The read_plan fix landed on the file-backed highway (build_iso_pipeline)
but the inline DiscStream (live single-pass) still passed the alternate
device-group half to the demux — a known FMTS bug on rip_mode="single".
DiscStream::with_key_map installs the proactive map and rewrites the
extent walk to the read plan, so the live single-pass path reads ONLY
our-phase units, exactly like the highway. DecryptingSectorSource gains
set_key_map for the already-constructed decorator. Non-forensic maps
return the extents unchanged, so every non-FMTS disc is byte-identical.
Test: with_key_map_reads_only_our_phase_units — a forensic Even segment
drops exactly its alternate units from the extent walk. Precommit green
on 1.86.
Matthew Jackson
a688e2c642