v1.10.1 (run 707) failed with ZERO failing steps: every step Success, `smoke`
printing "101 passed, 0 failed", `smoke-studio` "104 passed, 0 failed", both
jobs red. The clipboard fix from f3b3748 worked exactly as predicted; this is a
second, independent defect that run 704 had masked.
CHAIN, measured end to end rather than reasoned:
`ARG BASE_IMAGE` has no default on purpose (the two-phase build always supplies
it), which trips BuildKit's InvalidDefaultArgInFrom check. buildx attaches that
warning's source context to the build metadata as
buildx.build.warnings[].sourceInfo.data — the ENTIRE Dockerfile, base64, on ONE
line. docker/build-push-action writes that metadata to $GITHUB_OUTPUT as a
`name<<ghadelimiter_<uuid>` heredoc. Gitea's act_runner truncates any single
line at exactly 65536 chars, so the closing delimiter was cut off:
invalid format delimiter 'ghadelimiter_...' not found before end of file
and the runner failed the job while attributing it to no step at all.
v1.9.4 run 695 SUCCESS: longest metadata line 56355, 0 delimiter errors
v1.10.0 run 704 failed : longest metadata line 65536, 1 delimiter error
v1.10.1 run 707 failed : longest metadata line 65536, 1 delimiter error
65536 = 2^16: cut AT the cap, not merely long. Independent route via file size
rather than log parsing: 42251 B at v1.9.4 (base64 56335, matching the log) vs
50034 B now (base64 66712, truncated). The cap corresponds to a 49152 B
Dockerfile, so this cycle's comment growth crossed it by 882 B.
Located by asking which top-level metadata key CONTAINS the base64, instead of
assuming: it is buildx.build.warnings -> sourceInfo -> data in BOTH runs.
THIS IS THE SECOND FIX FOR THIS BUG. The first, `provenance: false` on the two
smoke build steps, was committed as 784fad7 and is REVERTED here: a real buildx
on another host showed provenance metadata present in both modes with a longest
string of 71 chars, i.e. the base64 was never in provenance. Shipping it would
have left the release broken a third time while looking like a fix.
Also rejected, each measured: floating action tags moving (act action-bundle
hashes byte-identical between runs 695 and 707, all four) and the build-check
annotation text changing (byte-identical).
FIX: `# check=skip=InvalidDefaultArgInFrom` as the FIRST line of
Dockerfile.variant — BuildKit parses `# check=` only before any other line, so
placement is load-bearing. No honest default exists for BASE_IMAGE: `scratch`
would satisfy the linter while being a lie, and would convert today's instant
"invalid reference format" into a failure deep in the build. Verified against
the actual edited file with `docker buildx build --check`: "Check complete, no
warnings found." Zero warnings means no sourceInfo, so the longest metadata line
drops 65536 -> ~1936 and the file's SIZE stops gating CI.
GUARD: scripts/check-dockerfile-directives.sh, wired into BOTH lint.yml and
docker-publish.yml's lint-gate, because a check that gates only `push` lets a
tag regress — the adoption slip that let doc-drift land 27 h after the v1.9.3
tag. It also fails if ARG BASE_IMAGE gains a default, so the directive cannot
rot into guarding a check that can no longer fire. Truth table, exit codes:
present 0, removed 1, demoted to line 2 → 1, ARG defaulted 1, file missing 2
(a gate that cannot run must not pass).
Release renamed v1.10.1 -> v1.10.2 with both failed tags left standing as
tombstones. Docs swept again (README "since" marker, Dockerfile decision
comments) because CI reads them from the TAG.
Gates: doc-drift 23 OK / 0 DRIFT; base-hash, workflow-shell, skill-floor,
lint-shell (17 files now), dockerfile-directives all rc=0.
Joakim Persson