File timestamp resolution is inconsistent with fs.stat / fs.utimes

[RustyMarvin]

In node 0.11.11 under windows 7
the file timestamp resolution of fs.stat seems to be 1 millisecond, but if i try to set the timestamps, the resolution seems to be only 1 second. This is inconsistent.

> process.version
'v0.11.11'
> fs.writeFileSync('test.txt', 'abc');
undefined
> fs.statSync('test.txt').mtime.getTime();
1391100066267
> fs.utimesSync('test.txt', new Date(1356171132123), new Date(1356171132123));
undefined
> fs.statSync('test.txt').mtime.getTime();
1356171132000

In node 0.10 the resolution seems to be always 1 second.

> process.version
'v0.10.23'
> fs.writeFileSync('test.txt', 'abc');
undefined
> fs.statSync('test.txt').mtime.getTime();
1391100029000
> fs.utimesSync('test.txt', new Date(1356171132123), new Date(1356171132123));
undefined
> fs.statSync('test.txt').mtime.getTime();
1356171132000

I think the resolution should be either 1 second or 1 millisecond, but not mixed.
The timestamp resolution of the underlying windows filesystem NTFS is 100 nanoseconds, so both solutions would be fine ;-)

[tjfontaine]

So there are a couple of things here, first in v0.10 the precision of stat was only ever 1 second, that was changed for v0.11 branch in 51f128d after the integration for libuv.

The other issue you're having here, is that the interface for fs.utimes(path) actually implements utime() which only accepts second resolution.

On the other hand, if you were to use fs.futimes you would actually get subsecond precision

var fs = require('fs');

fs.writeFileSync('test.txt', 'abc');
console.log(fs.statSync('test.txt').mtime.getTime());
var a = new Date(1356171132123);
var b = new Date(1356171132321);
fs.utimesSync('test.txt', a, b);
console.log(fs.statSync('test.txt').mtime.getTime());
var fd = fs.openSync('test.txt', 'r+');
fs.futimesSync(fd, a, b);
console.log(fs.statSync('test.txt').mtime.getTime());

./node t.js
1391135755349
1356171132000
1356171132870

Huge caveat being that this requires filesystems to support subsecond resolution, which not all do -- of note HFS, ext[2,3], FAT.

[fcostarodrigo]

Could the documentation (It only says Integer) be improved to make this clear? It looks like I can pass new Date(), but Date.now() needs to be divided by 1000. According to MDN Date.prototype.valueOf() and Date.now() both return: "The number of milliseconds between 1 January 1970 00:00:00 UTC and the given date."

var fs = require('fs');

fs.writeFileSync('test.txt', 'abc');
console.log('    ok', fs.statSync('test.txt').atime.getTime());

fs.utimesSync('test.txt', new Date(), new Date());
console.log('    ok', fs.statSync('test.txt').atime.getTime());

console.log('    ok', Date.now());

fs.utimesSync('test.txt', Date.now(), Date.now());
console.log('not ok', fs.statSync('test.txt').atime.getTime());

fs.utimesSync('test.txt', Date.now() / 1000, Date.now() / 1000);
console.log('    ok', fs.statSync('test.txt').atime.getTime());

Output

    ok 1474133782000
    ok 1474133783000
    ok 1474133783702
not ok 1474133783702000
    ok 1474133783000

[cjihrig]

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