`& ([scriptblock]::Create((irm .../install.ps1)))` is the documented
Windows install form, and on this line it failed twice before doing any
work:
- The MSIX rewrite re-added a UTF-8 BOM that had been stripped twice
before. Windows PowerShell 5.1 irm keeps it as a literal U+FEFF, so
param( was no longer the first statement: "The assignment expression is
not valid".
- Initialize-ResolvedPaths read and wrote $script:HermesHome and
$script:InstallDir. Under -File, script scope is where param() binds.
Under the scriptblock form param() binds in the scriptblock scope and
$script: names the caller session, so -HermesHome read as empty and
Join-Path threw. Without -HermesHome, the normalized paths never reached
the bare $HermesHome/$InstallDir every stage reads.
The paths are now computed locally and written to scope 1, where param()
bound under -File, the scriptblock form, and dot-sourcing.
Verified on Windows 11 arm64 (PS 5.1): the old file reproduces both
errors, -ShowResolvedPaths is correct under all three entry forms, and a
fresh install clones into the requested home and reaches pm install.
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