Established empirically in a clean Debian 13 container (2026-07-28), not inferred
from the dev host:
1.85.0 (apt install rustc, Debian trixie) -> FAILS, aws-sdk-* need >= 1.91.1
1.97.1 (rustup default stable, today) -> FAILS, ethnum E0512 transmute
1.94.0 -> builds clean, workspace, 2m39s
Both obvious reviewer paths break: the distro compiler is too old and current
rustup stable is too new. Before this pin the build reproduced on our host only
because the toolchain had been restored from the previous machine — reproducible
by accident rather than by construction.
Verified the pin works: set the shell default to the BROKEN stable, and the repo
still resolved 1.94.0 and built.
Minimal native prerequisites, also tested in the clean container:
protobuf-compiler (lance-encoding/lance-file build scripts need protoc),
pkg-config, libssl-dev.
NOT required despite being installed on the dev host: cmake, clang, libclang-dev.
