repo: the term wall — names this organisation does not use, refused in CI

.github/actions/term-wall/CONTRACT.md

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+# The term wall — contract v1
+
+Names this organisation does not use must not appear in any of its
+repositories: not affirmed, not negated, not cited. The wall refuses
+them, and the wall itself never carries them in any readable or
+encoded form.
+
+## Instruments
+
+1. `.github/actions/term-wall/term-wall.sh` (run by the composite
+   action `.github/actions/term-wall`) — every repo's `ci` job runs it.
+2. `ops/devlane/workflow/checks/term_wall.py` — the lane's local copy,
+   run by the commit-msg hook and by apply-push's guards.
+
+## The pattern is configuration, never tree content
+
+- The pattern is an extended, case-insensitive regular expression read
+  from the environment variable `TERM_WALL`. In CI the calling step
+  passes it: `env: TERM_WALL: ${{ vars.TERM_WALL }}` — a composite
+  action cannot read `vars` itself, so the action declares no default
+  and refuses when the step did not pass one. Locally the
+  Python check reads `TERM_WALL`, falling back to the gitignored file
+  `<root>/ops/bin/term-wall.conf` (one line: the pattern).
+- No tracked file may contain the pattern, a piece of it, or any
+  encoding of the names (hex, base64, bracket tricks, escapes). The
+  self-test's planted fault comes from `vars.TERM_WALL_PLANT` (a string
+  the pattern matches), never from the tree.
+- An unset or empty pattern is a refusal, exit 2, stdout empty, one
+  line on stderr: `pattern: expected TERM_WALL set; found empty;
+  needed the org variable (CI) or ops/bin/term-wall.conf (local)`.
+  The wall never passes vacuously.
+
+## Surfaces (term-wall.sh)
+
+1. tracked content — every `git ls-files` path, binaries skipped,
+   case-insensitive;
+2. tracked paths;
+3. the commit messages of the change — `pull_request`: `base..head`;
+   `push`: `before..head`, or only the head commit when `before` is
+   all zeros — read from git (fetching what the checkout lacks), never
+   from an API: the action needs no token and declares none;
+4. the pull request title and body (from the event payload);
+5. the branch name (`GITHUB_HEAD_REF` for a PR, `GITHUB_REF_NAME` for
+   a push).
+
+Outside GitHub Actions (no `GITHUB_EVENT_PATH`), surfaces 1 and 2 run
+against the current directory. The Python check covers surface 1 and
+2 (`[--root DIR] [PATH ...]`), one message (`--message-file FILE`), a
+range of commit messages (`--range BASE..HEAD`), or `--stdin`.
+
+## Outcomes, on the wire
+
+| exit | meaning |
+|---|---|
+| 0 | clean; exactly one summary line on stdout |
+| 1 | at least one hit, every hit printed on stdout in the pinned format below; a surface that could not be read (fetch failed, payload unreadable) is itself a hit — could-not-look is never a pass |
+| 2 | refusal; stdout empty, one stderr line `<class>: expected …; found …; needed …` |
+
+Refusal classes: `pattern` (unset or empty), `git work tree` (not
+inside one), `message` (missing message file), `range` (unresolvable).
+
+## Hit format, pinned
+
+One stdout line per hit: `<surface>: <location>: <line with each
+match replaced by [forbidden name]>`. The location never contains a
+colon. The raw matched text never appears in any output.
+
+| surface | location |
+|---|---|
+| `content` | `<path> line <n>` |
+| `path` | `<path>` |
+| `commit messages` | `<sha12> line <n>` |
+| `pull request title` | `line <n>` |
+| `pull request body` | `line <n>` |
+| `branch name` | `<name>` |
+| `event payload` | `<payload path>` — the hit when the payload cannot be read |
+| `message` (`--message-file`) | `line <n>` |
+| `range` (`--range`) | `<sha12> line <n>` |
+| `stdin` | `line <n>` |
+
+## Self-test (the `.github` repo's own ci)
+
+With the calling step passing `env: TERM_WALL_PLANT: ${{ vars.TERM_WALL_PLANT }}` as the planted fault: a planted file fires
+(exit 1, masked hit), a clean neighbour stays quiet (exit 0), and an
+empty `TERM_WALL` refuses (exit 2).
+
+## Tests
+
+Tests execute the real instrument as a subprocess inside temporary git
+repositories they create; nothing about the wall is mocked. They set
+`TERM_WALL` explicitly to a test-only pattern (for example
+`zz[q]orblat`) and plant matches of it, so no forbidden name exists
+anywhere. They are deterministic and hermetic: no network, no sleeps,
+no dependence on the caller's cwd, environment, or git identity
+(configure user.name/user.email in each temp repo). Every test asserts
+the exit code and the output shape. Push and pull-request events are
+simulated with an event JSON file and the `GITHUB_*` variables.

.github/actions/term-wall/action.yml

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+name: term wall
+description: >-
+  Refuses names this organisation does not use — in tracked content, in
+  file paths, in the change's commit messages (read from git, never from
+  an API: no token needed or declared), in the pull request title and
+  body, and in the branch name. The pattern comes only from the
+  TERM_WALL environment variable the calling step passes from the
+  org-level Actions variable — a composite action cannot read vars
+  itself, so this action declares no default; an unset or empty
+  pattern is a refusal, never a pass. The wall never spells what it
+  refuses and masks every hit it prints.
+runs:
+  using: composite
+  steps:
+    - name: term wall
+      shell: bash
+      run: bash "$GITHUB_ACTION_PATH/term-wall.sh"

.github/actions/term-wall/term-wall.sh

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+#!/usr/bin/env bash
+# term-wall.sh — names this organisation does not use, refused everywhere.
+#
+# The pattern is configuration, never tree content: it is read only from
+# the TERM_WALL environment variable (in CI the calling step passes it,
+# `env: TERM_WALL: ${{ vars.TERM_WALL }}` — a composite action cannot
+# read `vars` itself, so the action declares no default). An unset or
+# empty pattern is a refusal, exit 2 — the wall never passes vacuously.
+# Every hit it prints is masked, so the log does not carry what the tree
+# may not.
+#
+# Surfaces, in order:
+#   1. tracked file content (case-insensitive, binaries skipped)
+#   2. tracked file paths
+#   3. the commit messages of the change — pull_request: base..head;
+#      push: before..head, or only the head commit when before is all
+#      zeros — read from git, fetching what the checkout lacks; never
+#      from an API: the action needs no token and declares none
+#   4. the pull request title and body (from the event payload)
+#   5. the branch name (GITHUB_HEAD_REF for a PR, GITHUB_REF_NAME for a push)
+#
+# Exit 0 clean, one summary line on stdout. Exit 1 on any hit, every hit
+# on stdout as "<surface>: <location>: <line with each match replaced by
+# [forbidden name]>" — the location never contains a colon; a surface
+# that could not be read (fetch failed, payload unreadable) is itself a
+# hit — could-not-look is never a pass. Exit 2 refusal: stdout empty,
+# one line on stderr shaped "class: expected …; found …; needed …".
+#
+# Outside GitHub Actions (no GITHUB_EVENT_PATH) only surfaces 1 and 2
+# run, against the current directory.
+set -uo pipefail
+
+refuse() { printf '%s\n' "$1" >&2; exit 2; }
+
+pat=${TERM_WALL:-}
+[[ -n $pat ]] || refuse 'pattern: expected TERM_WALL set; found empty; needed the org variable (CI) or ops/bin/term-wall.conf (local)'
+
+# A pattern grep or sed cannot use would make every scan silently vacuous
+# and could leak raw text past the mask — refuse it up front.
+printf '' | grep -i -E -- "$pat" >/dev/null 2>&1
+[[ $? -le 1 ]] || refuse 'pattern: expected TERM_WALL to be an extended regular expression grep accepts; found one it rejects; needed a working pattern in the org variable (CI) or ops/bin/term-wall.conf (local)'
+printf '' | sed -E "s/($pat)/[forbidden name]/Ig" >/dev/null 2>&1 \
+    || refuse 'pattern: expected TERM_WALL usable in a sed substitution; found one sed rejects (an unescaped "/"?); needed a working pattern in the org variable (CI) or ops/bin/term-wall.conf (local)'
+
+git rev-parse --is-inside-work-tree >/dev/null 2>&1 \
+    || refuse 'git work tree: expected to run inside a git work tree; found none; needed a checkout (CI) or a repository directory (local)'
+
+rc=0
+mask() { sed -E "s/($pat)/[forbidden name]/Ig"; }
+
+emit() {  # emit <surface> <location> <masked line> — one hit. Called only
+          # from the main shell, never from a pipeline stage, so the exit
+          # code it sets survives.
+    printf '%s: %s: %s\n' "$1" "$2" "$3"
+    rc=1
+}
+
+scan() {  # scan <surface> <location prefix> <text> — text as an argument,
+          # never a pipe: a hit must set rc in this shell, and a pipeline's
+          # stages run in subshells. Each hit's location is
+          # "<prefix>line <n>".
+    local surface=$1 prefix=$2 text=$3 found line
+    [[ -n $text ]] || return 0
+    found=$(printf '%s\n' "$text" | grep -i -n -E -- "$pat" 2>/dev/null | mask || true)
+    [[ -n $found ]] || return 0
+    while IFS= read -r line; do
+        emit "$surface" "${prefix}line ${line%%:*}" "${line#*:}"
+    done <<< "$found"
+}
+
+scan_name() {  # scan_name <surface> <value> — for surfaces whose location
+               # is the (masked) value itself: a path, a branch name.
+    local surface=$1 value=$2 masked
+    [[ -n $value ]] || return 0
+    printf '%s\n' "$value" | grep -i -E -- "$pat" >/dev/null 2>&1 || return 0
+    masked=$(printf '%s\n' "$value" | mask)
+    emit "$surface" "$masked" "$masked"
+}
+
+# 1. tracked content
+content=$(git ls-files -z 2>/dev/null | xargs -0 -r grep -I -H -i -n -E -- "$pat" 2>/dev/null | mask || true)
+if [[ -n $content ]]; then
+    while IFS= read -r line; do
+        file=${line%%:*}; rest=${line#*:}
+        emit "content" "$file line ${rest%%:*}" "${rest#*:}"
+    done <<< "$content"
+fi
+
+# 2. tracked paths
+paths=$(git ls-files 2>/dev/null | grep -i -E -- "$pat" 2>/dev/null | mask || true)
+if [[ -n $paths ]]; then
+    while IFS= read -r line; do
+        emit "path" "$line" "$line"
+    done <<< "$paths"
+fi
+
+# 3-5. the change itself, when running under Actions
+if [[ -n ${GITHUB_EVENT_PATH:-} && -f ${GITHUB_EVENT_PATH:-} ]]; then
+    event=${GITHUB_EVENT_NAME:-}
+    payload_ok=1
+    jq empty "$GITHUB_EVENT_PATH" >/dev/null 2>&1 || payload_ok=0
+    if [[ $payload_ok -eq 0 ]]; then
+        emit "event payload" "$GITHUB_EVENT_PATH" "could not read the event payload (could-not-look is never a pass)"
+    fi
+    base="" head="" want_messages=0
+    case $event in
+        pull_request|pull_request_target)
+            if [[ $payload_ok -eq 1 ]]; then
+                base=$(jq -r '.pull_request.base.sha // empty' "$GITHUB_EVENT_PATH" 2>/dev/null) || base=""
+                head=$(jq -r '.pull_request.head.sha // empty' "$GITHUB_EVENT_PATH" 2>/dev/null) || head=""
+                scan "pull request title" "" "$(jq -r '.pull_request.title // ""' "$GITHUB_EVENT_PATH" 2>/dev/null)"
+                scan "pull request body" "" "$(jq -r '.pull_request.body // ""' "$GITHUB_EVENT_PATH" 2>/dev/null)"
+                want_messages=1
+            fi
+            scan_name "branch name" "${GITHUB_HEAD_REF:-}"
+            ;;
+        push)
+            if [[ $payload_ok -eq 1 ]]; then
+                base=$(jq -r '.before // empty' "$GITHUB_EVENT_PATH" 2>/dev/null) || base=""
+                head=$(jq -r '.after // empty' "$GITHUB_EVENT_PATH" 2>/dev/null) || head=""
+                want_messages=1
+            fi
+            scan_name "branch name" "${GITHUB_REF_NAME:-}"
+            ;;
+    esac
+    if [[ $want_messages -eq 1 ]]; then
+        only_head=0
+        [[ $event == push && ( -z $base || $base =~ ^0+$ ) ]] && only_head=1
+        if [[ -z $head || ( $only_head -eq 0 && -z $base ) ]]; then
+            emit "commit messages" "$event" "could not resolve the change's commits from the event payload (could-not-look is never a pass)"
+        else
+            refs=("$head"); [[ $only_head -eq 0 ]] && refs=("$base" "$head")
+            # Fetch what the checkout lacks; a shallow clone would walk a
+            # truncated history without erroring, so unshallow it.
+            shallow=$(git rev-parse --is-shallow-repository 2>/dev/null) || shallow=false
+            missing=0
+            for ref in "${refs[@]}"; do
+                git cat-file -e "$ref^{commit}" 2>/dev/null || missing=1
+            done
+            fetch_failed=0
+            if [[ $shallow == true || $missing -eq 1 ]]; then
+                fetch_opts=(--no-tags --quiet)
+                [[ $shallow == true ]] && fetch_opts+=(--unshallow)
+                if ! fetch_err=$(git fetch "${fetch_opts[@]}" origin "${refs[@]}" 2>&1); then
+                    emit "commit messages" "${refs[*]}" "could not fetch the change from origin — $(printf '%s' "$fetch_err" | mask | tr '\n' ' ' | head -c 300) (could-not-look is never a pass)"
+                    fetch_failed=1
+                fi
+            fi
+            if [[ $fetch_failed -eq 0 ]]; then
+                if [[ $only_head -eq 1 ]]; then
+                    range=$head
+                    shas=$(git rev-list -n 1 "$head" 2>/dev/null); list_rc=$?
+                else
+                    range="$base..$head"
+                    shas=$(git rev-list "$base..$head" 2>/dev/null); list_rc=$?
+                fi
+                if [[ $list_rc -eq 0 ]]; then
+                    while IFS= read -r sha; do
+                        [[ -n $sha ]] || continue
+                        if msg=$(git log -1 --format=%B "$sha" 2>/dev/null); then
+                            scan "commit messages" "${sha:0:12} " "$msg"
+                        else
+                            emit "commit messages" "${sha:0:12}" "could not read the commit message from git (could-not-look is never a pass)"
+                        fi
+                    done <<< "$shas"
+                else
+                    emit "commit messages" "$range" "could not read the commit messages from git (could-not-look is never a pass)"
+                fi
+            fi
+        fi
+    fi
+fi
+
+if [[ $rc -eq 0 ]]; then
+    echo "term wall: clean — $(git ls-files 2>/dev/null | wc -l) tracked files, their paths, and the change's messages, title, body and branch name carry no forbidden name"
+fi
+exit "$rc"