Suggestion for new rule - Ensure that variables used in a function is always declared in the local scope

[hallgeirl]

In order to reduce the number of hard to debug errors, we run our PowerShell scripts with Set-StrictMode -Version Latest. This lets us catch issues where we e.g. have misspelled a variable name (or forgot to assign it before using it) during runtime. But it would be immensely useful to catch these kinds of errors before we run the scripts, e.g. during an automated build.

We have deployment scripts that run for quite a long time (several hours), and silly misspelled variable names or misplaced variable assignments then costs quite a bit of development time. Catching these errors early would be immensely useful.

Example of something that should cause an error:

function Get-Foobar()
{
    if ($b + 2 -gt 5)
    {
        return $b
    }

    return 5
}

This would be OK:

function Get-Foobar($b)
{
    if ($b + 2 -gt 5)
    {
        return $b
    }

    return 5
}

As would this:

function Get-Foobar()
{
    $b = 123;
    if ($b + 2 -gt 5)
    {
        return $b
    }

    return 5
}

[ghidalgo3]

I agree, this rule would have saved me a lot of time in long-running scripts that cannot be easily reentered. I expect that someone will say "just make sure you spell your variables correctly!" and obviously that defeats the point of the analyzer.

Bumping this suggestion, hope it becomes a feature.

[kapilmb]

Moving this issue to backlog as I think it is closely related to the issue #636. We will revisit this issue after #636 is solved.

[CJHarmath]

+1