pub fn check_session_path(p: &str, source: &str) -> Result<(), String>Expand description
Classify a session-path value: does it look like a
key=value workload-param token (e.g. scenario=foo)
rather than a real filesystem path? The umbrella
--session <kv> parser splits only on :, so a
=-shaped token slipping into the path slot would silently
materialise directories like <cwd>/scenario=foo/....
Heuristic: the head of head=tail matches the workload-
param ABNF (alphanumeric / underscore / hyphen, no slash).
A real path like /var/tmp/k=v keeps a leading slash in
the head and passes through unchanged. Leading ./ or
../ likewise excludes the head from the param-shape
check (the head contains a /).
Returns Err(<error message>) when the value should be
rejected; Ok(()) when it’s safe to use as a session
path.