using module statement with a relative path not treated as relative to the location of the enclosing script when forward slashes are used #7424
Description
Update: @PetSerAl has determined that the problem only surfaces with / as the path separator, not \.
Needless to say, / should be supported, because it is the native paths separator on Unix-like platforms and since it must be used for filesystem paths that work across all platforms.
Steps to reproduce
Set-Location /tmp # change to tmp dir. (make sure it exists)
# Create a module
'function Get-Foo { "hi from t.psm1" }' > t.psm1
# Create a script that references the module
# with `using module` and a *relative path* with */*
# Using '.\t.psm1` would *not* surface the problem.
'using module ./t.psm1; Get-Foo' > t.ps1
# Invoke the script from the current location:
./t.ps1
# Change to a different location and invoke again.
Set-Location /; /tmp/t.ps1Expected behavior
hi from t.psm1
hi from t.psm1
Actual behavior
hi from t.psm1
/tmp/t.ps1 : The specified module '/t.psm1' was not loaded because no valid module file was found in any module directory.
# ...
That is, invoking the script from a location other than the one where it resides breaks the using module statement, because the relative path is seemingly interpreted relative to the current location rather than the script's.
As an aside: Fixing this also requires attention to symlinks: if the enclosing script is a symlink, its ultimate target's location should serve as the reference point.
Environment data
PowerShell Core v6.1.0-preview.4 on macOS 10.13.6
PowerShell Core v6.1.0-preview.4 on Ubuntu 16.04.4 LTS
PowerShell Core v6.1.0-preview.4 on Microsoft Windows 10 Pro (64-bit; Version 1803, OS Build: 17134.165)
Windows PowerShell v5.1.17134.165 on Microsoft Windows 10 Pro (64-bit; Version 1803, OS Build: 17134.165)