blockifier,apollo_starknet_os_program: support linear message cost

[dorimedini-starkware]

No description provided.

[reviewable-StarkWare]

This change is 

[github-actions]

Artifacts upload workflows:

• Started at 2026-05-24T09:50:56Z
• Started at 2026-05-24T10:14:22Z

[dorimedini-starkware]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• blockifier,apollo_starknet_os_program: support linear message cost #14153 👈 (View in Graphite)
• starknet_os: os resources test - add send_message_to_l1 #14143 : 1 other dependent PR (#14144 )
• starknet_os: os resources test - add replace_class #14142
• starknet_os: os resources test - support virtual builtins, add sha256 #14141
• starknet_os: define sha256 batch resources constants #14140
• starknet_os: os resources test - add keccak #14139
• starknet_os: os resources test - add 3 more syscalls #14138
• starknet_os: os resources test - remove all fee transfer syscalls #14137
• starknet_os: os resources test - add emit event #14136
• starknet_os: os resources test - add meta tx #14135
• starknet_os: os resources test - measure linear factor, add deploy #14134
• starknet_os: os resources test - library call #14129
• starknet_os: initial test, measure call contract resources #14128
• blockifier_test_utils: add option to deploy from zero in test accounts #14258
• starknet_os_flow_tests: helper function to declare explicit classes #14257
• starknet_os: os resources test - create fixed deployable account #14173
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[cursor]

PR Summary

High Risk
Changes fee metering and OS syscall gas for L1 messaging across sequencer, blockifier, and OS program hashes; misalignment would cause execution/proof failures or incorrect charges.

Overview
SendMessageToL1 is no longer a flat syscall cost: gas and OS step budgets now scale with L1 message payload length, aligned across the Starknet OS, blockifier, and versioned constants.

The OS adds SEND_MESSAGE_TO_L1_PAYLOAD_FACTOR_GAS_COST and charges SEND_MESSAGE_TO_L1_GAS_COST + factor × payload_size in execute_send_message_to_l1. Generated constants.cairo / template and constants_test.rs follow the same linear-cost pattern as Deploy and MetaTxV0. Deploy syscall gas constants and 0_14_3 OS resource entries for Deploy are retuned slightly (base vs calldata factor).

Blockifier applies payload-length linear costing in native (get_syscall_cost(payload.len())), shared syscall_base, deprecated syscalls (linear_factor), and VM syscalls via get_linear_factor_length on SendMessageToL1Request. blockifier_versioned_constants_0_14_3.json models SendMessageToL1 as constant + calldata_factor (and updates Deploy resources). Tests and the OS resources contract exercise empty and one-felt payloads; program_hash.json reflects the OS program change.

^{Reviewed by Cursor Bugbot for commit bd8c21c. Bugbot is set up for automated code reviews on this repo. Configure here.}