feat(coprocessor): solana host-listener poc scaffold and feedback loop

[Eikix]

Summary

Draft PR for Solana host-listener PoC scaffold and fast feedback loop.

Goal: validate Solana host feasibility against existing EVM listener semantics without broad refactors.

Included

• New solana-listener service scaffold in coprocessor/fhevm-engine/solana-listener
• Finalized RPC source with both emit! log decoding and emit_cpi! inner-instruction decoding
• Ingest mapping into existing coprocessor DB tables (computations, allowed_handles, pbs_computations, cursor state)
• ACL gate behavior for request_add -> allow
• Localnet integration harness (Docker + local validator + optional tfhe-worker)
• Anchor host program PoC in solana/host-programs/zama-host
• Exploration docs, parity matrix, testing tiers, and no-doc-rot protocol

Recent hardening / cleanup

• Host program naming/layout simplified (no v0 suffix noise).
• Host op logic deduplicated across emit! and emit_cpi! entrypoints.
• RPC source now fails closed on unavailable finalized blocks (no cursor advance on missing getBlock result).
• Removed in-code TODO from listener path.
• Tier-2 scaffold script trimmed (removed unused event-mode argument branch).
• Listener CLI defaults to real DB writes (SOLANA_DRY_RUN=false) with explicit dry-run opt-in.

Review focus

• Cursor/replay semantics in solana_rpc_source
• Event decoding assumptions (logMessages + innerInstructions)
• Ingestion parity and ACL gate transitions
• Test harness readability/maintainability

Notes

• Draft by design for iterative review.
• Localnet/e2e integration tests are #[ignore] and run manually.

[mergify]

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[Eikix]

Pushed a follow-up commit that addresses the new inline feedback: 988f5b5a.

What changed:

• switched solana_poc_runner instruction encoding to Anchor-generated instruction types (zama_host::instruction::*) instead of manual discriminator bytes.
• fixed runner correctness bug: tenant seeding now uses --host-chain-id (no hardcoded 12345).
• fixed runner correctness bug: ingest/db path now uses the inserted tenant_id returned from DB.
• removed noisy into_listener_pubkey helper and decode directly into ProgramEvent fields.
• clarified runner defaults: replaced raw random UUID default with explicit placeholder DEFAULT_TENANT_API_KEY; renamed/explained host-chain-id placeholder in reserved non-EVM range.
• kept the key-dir override path (--keys-dir / SOLANA_POC_KEYS_DIR) and docs/tests wiring from the report.

Validation run:

• cargo fmt -p solana-listener
• SQLX_OFFLINE=true cargo check -p solana-listener --features solana-e2e
• cargo test -p solana-listener poller::solana_rpc_source::tests::decodes_op_requested_add_from_program_data_line

[Eikix]

Tier-3 parity scorecard update (2026-02-11)

Ran:
/Users/work/.codex/worktrees/66ae/fhevm/test-suite/fhevm/scripts/solana-poc-tier3-e2e.sh --case all

Result: EXIT_CODE=0 (all cases passed)

Area	Tier-3 test	Status	Duration
ADD	localnet_solana_request_add_computes_and_decrypts	PASS	62.31s
SUB	localnet_solana_request_sub_computes_and_decrypts	PASS	61.98s
Binary ops	localnet_solana_request_binary_ops_computes_and_decrypts	PASS	172.62s
Unary ops	localnet_solana_request_unary_ops_computes_and_decrypts	PASS	104.92s
If/Then/Else	localnet_solana_request_if_then_else_computes_and_decrypts	PASS	62.16s
Cast	localnet_solana_request_cast_computes_and_decrypts	PASS	52.25s
Trivial encrypt	localnet_solana_request_trivial_encrypt_computes_and_decrypts	PASS	45.93s
Rand	localnet_solana_request_rand_computes_and_decrypts	PASS	51.24s
Rand bounded	localnet_solana_request_rand_bounded_computes_and_decrypts	PASS	49.84s
ACL gate	localnet_acl_gate_blocks_then_allows_compute	PASS	57.25s

Explorer-visible demo evidence (ADD + ALLOW canonical flow):

• request_add_signature=2Cung4UE36Ky1LkaLLGQT3JgKvD5Udmc85Zi82XRyBKp3ABgP3r7FpYpU2mJzRtuPFK421TkB1pEESTJ7wJD5JTy
• allow_signature=4DDdwLDaNQWirrrTLoDeaC19xnQGf74wzRrwqddvFeohDUALwupjQr1aTRzyfyqfcUGuNBT2shPDgEqgnbYmoeso
• DB ingest counters: computations=1, allowed_handles=1, pbs_computations=1

Small follow-up fix included: default host_chain_id in solana_poc_runner reverted to schema-compatible value (12345) to avoid tenants_chain_id_check violations in the local demo path.