System.IO.Tests.File_GetSetTimes.SetDateTimeMax fails on Ubuntu 18.04 in the CI

[janvorli]

In two of my unrelated CIs, the System.IO.Tests.File_GetSetTimes.SetDateTimeMax test keeps failing on Ubuntu 18.04 with the following error:

Assert.Equal() Failure\nExpected: 9999-04-11T23:47:17.0210000Z\nActual:   2446-05-10T22:38:55.0000000Z

There was a notice from the engineering team that they have updated Ubuntu 18.04 image to the latest version, so I wonder if it is related. Setting the file time calls utimes or utimensat glibc functions, so their implementation w.r.t. clipping the max time could have possibly changed.

Runfo Tracking Issue: System.IO.Tests.File_GetSetTimes.SetDateTimeMax fails on Ubuntu 18.04 in the CI

Build	Definition	Kind	Run Name

Build Result Summary

Day Hit Count	Week Hit Count	Month Hit Count
0	0	0

[janvorli]

Here is a link to the report on the test failure:
https://dev.azure.com/dnceng/public/_build/results?buildId=844366&view=ms.vss-test-web.build-test-results-tab&runId=26886200&resultId=147130&paneView=debug

[janvorli]

I can repro the issue on my local Ubuntu 18.04 VM too.

[janvorli]

It seems there was a kernel patch that enabled limits on the time stamps, see https://lore.kernel.org/lkml/20190730014924.2193-10-deepa.kernel@gmail.com/. The timestamp limit mentioned in that page matches what we are getting as the actual value in the test.

[stephentoub]

I'm disabling the test for now on Linux in #43178.

[danmoseley]

Fix I guess is to update

runtime/src/libraries/System.IO.FileSystem/tests/File/GetSetTimes.cs

Line 16 in 5104f58

private static bool SupportsLongMaxDateTime => PlatformDetection.IsWindows || (!PlatformDetection.Is32BitProcess && !PlatformDetection.IsOSXLike);

[danmoseley]

Eh, I guess not that simple; it seems it's filesystem specific.

[am11]

Since from this point onward, Linux kernels will not have long max datetime support, I think we can simply exclude Linux from this test's matrix? macOS and 32bit Unix are already excluded, regardless of filesystem type (e.g. NTFS macOS will pass this test in practice but we seem to only care about the default file system of platform).
IMO:

--- a/src/libraries/System.IO.FileSystem/tests/File/GetSetTimes.cs
+++ b/src/libraries/System.IO.FileSystem/tests/File/GetSetTimes.cs
@@ -11,10 +11,6 @@ namespace System.IO.Tests
 {
     public class File_GetSetTimes : StaticGetSetTimes
     {
-        // OSX has the limitation of setting upto 2262-04-11T23:47:16 (long.Max) date.
-        // 32bit Unix has time_t up to ~ 2038.
-        private static bool SupportsLongMaxDateTime => PlatformDetection.IsWindows || (!PlatformDetection.Is32BitProcess && !PlatformDetection.IsOSXLike);
-
         protected override string GetExistingItem()
         {
             string path = GetTestFilePath();
@@ -148,7 +144,7 @@ public void SetUptoNanoseconds()
             Assert.Equal(ticks, dateTime.Ticks);
         }
 
-        [ConditionalFact(nameof(SupportsLongMaxDateTime))]
+        [PlatformSpecific(TestPlatforms.Windows)]
         public void SetDateTimeMax()
         {
             string file = GetTestFilePath();

[danmoseley]

Seems this issue can be closed, since the test no longer runs on Linux?