🐛 Bug: --check-leaks only detects leak the first time (e.g. when running twice with `--watch`)

[fatso83]

I have the following bit of code, for which mocha correctly detects a leak:

describe('leak detection', function() {

    function testMe(){
        x = 123; // here I add 'var ' to make the test pass
    }

    it('should not leak', function() {
        testMe();
    });
});

By substituting 'x' for 'var x' the test passes. Seemingly, the same applies when running mocha with the --watch task, but when I remove the var statement the test still passes without any error about leaking. This is a bug.

$ mocha --check-leaks --watch

  leak detection
    ✓ should not leak
    1) should not leak

  1 passing (13ms)
  1 failing

  1) leak detection should not leak:
     Error: global leak detected: x

  leak detection
    ✓ should not leak

  1 passing (1ms)

  leak detection
    ✓ should not leak

  1 passing (2ms)

Using mocha 2.3.3 on Node 4.2.1

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[ScottFreeCode]

This behavior is still present; doesn't have anything to do with adding or removing var, it's just that after the assignment of the global in the first run, subsequent runs don't detect the assignment because Mocha's global leak detection specifically ignores globals that were already there before the test started.

I don't know if there's a reasonable fix for that, however.

[anpaul0615]

I think adding reset logic (always set to first runtime global variables) to the lib\cli\watch-run.js will be able to detect it properly every run on watch mode.