Group branches.yaml by EL/CL/MEV/ZK/Tooling/Other/Lean

[barnabasbusa]

Summary

• Restructures branches.yaml so each top-level key is a group (el, cl, mev, zk, tooling, other, lean) instead of a flat client dict
• Each group can declare common_branches: that get merged into every client in the group, with skip_common: true as a per-client opt-out — devnet branches (bal-devnet-3/bal-devnet-7/glamsterdam-devnet-4 for EL, glamsterdam-devnet-4 for CL) are now written once per group rather than repeated under every client
• generate_config.py gains a small flatten_groups() step that runs before the existing expansion logic, so the rest of the script is untouched and the generated config.yaml is byte-identical to before

Common-branch opt-outs

• el.common_branches: opted out by ethereumjs
• cl.common_branches: opted out by caplin, consensoor

Test plan

• python3 generate_config.py runs cleanly and reports 148 configurations (same as before)
• Per-client branch lists verified identical pre/post for every EL and CL client (besu, erigon, ethereumjs, ethrex, geth, nethermind, nimbus-eth1, reth, caplin, consensoor, grandine, lighthouse, lodestar, nimbus-eth2, prysm-beacon-chain, teku)
• 39 distinct client repositories in the generated config.yaml (37 base + prysm/nimbus splits) — none lost
• Sanity-check a scheduled build run against this branch before merging

[qu0b-reviewer]

🤖 qu0b-reviewer

Now I have enough context. Here is my review:

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Summary

The PR restructures branches.yaml from a flat per-client list to a grouped structure (EL/CL/MEV/ZK/Tooling/Other/Lean), introducing common_branches: per group and skip_common: per-client. The Python generator was updated to flatten this back. The primary risk is silent data loss: two clients lost devnet branch coverage that was their only reason for inclusion.

Issues

• 🔴 blocker branches.yaml — erigon was added in PR Update branches.yaml #385 specifically for devnet testing (bal-devnet-3, bal-devnet-7, glamsterdam-devnet-4). The PR stripped those three branches by not including erigon in the common_branches block and not listing them individually. Erigon now builds main and performance only — zero devnet coverage. Is that intentional?

• 🔴 blocker branches.yaml — nimbus-eth1 has the same problem: master was its only branch before, with the three devnets added in Update branches.yaml #385. Now those devnets are gone from nimbus-eth1 (the common branches are for the EL group, but nimbus-eth1 isn't in EL). nimbus-eth1 is in EL and groups to nimbus-eth2/nimbus-validator-client via nimbus expansion — so it's unclear whether it needs devnet coverage at all, but the PR Update branches.yaml #385 intent was clearly to add it.

• 🟡 concern branches.yaml:31 — ethereumjs moved from a standalone top-level entry to under el.clients: with skip_common: true. This works but requires DEFAULT_REPOS['ethereumjs'] in generate_config.py to already exist (it does, from the prior ethereumjs PR). The coupling is non-obvious — a future maintainer deleting ethereumjs from DEFAULT_REPOS would silently break builds with no error from the Python generator.

Suggestions

• 🟢 nit generate_config.py:100 — The flatten_groups function silently skips any top-level YAML key whose value is not a dict (if not isinstance(group_data, dict): continue). This is mute today but creates a silent no-op if someone accidentally nests a client at the wrong level. A warning would help catch typos like tooling: → EL: or estrator:.

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_{Reviewed @ 93a6e0c0
"Async by default."}