Two bash defects in the 9d8b185 prefix-cache wiring, both measured live
on the 2026-10-05 deploy attempt (unit crash-looped 190x, exit 127,
endpoint down for the whole 3600 s health window):
1. A # comment block inside the backslash-continued podman run
terminates the continuation: the comment swallows the joined line
and the flag line then runs as its own command
('--no-enable-prefix-caching: command not found'). The comment moves
above the run block, with a no-comments-in-chain note.
2. The ${VAR:+A}${VAR:--B} double-expansion is ambiguous: when the
variable is set, ${VAR:--B} parses as a SUBSTRING OFFSET, not the
:- default — measured render was '--no-enable-prefix-caching1'.
The flag is now branched explicitly into
FRANK_PRIMARY_PREFIX_CACHE_FLAG (exactly one of the two flags
reaches the engine; unset keeps the historical flag).
Seam: the render test sources the shipped env through the branch and
asserts the exact flag word the engine receives (render-assert, the
same pattern the spec knobs use). bash -n clean; all 22 frank-primary
seams pass.
Frank
b820d341f5