v3.2.0 regression: breaks on Windows PowerShell 5.1 (ternary, pipe-leading whitespace) and rejects manifests without AliasesToExport #140

Summary

ModuleBuilder 3.2.0 (released 2026-05-11) introduces two regressions that block consumers that previously worked on v3.1.7 / v3.1.8:

1. Windows PowerShell 5.1 cannot import the module at all — the built ModuleBuilder.psm1 uses PowerShell 7-only syntax.
2. Build-Module now fails on PowerShell 7+ when the source manifest does not contain an uncommented AliasesToExport — this used to be optional.

Bug 1: Parse errors on Windows PowerShell 5.1

Import-Module ModuleBuilder fails before any user code runs:

At ...\ModuleBuilder\3.2.0\ModuleBuilder.psm1:1003 char:81
+ ... "Add-Parameter $($InputObject.Extent.File -ne "scriptblock" ? $InputO ...
Unexpected token '?' in expression or statement.

At ...\ModuleBuilder\3.2.0\ModuleBuilder.psm1:1858 char:9
+         | Where-Object { $_.OutputType.Name -eq "TextReplacement" -or ...
An empty pipe element is not allowed.

Root causes in the shipped .psm1:

• Line 1003: ternary operator ? : (PowerShell 7+ only)
• Line 1858: pipe-leading whitespace / multi-line pipeline starting with | (PowerShell 7+ only)

This is a regression of the same class as #135 / fixed in #136 — PS 5.1 parse errors caused by newer-syntax constructs in code paths that PS 5.1 has to parse at module-load time.

Bug 2: AliasesToExport now mandatory on PowerShell 7+

Even where the module imports successfully (i.e. on PS 7), Build-Module now rejects source manifests that have AliasesToExport commented out:

Get-Metadata: Can't find 'AliasesToExport' in <source>\<Module>.psd1

The field was optional in v3.1.x. It is unclear from the changelog whether this is intentional (in which case it is a breaking change that should be documented and major-version-bumped) or an unintended side-effect.

Repro

1. Install-Module ModuleBuilder -RequiredVersion 3.2.0
2. On Windows PowerShell 5.1: Import-Module ModuleBuilder → parse error.
3. On PowerShell 7+ with any source manifest that has # AliasesToExport = @() commented out: Build-Module → Get-Metadata error.

Environment

• ModuleBuilder: 3.2.0 (PSGallery, published 2026-05-11)
• PowerShell: 5.1 (Windows PowerShell) and 7.4 / 7.6 (pwsh)
• Last known-good version: 3.1.9

Workaround

Pin to < 3.2.0:

Install-Module ModuleBuilder -MaximumVersion 3.1.9 -Scope CurrentUser

Suggestion

Given #135 / #136 covered the same class of issue, a CI job that runs Import-Module on Windows PowerShell 5.1 (e.g. on windows-latest with shell: powershell) would catch this regression at PR time.