Quartz v5.25

Bootstrap Replay Handoff — Apr 9, 2026

Situation

The bootstrap chain is broken. The binary at HEAD cannot compile the source at HEAD. The break was introduced when compiler source features were added without rebuilding the binary and verifying fixpoint.

Last Verified Fixpoint

Commit 4a088d43 — “feat: complete UFCS unification for IntMap, Range, Arena, Pool”

  • Binary version: 5.12.15-alpha
  • Self-compiles cleanly: 0 errors, ~600K lines IR
  • Also verified at 2b013e20 and 102fedd1 (same binary, later source)

Root Cause

At commit 4597aa43 (“Phase TH Tiers 1+3”), HashMap<String, Int> type annotations were added to struct fields in typecheck_util.qz. The binary at that commit (5.12.15) could handle this fine. But at some point in the dogfooding sprint that followed, the binary was rebuilt from source that used features the binary didn’t support, breaking the chain. Every subsequent rebuild propagated the broken state.

The Break Point

Between 4a088d43 (works) and 738d2610 (broken — 9 errors about missing functions). Commits that touched the binary in this range:

  • 738d2610 — Vec mutation intrinsics
  • 81747947 — reverse, sort, unique, flatten
  • 4df609b9 — enumerate, zip, partition
  • 7563bf6b — shovel operator
  • 0fb2d700 — Lexer mode stack

Recovery Plan: Incremental Replay

Strategy

Start from the last verified fixpoint (4a088d43). Replay commits one at a time. At each binary-changing commit, rebuild and verify fixpoint. If a commit breaks fixpoint, fix the source before proceeding.

Steps

  1. Create a replay branch from 4a088d43
  2. Cherry-pick commits from 4a088d43..HEAD one at a time (or in batches for non-compiler commits like spec files)
  3. For each commit that touches self-hosted/: a. Cherry-pick or apply the commit b. Run quake guard (backup → build → fixpoint → stamp) c. If fixpoint passes, commit with binary + stamp d. If fixpoint fails, debug and fix before proceeding
  4. For commits that only touch spec/, docs/, std/ (non-compiler):
    • These can be cherry-picked in bulk without rebuilding
  5. Verify at the end that the replayed branch matches HEAD’s source

Optimization: Batch Non-Compiler Commits

Many of the ~100 commits are dogfooding spec file conversions (triple-quoted strings). These don’t touch the compiler and can be batched:

  • ~60 spec dogfooding commits → batch into 1-2 commits
  • ~10 documentation commits → batch
  • ~30 actual compiler feature commits → replay individually

Key Commits to Watch

These are the binary-changing commits between the fixpoint and HEAD. Each one needs careful rebuild:

  1. 738d2610 — Vec mutation intrinsics (capacity, truncate, dedup, retain, extend)
  2. 81747947 — reverse, sort, unique, flatten
  3. 4df609b9 — enumerate, zip, partition
  4. 7563bf6b — shovel operator
  5. 0fb2d700 — Lexer mode stack for string interpolation
  6. 87c0eb01 — Match arm enhancements
  7. c1031c59 — Length-based pre-dispatch
  8. 64118f8f — Dogfood 700+ arm string match
  9. 31403f34 — “Commit working compiler binary”
  10. aef2610b — Open UFCS
  11. 0c73a2fc — Self type alias
  12. dc3d196a — Trait default methods
  13. Various dogfooding/trait/UFCS commits
  14. Memory optimization Phase 1+2

Prevention: Quake Guard

A quake guard task has been added to Quakefile.qz:

  • Backs up current binary
  • Builds compiler
  • Verifies fixpoint (gen1 == gen2)
  • Writes .fixpoint stamp file
  • Stages binary + stamp for commit

A git pre-commit hook at .git/hooks/pre-commit enforces:

  • Compiler source changes REQUIRE binary + .fixpoint stamp staged
  • Stamp must match current source hash
  • Blocks commit if any check fails

Git Bundle Backup

Full repo backup at: /Users/mathisto/projects/quartz-full-backup-20260409.bundle

To restore: git clone quartz-full-backup-20260409.bundle quartz-restored

Working Binaries Available

  • self-hosted/bin/quartz — broken (at HEAD)
  • self-hosted/bin/backups/quartz-prev — from Phase 1 memory opt era (broken for self-compile)
  • /tmp/quartz-4a08 — from 4a088d43 (WORKING fixpoint, 5.12.15)
  • Various self-hosted/bin/quartz-pre-* backups

Estimated Time

The replay is mechanical:

  • ~30 compiler commits need individual rebuild+fixpoint (~5 min each = ~2.5 hours)
  • ~70 non-compiler commits can be batched (~10 min total)
  • Debug time for broken fixpoints: unknown, but features already work in the source
  • Total estimate: 3-4 hours

IMPORTANT

  • The git pre-commit hook and quake guard task are in the CURRENT working tree
  • They need to be carried forward during the replay
  • After replay reaches HEAD, the Quakefile.qz changes should be the final commit