fix(ci): the content scan could not match R-C2-01/02 — a digit in the workstream segment

Checked as part of closing the C2 coverage gaps, and it was live on main. The content
scan's pattern was `R-[A-Z]+-[0-9]+`, which CANNOT match an ID whose workstream segment
carries a digit: `[A-Z]+` consumes the `C` of `R-C2-01` and then demands a `-` where the
`2` is. `R-C2-01` and `R-C2-02` are the only two such IDs in
conformance/requirements/registry.yaml, and the scan was blind to BOTH.

REPRODUCED before the fix, on a throwaway repo whose only change is a manifest declaring
both IDs on real (non-comment) lines, in a path the map keys to nothing:

    $ REPO_ROOT=$T BASE_REF=main ci/touched-requirements.sh
    R-NET-06                     # the all-letter control ID was the ONLY output

It failed by UNDER-attributing, which is the fail-OPEN direction: a change that retyped a
`conformance.home.k3s/R-C2-01` tag, or a manifest self-declaring R-C2-02, contributed
those IDs to NOBODY, so the C2 tests were filtered out of the merge gate. Same defect
class as the map's `*) : ;;` arm — a miss that reads as "nothing touched".

Every other consumer in the repo already allowed the digit, which is why this was the lone
dissenter: test_requirements_for_path() twenty lines above in this same script,
conformance/lib/coverage.py, conformance/lib/status.py and conformance/lib/
run_l1_offline.py all use `R-[A-Z0-9]+-[0-9]+`. Aligned to that form, with the reason
recorded at the line.

SCOPE OF THE HOLE. path_requirements() has no arm for platform/homepage/* or
platform/headlamp/* either, so before this the ONLY route to R-C2-01/02 was detection rule
3 (editing the C2 conformance test itself). No path-map arm is added here: c2-root-surface
declares `scope: whole-repo`, so ci/l0.sh Stage 3b's --include-scope union selects it on
EVERY gate invocation regardless of the touched set — which is the right mechanism for an
invariant whose input surface is the whole tree, and strictly stronger than a two-component
path arm would be.

REGRESSION-TESTED, in ci/tests/touched-requirements.test.sh (the suite `make -C ci test`
runs): a fixture declaring R-C2-01 / R-C2-02 / R-OBS-04 from `notes/` — a path outside
path_requirements(), so the IDs can only come from the content scan — asserts both digit
IDs ARE attributed, that the all-letter form still is (control), and that a purely numeric
workstream is not invented (the pattern must not widen the gate on noise).

PROVEN TO DETECT BREAKAGE: with the pattern reverted to `R-[A-Z]+-[0-9]+` the suite reports
`FAIL (2 failed, 14 passed)` naming both C2 IDs as missing; restored, all three ci/ suites
pass (16 assertions in this one).

ALSO: conformance/tests/l0-static/whole-repo-invariants-wired/check.sh cites this pattern
in the comment explaining why its BOGUS_REQ fixture is lowercase. Citation updated so the
reasoning still reads true; the fixture is unaffected (grep -E is case-sensitive, and the
check still passes 26/26).

NOTE: another branch may be editing this same script concurrently. This is a one-line
change to one statement plus its comment — expect a trivial conflict and keep the
`[A-Z0-9]` form.

Co-Authored-By: Claude Opus 5 <[email protected]>

ci/tests/touched-requirements.test.sh

@@ -136,6 +136,39 @@ printf 'touched set (clusters/ path map):\n%s\n---\n' "$OUT4"
 assert_present "R-ENV-02"     "$OUT4" "clusters/* attributes R-ENV-02 (selects placeholder-guard-coupling HALF A)"
 assert_present "R-GITOPS-01"  "$OUT4" "clusters/* attributes R-GITOPS-01"
 
+# ---------------------------------------------------------------------------------------
+# THE ID PATTERN MUST ALLOW A DIGIT IN THE WORKSTREAM SEGMENT (added 2026-09-13)
+#
+# The content scan's pattern was `R-[A-Z]+-[0-9]+`, which CANNOT match `R-C2-01` or
+# `R-C2-02` — `[A-Z]+` consumes the `C` and then demands a `-` where the `2` is. Those are
+# the only two registry IDs whose workstream segment carries a digit, and the scan was blind
+# to BOTH, in the fail-OPEN direction: a change self-declaring a C2 requirement contributed
+# it to nobody, so the C2 conformance tests were filtered out of the merge gate. Found while
+# wiring conformance/tests/l0-static/c2-root-surface, which closes those two coverage gaps.
+#
+# `notes/` is outside path_requirements() on purpose, so the IDs below can only have come
+# from the CONTENT SCAN. A neighbouring all-letter ID is asserted too, so a regex that
+# somehow matched only the digit form would still fail here.
+git -C "$TMP" checkout -q -b feature5 main
+cat > "$TMP/notes/c2.yaml" <<'YAML'
+kind: Test
+metadata:
+  labels:
+    conformance.home.k3s/R-C2-01: "true"
+    conformance.home.k3s/R-C2-02: "true"
+    conformance.home.k3s/R-OBS-04: "true"
+YAML
+git -C "$TMP" add -A && git -C "$TMP" commit -qm "declare R-C2-01 / R-C2-02"
+OUT5="$(REPO_ROOT="$TMP" BASE_REF=main "$SCRIPT" 2>/dev/null)"
+printf 'touched set (digit in the workstream segment):\n%s\n---\n' "$OUT5"
+assert_present "R-C2-01"  "$OUT5" "an R-ID with a DIGIT in the workstream segment IS attributed (R-C2-01)"
+assert_present "R-C2-02"  "$OUT5" "the second such ID is attributed too (R-C2-02)"
+assert_present "R-OBS-04" "$OUT5" "an all-letter workstream segment still works (control)"
+# The pattern must not become so loose that a non-ID token is read as a requirement: a bare
+# numeric workstream is not a registry shape, and attributing one would WIDEN the gate on
+# noise (over-broad selection, never a false green, but noisy and misleading).
+assert_absent  "R-1-01"   "$OUT5" "a purely numeric workstream segment is not invented from thin air"
+
 echo
 if [ "$FAIL" -eq 0 ]; then echo "touched-requirements tests: PASS ($PASS assertions)"; exit 0;
 else echo "touched-requirements tests: FAIL ($FAIL failed, $PASS passed)"; exit 1; fi

ci/touched-requirements.sh

@@ -345,6 +345,21 @@ main() {
   done <<< "$files"
 
   # Self-declared R-IDs on the ADDED/REMOVED lines of the change (see changed_diff).
+  #
+  # THE ID PATTERN IS `R-[A-Z0-9]+-[0-9]+`, NOT `R-[A-Z]+-[0-9]+`. The WORKSTREAM segment may
+  # contain a DIGIT: `R-C2-01` and `R-C2-02` (command & control UI) are the only two such IDs
+  # in conformance/requirements/registry.yaml today, and the stricter pattern silently failed
+  # to match BOTH of them — `[A-Z]+` consumes the `C` and then demands a `-` where the `2` is.
+  # Every other consumer in the repo already allows the digit: test_requirements_for_path()
+  # twenty lines above uses `R-[A-Z0-9]+-[0-9]+`, as do conformance/lib/coverage.py,
+  # conformance/lib/status.py and conformance/lib/run_l1_offline.py. This grep was the lone
+  # dissenter, and it dissented by UNDER-attributing — the fail-OPEN direction. A change that
+  # retyped a `conformance.home.k3s/R-C2-01` tag, or a manifest self-declaring R-C2-02 from a
+  # path the map keys elsewhere, contributed those IDs to NOBODY, so the C2 tests were
+  # filtered out of the merge gate. Same defect class as the map's `*) : ;;` arm: a miss that
+  # reads as "nothing touched". path_requirements() has no arm for platform/homepage/* or
+  # platform/headlamp/* either, so before this fix the ONLY route to R-C2-01/02 was rule 3
+  # (editing the C2 test itself). Regression-tested in ci/tests/touched-requirements.test.sh.
   # `^[+-]` keeps hunk headers (`@@`) and the `+++`/`---` file headers out of scope.
   # `sed 's/^[+-]//'` then strips the single-char diff marker (safe: -U0 emits one), so
   #   what remains is the SOURCE line, and `grep -vE '^[[:space:]]*#'` drops whole-line
@@ -358,7 +373,7 @@ main() {
     | grep -vE '^(\+\+\+|---)' \
     | sed -E 's/^[+-]//' \
     | grep -vE '^[[:space:]]*#' \
-    | grep -hoE 'R-[A-Z]+-[0-9]+' \
+    | grep -hoE 'R-[A-Z0-9]+-[0-9]+' \
     | tr '\n' ' ' || true)"
 
   # Normalize: split, unique, sort. Emit to stdout.

conformance/tests/l0-static/whole-repo-invariants-wired/check.sh

@@ -85,7 +85,7 @@ done
 # second would fail.
 # Deliberately LOWERCASE: conf_normalize_reqs() upper-cases it, so the selection behaves
 # identically — but the literal here does not match ci/touched-requirements.sh's content-scan
-# pattern `R-[A-Z]+-[0-9]+`, so editing this file does not attribute a nonexistent requirement
+# pattern `R-[A-Z0-9]+-[0-9]+`, so editing this file does not attribute a nonexistent requirement
 # to the change. (Same reason the synthetic fixture below carries no requirement label at all.)
 BOGUS_REQ="r-nosuchreq-99"
 sel_without="$(bash "$RUN_SH" --layer l0 --requirements "$BOGUS_REQ" --print-selection 2>/dev/null || true)"