A small node fs.watch test case. Calls to FSWatcher.close() hang on Mac if the number of watch calls is too high---sometimes as low as 4 or 5. Reproduces on 0.10.18 and 0.11.7 but not 0.8.20.

node-watcher-test.js

/*jslint node:true, vars: true, plusplus: true */
/*global require */

var fs = require("fs");

(function () {
    "use strict";
    
    function getDirectoryNames(prefix, depth) {
        var dirname = "",
            dirnames = [],
            i;
        
        for (i = 0; i < depth; i++) {
            dirname += prefix + i + "/";
            dirnames.push(dirname);
        }
        
        return dirnames;
    }
    
    function createDirectories(dirs) {
        dirs.forEach(function (dir) {
            try {
                fs.mkdirSync(dir);
            } catch (err) { }
        });
    }
    
    function watchDirectories(dirs) {
        console.log("Watching directories...");
        var watchers = {};
        dirs.forEach(function (dir) {
            console.log("Watching: ", dir);
            watchers[dir] = fs.watch(dir, function (e) {
                console.log("Change: ", dir);
            });
        });
        console.log("Done.");
        return watchers;
    }
    
    function unwatchDirectories(watchers) {
        var dir;
        console.log("Unwatching directories...");
        Object.keys(watchers)
            .sort(function (a, b) {
                return a.length - b.length;
            })
            .forEach(function (dir) {
                var watcher = watchers[dir];
                console.log("Unwatching: ", dir);
                watcher.close();
            });
        console.log("Done.");
    }
    
    var NUM_DIRS = 5;
    
    var dirnames1 = getDirectoryNames("t1-", NUM_DIRS),
        dirnames2 = getDirectoryNames("t2-", NUM_DIRS);

    createDirectories(dirnames1);
    createDirectories(dirnames2);


    var watchers1 = watchDirectories(dirnames1);
    
    unwatchDirectories(watchers1);
    
    var watchers2 = watchDirectories(dirnames2);
    
    unwatchDirectories(watchers2);
}());