fix(ci): skip the BuildKit check whose warning embedded this Dockerfile in CI output

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.

.gitea/workflows/docker-publish.yml

@@ -222,6 +222,13 @@ jobs:
       - name: Components the next build would bake differently are named in the CHANGELOG
         run: bash scripts/check-doc-drift.sh
 
+      # Runs HERE as well as in lint.yml deliberately. A guard that gates only
+      # `push` lets a tag regress — the adoption slip that let doc-drift land
+      # 27 h after the v1.9.3 tag. This one protects the tag build from the
+      # zero-failing-step failure mode that killed v1.10.0 and v1.10.1.
+      - name: Dockerfile.variant still opens with its BuildKit check directive
+        run: bash scripts/check-dockerfile-directives.sh Dockerfile.variant
+
   resolve-versions:
     # Gated: a defective tree must not reach a 46-minute base build.
     needs: [lint-gate]

.gitea/workflows/lint.yml

@@ -90,6 +90,12 @@ jobs:
         # actionlint so the more precise diagnostic surfaces first.
         run: bash scripts/check-workflow-shell.sh .gitea/workflows
 
+      - name: Dockerfile.variant still opens with its BuildKit check directive
+        # See scripts/check-dockerfile-directives.sh: without that first line the
+        # smoke jobs fail with `invalid format delimiter 'ghadelimiter_...'` and
+        # NO failing step. Also wired into docker-publish.yml's lint-gate.
+        run: bash scripts/check-dockerfile-directives.sh Dockerfile.variant
+
       - name: Install actionlint (pinned)
         env:
           ACTIONLINT_VERSION: 1.7.12

CHANGELOG.md

@@ -11,21 +11,73 @@ Pre-v1.0.0 tags followed the pi npm version (`v{pi_version}[letter]`).
 
 ---
 
-## v1.10.1 — 2026-10-02
+## v1.10.2 — 2026-10-02
 
-**v1.10.0 was tagged and never published.** Its tag build (run 704) failed one
+**v1.10.0 and v1.10.1 were both tagged and never published.** Neither failure
-assertion out of 104 — a smoke check that required a pi dependency upstream had
+was in the image — both were in the test and CI harness, and each hid the other:
-deliberately deleted — so every publish job skipped and no image, no `latest`,
-no Hub description was ever written. v1.10.1 is that same release plus the fix
-to the assertion: **everything described under v1.10.0 below ships here**, and
-that section remains the content record for this release. Nothing in it changed.
 
-The tag number moves rather than being re-pointed because CI had already
+| tag | run | symptom | cause |
-consumed v1.10.0; a version that failed its build should stay failed and
+|---|---|---|---|
-readable, not be quietly overwritten with different bytes.
+| v1.10.0 | 704 | `smoke` 100 passed / **1 failed**; `smoke-studio` 103 / **1** | a smoke assertion required a pi dependency upstream had deleted |
+| v1.10.1 | 707 | `smoke` **101 passed / 0 failed**, `smoke-studio` **104 / 0**, and both jobs red anyway with **no failing step** | base64(`Dockerfile.variant`) in buildx's warning metadata crossed act_runner's 64 KiB line cap |
+
+In both runs every publish job skipped, so no image, no `latest`, and no Hub
+description was ever written — the gates did their job twice. **Everything
+described under v1.10.0 below ships here**; that section remains the content
+record and nothing in it changed.
+
+The tag number moves each time rather than being re-pointed, because CI had
+already consumed the previous one. A version that failed its build should stay
+failed and readable, not be quietly overwritten with different bytes.
 
 ### Fixed
 
+- **A job can fail with every step green, a smoke suite reporting `0 failed`,
+  and no failing step anywhere — and it cost two tags** — `Dockerfile.variant`
+  now opens with `# check=skip=InvalidDefaultArgInFrom`, and
+  `scripts/check-dockerfile-directives.sh` keeps it there.
+
+  The chain, measured rather than reasoned: `ARG BASE_IMAGE` deliberately has no
+  default (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 `$GITHUB_OUTPUT` as a `name<<ghadelimiter_<uuid>` heredoc,
+  and Gitea's act_runner truncates any single line at exactly 65536 chars. Once
+  base64 of the file passed 64 KiB the closing delimiter was cut off and the
+  runner reported `invalid format delimiter 'ghadelimiter_...' not found before
+  end of file`, then failed the job while attributing it to nothing.
+
+  Numbers: the file was 42251 B at v1.9.4 → base64 56355 chars, fine; it is
+  50034 B now → base64 66712, truncated to exactly 65536 (2^16, i.e. cut *at*
+  the cap, not merely long). The cap corresponds to a 49152 B Dockerfile, so
+  this release's comment growth — much of it comments added while documenting
+  the v1.10.0 round — crossed it by **882 bytes**. Confirmed two ways: by
+  parsing the metadata out of both job logs, and independently by arithmetic on
+  the file size at each tag. Verified fixed by running `docker buildx build
+  --check` against the actual edited file: *"Check complete, no warnings
+  found."* With zero warnings there is no `sourceInfo`, so the longest metadata
+  line drops from 65536 to ~1936 chars and the Dockerfile's **size stops being
+  coupled to whether CI passes**.
+
+  Hypotheses measured and rejected on the way, each of which would have produced
+  a wrong fix: floating action tags moving (the act action-bundle hashes are
+  byte-identical between the green v1.9.4 run and the red one — all four); the
+  build-check annotation text changing (byte-identical); and `provenance: false`,
+  which was written, tested against a real buildx, and **reverted** when the
+  metadata turned out to carry the base64 under `buildx.build.warnings`, not
+  under provenance. The published images are unaffected either way: they are
+  built by raw `docker buildx build --push`, which never writes
+  `$GITHUB_OUTPUT` metadata.
+
+  The new guard runs in **both** `lint.yml` and the publish workflow's
+  `lint-gate`, because a check that gates only `push` lets a tag regress — the
+  same adoption slip that let doc-drift land 27 h after the v1.9.3 tag. It
+  also fails if `ARG BASE_IMAGE` ever gains a default, so the skip directive
+  cannot rot into pointing at a check that can no longer fire. Truth table:
+  directive present → rc=0; removed → rc=1; demoted to line 2 → rc=1; ARG given
+  a default → rc=1; file missing → rc=2 (cannot-run must not pass).
+
 - **The smoke suite asserted a pi dependency that upstream deleted, and it cost
   this release its first tag build** — `scripts/smoke-test.sh` required
   `@mariozechner/clipboard` to be installed and `require()`-able at every install
@@ -60,13 +112,15 @@ readable, not be quietly overwritten with different bytes.
 
 ---
 
-## v1.10.0 — 2026-10-02 (tagged, never published — superseded by v1.10.1)
+## v1.10.0 — 2026-10-02 (tagged, never published — content shipped as v1.10.2)
 
 > Tagged 2026-10-02 at commit `12f99c4`. Its build (run 704) went red on the
 > stale clipboard assertion described under v1.10.1, so `build-variant`,
 > `build-variant-studio`, `promote-base-latest` and `update-description` all
 > skipped and nothing reached the Hub. No image carries this tag. The content
-> below is accurate and shipped as **v1.10.1**.
+> below is accurate and shipped as **v1.10.2**. v1.10.1 (commit `c2c42c3`,
+> run 707) was the first attempt at republishing it and died on the separate
+> act_runner line-cap bug described under v1.10.2.
 
 Three small fixes found by the v1.9.4 first-boot acceptance and the CI base
 hash prediction, plus one boot-time wiring fix that stops a recurring `git push`

Dockerfile.variant

@@ -1,3 +1,37 @@
+# check=skip=InvalidDefaultArgInFrom
+#
+# ^ MUST stay the FIRST line of this file, and it is load-bearing for CI, not
+# style. BuildKit parses `# check=` only before any other line, so moving it
+# below the title comment silently disables it.
+#
+# Why it exists: `ARG BASE_IMAGE` (below) deliberately has NO default — this
+# file is only ever built by the two-phase CI with --build-arg BASE_IMAGE=
+# <image>:base-<hash>. BuildKit's InvalidDefaultArgInFrom check flags that as
+# "default value for global ARG results in an empty or invalid base image
+# name". There is no honest default to give it: `scratch` would satisfy the
+# linter while being a lie (nothing here can build FROM scratch), and it would
+# convert today's instant "invalid reference format" into a failure deep in the
+# build. So the check is skipped by name, with the reason written down.
+#
+# What the warning actually COST, which is why this is not cosmetic: buildx
+# attaches the 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, and Gitea's act_runner truncates any
+# single line at exactly 65536 chars. Once base64(this file) crossed 64 KiB the
+# closing delimiter was cut off, and the runner failed the job with
+#   invalid format delimiter 'ghadelimiter_...' not found before end of file
+# and NO failing step: every step green, smoke suite "0 failed", job red.
+# Measured: 42251 B at v1.9.4 -> base64 56355 (fine); 50034 B at v1.10.1 ->
+# base64 66712, truncated to exactly 65536. The cap corresponds to a 49152 B
+# Dockerfile, so this release's comment growth crossed it by 882 B. It killed
+# v1.10.0 (run 704, where a stale clipboard assertion hid it) and v1.10.1
+# (run 707). With zero warnings there is no sourceInfo, so the longest metadata
+# line drops from 65536 to ~1936 chars and the Dockerfile's SIZE stops being
+# coupled to CI passing at all.
+#
+# If this ever recurs — job red, zero failing steps, suite reporting 0 failed —
+# grep the job log for `ghadelimiter` first.
 # pi-devbox — variant image
 #
 # FROMs a base-<hash> image produced by Dockerfile.base and adds only
@@ -154,11 +188,11 @@ ARG USER_NAME=developer
 # (e7d77dc -> 1529e14 -> 731c3d4 in the nine days to 2026-10-01), so waiting for
 # a tag means holding pi indefinitely. A full SHA keeps the one property
 # `master` does not have: rebuilding this tag later produces the SAME image.
-# v1.9.5 SKIPPED 0.99.x and 1.0.0 for lack of evidence. v1.10.1 went and got the
+# v1.9.5 SKIPPED 0.99.x and 1.0.0 for lack of evidence. v1.10.2 went and got the
 # evidence instead of waiting for obsmem to mention a version, because "no issue
 # names 1.0" is an absence of a statement, not a measurement.
 #
-# v1.10.1: 0.87.1 -> 1.0.0. MEASURED 2026-10-02 against the published npm
+# v1.10.2: 0.87.1 -> 1.0.0. MEASURED 2026-10-02 against the published npm
 # tarballs for 0.87.1 and 1.0.0, unpacked side by side:
 #   1. NO `### Breaking Changes` SECTION IN 1.0.0 AT ALL. The changelog's
 #      breaking sections belong to 0.87.0, 0.86.0, 0.84.3, 0.84.0, 0.83.0,
@@ -273,7 +307,7 @@ ARG PI_ATELIER_REPO=https://github.com/michaelmjhhhh/pi-atelier.git
 # pi >=0.84.0, so it still spans the pinned 0.85.1. 13 commits v0.10.1..v0.10.3,
 # all under src/ tests/ docs/ scripts/ plus metadata; no entry-point move.
 #
-# v1.10.1: v0.10.3 -> v0.13.0, closing the two-minor gap v1.9.5 flagged as the
+# v1.10.2: v0.10.3 -> v0.13.0, closing the two-minor gap v1.9.5 flagged as the
 # residual risk of the pi bump. peerDependencies are UNCHANGED at pi >=0.84.0
 # across v0.10.3, v0.12.1 and v0.13.0 — still a FLOOR, so still not evidence of
 # anything; the floor is satisfied by 1.0.0 either way. What was actually

README.md

@@ -358,7 +358,7 @@ DOT syntax errors instead of crashing. Then in Studio: open the PNG (or a
 `.md` that embeds it) and hit **refresh-from-disk** after each edit.
 Note: SVG is **not** in Studio's local-image-link allowlist — use PNG.
 
-## Terminal UI mode: fullscreen is the default (since v1.10.1)
+## Terminal UI mode: fullscreen is the default (since v1.10.2)
 
 pi **1.0.0** changed the default terminal UI mode to **fullscreen**, and this
 image adopts upstream's default rather than overriding it. Fullscreen draws into

scripts/check-dockerfile-directives.sh

@@ -0,0 +1,69 @@
+#!/usr/bin/env bash
+# Guard: Dockerfile.variant must OPEN with its BuildKit `# check=` directive.
+#
+# Why this is a gate and not a comment. BuildKit parses `# check=` ONLY before
+# any other line in the file, so moving it below the title comment — or dropping
+# it during an unrelated header edit — silently re-enables the
+# InvalidDefaultArgInFrom warning on `ARG BASE_IMAGE` / `FROM ${BASE_IMAGE}`.
+#
+# A re-enabled warning is not cosmetic. buildx attaches the 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 $GITHUB_OUTPUT as a `name<<ghadelimiter_<uuid>` heredoc, and
+# Gitea's act_runner truncates any single line at exactly 65536 chars. Since
+# base64(Dockerfile.variant) passed 64 KiB (50034 B source -> 66712 chars, cut
+# to 65536), the closing delimiter is lost and act_runner fails the job with
+#   invalid format delimiter 'ghadelimiter_...' not found before end of file
+# while attributing it to NO step: every step reports Success, the smoke suite
+# prints "0 failed", and the job is red regardless. That cost two tags —
+# v1.10.0 (run 704, where a stale clipboard assertion masked it) and v1.10.1
+# (run 707) — and most of a session to localise.
+#
+# So: one deterministic grep, run both on push AND in the publish workflow's
+# lint-gate. A check that gates only `push` lets a tag regress — the same
+# adoption slip that let doc-drift land 27 h after the v1.9.3 tag.
+#
+# Exit codes: 0 OK, 1 violation, 2 cannot-run (missing file) — matching
+# lint-shell.sh / check-skill-floor.sh / check-doc-drift.sh, because a gate that
+# cannot run must not pass.
+set -euo pipefail
+
+DF="${1:-Dockerfile.variant}"
+EXPECTED='# check=skip=InvalidDefaultArgInFrom'
+
+if [ ! -f "$DF" ]; then
+  echo "::error::check-dockerfile-directives: '$DF' not found (cannot-run)" >&2
+  exit 2
+fi
+
+first="$(head -n 1 "$DF")"
+if [ "$first" != "$EXPECTED" ]; then
+  {
+    echo "::error::$DF line 1 must be exactly: $EXPECTED"
+    echo "::error::found instead: ${first:-<empty>}"
+    echo "::error::"
+    echo "::error::BuildKit only honours '# check=' before any other line. Without it the"
+    echo "::error::InvalidDefaultArgInFrom warning returns, buildx embeds this whole file as"
+    echo "::error::base64 in buildx.build.warnings[].sourceInfo.data, that single line exceeds"
+    echo "::error::act_runner's 65536-char cap, and the smoke jobs fail with"
+    echo "::error::  invalid format delimiter 'ghadelimiter_...' not found before end of file"
+    echo "::error::and NO failing step. See the header of $DF for the full measurement."
+  } >&2
+  exit 1
+fi
+
+# Second, independent assertion: the condition the directive exists FOR. If a
+# later edit gives ARG BASE_IMAGE a default, the directive becomes dead weight
+# and should be removed deliberately rather than left to rot — and if the ARG is
+# renamed, this guard would otherwise keep passing while guarding nothing.
+if ! grep -qE '^ARG BASE_IMAGE$' "$DF"; then
+  {
+    echo "::error::$DF no longer contains a bare 'ARG BASE_IMAGE' (no default)."
+    echo "::error::That is the only thing '$EXPECTED' suppresses. Either restore the bare ARG"
+    echo "::error::or drop the directive and this guard together — do not leave a skip"
+    echo "::error::directive pointing at a check that can no longer fire."
+  } >&2
+  exit 1
+fi
+
+echo "Dockerfile directive guard OK — $DF opens with the check-skip directive and still declares a bare ARG BASE_IMAGE."