build.ps1: harden $Task validator to reject per-element empty/whitespace

[tablackburn]

Background

PR #23 added [ValidateNotNullOrEmpty()] to the $Task parameter in build.ps1:

[ValidateNotNullOrEmpty()]
[string[]]$Task = 'default',

During the cross-repo propagation sweep of this style change (SrrDBAutomationToolkit#20, YouTubeMusicPS#22, ScheduledTasksManager#41, PlexAutomationToolkit#54, ReScenePS#17), Copilot's PR reviewer on ScheduledTasksManager#41 flagged that [ValidateNotNullOrEmpty()] on a [string[]] parameter:

• ✅ rejects $null
• ✅ rejects @() (empty collection)
• ❌ does not reject @('') — ./build.ps1 -Task '' binds as a single-element array containing an empty string and slips past validation

The cross-repo sweep was merged as-is (matching the canonical template) with this gap acknowledged. Tightening the validator at the source means future template-derived repos get the better version for free, and a follow-up propagation PR can clean up the consumer repos.

Proposed fix

Replace the single-attribute validator with a ValidateScript that rejects per-element null/empty/whitespace. Sketch:

[ValidateScript({
    foreach ($t in $_) {
        if ([string]::IsNullOrWhiteSpace($t)) {
            throw "-Task values cannot be null, empty, or whitespace."
        }
    }
    $true
})]
[string[]]$Task = 'default',

Alternative: drop the [string[]] and use [string]$Task if multiple tasks aren't actually a supported use case — but Invoke-psake -TaskList does accept arrays, so the array form should probably stay.

Verification

• Default invocation (./build.ps1) still resolves $Task = 'default'.
• ./build.ps1 -Task '' fails fast with a parameter-validation error.
• ./build.ps1 -Task @('Build', '') fails fast.
• ./build.ps1 -Task @() and ./build.ps1 -Task $null still fail fast (existing behavior preserved).

Downstream propagation

After the template lands, consumer repos that just received the basic validator need a follow-up PR:

• SrrDBAutomationToolkit
• YouTubeMusicPS
• ScheduledTasksManager
• PlexAutomationToolkit
• ReScenePS

JsmOperations already has the basic [ValidateNotNullOrEmpty()] form and should be swept the same way.

Origin

Surfaced 2026-05-11 by Copilot review on ScheduledTasksManager#41 during the build.ps1 validator sweep. Filed here so the fix lives in the template; cross-repo cleanup follows once the template-side fix is in.

[tablackburn]

Adjacent findings surfaced during the cross-repo validator sweep (JsmOps#8, 2026-05-11). Folding them in here so the template fix can cover all three in one pass.

Finding 2 — stale .PARAMETER help text on Compare-SemVerPrerelease

The help block in tests/ManifestHelpers.psm1 says:

.PARAMETER FirstPrerelease
The first prerelease identifier (e.g., "alpha.1"). Must not be null.

.PARAMETER SecondPrerelease
The second prerelease identifier (e.g., "beta.2"). Must not be null.

With [ValidateNotNullOrEmpty()] on both, the binding contract is now "null or empty". Update the help text to match.

Finding 3 — redundant in-body guards on Test-VersionConstraint

if ([string]::IsNullOrWhiteSpace($ManifestVersion)) {
    throw 'ManifestVersion cannot be empty or whitespace'
}
if ([string]::IsNullOrWhiteSpace($RequirementsVersion)) {
    throw 'RequirementsVersion cannot be empty or whitespace'
}

With [ValidateNotNullOrEmpty()] on both params, these guards only fire for whitespace now — empty fails at parameter binding first, so the "empty or whitespace" error text is misleading.

Two reasonable resolutions:

• Minimal: drop the "empty" half from the error string and the leading "Validate input versions are not empty" comment.
• Consolidated: replace the in-body guards with [ValidateScript({ -not [string]::IsNullOrWhiteSpace($_) })] so all rejection happens at parameter binding under a single failure mode. Pairs naturally with the per-element ValidateScript proposed in the original issue body.

Propagation

After the template lands the fix, consumer cleanup follows:

• JsmOperations (PR [pre-commit.ci] pre-commit autoupdate #8 just merged with the canonical-aligned validators)
• (Other consumers don't carry tests/ManifestHelpers.psm1 yet, but will inherit the canonical shape when they adopt it.)

Origin

Both findings surfaced by Copilot review on JsmOps#8 (2026-05-11). Replied + resolved there as out-of-scope; tracked here.

[tablackburn]

Finding 4 — $root vs $Root case mismatch in tests/MetaFixers.psm1

Surfaced 2026-05-12 by Copilot review on JsmOps#9. The body of Get-UnicodeFilesList references the parameter via lowercase $root:

[Parameter(Mandatory = $true)]
[ValidateNotNullOrEmpty()]
[string]$Root
)

$root | Get-TextFilesList | Where-Object {
    Test-FileUnicode -FileInfo $_
}

PowerShell is case-insensitive so this works, but it's inconsistent with the rest of the file (and inconsistent with how the parameter is declared). Easy to misread, especially under Set-StrictMode -Version 'Latest'.

Fix: rename the reference to $Root to match the param declaration. Trivial 1-line change.

Propagation: after the template fix lands, consumer cleanup follows the same six repos already enumerated for the broader hardening.