[jira] [Updated] (MESOS-5880) Semantics of `environment` differ across Windows and POSIX

["Alex Clemmer (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/MESOS-5880?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Alex Clemmer updated MESOS-5880:
--------------------------------
    Summary: Semantics of `environment` differ across Windows and POSIX  (was: Make `environment` semantics uniform across Windows and POSIX)

> Semantics of `environment` differ across Windows and POSIX
> ----------------------------------------------------------
>
>                 Key: MESOS-5880
>                 URL: https://issues.apache.org/jira/browse/MESOS-5880
>             Project: Mesos
>          Issue Type: Bug
>          Components: stout
>            Reporter: Alex Clemmer
>            Assignee: Alex Clemmer
>              Labels: mesosphere, stout
>
> Preliminary investigation shows that our current Windows implementations of `os::environment`, `os::setenv`, and `os::getenv` fail to set flags in some cases. This leads to test failures on Windows in:
> * `flags_tests.cpp` (MESOS-3437), namely `LoadFromEnvironment`
> * `os_tests.cpp` (MESOS-3441), namely `Environment`
> A preliminary investigation shows:
> * These failures occur because the C standard API for environment variables are incompatible. That is, `os::environment` uses the C standard implementation of the `environ` macro, while `os::setenv` and `os::putenv` use the Win32 APIs for environment variables, like `GetEnvironmentVariable` and `SetEnvironmentVariable`. But, `SetEnvironmentVariable` does not affect the environment reported by `environ`, so updates are not reflected when we call `os::environ`.
> * It is unlikely we will want to use the C equivalents of the `Get/SetEnvironmentVariable`, (that is, `setenv_s` and friends), because they have different behavior on Windows than on other libc implementations. Specifically, on Windows `setenv_s("yourvar", "")` unsets the variable `yourvar`, while on other implementations, it sets the value of `yourvar` to be the empty string.
> * But, transitioning to a pure Win32 implementation (i.e., one using `Set/GetEnvironmentVariable`, `GetEnvironmentStrings`, etc.), probably requires changing or getting rid of `os::environment*` APIs. Specifically, `os::raw::environment` and `os::environmentp` will probably be eliminated.



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