 
     /**
      * Splits this duration into seconds, and nanoseconds and executes the given [action] with these components.
@@ -143,8 +150,10 @@ public inline class Duration internal constructor(internal val value: Double) :
      *   If the value doesn't fit in [Long] range, i.e. it's greater than [Long.MAX_VALUE] or less than [Long.MIN_VALUE],
      *   it is coerced into that range.
      */
-    public inline fun <T> toComponents(action: (seconds: Long, nanoseconds: Int) -> T): T =
+    public inline fun <T> toComponents(action: (seconds: Long, nanoseconds: Int) -> T): T {
-        action(inSeconds.toLong(), nanosecondsComponent)
+        contract { callsInPlace(action, InvocationKind.EXACTLY_ONCE) }
+        return action(inSeconds.toLong(), nanosecondsComponent)
+    }
 
     @PublishedApi
     internal val hoursComponent: Int get() = (inHours % 24).toInt()