fix: auto-load BPF upgradeable programs (#240)

[alex-sumner]

Fixes #240

Summary

When programs are deployed via BPF Loader Upgradeable, only the ProgramData account gets written to the ExecutionRecord, not the Program account. This causes subsequent transactions to fail.

Changes

• Set executable flag for Program accounts in sync_accounts()
• Add load_all_existing_programs() to scan and load uncached programs
• Auto-load programs during transaction execution if missing from cache
• Sync BPF loader accounts even when not writable in execute_tx_helper()
• Add load_existing_programs() public API
• Add tests

Test Plan

• cargo test --package litesvm --test bpf_upgradeable_autoload (4 tests pass)

[alex-sumner]

Any feedback on this contribution would be welcome. At the moment we are maintaining our own fork of litesvm because we need these changes for some of our Solana tests. It would be great if this could be merged. Happy to look at it again if you think it needs changes, or just to hear your thoughts on it.

[Aursen]

The main problem of this PR is the impact on performance. What's the use case to it ?

[alex-sumner]

The main problem of this PR is the impact on performance. What's the use case to it ?

Thanks, I agree it is too expensive. The use case is making freshly deployed or synced BPF upgradeable programs immediately invokable in LiteSVM without requiring a separate full-program reload step.

I’ve updated it so sync_accounts() no longer scans the full accounts DB after every transaction. The patch now only does what's needed for the upgradeable-loader case:

• sync loader-owned program accounts from post-execution state even if they aren’t marked writable,
• fix up upgradeable Program accounts to be executable when they deserialize as UpgradeableLoaderState::Program,
• keep load_existing_programs() as an explicit recovery/init API