blob: e13f243e7fba1c55310e6f576cd41ecd796b6a1a [file] [log] [blame]
* Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
* for details. All rights reserved. Use of this source code is governed by a
* BSD-style license that can be found in the LICENSE file.
* @assertion Let d be the declaration of a variable v. If d is a local or
* instance variable, then the invocation of the implicit getter of v
* evaluates to the value stored in v.
* If d is a static or library variable then the implicit getter method of v
* executes as follows:
* - Non-constant variable declaration with initializer. If d is of one of the
* forms var v = e; , T v = e; , final v = e; , final T v = e; , static
* v = e; , static T v = e; , static final v = e; or static final T v = e;
* and no value has yet been stored into v then the initializer expression
* e is evaluated. If, during the evaluation of e, the getter for v is
* invoked, a CyclicInitializationError is thrown. If the evaluation
* succeeded yielding an object o, let r = o, otherwise let r = null. In
* any case, r is stored into v. The result of executing the getter is r.
* - Constant variable declaration. If d is of one of the forms const v = e; ,
* const T v = e; , static const v = e; or static const T v = e; the result
* of the getter is the value of the compile time constant e. Note that a
* compile time constant cannot depend on itself, so no cyclic references
* can occur. Otherwise
* - Variable declaration without initializer. The result of executing the
* getter method is the value stored in v.
* @note NNBD Spec now reads: If a variable or field is read from during the
* process of evaluating its own initializer expression, and no write to the
* variable has occurred, the read is treated as a first read and the
* nitializer expression is evaluated again.
* A toplevel or static variable with an initializer is evaluated as if it was
* marked [late]. Note that this is a change from pre-NNBD semantics in that:
* Throwing an exception during initializer evaluation no longer sets the
* variable to [null]
* Reading the variable during initializer evaluation is no longer checked for,
* and does not cause an error.
* @description Checks that if during the evaluation of [e], the getter for [v]
* is invoked, a [CyclicInitializationError] is not thrown. Confirms that [func]
* gets recursively called by incrementing a counter and stopping the infinite
* recursion after 20 cycles. This avoids relying on particulars of the behavior
* on stack overflow and makes the test cheaper to run.
* @author msyabro
* @Issue 42470
* @issue 42642
import "../../../Utils/expect.dart";
int count = 0;
f(func) {
try {
throw 1; // caugth exceptions do not matter
} on int catch (_) {
if (count < 20) func();
count = 0;
class C {
static var sVar = f(() => sVar);
static int? sTyped = f(() => sTyped);
static final sFinal = f(() => sFinal);
static final int? sFinalTyped = f(() => sFinalTyped);
main() {
() => C.sVar;
Expect.equals(null, C.sVar);
() => C.sTyped;
Expect.equals(null, C.sTyped);
() => C.sFinal;
Expect.throws(() { C.sFinal; });
() => C.sFinalTyped;
Expect.throws(() { C.sFinalTyped; });