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fs.statSync, fs.stat and fs.promises.stat returns 'Invalid Date' for atime/ctime/mtime with negative epoch time #43707

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#43714
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fs.statSync, fs.stat and fs.promises.stat returns 'Invalid Date' for atime/ctime/mtime with negative epoch time#43707
#43714
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confirmed-bugIssues and PRs for confirmed bugs.fsIssues and PRs related to file-system APIs and the fs module.

Description

@hideishi-m
hideishi-m
opened on Jul 7, 2022

Version

v16.15.1

Platform

Linux localhost.localdomain 4.18.0-394.el8.x86_64 #1 SMP Tue May 31 16:19:11 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

Subsystem

File system

What steps will reproduce the bug?

  1. create a file with minus epoch time.
$ touch --date=@-1 hogehoge
$ ls --full-time hogehoge
-rw-rw-r--. 1 kusanagi kusanagi 0 1969-12-31 23:59:59.000000000 +0000 hogehoge
  1. run the following code to test fs.statSync and fs.promises.stat for file hogehoge.
import { stat } from 'fs/promises';
import { statSync } from 'fs';

async function test() {
        const stats = await stat('hogehoge');
        console.log({stats});
        console.log(stats.mtime);
        console.log(stats.mtime.getTime());
}

function testSync() {
        const stats = statSync('hogehoge');
        console.log({stats});
        console.log(stats.mtime);
        console.log(stats.mtime.getTime());
}

await test();
testSync();
{
  stats: Stats {
    dev: 64768,
    mode: 33204,
    nlink: 1,
    uid: 1000,
    gid: 1000,
    rdev: 0,
    blksize: 4096,
    ino: 56395369,
    size: 0,
    blocks: 0,
    atimeMs: 1.8446744073709552e+22,
    mtimeMs: 1.8446744073709552e+22,
    ctimeMs: 1657161984281.557,
    birthtimeMs: 1657161921560.5312,
    atime: Invalid Date,
    mtime: Invalid Date,
    ctime: 2022-07-07T02:46:24.282Z,
    birthtime: 2022-07-07T02:45:21.561Z
  }
}
Invalid Date
NaN
{
  stats: Stats {
    dev: 64768,
    mode: 33204,
    nlink: 1,
    uid: 1000,
    gid: 1000,
    rdev: 0,
    blksize: 4096,
    ino: 56395369,
    size: 0,
    blocks: 0,
    atimeMs: 1.8446744073709552e+22,
    mtimeMs: 1.8446744073709552e+22,
    ctimeMs: 1657161984281.557,
    birthtimeMs: 1657161921560.5312,
    atime: Invalid Date,
    mtime: Invalid Date,
    ctime: 2022-07-07T02:46:24.282Z,
    birthtime: 2022-07-07T02:45:21.561Z
  }
}
Invalid Date
NaN

How often does it reproduce? Is there a required condition?

Always.

What is the expected behavior?

ctime/mtime/atime with negative epoch time shall be treated as it is.
In other words, if -1 then it shall be 1 second before epoch.

Actually, Date() supports negative epoch time.

$ node
Welcome to Node.js v16.15.1.
Type ".help" for more information.
> new Date(-1)
1969-12-31T23:59:59.999Z
>

As stat(2) supports negative epoch time, which can be observed via ls command, I don't see why fs.stat/fs.statSync/fs.promises.stat treats negative epoch as NaN.

What do you see instead?

$ touch --date=@-1 hogehoge
$ ls --full-time hogehoge
-rw-rw-r--. 1 kusanagi kusanagi 0 1969-12-31 23:59:59.000000000 +0000 hogehoge

$ cat > test.mjs
import { stat } from 'fs/promises';
import { statSync } from 'fs';

async function test() {
        const stats = await stat('hogehoge');
        console.log({stats});
        console.log(stats.mtime);
        console.log(stats.mtime.getTime());
}

function testSync() {
        const stats = statSync('hogehoge');
        console.log({stats});
        console.log(stats.mtime);
        console.log(stats.mtime.getTime());
}

await test();
testSync();

$ node test.mjs
{
  stats: Stats {
    dev: 64768,
    mode: 33204,
    nlink: 1,
    uid: 1000,
    gid: 1000,
    rdev: 0,
    blksize: 4096,
    ino: 56395369,
    size: 0,
    blocks: 0,
    atimeMs: 1.8446744073709552e+22,
    mtimeMs: 1.8446744073709552e+22,
    ctimeMs: 1657161984281.557,
    birthtimeMs: 1657161921560.5312,
    atime: Invalid Date,
    mtime: Invalid Date,
    ctime: 2022-07-07T02:46:24.282Z,
    birthtime: 2022-07-07T02:45:21.561Z
  }
}
Invalid Date
NaN
{
  stats: Stats {
    dev: 64768,
    mode: 33204,
    nlink: 1,
    uid: 1000,
    gid: 1000,
    rdev: 0,
    blksize: 4096,
    ino: 56395369,
    size: 0,
    blocks: 0,
    atimeMs: 1.8446744073709552e+22,
    mtimeMs: 1.8446744073709552e+22,
    ctimeMs: 1657161984281.557,
    birthtimeMs: 1657161921560.5312,
    atime: Invalid Date,
    mtime: Invalid Date,
    ctime: 2022-07-07T02:46:24.282Z,
    birthtime: 2022-07-07T02:45:21.561Z
  }
}
Invalid Date
NaN

Additional information

No response

Activity

  1. targos commented on Jul 7, 2022

    @targos
    targos
    on Jul 7, 2022
    Member

    @nodejs/fs

  2. bnoordhuis
    added
    confirmed-bugIssues and PRs for confirmed bugs.
    fsIssues and PRs related to file-system APIs and the fs module.
    on Jul 7, 2022

  3. bnoordhuis commented on Jul 7, 2022

    @bnoordhuis
    bnoordhuis
    on Jul 7, 2022
    Member

    It's a signed-to-unsigned conversion bug:

    $ touch -t 196912312359.59 x && node -p 'fs.statSync("x", {bigint: true})' | grep Ns
  atimeNs: 18446744073709548015000000000n,
  mtimeNs: 18446744073709548015000000000n,
  ctimeNs: 1657177398636601096n,
  birthtimeNs: 1657177398636510656n,

    Internally, the stats are handed off from C++ to JS in a BigUint64Array but that makes negative values wrap around. The fix is to use a BigInt64Array instead. Pull request welcome.

    edit: in particular, it's this (insidiously misnamed) field:

    node/src/node_file.h

    Line 21 in 7d13f5e

    AliasedBigUint64Array stats_field_bigint_array;

    And here is where it's converted to a stats object:

    node/lib/internal/fs/utils.js

    Lines 534 to 545 in 7d13f5e

    if (isBigUint64Array(stats)) {
    return new BigIntStats(
    stats[0 + offset], stats[1 + offset], stats[2 + offset],
    stats[3 + offset], stats[4 + offset], stats[5 + offset],
    stats[6 + offset], stats[7 + offset], stats[8 + offset],
    stats[9 + offset],
    nsFromTimeSpecBigInt(stats[10 + offset], stats[11 + offset]),
    nsFromTimeSpecBigInt(stats[12 + offset], stats[13 + offset]),
    nsFromTimeSpecBigInt(stats[14 + offset], stats[15 + offset]),
    nsFromTimeSpecBigInt(stats[16 + offset], stats[17 + offset])
    );
    }

  4. LiviaMedeiros commented on Jul 7, 2022

    @LiviaMedeiros
    LiviaMedeiros
    on Jul 7, 2022
    Member

    Non-bigint stats are returned as Float64Array so perhaps this requires adjusting unsigned long longs (or what it's aliased to) in C++ bindings as well.

  5. bnoordhuis commented on Jul 7, 2022

    @bnoordhuis
    bnoordhuis
    on Jul 7, 2022
    Member

    Sorry yes, I forgot to mention that. That logic is here:

    node/src/node_file-inl.h

    Lines 93 to 95 in 7d13f5e

    #define SET_FIELD_WITH_TIME_STAT(stat_offset, stat) \
    /* NOLINTNEXTLINE(runtime/int) */ \
    SET_FIELD_WITH_STAT(stat_offset, static_cast<unsigned long>(stat))

  6. nodejs-github-bot
    closed this as completedin #43714on Jul 18, 2022
  7. nodejs-github-bot
    added a commit that references this issue on Jul 18, 2022

    fs: use signed types for stat data

    5d8281e

  8. LiviaMedeiros commented on Jul 18, 2022

    @LiviaMedeiros
    LiviaMedeiros
    on Jul 18, 2022
    Member

    Note: on Windows platform, there still is an overflow on negative dates, to postpone Y2038 overflow.
    It shouldn't lead to Invalid Date, and right now is unavoidable without breaking underlying ABI.

  9. danielleadams
    added a commit that references this issue on Jul 26, 2022

    fs: use signed types for stat data

    100f6de
  10. targos
    added a commit that references this issue on Sep 5, 2022

    fs: use signed types for stat data

    a513f2b

  11. girlfriendfletcher commented on Oct 14, 2025

    @girlfriendfletcher
    girlfriendfletcher
    on Oct 14, 2025

    @LiviaMedeiros https://treacherylex.github.io/2gzu7uSJzYgn4NSrXqx6vOeaoaPwIOdxYI2RjPi0y_ZNSbr1lTsp/

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