Process properties throw Win32Exceptions instead of documented InvalidOperationException

[drauch]

Description

You are not allowed to get some properties on the Process class (at least on Linux) after the process has exited. Reasoning (for the StartTime property) can be found here: #18540 . However, for Linux the correct exception should be documented on https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.process.starttime?view=net-10.0

It is already weird that StartTime throws a _Win32_Exception on Linux if the process has already exited, but it is at least somewhat symmetric to Windows.

However, I realized the same problem exists for other properties as well where this behavior is not documented at all, e.g., TotalProcessorTime throws a Win32Exception which it does not do on Windows (and the exception type is not even documented).

Please bring this in order, either documentation-wise or better implementation wise (Win32Exception is very weird on non Windows platforms).

Best regards,
D.R.

Reproduction Steps

Call Process.TotalProcessorTime on Linux after a process has exited => throws undocumented Win32Exception.

Expected behavior

According to docs: should not throw at all.

Actual behavior

Throws Win32Exception.

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

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[drauch]

Follow-up question: are at least ExitCode and ExitTime guaranteed to not throw on Windows & Linux?

[SamMonoRT]

@adamsitnik - - please triage for 11 or future

[adamsitnik]

Reasoning (for the StartTime property) can be found here: #18540

I've provided more details in #125038 (comment). Long story short, on Unix when the process exits we reap it and after that all information about it is gone (unless some other process happens to re-use the same PID).

Win32Exception is very weird on non Windows platforms

Initially .NET was Windows-only, that is why the type is called Win32Exception. Since all the public APIs were throwing it and we wanted the behavior to be consistent of every platform, we decided to throw Win32Exception on Unix as well. If we were designing the platform from scratch today, we would have not choose this name.

Follow-up question: are at least ExitCode and ExitTime guaranteed to not throw on Windows & Linux?

ExitCode is guaranteed to work for child processes (on Unix, the process can't obtain exit status of non-child process)

[drauch]

@adamsitnik In response to #125038 (comment) (can't comment there anymore, since you closed the issue), can't you cache certain values at process startup (e.g., Process.StartTime) in the Process object and still return it after the process has exited (without re-querying the now-gone information on Linux, just by returning the value from the cache in the Process object?).