JavaScript heap out of memory

🐛 Bug Report

I wanted to test out fast-check, so I wrote a simple function with a single property test. My test generates two integers and a natural number. If I set a precondition on one of the integers that it can’t equal zero, the test suite fails to finish and fails with a heap space exception.

const _ = require("lodash");
const fc = require("fast-check");

const divisibleCount = (x, y, k) => {
  return _.chain(y - x)
    .range()
    .map(n => x + n)
    .reject(n => n % k)
    .size()
    .value();
};

test("works", () => {
  fc.assert(
    fc.property(fc.integer(), fc.integer(), fc.nat(), (x, k, n) => {
      fc.pre(k !== 0);
      let y = x + n * k;
      return n === divisibleCount(x, y, k);
    })
  );
});

It seems like the suite runs to completion without the precondition, but I’m guessing this is because k = 0 causes the function under test to fail, so it doesn’t go through a large number of combinations.

To Reproduce

I pushed my simple repo that recreates the issue for me. Just clone it, and run the test suite.

Steps to reproduce:

git clone https://github.com/pcorey/count_the_divisible_numbers \
cd count_the_divisible_numbers \
yarn \
yarn test

Expected behavior

I would expect the test suite to pass, or at least to run to completion. Instead, I’m getting a “JavaScript heap out of memory” error:

FATAL ERROR: invalid table size Allocation failed - JavaScript heap out of memory
 1: 0x10007e71b node::Abort() [/Users/pcorey/.nvm/versions/node/v12.12.0/bin/node]
 2: 0x10007e89f node::OnFatalError(char const*, char const*) [/Users/pcorey/.nvm/versions/node/v12.12.0/bin/node]
 3: 0x100176137 v8::Utils::ReportOOMFailure(v8::internal::Isolate*, char const*, bool) [/Users/pcorey/.nvm/versions/node/v12.12.0/bin/node]
 4: 0x1001760d3 v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, bool) [/Users/pcorey/.nvm/versions/node/v12.12.0/bin/node]
 ...

Your environment

Packages / Softwares	Version(s)
fast-check	1.19.0
node	12.12.0

[ca-d]

@pcorey @dubzzz I don’t know what it says about the state of communication on the wider web in general, but I feel the strong urge to point out how much my heart was warmed by the mutually constructive, respectful, and kind way in which the two of you exchanged feedback on each other’s code in this thread. Thank you ❣️

[pcorey]

No worries. Thanks for the help @dubzzz.