PSAvoidTrailingWhitespace: Rule not applied when using formatter + single character lines with trailing whitespace are truncated

[liamjpeters]

PR Summary

• Added PSAvoidTrailingWhitespace to the list of rules considered by the formatter (an entry for the rule is still required in the Rules part of settings).

  Fixes #1992

• Fixed an issue where lines starting with and containing a single character, that have trailing white-space, are truncated when formatted/fixed. See comment in #1992 for explanation.

  Fixes #1757

PR Checklist

• [x] PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• [x] Summarized changes
• [x] Change is not breaking
• [x] Make sure all .cs, .ps1 and .psm1 files have the correct copyright header
• [x] Make sure you've added a new test if existing tests do not effectively test the code changed and/or updated documentation
• [x] This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: to the beginning of the title and remove the prefix when the PR is ready.

[Ju-l1a]

I don't know if this is to do with this issue specifically but I've found that with this branch the fix for PSAvoidTrailingWhitespace gets applied when using Invoke-ScriptAnalyzer -Fix ... but not when using Invoke-Formatter .... I don't seem to have this problem for any other rules I've tried.

Edit: actually I'm getting the same for PSPossibleIncorrectComparisonWithNull.

[liamjpeters]

Hey @Ju-l1a 👋,

You need to tell the formatter to include that rule when carrying out the formatting.

$Settings = @{
    IncludeRules = @("PSAvoidTrailingWhitespace")
    Rules = @{
        "PSAvoidTrailingWhitespace" = @{}
    }
}

So the below code, with lots of trailing whitespace:

$ScriptDef = @"
    Function Get-Example {
        'Example'`t`t`t
    }`t`t`t
"@

Is not altered when running:

Invoke-Formatter -ScriptDefinition $ScriptDef

But is fixed when running:

Invoke-Formatter -ScriptDefinition $ScriptDef -Settings $Settings

Hope that helps!