Description
We use a DSL to configure a system.
We load it with vm.
Sometimes, for debuging purposes, we use top level variables in the DSL,
that are read and modified by several functions.
After a few executions of these functions, modifications done by one function
is not seen by others.
Tested with iojs-1.1.0.
It doesn't happen with node-0.12.0.
The following code reproduces the bug in a simplified framework.
The DSL executor:
var vm = require('vm');
var fs = require('fs');
function include(script) {
vm.runInContext(fs.readFileSync(script), ctxt, script);
}
var jobs = [];
function job(name, n, action) {
jobs.push({name: name, times: n, action: action});
}
var sandbox = {
console: console,
job: job
};
var ctxt = vm.createContext(sandbox);
function load() {
for (var i = 2; i < process.argv.length; i++) include(process.argv[i]);
}
function execute(jobs) {
for (var i = 0; i < 2; i++) {
for (var j = 0; j < jobs.length; j++) {
var job = jobs[j];
var times = job.times;
var action = job.action;
console.info("Executing " + job.name + " (" + times + ")");
for (var k = 0; k < times; k++) {
action();
}
}
}
}
load();
execute(jobs);A configuration script to give as argument
var n = 0;
job("Action 1", 1000, function() {
n++;
});
job("Action 2", 1, function() {
console.info("Action 2 output: " + n);
n=0;
});Executed with node-0.12.0 the result is as expected:
Executing Action 1 (1000)
Executing Action 2 (1)
Action 2 output: 1000
Executing Action 1 (1000)
Executing Action 2 (1)
Action 2 output: 1000
Executed with iojs-1.1.0 the result is
Executing Action 1 (1000)
Executing Action 2 (1)
Action 2 output: 517
Executing Action 1 (1000)
Executing Action 2 (1)
Action 2 output: 0
The value 517 differs on each execution.
I suppose it depends on the V8 optimization process.
Probably related to #548
and nodejs/node-v0.x-archive#9084