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cloud-lab Dockerfile.client: mid-file ARG invisible to FROM — client and killer images unbuildable on docker/buildkit 29 (golang:-bookworm)

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#724 0 comments 0 reactions 0 assignees View on GitHub

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@Amperstrand is already working on this.

Since Oct 7, 2026.

  • #728 by @Amperstrand — open

Assessment

Difficulty
1/5
Estimated time
Under an hour
Newbie friendliness
25/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Stale
Tech stack
docker, go
Domain
build-system

Research direction

Read tests/cloud-lab/Dockerfile.client and compare its ARG placement with tests/cloud-lab/Dockerfile.tollgate:10-11; packaging/build-inputs.json and packaging/build-env.sh show the Go version source. Reproduce with docker compose build client from tests/cloud-lab. Done means the client and killer image builds proceed past the invalid FROM parse; an open linked pull request already addresses this issue.

Written by the indexing model from the issue text.

Description

Summary

tests/cloud-lab/Dockerfile.client declares ARG GO_VERSION AFTER the first FROM, so the second stage's FROM golang:${GO_VERSION}-bookworm cannot see it on docker/buildkit 29 — the build fails with failed to parse stage name "golang:-bookworm": invalid reference format. Dockerfile.tollgate does it correctly (ARG before any FROM) — the client file diverges.

This also breaks run-crash-injection.sh, whose killer image builds from Dockerfile.client.

Verified on

  • Commit: 68ad5144ab09cb4723d8f3f655cbba1ac7ea9de5 (main, 2026-10-07)
  • docker 29.1.3 / buildkit (linux/amd64)

Evidence (verbatim)

#2 WARN: InvalidDefaultArgInFrom: Default value for ARG golang:${GO_VERSION}-bookworm results in empty or invalid base image name (line 13)
#2 WARN: UndefinedArgInFrom: FROM argument 'GO_VERSION' is not declared (line 13)
...
target killer: failed to solve: failed to parse stage name "golang:-bookworm": invalid reference format

The file today (tests/cloud-lab/Dockerfile.client, abridged):

FROM rust:1.88-bookworm AS rust-builder
RUN cargo install cdk-cli --locked
# Toolchain from the manifest — see Dockerfile.tollgate's header note.
ARG GO_VERSION=1.26.8                      # <-- declared mid-file: stage-scoped, invisible to the FROM below
FROM golang:${GO_VERSION}-bookworm AS go-builder

Reproduce

git checkout 68ad5144ab09cb4723d8f3f655cbba1ac7ea9de5
cd tests/cloud-lab
export TG_GO_VERSION="$(jq -r '.go.version' ../../packaging/build-inputs.json)"
docker compose build client    # dies at parse; same for ./run-crash-injection.sh (killer)

Note the trap: exporting TG_GO_VERSION does NOT help — compose's ${TG_GO_VERSION:-1.26.8} default is bypassed when the variable is set-but-empty, and even set correctly the Dockerfile still needs the ARG at global scope for FROM interpolation.

Fix

Hoist the declaration above the first FROM (keep or drop the mid-file one — hoisting alone fixes FROM; the stage also sees global ARGs for RUN):

ARG GO_VERSION=1.26.8
FROM rust:1.88-bookworm AS rust-builder
...
FROM golang:${GO_VERSION}-bookworm AS go-builder

One line, matches Dockerfile.tollgate's existing pattern. After the fix, docker compose build client and ./run-crash-injection.sh proceed past the parse.

References

  • Correct pattern in-tree: tests/cloud-lab/Dockerfile.tollgate:10-11
  • Toolchain pinning: packaging/build-inputs.json (.go.version), packaging/build-env.sh
Dominant language
Go
Stars
12
Forks
14
Avg merge
1d 4h
Merged PRs (30d)
244

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