Use set on Windows, not export

[ilonatommy]

Found in library logs: #116695 (comment).

'export' is not recognized as an internal or external command

log

TargetOS is browser and command form should not depend on it. The change removes the error from logs.

[Copilot]

Pull Request Overview

This PR addresses an issue from runtime logs by correcting the command used for setting environment variables on Windows.

• Replace condition from using "$(TargetOS)" to using "$(OS)" for proper Windows detection.
• Update both Windows and non-Windows branches to ensure the appropriate command ("set" for Windows, "export" for others) is used.

Comments suppressed due to low confidence (2)

eng/testing/xunit/xunit.console.targets:16

• Ensure that the $(OS) variable is consistently set in all expected environments; if there is any risk it might be missing in some CI configurations, consider adding a fallback or additional documentation.

    <SetScriptCommands Condition="'$(OS)' == 'Windows_NT'" Include="set XUNIT_HIDE_PASSING_OUTPUT_DIAGNOSTICS=1" />

eng/testing/xunit/xunit.console.targets:17

• Verify that using the $(OS) condition for non-Windows environments reliably covers all target platforms, and document any assumptions if necessary.

    <SetScriptCommands Condition="'$(OS)' != 'Windows_NT'" Include="export XUNIT_HIDE_PASSING_OUTPUT_DIAGNOSTICS=1" />

[lewing]

This keeps getting flipped back and forth https://github.com/dotnet/runtime/pull/107349/files

[ilonatommy]

This keeps getting flipped back and forth https://github.com/dotnet/runtime/pull/107349/files

We can wait for @pavelsavara but looking in the binlog, the check for TargetOS does not make sense.

javascript.interop.tests.binlog.zip

[maraf]

We have non trivial amount placed where we set envvars like this. We have to always duplicate the lines. Could we do better?

[maraf]

This keeps getting flipped back and forth https://github.com/dotnet/runtime/pull/107349/files

Wasm.Build.Tests use OS as well

[ilonatommy]

We have non trivial amount placed where we set envvars like this. We have to always duplicate the lines. Could we do better?

For this particular case (envvar setting) we could have

<PropertyGroup>
  <EnvVarCommand Condition="'$(OS)' == 'Windows_NT'">set</EnvVarCommand>
  <EnvVarCommand Condition="'$(OS)' != 'Windows_NT'">export</EnvVarCommand>
</PropertyGroup>

<ItemGroup>
  <SetScriptCommands Include="$(EnvVarCommand) XUNIT_HIDE_PASSING_OUTPUT_DIAGNOSTICS=1" />
</ItemGroup>

not yet sure where to set the 1st part, to be early enough for all the test cases.

Edit:
we also are checking for Condition="'$(TargetsWindows)' == 'true' or '$(TargetPlatformIdentifier)' == 'windows'"

runtime/eng/testing/tests.props

Line 30 in 3c5f74a

<RunScriptCommands Condition="'$(TargetsWindows)' == 'true' or '$(TargetPlatformIdentifier)' == 'windows'" Include="set MONO_ENV_OPTIONS='$(MonoEnvOptions)'" />

for WindowsShell in helix-related actions and for TestWrapperTargetsWindows in helix&arcade.