[piob-io]

Summary

quay.io/minio/minio and quay.io/minio/mc started requiring authentication (every manifest request now returns 401 UNAUTHORIZED, including for the pinned RELEASE.2025-09-07T16-13-09Z / RELEASE.2025-08-13T08-35-41Z tags). Since Dockerfile pulls both as build stages, test / prepare and the validate-dockerfile job for Dockerfile fail, and because test / run depends on prepare, the entire Linux integration test matrix has been silently skipped on every branch — master's scheduled runs have failed the same way since 09-25 (e.g. https://github.com/useblacksmith/buildkit/actions/runs/36407431457), and the two red checks on #39 are this.

Upstream hit the same break and moved the S3 test fixture to pgsty/silo (a MinIO fork shipping both the server and mcli) in moby/buildkit@4509d3a. This is a straight port of that commit onto our fork:

-ARG MINIO_VERSION=RELEASE.2025-09-07T16-13-09Z
-ARG MINIO_MC_VERSION=RELEASE.2025-08-13T08-35-41Z
+ARG SILO_VERSION=RELEASE.2026-09-03T13-18-01Z
-FROM quay.io/minio/minio:${MINIO_VERSION} AS minio
-FROM quay.io/minio/mc:${MINIO_MC_VERSION} AS minio-mc
+FROM pgsty/silo:${SILO_VERSION} AS silo
-COPY --link --from=minio /usr/bin/minio /usr/bin/
-COPY --link --from=minio-mc /usr/bin/mc /usr/bin/
+COPY --link --from=silo /usr/bin/silo /usr/bin/
+COPY --link --from=silo /usr/bin/mcli /usr/bin/mc

util/testutil/helpers/minio.go just renames minioBin → siloBin = "silo"; silo keeps the server --json --address CLI and the MINIO_ROOT_USER/MINIO_ROOT_PASSWORD env, so NewMinioServer and the s3 cache tests are otherwise unchanged. Test-only change, no effect on shipped binaries.

Checks: gofmt, go build ./util/testutil/..., go vet ./util/testutil/helpers. The real verification is CI on this PR (test / prepare + the Linux test / run matrix coming back).

Link to Devin session: https://app.devin.ai/sessions/58d4432cc29646cda20732dd71045579
Open in Devin Desktop: https://app.devin.ai/desktop/session/58d4432cc29646cda20732dd71045579?variant=devin
Requested by: @piob-io

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[devin-ai-integration]

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