Path Portability

Core rule

Paths must survive spaces, Unicode, alternate drives, different user homes, and invocation from a different working directory.

Contract

• Resolve known roots at runtime; never embed another machine’s home or drive.
• Distinguish absolute paths from paths relative to the script/config that owns them.
• Quote only at the boundary that requires quoting; do not store shell-escaped strings as filesystem paths.
• Use path APIs rather than string concatenation.
• For subprocesses, pass argument arrays when the platform/API supports them.
• Test a path containing spaces, non-ASCII characters, and a different current directory.
• For archives, reject traversal (..), absolute members, and unsafe device names.

On Windows, verify PowerShell 5.1/cmd quoting separately from POSIX shells. A path that works at C:\work is not portability evidence.