Invocation-with-odd-paths

Invocation with odd paths

The invocation and dot-sourcing operators & and . are used to invoke commands and script blocks. In particular they are used to invoke scripts specified by their paths. It turns out some paths are troublesome.

The script test.1.invocation.ps1 creates the script .\test[\test.ps1 in the odd directory test[. Then this test script is invoked by the operator & using the relative and full paths:

    # this works in v2, v3, v4 and fails in v5
    & '.\test[\test.ps1'

    # this fails due to the invalid wildcard
    & "$PSScriptRoot\test[\test.ps1"

The script test.2.dot-sourcing.ps1 shows that the dot-sourcing operator . has the same issues.

Best workaround

Ensure your scripts are not in the paths with wildcard characters. If this is the option then this is the best workaround. Note that PowerShell has other issues in paths with wildcard characters. For example:

• Get-Item
• Test-Path
• Unexpected-start-location

True workaround

Escape wildcard characters in full paths with backticks. Note that this can be tricky in double quoted strings, backticks should be escaped themselves and proper number of backticks is not always obvious.

Consider to avoid relative paths. They are treated differently depending on the version. Relative paths are processed literally in v2, v3, v4. In v5 they have the same issue as full paths but use different escaping.

The script test.3.escaped.ps1 shows how to escape full paths and relative paths. The latter is needed only in v5, in other versions escaping causes errors.