[Bug]: CDP SDK v1.48.1 permit2_data Bug Causes On-Chain Swaps to Revert on Base

[fdletter1980]

Issue Summary

CDP SDK v1.48.1 (and v1.48.0) returns permit2_data as an empty dict ({}) or the string "0" instead of a proper Permit2Data instance with a valid .eip712 field. This causes every on-chain swap involving an ERC-20 source token (e.g. cbBTC) to revert on Base mainnet. Native ETH swaps are unaffected because they don't invoke Permit2 at all.

Environment

• CDP SDK version: 1.48.1 (also reproduced on 1.48.0)
• Language/runtime: Python 3.11.15
• Network: Base mainnet (chainId 8453)
• Account type: Regular EVM account (EOA), server-managed via CDP's TEE (not a smart account)
• Affected tokens: cbBTC (0xcbB7C0000aB88B473b1f5aFd9ef808440eed33Bf) as source token; USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) as destination

Steps to Reproduce

1. Create a swap quote for an ERC-20 → token swap (e.g. cbBTC → USDC) using account.quote_swap().
2. Execute the returned quote via swap_quote.execute() (equivalently, QuoteBasedSendSwapTransactionOptions with swap_quote set).
3. Inspect swap_quote.permit2_data (or the underlying getattr(swap_data, "permit2_data", None)) — it is {} or "0" rather than an object exposing .eip712.
4. Observe the resulting transaction revert on-chain.
5. For contrast: repeat with an ETH → USDC swap using the quote-based path — same revert occurs, confirming this isn't token-specific to cbBTC alone.
6. For further contrast: repeat with the inline path (account.swap() called directly without a swap_quote, i.e. InlineSendSwapTransactionOptions with taker=<own address>) — this succeeds for ETH→USDC (no Permit2 involved, since ETH is not an ERC-20) but cannot be used for cbBTC or any ERC-20 source token, which requires a Permit2-signed approval regardless of path.

Minimal repro

import asyncio
from cdp import CdpClient
from cdp.actions.evm.swap import AccountSwapOptions

CBBTC_BASE = "0xcbB7C0000aB88B473b1f5aFd9ef808440eed33Bf"
USDC_BASE = "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"

async def main():
    async with CdpClient() as cdp:
        account = await cdp.evm.get_or_create_account(name="MyFundedAccount")

        # Step 1: create the quote
        swap_quote = await account.quote_swap(
            from_token=CBBTC_BASE,
            to_token=USDC_BASE,
            from_amount="100000",  # 0.001 cbBTC (8 decimals)
            network="base",
            slippage_bps=100,
        )

        # Inspect permit2_data before executing
        print("permit2_data:", getattr(swap_quote, "permit2_data", None))
        # Observed: {} or "0" — expected: Permit2Data(...) with a populated .eip712 field

        if not swap_quote.liquidity_available:
            print("Insufficient liquidity")
            return

        # Step 2: execute — reverts on-chain
        result = await swap_quote.execute()
        print(f"Transaction hash: {result.transaction_hash}")

asyncio.run(main())

Case 1: Empty Dict {}
permit2_data = {}
Characteristics:

Type: dict
Has no "eip712" key
hasattr(permit2_data, "eip712") → False
isinstance(permit2_data, dict) → True
permit2_data.get("eip712", None) → None
Code path (from signal_executor.py lines 435-453):

p2 = getattr(swap_data, "permit2_data", None)
if p2 is not None and not hasattr(p2, "eip712"):
if isinstance(p2, dict) and "eip712" in p2:
# Has eip712 nested key — would wrap it
...
else:
# No valid permit2 data — disable signing
print("⚠️ permit2_data present but invalid (no eip712), disabling permit2 signing")
swap_data.requires_signature = False
Result: requires_signature is set to False, but the transaction still reverts on-chain because the underlying permit2 structure is invalid.

Case 2: String "0"
permit2_data = "0"
Characteristics:

Type: str
hasattr(permit2_data, "eip712") → False (strings don't have attributes)
isinstance(permit2_data, dict) → False
Direct comparison: permit2_data == "0" → True
Code path:

p2 = getattr(swap_data, "permit2_data", None)
if p2 is not None and not hasattr(p2, "eip712"):
# p2 = "0" → hasattr("0", "eip712") is False → enters this branch
if isinstance(p2, dict) and "eip712" in p2:
# False — p2 is a string, not a dict
...
else:
# No valid permit2 data — disable signing
print("⚠️ permit2_data present but invalid (no eip712), disabling permit2 signing")
swap_data.requires_signature = False
Result: Same as Case 1 — requires_signature disabled, transaction reverts on-chain.

Expected Behavior

• quote_swap() returns a permit2_data object with a well-formed .eip712 field suitable for signing.
• The subsequent execute() call submits a valid transaction that completes successfully on-chain, and the account receives the quoted output token amount.

Actual Behavior

• permit2_data is malformed ({} or "0") for ERC-20-sourced swaps.
• The resulting transaction reverts immediately on submission; no output token is received and gas is consumed.
• This affects both the quote-based path (quote_swap() + execute()) and, in effect, the all-in-one account.swap() path, since it uses the same quote generation internally.
• The inline path (account.swap() without swap_quote) avoids permit2_data entirely by using taker=<own address> directly, but this only works for native ETH — it cannot satisfy the Permit2 approval flow required for ERC-20 source tokens like cbBTC.

Evidence

• Reproduced on both SDK 1.48.0 and 1.48.1 — same failure mode, no change between versions.
• permit2_data inspection consistently returns {} or "0" instead of a Permit2Data instance exposing .eip712.
• Increasing the gas limit (tested up to 300,000) does not resolve the revert — confirms this is a calldata/signature validity issue, not a gas estimation issue.
• The server-side account.swap() (all-in-one) path also reverts, since it relies on the same quote generation as the two-step path.
• The inline path succeeds only for ETH→USDC; it fails for any ERC-20 source token requiring Permit2.

Possible Workarounds

• Manual execution via app.coinbase.com (Trade → Swap) bypasses the SDK entirely and works — confirms the issue is isolated to the SDK's swap/quote generation, not the underlying CDP infrastructure or account permissions.
• Inline swap path works around the bug only for native ETH; not viable for ERC-20 tokens.
• No SDK-side workaround currently exists for ERC-20 → token swaps.

Suggested Fix

• Ensure quote_swap() / create_swap_quote() populates permit2_data with a valid Permit2Data instance (including a correctly structured .eip712 payload) for all ERC-20 source tokens.
• Alternatively, expose a supported path for submitting a pre-approved ERC-20 swap (via standing approve() to the Permit2 contract) that bypasses per-swap Permit2 signing entirely, for cases where the token already has sufficient allowance.

Issue Type

• Bug report — regression introduced in SDK v1.48.0, persists in v1.48.1
• Component: CDP EVM swap module → Permit2 data generation/handling
• Severity: High — blocks all on-chain ERC-20 token swaps on Base mainnet via the SDK