with_cycles() on create_canister does not transfer cycles on mainnet

[deucalioncodes]

Bug

When calling management_canister.create_canister({...}).with_cycles(500_000_000_000) from a canister on mainnet, cycles are deducted from the caller canister but not deposited into the newly created canister. The new canister ends up with 0 cycles.

Workaround

Use an explicit deposit_cycles call after create_canister:

# Step 1: create (cycles here seem to be consumed but not transferred)
create_result = yield management_canister.create_canister(
    {"settings": None}
).with_cycles(deploy_cycles)

# Step 2: explicitly deposit cycles into the new canister
deposit_result = yield management_canister.deposit_cycles(
    {"canister_id": new_canister_id}
).with_cycles(deploy_cycles)

Root cause hypothesis

The with_cycles() method sets self.args[3] = cycles and self.payment = cycles, and the Rust shim in perform_service_call extracts payment via service_call.get_attr("payment").and_then(|p| p.extract_u64()). If extract_u64() fails silently for large Python ints (500B), it falls back to unwrap_or(0u64), meaning 0 cycles are attached.

Alternatively, call_raw in async_handler.rs also extracts cpython_get_arg(args, 3)?.extract_u64()? — need to verify which code path is actually used for @update generators.

Environment

• Deployer canister: 3dwln-xiaaa-aaaag-ayrva-cai (mainnet)
• ic-basilisk: 0.11.25
• Confirmed: deposit_cycles.with_cycles() DOES work correctly for the same amount (500B)
• The issue appears to be specific to create_canister or possibly other management canister methods

Impact

Any canister using management_canister.create_canister(...).with_cycles(N) will create canisters with insufficient funds, leading to failures on subsequent operations.