fix: autogenerate bare protocol versions

[MasterPtato]

Description

Please include a summary of the changes and the related issue. Please also include relevant motivation and context.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[railway-app]

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[MasterPtato]

• fix(pb-envoy): hard abort ws to tunnel on ping error #4776
• fix(outbound): implement drain grace period #4775
• fix(pb): fix pool config defaults #4774
• fix(pb): remove actor sleep ts when allocated #4772
• refactor(gateway): clean up and fix lost tunnel msgs #4771
• refactor(pb): fix actor overdue alarm handling #4770
• fix: update railway docs to include graceful shutdown #4715
• fix: add wf registry command #4714
• chore: move code #4713
• fix(gas): add large txn retries for pulling signals, tighten commit interval for actors #4712
• fix: improve epoxy propose errors, add gcp logging fmt #4698
• fix: autogenerate bare protocol versions #4696 👈 (View in Graphite)
• main

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[claude]

Code Review: PR #4696 — fix: autogenerate bare protocol versions

Summary

This PR eliminates manually-maintained version constants by having each build.rs scan its schema directory and inject the highest version number into the generated combined_imports.rs file. It also renames the namespace.runner_config.vN.bare schema files to pegboard.namespace.runner_config.vN.bare (adding the pegboard. prefix for consistency), and updates all references in versioned/ and runner_configs.rs.

The intent is solid and the mechanics generally work. A few issues worth addressing before merge.

---

Issues

1. Silent zero version when schema directory is empty

In find_highest_version, if no .bare files match the expected vN.bare pattern, highest_version stays at 0. For ups-protocol this silently injects pub const PROTOCOL_VERSION: u16 = 0. epoxy-protocol protects against this by checking highest_version_path.exists() after the scan, but ups-protocol has no equivalent guard. Add an explicit panic/error when highest_version == 0.

2. Panic on filenames without a dot in find_highest_version

.split_once('.')
.unwrap()  // panics if no '.' in filename

If a file like README (no extension) ever lands in the schema directory, .unwrap() on split_once('.') returning None will panic the build. The data/build.rs approach (strip_suffix(".bare") + rfind(".v")) handles this more gracefully. The new copies in epoxy-protocol and ups-protocol propagate this fragility. A safer pattern: let Some((bare_name, _)) = file_name.split_once('.') else { continue; };

3. Duplicated find_highest_version across three crates

find_highest_version is copy-pasted verbatim into envoy-protocol/build.rs, epoxy-protocol/build.rs, and ups-protocol/build.rs. Any fix to the issues above must be applied in three places. Consider moving this into vbare_compiler (the natural home) or a shared build-utils crate.

4. Auto-detected PROTOCOL_VERSION decoupled from hardcoded module re-export

After this change:

• pub use generated::v2::*; — still hardcoded
• pub use generated::PROTOCOL_VERSION; — now auto-detected as highest version

If someone adds v3.bare, PROTOCOL_VERSION automatically becomes 3 while pub use generated::v2::* still re-exports v2 types. The two silently diverge. CLAUDE.md says "never modify an existing published *.bare runner protocol version" precisely to prevent accidental bumps, but this decoupling removes the compile-time check that kept them in sync. An assertion or co-located comment would make the invariant explicit.

5. PEGBOARD_RUNNER_ADDRESS_VERSION silently dropped

The old data/src/lib.rs exposed PEGBOARD_RUNNER_ADDRESS_VERSION: u16 = 1. The new code drops it because no pegboard.runner.address.vN.bare schema file exists. A grep confirms it was dead code — but this should be called out explicitly in the PR description so reviewers know it was intentional.

---

Minor / Style

• Missing cargo:rerun-if-changed in ups-protocol/build.rs: verify incremental Cargo builds trigger a rebuild when schema files change.
• Version narrowing from u32 to u16: parsed as u32, emitted as u16. Not a practical issue, but worth a comment.
• result.sort_by(|(a, _), (b, _)| a.cmp(b)) can be simplified to result.sort_by_key(|(a, _)| a.clone()). Minor.

---

What's Working Well

• Auto-generating version constants from schema files eliminates the class of bugs where someone adds vN.bare but forgets to bump the constant manually.
• The pegboard. prefix rename is clean and makes the identifier-to-module-name derivation consistent.
• find_schema_versions in data/build.rs correctly groups multiple schemas by identifier and takes the maximum version per identifier — more robust than the single-schema approach.
• The pub use generated::PEGBOARD_* re-exports are clean and eliminate drift between manual constants and generated code.

---

Checklist

• Guard against zero version in ups-protocol/build.rs when no schemas are found
• Fix or document the .unwrap() panic risk on filenames without a dot in the new find_highest_version copies
• Add a comment or assertion co-locating PROTOCOL_VERSION with pub use generated::vN::* to prevent silent version skew
• Confirm PEGBOARD_RUNNER_ADDRESS_VERSION removal is intentional and note it in the PR description
• Verify cargo:rerun-if-changed coverage for ups-protocol schema directory