The mint multi-SDK compatibility pipeline had exactly one recorded run
(28730530597, 2026-07-05), which died at "Enable buildx": the self-hosted
sm-standard-4 pod it landed on had no /var/run/docker.sock, so
`docker buildx create` failed to connect to the Docker API before any test
ran. Same heterogeneous-fleet root cause ci-1 fixed for the weekly s3-tests
sweep.
- Pin the job to GitHub-hosted ubuntu-latest, which reliably ships a running
Docker daemon + buildx + python3. Header note records the diagnosis and the
dind-sm-standard-2 tradeoff.
- Pin MINT_IMAGE default to the linux/amd64 digest for minio/mint:edge
resolved 2026-07-10 (was the rolling :edge tag); workflow_dispatch can still
override. Header comment records the refresh command.
- Quote shellcheck-flagged vars and drop an unused loop var so actionlint
passes with zero findings.
- Left report-only (ci-3 adds baseline gating later, per adjudication G4) and
a TODO(ci-8) alerting hook on the scheduled job.
Refs: rustfs/backlog#1149 (ci-2), rustfs/backlog#1155
