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Lesson 245: Bevy Playtest Crash build_label Receipt on BUILD_RECEIPT (2026)

Direct answer: Before July playtest scale invites on Bevy 0.17 wasm, file playtest_crash_label_receipt_v1.json proving console_error_panic_hook is enabled in release wasm, a custom panic hook prints surface= + build_label=, a forced internal panic probe is captured, and child wasm_build_label_receipt_v1 from wasm boot preflight is GREEN—then promote BUILD_RECEIPT playtest_crash_label_ok. Distinct from Lesson 214 minidump symbolicate (desktop stacks) and Lesson 242 WASM heap cap (tab OOM).

Lesson hero for Bevy playtest crash build_label receipt

Why this matters now (July 2027 Bevy wasm playtest scale)

July 2027 teams scale itch WASM cohorts the week after Q3 capstone 244 goes GREEN. Facilitators paste RuntimeError: unreachable with no build_label—engineering hotfixes summer-playtest-2027-rc0 while players still run rc1. wasm boot preflight proves first-frame tags; this lesson proves panic paths carry the same identity.

The Bevy crash log correlation preflight is the ninety-second checklist—245 is the BUILD_RECEIPT milestone. Pair Lesson 239 tag wasm_crash → this row.

Beginner path (panic hook + probe)

Step Action Success check
1 Confirm child wasm boot receipt GREEN L1 child wasm_label_pass
2 Enable console_error_panic_hook in release wasm L2 pass
3 Install custom panic context hook L3 build_label= in text
4 Run internal panic probe (password itch) L4 screenshot/log
5 Verify surface=itch_public on panic L5 pass
6 File receipt + BUILD_RECEIPT crash_label_ok: true

Time: ~58 minutes first Trunk panic wiring; ~12 minutes when hooks are pinned.

Developer path (gates L1–L6)

Gate Check Fail when
L1 Child wasm_build_label_receipt_v1 wasm_label_pass: false
L2 console_error_panic_hook in release Silent wasm panic
L3 Custom set_hook context Panic without build_label=
L4 Forced internal panic probe No capture filed
L5 surface on panic line Missing itch_public / webgl_playtest
L6 playtest_crash_label_receipt_v1.json crash_label_ok: false

L1 — child receipt crosswalk

Field Child (boot) This lesson (crash)
Schema wasm_build_label_receipt_v1 playtest_crash_label_receipt_v1
Gates W1–W6 L1–L6
Scope First-frame boot log Panic console block
Path release-evidence/html5/WASM_BUILD_LABEL_RECEIPT.json release-evidence/crash/PLAYTEST_CRASH_LABEL_RECEIPT.json

Do not duplicate W2–W5 Trunk proof inside crash receipt—reference child path.

playtest_crash_label_receipt_v1.json

{
  "schema": "playtest_crash_label_receipt_v1",
  "engine": "bevy",
  "bevy_version": "0.17.x",
  "build_label": "summer-playtest-2027-rc1",
  "surface": "itch_public",
  "child_receipts": {
    "wasm_build_label": "release-evidence/html5/WASM_BUILD_LABEL_RECEIPT.json"
  },
  "panic_probe": {
    "method": "internal_key_f12",
    "log_excerpt": "surface=itch_public build_label=summer-playtest-2027-rc1 panic=...",
    "screenshot": "release-evidence/crash/PLAYTEST_WASM_PANIC_PROBE_2027-07-14.png"
  },
  "gates": {
    "L1_child_wasm_boot": "pass",
    "L2_console_panic_hook": "pass",
    "L3_custom_context_hook": "pass",
    "L4_forced_panic_probe": "pass",
    "L5_surface_tag": "pass",
    "L6_receipt": "pass"
  },
  "crash_label_ok": true,
  "promotion_allowed": true
}

Pin under release-evidence/crash/PLAYTEST_CRASH_LABEL_RECEIPT.json.

BUILD_RECEIPT row (L6)

Column Source
playtest_crash_label_ok crash_label_ok: true
wasm_build_label Child receipt (L1)
build_label Matches Lesson 201 playtest pin

Thursday row review — Wasm crash row: panic includes build_label Y/N.

Key takeaways

  1. Boot receipt ≠ crash receipt—W6 GREEN does not imply L3 GREEN.
  2. crash_symbolicate_receipt_v1 (Lesson 214) is desktop minidump—do not merge schemas.
  3. Forced panic probe must be internal-only—no public itch panic buttons.
  4. Tag wasm_crash via Lesson 239—not ad-hoc Discord strings.
  5. Q3 capstone 244 does not include Bevy—245 is Q4 scale hardening.
  6. Phaser heap cap 242 is 20-minute OOM—different BUILD_RECEIPT column.
  7. promotion_allowed on this receipt is crash path only—not full July scale gate until 253 capstone.
  8. Pair your first Bevy 0.17 platformer blog for engine setup—not panic policy.
  9. Facilitators reject console pastes missing build_label=—policy in preflight, proof in 245.
  10. Forward: Lesson 246 Ren'Py save/language isolation (when published).

Common mistakes

  • Panic hook only in debug wasm builds.
  • Label unknown on panic while boot log looks fine—rebuild Trunk env.
  • Merging into crash_symbolicate_receipt_v1 for wasm-only week.
  • Public itch page with always-on panic key.
  • Chasing heap cap when console shows bounds panic—wrong tag.

Troubleshooting

Symptom Lane
L1 child fail wasm boot preflight
Silent panic L2 console_error_panic_hook
No build_label= in panic L3 custom hook order
Desktop stacks only Lesson 214
Wrong depot hotfixed Lesson 244 S9 crosswalk

Mini exercise (55 minutes)

  1. Ship wasm without L3—reproduce unlabeled panic.
  2. Add hook; pass L4 forced probe on password itch.
  3. Attach child WASM_BUILD_LABEL_RECEIPT.json.
  4. File receipt; set BUILD_RECEIPT playtest_crash_label_ok GREEN.

Continuity — Q4 2027 July playtest scale (245–253)

Lesson Receipt focus
244 Q3 capstone (prior arc)
245 (this) Bevy wasm crash build_label
246 Ren'Py save/language
253 Q4 capstone

Previous: Lesson 244 — Q3 summer playtest capstone
Next: Lesson 246 — Ren'Py playtest save language isolation

FAQ

Same as wasm boot preflight?
Boot = W1–W6 first frame; 245 = L1–L6 panic lines.

Same as Lesson 214?
214 = desktop minidump symbolication; 245 = browser panic text.

Same as Lesson 242?
242 = heap cap at 20 min; 245 = panic context on crash.

Need 244 before 245?
244 closes Q3 eight-pack; 245 starts Q4 scale hardening—run 244 before July invite scale.

Unlabeled wasm panics are hotfix roulette—child boot receipt, panic hook, forced probe, then playtest_crash_label_ok on BUILD_RECEIPT.