stack-traces.js

// Copyright 2009 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
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//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

function testMethodNameInference() {
  function Foo() { }
  Foo.prototype.bar = function () { FAIL; };
  (new Foo).bar();
}

function testNested() {
  function one() {
    function two() {
      function three() {
        FAIL;
      }
      three();
    }
    two();
  }
  one();
}

function testArrayNative() {
  [1, 2, 3].map(function () { FAIL; });
}

function testImplicitConversion() {
  function Nirk() { }
  Nirk.prototype.valueOf = function () { FAIL; };
  return 1 + (new Nirk);
}

function testEval() {
  eval("function Doo() { FAIL; }; Doo();");
}

function testNestedEval() {
  var x = "FAIL";
  eval("function Outer() { eval('function Inner() { eval(x); }'); Inner(); }; Outer();");
}

function testEvalWithSourceURL() {
  eval("function Doo() { FAIL; }; Doo();\n//# sourceURL=res://name");
}

function testNestedEvalWithSourceURL() {
  var x = "FAIL";
  var innerEval = 'function Inner() { eval(x); }\n//@ sourceURL=res://inner-eval';
  eval("function Outer() { eval(innerEval); Inner(); }; Outer();\n//# sourceURL=res://outer-eval");
}

function testValue() {
  Number.prototype.causeError = function () { FAIL; };
  (1).causeError();
}

function testConstructor() {
  function Plonk() { FAIL; }
  new Plonk();
}

function testRenamedMethod() {
  function a$b$c$d() { return FAIL; }
  function Wookie() { }
  Wookie.prototype.d = a$b$c$d;
  (new Wookie).d();
}

function testAnonymousMethod() {
  (function () { FAIL }).call([1, 2, 3]);
}

function testFunctionName() {
  function gen(name, counter) {
    var f = function foo() {
      if (counter === 0) {
        FAIL;
      }
      gen(name, counter - 1)();
    }
    if (counter === 4) {
      Object.defineProperty(f, 'name', {get: function(){ throw 239; }});
    } else if (counter == 3) {
      Object.defineProperty(f, 'name', {value: 'boo' + '_' + counter});
    } else {
      Object.defineProperty(f, 'name', {writable: true});
      if (counter === 2)
        f.name = 42;
      else
        f.name = name + '_' + counter;
    }
    return f;
  }
  gen('foo', 4)();
}

function testFunctionInferredName() {
  var f = function() {
    FAIL;
  }
  f();
}

function CustomError(message, stripPoint) {
  this.message = message;
  Error.captureStackTrace(this, stripPoint);
}

CustomError.prototype.toString = function () {
  return "CustomError: " + this.message;
};

function testDefaultCustomError() {
  throw new CustomError("hep-hey", undefined);
}

function testStrippedCustomError() {
  throw new CustomError("hep-hey", CustomError);
}

MyObj = function() { FAIL; }

MyObjCreator = function() {}

MyObjCreator.prototype.Create = function() {
  return new MyObj();
}

function testClassNames() {
  (new MyObjCreator).Create();
}

// Utility function for testing that the expected strings occur
// in the stack trace produced when running the given function.
function testTrace(name, fun, expected, unexpected) {
  var threw = false;
  try {
    fun();
  } catch (e) {
    for (var i = 0; i < expected.length; i++) {
      assertTrue(e.stack.indexOf(expected[i]) != -1,
                 name + " doesn't contain expected[" + i + "] stack = " + e.stack);
    }
    if (unexpected) {
      for (var i = 0; i < unexpected.length; i++) {
        assertEquals(e.stack.indexOf(unexpected[i]), -1,
                     name + " contains unexpected[" + i + "]");
      }
    }
    threw = true;
  }
  assertTrue(threw, name + " didn't throw");
}

// Test that the error constructor is not shown in the trace
function testCallerCensorship() {
  var threw = false;
  try {
    FAIL;
  } catch (e) {
    assertEquals(-1, e.stack.indexOf('at new ReferenceError'),
                 "CallerCensorship contained new ReferenceError");
    threw = true;
  }
  assertTrue(threw, "CallerCensorship didn't throw");
}

// Test that the explicit constructor call is shown in the trace
function testUnintendedCallerCensorship() {
  var threw = false;
  try {
    new ReferenceError({
      toString: function () {
        FAIL;
      }
    });
  } catch (e) {
    assertTrue(e.stack.indexOf('at new ReferenceError') != -1,
               "UnintendedCallerCensorship didn't contain new ReferenceError");
    threw = true;
  }
  assertTrue(threw, "UnintendedCallerCensorship didn't throw");
}

// If an error occurs while the stack trace is being formatted it should
// be handled gracefully.
function testErrorsDuringFormatting() {
  function Nasty() { }
  Nasty.prototype.foo = function () { throw new RangeError(); };
  var n = new Nasty();
  n.__defineGetter__('constructor', function () { CONS_FAIL; });
  assertThrows(()=>n.foo(), RangeError);
  // Now we can't even format the message saying that we couldn't format
  // the stack frame.  Put that in your pipe and smoke it!
  ReferenceError.prototype.toString = function () { NESTED_FAIL; };
  assertThrows(()=>n.foo(), RangeError);
}


// Poisonous object that throws a reference error if attempted converted to
// a primitive values.
var thrower = { valueOf: function() { FAIL; },
                toString: function() { FAIL; } };

// Tests that a native constructor function is included in the
// stack trace.
function testTraceNativeConstructor(nativeFunc) {
  var nativeFuncName = nativeFunc.name;
  try {
    new nativeFunc(thrower);
    assertUnreachable(nativeFuncName);
  } catch (e) {
    assertTrue(e.stack.indexOf(nativeFuncName) >= 0, nativeFuncName);
  }
}

// Tests that a native conversion function is included in the
// stack trace.
function testTraceNativeConversion(nativeFunc) {
  var nativeFuncName = nativeFunc.name;
  try {
    nativeFunc(thrower);
    assertUnreachable(nativeFuncName);
  } catch (e) {
    assertTrue(e.stack.indexOf(nativeFuncName) >= 0, nativeFuncName);
  }
}


function testOmittedBuiltin(throwing, omitted) {
  var reached = false;
  try {
    throwing();
    reached = true;
  } catch (e) {
    assertTrue(e.stack.indexOf(omitted) < 0, omitted);
  } finally {
    assertFalse(reached);
  }
}


testTrace("testArrayNative", testArrayNative, ["Array.map"]);
testTrace("testNested", testNested, ["at one", "at two", "at three"]);
testTrace("testMethodNameInference", testMethodNameInference, ["at Foo.bar"]);
testTrace("testImplicitConversion", testImplicitConversion, ["at Nirk.valueOf"]);
testTrace("testEval", testEval, ["at Doo (eval at testEval"]);
testTrace("testNestedEval", testNestedEval, ["eval at Inner (eval at Outer"]);
testTrace("testEvalWithSourceURL", testEvalWithSourceURL,
    [ "at Doo (res://name:1:18)" ]);
testTrace("testNestedEvalWithSourceURL", testNestedEvalWithSourceURL,
    [" at Inner (res://inner-eval:1:20)",
     " at Outer (res://outer-eval:1:37)"]);
testTrace("testValue", testValue, ["at Number.causeError"]);
testTrace("testConstructor", testConstructor, ["new Plonk"]);
testTrace("testRenamedMethod", testRenamedMethod, ["Wookie.a$b$c$d [as d]"]);
testTrace("testAnonymousMethod", testAnonymousMethod, ["Array.<anonymous>"]);
testTrace("testFunctionName", testFunctionName,
    [" at foo_0 ", " at foo_1", " at foo ", " at boo_3 ", " at foo "]);
testTrace("testFunctionInferredName", testFunctionInferredName, [" at f "]);
testTrace("testDefaultCustomError", testDefaultCustomError,
    ["hep-hey", "new CustomError"],
    ["collectStackTrace"]);
testTrace("testStrippedCustomError", testStrippedCustomError, ["hep-hey"],
    ["new CustomError", "collectStackTrace"]);
testTrace("testClassNames", testClassNames,
          ["new MyObj", "MyObjCreator.Create"], ["as Create"]);
testCallerCensorship();
testUnintendedCallerCensorship();
testErrorsDuringFormatting();

testTraceNativeConversion(String);  // Does ToString on argument.
testTraceNativeConversion(RegExp);  // Does ToString on argument.

testTraceNativeConstructor(String);  // Does ToString on argument.
testTraceNativeConstructor(RegExp);  // Does ToString on argument.

// Omitted because QuickSort has builtins object as receiver, and is non-native
// builtin.
testOmittedBuiltin(function(){ [thrower, 2].sort(function (a,b) {
                                                     (b < a) - (a < b); });
                   }, "QuickSort");

var reached = false;
var error = new Error();
error.toString = function() { reached = true; };
error.stack;
assertFalse(reached);

reached = false;
error = new Error();
Array.prototype.push = function(x) { reached = true; };
Array.prototype.join = function(x) { reached = true; };
error.stack;
assertFalse(reached);

var fired = false;
error = new Error({ toString: function() { fired = true; } });
assertTrue(fired);
error.stack;
assertTrue(fired);

// Check that throwing exception in a custom stack trace formatting function
// does not lead to recursion.
Error.prepareStackTrace = function() { throw new Error("abc"); };
var message;
try {
  try {
    throw new Error();
  } catch (e) {
    e.stack;
  }
} catch (e) {
  message = e.message;
}

assertEquals("abc", message);

// Test that modifying Error.prepareStackTrace by itself works.
Error.prepareStackTrace = function() { Error.prepareStackTrace = "custom"; };
new Error().stack;

assertEquals("custom", Error.prepareStackTrace);

// Check that the formatted stack trace can be set to undefined.
error = new Error();
error.stack = undefined;
assertEquals(undefined, error.stack);

// Check that the stack trace accessors are not forcibly set.
var my_error = {};
Object.freeze(my_error);
assertThrows(function() { Error.captureStackTrace(my_error); });

my_error = {};
Object.preventExtensions(my_error);
assertThrows(function() { Error.captureStackTrace(my_error); });

var fake_error = {};
my_error = new Error();
var stolen_getter = Object.getOwnPropertyDescriptor(my_error, 'stack').get;
Object.defineProperty(fake_error, 'stack', { get: stolen_getter });
assertEquals(undefined, fake_error.stack);

// Check that overwriting the stack property during stack trace formatting
// does not crash.
error = new Error("foobar");
error.__defineGetter__("name", function() { error.stack = "abc"; });
assertTrue(error.stack.startsWith("Error"));
assertTrue(error.stack.includes("foobar"));

error = new Error("foobar");
error.__defineGetter__("name", function() { delete error.stack; });
// The first time, Error.stack returns the formatted stack trace,
// not the content of the property.
assertTrue(error.stack.startsWith("Error"));
assertEquals(error.stack, undefined);

// Check that repeated trace collection does not crash.
error = new Error();
Error.captureStackTrace(error);

// Check property descriptor.
var o = {};
Error.captureStackTrace(o);
assertEquals([], Object.keys(o));
var desc = Object.getOwnPropertyDescriptor(o, "stack");
assertFalse(desc.enumerable);
assertTrue(desc.configurable);
assertTrue(desc.writable);

// Check that exceptions thrown within prepareStackTrace throws an exception.
Error.prepareStackTrace = function(e, frames) { throw 42; }
assertThrows(() => new Error().stack);

// Check that we don't crash when CaptureSimpleStackTrace returns undefined.
var o = {};
var oldStackTraceLimit = Error.stackTraceLimit;
Error.stackTraceLimit = "not a number";
Error.captureStackTrace(o);
Error.stackTraceLimit = oldStackTraceLimit;

// Check that we don't crash when a callsite's function's script is empty.
Error.prepareStackTrace = function(e, frames) {
  assertEquals(undefined, frames[0].getEvalOrigin());
}
try {
  DataView();
  assertUnreachable();
} catch (e) {
  assertEquals(undefined, e.stack);
}

// Check that a tight recursion in prepareStackTrace throws when accessing
// stack. Trying again without a custom formatting function formats correctly.
var err = new Error("abc");
Error.prepareStackTrace = () => Error.prepareStackTrace();
try {
  err.stack;
  assertUnreachable();
} catch (e) {
  err = e;
}

Error.prepareStackTrace = undefined;
assertTrue(
    err.stack.indexOf("RangeError: Maximum call stack size exceeded") != -1);
assertTrue(err.stack.indexOf("prepareStackTrace") != -1);

// Check that the callsite constructor throws.

Error.prepareStackTrace = (e,s) => s;
var constructor = new Error().stack[0].constructor;

assertThrows(() => constructor.call());
assertThrows(() => constructor.call(
    null, {}, () => undefined, {valueOf() { return 0 }}, false));

// Test stack frames populated with line/column information for both call site
// and enclosing function:
Error.prepareStackTrace = function(e, frames) {
  assertMatches(/stack-traces\.js/, frames[0].getFileName());
  assertEquals(3, frames[0].getEnclosingColumnNumber());
  assertEquals(11, frames[0].getColumnNumber());
  assertTrue(frames[0].getEnclosingLineNumber() < frames[0].getLineNumber());
}
try {
  function a() {
    b();
  }
  function b() {
    throw Error('hello world');
  }
  a();
} catch (err) {
  err.stack;
}