fix(renovate): the cron fired outside Renovate's own window, so it would never open a PR

.gitea/workflows/renovate.yaml shipped with `cron: "15 3 * * *"`. Gitea Actions cron is UTC, and renovate.json carries schedule ["after 3am and before 6am"] with timezone America/New_York -- and THAT inner schedule is authoritative: Renovate re-checks it and declines to open PRs outside it. 03:15 UTC -> 23:15 EDT, the PREVIOUS EVENING in New York window -> 03:00-06:00 local => NOT INSIDE (3h45m early) The original comment claimed the cron sat "slightly ahead" of the window. It sat 3h45m behind it, on the previous day. Every nightly run would have started, logged "not within schedule", opened ZERO PRs and exited SUCCESSFULLY -- a green tick forever, indistinguishable from "nothing needed updating", hiding the ~30 pending updates PR #73 existed to surface. Changed to `15 8 * * *`, chosen to survive DST rather than to look tidy: EDT (UTC-4): local 03:00-06:00 == 07:00-10:00 UTC EST (UTC-5): local 03:00-06:00 == 08:00-11:00 UTC 08:15 UTC is inside BOTH (04:15 EDT / 03:15 EST), verified by computation at both extremes, so neither switchover needs an edit. A cron cannot follow DST. Also confirmed while here: RENOVATE_TOKEN now exists as a repo Actions secret, so the workflow's fail-hard preflight will pass. STILL UNRESOLVED and the likelier remaining bug: renovate.json's `enabledManagers` lists bare `regex`, where modern Renovate names the custom manager `custom.regex`. If the bare name is ignored, every inline `# renovate:` marker in the tree does nothing. Deliberately NOT changed -- guessing at a key that could fail validation and take the whole run down is worse than a question one dry run answers. See the handoff. Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Merge pull request 'fix(conformance): one regex made the merge gate take 28 minutes instead of 2' (#76 ) from fix/ha-check-catastrophic-regex into main
2026-10-18 03:12:28 -05:00 · 2026-10-18 07:51:51 +00:00 · 2026-10-18 02:38:23 -05:00
4 changed files with 189 additions and 8 deletions
@@ -74,12 +74,26 @@ name: renovate

 on:
  schedule:
-    # 03:15 UTC daily. renovate.json ALSO carries `"schedule": ["after 3am and before 6am"]` in
-    # America/New_York, and that inner schedule is the authoritative one — Renovate re-checks it and
-    # will decline to open PRs outside it. The two are deliberately both present: this cron decides
-    # when the process RUNS, renovate.json decides when it may ACT. Keeping the cron slightly ahead
-    # of the repo window means a run is always in flight when the window opens.
-    - cron: "15 3 * * *"
+    # 08:15 UTC daily. renovate.json ALSO carries `"schedule": ["after 3am and before 6am"]` with
+    # `"timezone": "America/New_York"`, and THAT inner schedule is authoritative — Renovate re-checks
+    # it and DECLINES TO OPEN PRs outside it. So this cron must fire INSIDE the local window, not
+    # merely near it.
+    #
+    # WAS `15 3 * * *`, WHICH NEVER WOULD HAVE WORKED (fixed 2026-10-18, before the first scheduled
+    # run). Gitea Actions cron is UTC, so 03:15 UTC is 23:15 the PREVIOUS EVENING in New York --
+    # 3h45m BEFORE the window opens, not "slightly ahead" of it as the original comment claimed.
+    # Every nightly run would have started, logged "not within schedule", opened zero PRs and
+    # exited SUCCESSFULLY. A green tick forever, and no updates ever: the exact "failure mode is a
+    # green tick" shape this repo keeps getting burned by, and indistinguishable from "nothing
+    # needed updating".
+    #
+    # THE WINDOW IN UTC MOVES WITH US DST, and a cron cannot follow it:
+    #   EDT (UTC-4, Mar-Nov): local 03:00-06:00 == 07:00-10:00 UTC
+    #   EST (UTC-5, Nov-Mar): local 03:00-06:00 == 08:00-11:00 UTC
+    # 08:15 UTC is the only quarter-hour comfortably inside BOTH (04:15 EDT / 03:15 EST), so the
+    # schedule keeps working across both switchovers without an edit. Do not "tidy" this back to an
+    # early-morning-UTC value without redoing this arithmetic.
+    - cron: "15 8 * * *"
  workflow_dispatch:
    inputs:
      dry_run:
@@ -445,8 +445,21 @@ join = re.search(r"--server https://\{\{\s*k3s_api_host", K3S_TEXT)
 check(join is not None,
      "roles/k3s_server does not join secondaries with `--server https://{{ k3s_api_host }}` "
      "— without a join target the servers are separate single-node clusters")
-join_when = re.search(r"--server https://.*?\n(?:.*\n){0,10}?\s*when:\s*k3s_server_mode\s*==\s*'secondary'",
-                      K3S_TEXT, re.S)
+# LINE-BOUNDED ON PURPOSE -- DO NOT "SIMPLIFY" BACK TO `.*` + re.S.
+# This was `--server https://.*?\n(?:.*\n){0,10}?\s*when:...` with re.S, which made every `.`
+# match newlines too. That is nested unbounded repetition (a `{0,10}` of a quantifier that can each
+# swallow the whole document), so a FAILED or late match backtracks exponentially. It cost
+# **19m54s of CPU in CI** (measured 2026-10-18 via `docker top` on the live job container) and made
+# the whole merge gate take ~28 minutes instead of ~2 on any change touching `infra/**` -- because
+# `ci/touched-requirements.sh` maps `infra/*` to R-ENV-01, which pulls in this whole-repo check.
+# It was latent for as long as the regex existed and only crossed the threshold when
+# roles/k3s_server grew by ~100 lines (the kubelet graceful-shutdown config, PR #71): K3S_TEXT is
+# every *.yml in that role concatenated, so the role growing is the input growing.
+# `[^\n]*` cannot cross a line, so the `{0,10}` is a genuine ten-line window with nothing to
+# backtrack into. Measured on the same input: 0.2 ms, same verdict (match found).
+join_when = re.search(
+    r"--server https://[^\n]*\n(?:[^\n]*\n){0,10}?[ \t]*when:[ \t]*k3s_server_mode[ \t]*==[ \t]*'secondary'",
+    K3S_TEXT)
 check(join_when is not None,
      "the join install task is not gated on k3s_server_mode == 'secondary' — the founder "
      "would also try to join itself")
@@ -0,0 +1,76 @@
+---
+date: 2026-10-18
+branch: fix/ha-check-catastrophic-regex
+title: "One regex made the merge gate take 28 minutes instead of 2"
+---
+
+## What changed
+
+The merge gate started taking **~28 minutes** instead of its usual **<2 minutes**, on every change
+touching `infra/**`. One regex was responsible for essentially all of it.
+
+`conformance/tests/l0-static/ha-control-plane-as-code/check.sh` contained:
+
+```python
+join_when = re.search(r"--server https://.*?\n(?:.*\n){0,10}?\s*when:\s*k3s_server_mode\s*==\s*'secondary'",
+                      K3S_TEXT, re.S)
+```
+
+With `re.S`, every `.` also matches newlines, so `.*?` and the nested `(?:.*\n){0,10}?` can each
+consume the entire document. That is **nested unbounded repetition** — ten levels of a quantifier
+that can each swallow everything — and a failed or late match backtracks exponentially.
+
+Replaced `.` with `[^\n]*` and dropped `re.S`, so the `{0,10}` is a genuine ten-line window with
+nothing to backtrack into. Same intent, same verdict, no DOTALL.
+
+**Why it surfaced now, and it was mine.** `K3S_TEXT` is every `*.yml` in `roles/k3s_server`
+concatenated. The regex was latent for as long as it existed; **PR #71 added ~100 lines to that role
+(the kubelet graceful-shutdown config), which grew the input past the point where exponential
+backtracking stopped being survivable.** Nothing about the check changed — my change grew its input.
+
+**Why only `infra/**` changes were slow.** `ci/touched-requirements.sh:268` maps `infra/*` to
+`R-ENV-01`, and the resulting L0 run is `--include-scope whole-repo --requirements R-ENV-01`, which
+pulls in this whole-repo check. Doc-only and `platform/**` changes never selected it, which is why
+#69 (1m55s) and #72 (1m53s) stayed fast while #71 (27m44s), the #73 merge (27m46s) and #75 all ran
+~28 minutes.
+
+## What I verified
+
+* **The hot spot, by measurement rather than reading.** `docker top` on the live CI job container for
+  run #299 showed `python3 -` with **19:54 of CPU time** under
+  `ha-control-plane-as-code/check.sh`, inside
+  `conformance/run.sh --layer l0 --include-scope whole-repo --requirements R-ENV-01`.
+* **Reproduced locally**: the check did not finish within a 100-second budget on an unmodified
+  checkout.
+* **Localised to the exact line** by extracting the inline Python and running it under
+  `faulthandler.dump_traceback_later(25)`, which named `re/__init__.py:177 in search` called from
+  the `join_when` line — not inferred from reading the patterns.
+* **The pattern is unique in the repo**: `grep -rlnE "\{0,[0-9]+\}\?" conformance/tests/l0-static/*/check.sh`
+  returns only this file, so there is no sibling with the same hazard.
+* **The fix is fast AND verdict-preserving**, tested against the real `K3S_TEXT` (22,179 chars, 403
+  lines): the new regex matches (`YES`) in **0.2 ms**. Sanity-checked that the thing it looks for
+  genuinely exists — one `--server https://` and three `k3s_server_mode == 'secondary'` occurrences.
+* **The whole check now runs in 0.199s, rc 0, 115 assertions**, with the same success message as
+  before.
+
+## What I did NOT verify
+
+* **I did not re-time the full gate in CI after the fix.** The expectation is that `infra/**` changes
+  return to the ~2-minute range, but that is arithmetic from the 19m54s figure, not a measured
+  post-fix run. The PR's own CI run is the first real datapoint — read it.
+* **I did not audit the other 23 L0 checks for different performance pathologies.** This one was
+  found because it was actively burning CPU in a live job; a check that is merely slow (not
+  exponential) would not have stood out, and `ci/gate.sh` has **no per-stage timing** at all
+  (`grep -nE "SECONDS|date \+|elapsed"` finds nothing), so there is no data on where the remaining
+  time goes.
+* **Nothing prevents this class of bug returning.** No check asserts gate stage runtime, and no lint
+  forbids nested quantifiers under `re.S`. A timing budget per stage, or a `re` lint, would close it;
+  neither is written here.
+* **I did not verify my claim about *why* only `infra/**` was affected beyond the path mapping and
+  the observed durations.** The correlation is strong (5 runs, two clear clusters) and the live
+  process list confirms the `--requirements R-ENV-01` scope, but I did not read
+  `conformance/run.sh`'s scope-selection logic end to end.
+* The regex rewrite assumes the `when:` clause is indented with spaces or tabs only (`[ \t]*`). A
+  file using some other whitespace before `when:` would now fail to match where the old DOTALL
+  version would have succeeded. Unlikely in YAML, and the current input matches, but it is a
+  narrowing.
@@ -0,0 +1,78 @@
+---
+date: 2026-10-18
+branch: fix/renovate-cron-window
+title: "The Renovate cron fired outside Renovate's own schedule, so it would never have opened a PR"
+---
+
+## What changed
+
+`.gitea/workflows/renovate.yaml` shipped (PR #73) with `cron: "15 3 * * *"`. **That schedule could
+never have produced a single PR.**
+
+Gitea Actions cron is **UTC**. `renovate.json` carries `"schedule": ["after 3am and before 6am"]`
+with `"timezone": "America/New_York"`, and that inner schedule is **authoritative** — Renovate
+re-checks it and declines to open PRs outside it. So:
+
+```
+cron 03:15 UTC  ->  23:15 EDT, the PREVIOUS EVENING in New York
+window          ->  03:00-06:00 local
+inside?         ->  NO (3h45m before the window opens)
+```
+
+The original comment claimed the cron was "slightly ahead of the repo window ... so a run is always
+in flight when the window opens". It is 3h45m *behind*, on the previous day. Every nightly run would
+have started, logged "not within schedule", opened **zero** PRs and exited **successfully** — a
+green tick forever, indistinguishable from "nothing needed updating". That is the same
+"failure-mode-is-a-green-tick" shape this repo keeps hitting, and it would have hidden the ~30
+pending updates PR #73 was written to surface.
+
+Changed to `cron: "15 8 * * *"`, chosen to survive DST rather than to be tidy. The window's UTC
+position moves:
+
+| | local window | in UTC |
+|---|---|---|
+| EDT (UTC-4, Mar–Nov) | 03:00–06:00 | 07:00–10:00 |
+| EST (UTC-5, Nov–Mar) | 03:00–06:00 | 08:00–11:00 |
+
+`08:15 UTC` is inside **both** (04:15 EDT / 03:15 EST), so no edit is needed at either switchover.
+A cron cannot follow DST, so this is the only way to get it right once.
+
+## What I verified
+
+* **The defect, by arithmetic rather than assertion:** `datetime(2026,10,18,03,15, UTC)` converted to
+  `America/New_York` via `zoneinfo` is `2026-10-17 23:15 EDT`; `3 <= hour < 6` is **False**.
+* **The fix, at both DST extremes:** `08:15 UTC` → `04:15 EDT` in July and `03:15 EST` in December,
+  both inside `03:00–06:00`. Computed, not reasoned.
+* **The inner schedule really is authoritative and really is set:** `renovate.json` on `main` carries
+  `timezone = America/New_York` and `schedule = ['after 3am and before 6am']`.
+* **`RENOVATE_TOKEN` now exists** as a repository Actions secret (listed by name via the Gitea API
+  alongside `SETTINGS_API_TOKEN`), so the workflow's fail-hard preflight will pass. It did not exist
+  when PR #73 was authored.
+* The edited workflow parses as YAML.
+
+## What I did NOT verify
+
+* **Renovate has still never executed.** This fixes *when* it runs, not *whether it works*. No run
+  has happened, so nothing here proves it extracts dependencies, authenticates to Gitea, or opens a
+  usable PR.
+* **`enabledManagers` may silently disable the custom managers — UNRESOLVED and the likelier
+  remaining bug.** `renovate.json` lists `enabledManagers: [..., 'regex', ...]` and defines
+  `customManagers` (correct modern key; `regexManagers` is absent, which is right). But modern
+  Renovate names the custom manager **`custom.regex`** in `enabledManagers`, not bare `regex`. If
+  the bare name is invalid or ignored, every inline `# renovate:` marker in the tree does nothing —
+  including the `external-snapshotter` `newTag` pin PR #73 flagged as probably inert. **I did not
+  change it**, because guessing at a config key that could fail validation and take the whole run
+  down is worse than leaving a question that one dry run answers definitively. The `dry_run: true`
+  dispatch log settles it: look for a per-manager dependency-extraction count, and for any config
+  validation warning naming `regex`.
+* **Whether a dry run inside vs outside the window differs usefully.** Renovate honours its schedule
+  even in dry-run, so a manual dispatch outside 03:00–06:00 local will also log "not within
+  schedule". That makes the first dispatch's output less informative than it looks; to see what
+  Renovate *would* do, either dispatch inside the local window or override the schedule for that
+  run. Not tested either way.
+* **No alert fires if the schedule stops firing.** PR #73 recorded this gap and it is still open: a
+  Renovate workflow that silently stops running (disabled Actions, expired token, deleted secret)
+  produces no signal at all. Closing it needs a check on last-successful-run age, which nothing
+  does.
+* No conformance test asserts the cron falls inside `renovate.json`'s window, so this exact bug can
+  return. A static check comparing the two is feasible and is not written.