Special case DateTime/TimeSpan in Format-Custom

[powercode]

Produce one-line output in Format-Custom for DateTime by default

Dates and times get really spammy in Format-Custom

This simple object with a datetime

[pscustomobject]@{Time = [datetime]::now} | format-custom

produces 148 lines of output!

class PSCustomObject
{
  Time = 
    class DateTime
    {
      Date = 
        class DateTime
        {
          Date = 
            class DateTime
            {
              Date = 
                class DateTime
                {
                  Date = 
                    class DateTime
                    {
                      Date = 2022-09-21 00:00:00
                      Day = 21
                      DayOfWeek = Wednesday
                      DayOfYear = 264
                      Hour = 0
                      Kind = Local
                      Millisecond = 0
                      Minute = 0
                      Month = 9
                      Second = 0
                      Ticks = 637993152000000000
                      TimeOfDay = 00:00:00
                      Year = 2022
                      DateTime = den 21 september 2022 00:00:00
                    }
                  Day = 21
                  DayOfWeek = Wednesday
                  DayOfYear = 264
                  Hour = 0
                  Kind = Local
                  Millisecond = 0
                  Minute = 0
                  Month = 9
                  Second = 0
                  Ticks = 637993152000000000
                  TimeOfDay = 
                    class TimeSpan
                    {
                      Ticks = 0
                      Days = 0
                      Hours = 0
                      Milliseconds = 0
                      Minutes = 0
                      Seconds = 0
                      TotalDays = 0
                      TotalHours = 0
                      TotalMilliseconds = 0
                      TotalMinutes = 0
                      TotalSeconds = 0
                    }
                  Year = 2022
                  DateTime = den 21 september 2022 00:00:00
                }
              Day = 21
              DayOfWeek = Wednesday
              DayOfYear = 264
              Hour = 0
              Kind = Local
              Millisecond = 0
              Minute = 0
              Month = 9
              Second = 0
              Ticks = 637993152000000000
              TimeOfDay = 
                class TimeSpan
                {
                  Ticks = 0
                  Days = 0
                  Hours = 0
                  Milliseconds = 0
                  Minutes = 0
                  Seconds = 0
                  TotalDays = 0
                  TotalHours = 0
                  TotalMilliseconds = 0
                  TotalMinutes = 0
                  TotalSeconds = 0
                }
              Year = 2022
              DateTime = den 21 september 2022 00:00:00
            }
          Day = 21
          DayOfWeek = Wednesday
          DayOfYear = 264
          Hour = 0
          Kind = Local
          Millisecond = 0
          Minute = 0
          Month = 9
          Second = 0
          Ticks = 637993152000000000
          TimeOfDay = 
            class TimeSpan
            {
              Ticks = 0
              Days = 0
              Hours = 0
              Milliseconds = 0
              Minutes = 0
              Seconds = 0
              TotalDays = 0
              TotalHours = 0
              TotalMilliseconds = 0
              TotalMinutes = 0
              TotalSeconds = 0
            }
          Year = 2022
          DateTime = den 21 september 2022 00:00:00
        }
      Day = 21
      DayOfWeek = Wednesday
      DayOfYear = 264
      Hour = 9
      Kind = Local
      Millisecond = 945
      Minute = 36
      Month = 9
      Second = 31
      Ticks = 637993497919455174
      TimeOfDay = 
        class TimeSpan
        {
          Ticks = 345919455174
          Days = 0
          Hours = 9
          Milliseconds = 945
          Minutes = 36
          Seconds = 31
          TotalDays = 0,400369739784722
          TotalHours = 9,60887375483333
          TotalMilliseconds = 34591945,5174
          TotalMinutes = 576,53242529
          TotalSeconds = 34591,9455174
        }
      Year = 2022
      DateTime = den 21 september 2022 09:36:31
    }
}

I suggest that we should special-case DateTime in the custom formatted to only print the string same string as we get when we limit the depth:

[pscustomobject]@{Obj = [PSCustomObject]@{Time = [datetime]::now}} | fc -Depth 1

class PSCustomObject
{
  Obj =
    class PSCustomObject
    {
      Time = 2022-09-21 09:38:35
    }
}

So that

[pscustomobject]@{Time = [datetime]::now} | format-custom

would output

class PSCustomObject
{
    Time = 2022-09-21 09:38:35
}

Maybe use -Force to get the full recursive version?

Proposed technical implementation details (optional)

No response

[SteveL-MSFT]

You can see a more real world case with dir * | select -first 1 | format-custom which has a datetime property that does the same. I would agree that the current output is probably not as useful as rendering datetime as a single string. If we are special casing datetime only, then I don't like using the ambiguous -force to get current behavior and would prefer something like -expanddatetime.

[dkaszews]

I don't like using the ambiguous -force to get current behavior and would prefer something like -expanddatetime.

+1 to that, -Force already has way too many different meanings, from obvious overwriting existing files in Move-Item to odd like showing hidden files in Get-ChildItem.

[powercode]

How about a more general parameter like -ExpandType:string[]?

# get single line date
dir | select -first 1 | format-custom 

# get way too much output
dir | select -first 1 | format-custom -ExpandType:System.Datetime, SomeFutureNoisyType

[powercode]

DateTime already has an entry for custom formatting, but it is not applied when datetime is a member.

        private static IEnumerable<FormatViewDefinition> ViewsOf_System_DateTime()
        {
            yield return new FormatViewDefinition("DateTime",
                CustomControl.Create()
                    .StartEntry()
                        .AddPropertyExpressionBinding(@"DateTime")
                    .EndEntry()
                .EndControl());
        }

[DateTime]::Now | format-custom

den 14 oktober 2022 09:51:00

[sdwheeler]

@JamesWTruher Can you provide an opinion here?

[JamesWTruher]

There are some types in dotnet which have elements of recursion and datetime is one of those. Remember that the a new formatting frame is not added once you start rendering, so if you have format-custom with any dotnet type which is recursive then this may occur. We do, IIRC, have a limit to the depth that we render (I think it's 5), and it is settable with the -depth parameter. Perhaps this is something that could be used.

And, as you've noticed, In the non-custom formatting cases, we simply call the ToString on the member.

This is all for the relatively low use case of Format-Custom where specific formatting has not been created. It seems a relatively low impact case to me to expend much energy. Especially considering that it might be a bit complicated to generalize a solution for any case where the object has this recursive behavior.