ConsoleHost tests fail with interactive use and redirected stdin #625

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1. lzybkr commented on Jan 23, 2018

   

   Jason Shirk (lzybkr)

   on Jan 23, 2018

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   It's possible this is related to #618 - as in, the fix might fix both.
2. daxian-dbw commented on Mar 16, 2018

   

   Dongbo Wang (daxian-dbw)

   on Mar 16, 2018

   Last edited by daxian-dbw

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   Jason Shirk (@lzybkr) I found when running on Windows, PSReadline detects whether the standard input or output is redirected, and in such a case, it will throw an NotSupportedException to let PowerShell handles the input.
   The code is at PlatformWindows.Init.

   However, it doesn't do the same on Unix platforms, and eventually Console.KeyAvailable throws an InvalidOperationException from ReadOneOrMoreKeys() because the stdin is redirected.

   Is it intentional for PSReadline to handle input and output on Unix even if stdin or stdout is redirected? Note that in the version of PSReadline that is currently used in PSCore, we throw NotSupportedException on all platforms when stdin or stdout is redirected.
3. lzybkr commented on Mar 16, 2018

   

   Jason Shirk (lzybkr)

   on Mar 16, 2018

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   Dongbo Wang (@daxian-dbw) - For some reason I thought corefx would handle redirected input because it's technically feasible to do so on Unix with a proper tty, but I see that they don't, and instead match Windows by throwing, see here.

   Parker Snell (@parkovski) implemented the necessary support for redirected input on Windows, most of that code would actually work for the most common terms on Unix, but corefx would have better support for more terminals because it reads the term database.

   So I do think it is a scenario that needs to be supported, but it should be fine to disable for now.

   As long as you are dealing with this issue, I wonder if #618 is related, it's possible docker is using redirected input as well, though I thought PSReadLine worked in docker, so I might be wrong here.
4. daxian-dbw commented on Mar 16, 2018

   

   Dongbo Wang (daxian-dbw)

   on Mar 16, 2018

   Last edited by daxian-dbw

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   So far, I don't see this issue is related to #618. But I didn't debug in a container, so no guarantee yet.

   So I do think it is a scenario that needs to be supported, but it should be fine to disable for now.

   So I guess redirected standard input/output will be supported by PSReadline in future, but for now, it's OK to disable PSReadline in such cases on all platforms. I will submit a PR to make PSReadline throw NotSupportedException on Unix too, in case that stdin or stdout is redirected.

   For #618, if it always happens when running in a container, then it would become a blocking issue for PSCore use PSReadline 2.0 by default. Will look into that later.
5. Jason Shirk (lzybkr)

   closed this as completedin #648on Mar 20, 2018
6. Jason Shirk (lzybkr)

   added a commit that references this issue on Mar 20, 2018

   Disable PSReadline on Unix when stdin or stdout is redirected (#648)

   ...

   This issue will close once commit 62cf9f8 is merged into the 'master' branch.

   62cf9f8