revive: cap remaining_gas to u64::MAX in substrate_execution #10924
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When calculating resource limits for nested calls through substrate_execution::new_nested_meter, the ratio-based scaling fails when deposit_left is very large (e.g., u128::MAX default). The ratio becomes near-zero because: - remaining_gas = weight_gas + deposit_gas (huge number from deposit) - ratio = requested_gas / remaining_gas ≈ 0 - nested_weight_limit = ratio × weight_left ≈ 0 This causes proxy contracts using delegatecall to fail with OutOfGas when called through ReviveApi.call, while the same calls succeed through eth_transact. Cap remaining_gas to u64::MAX since Ethereum gas is a u64 value. This ensures the ratio is 1.0 when requesting all gas, giving the nested call the full remaining weight.
Add regression tests for the gas limit cap fix in substrate_execution. These tests validate that nested calls requesting all gas receive meaningful weight allocation when using large deposit limits. Note: The tests use Balance = u64, so the bug doesn't fully manifest. The fix is critical for u128 production configs where deposit_left can exceed u64::MAX.
pgherveou
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Jan 28, 2026
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need to review these AI written tests
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Summary
see paritytech/contract-issues#256
Problem
When calculating resource limits for nested calls through
substrate_execution::new_nested_meter, the ratio-based scaling fails whendeposit_leftis very large (e.g.,u128::MAXdefault for unlimited deposit).The calculation flow:
remaining_gas = weight_gas + deposit_gas→ huge number (deposit dominates at ~10^38)requested_gas = u64::MAX(~10^19)ratio = requested_gas / remaining_gas≈ 0.0000000000000027nested_weight_limit = ratio × weight_left≈ 0Solution
Cap
remaining_gastou64::MAXsince Ethereum gas is a u64 value. This ensures the ratio is 1.0 when a contract requests all gas, giving the nested call the full remaining weight.Test plan