PUSH0 is not supported by all chains

Description

• The PUSH0 opcode was introduced in Ethereum's Shanghai upgrade (April 2023) as part of EIP-3855 to optimize gas costs. While supported on Ethereum mainnet and most modern EVM chains, some L2s and alternative EVM implementations may not yet support this opcode.

• Contracts compiled with Solidity 0.8.20+ may include PUSH0 instructions by default, potentially causing deployment failures or runtime errors on unsupported chains like:

  • Older Ethereum testnets not upgraded

  • Certain Layer 2 solutions

  • Alternative EVM chains (Polygon zkEVM, BSC before upgrades)

Risk

Likelihood: Medium

• Deploying to chains that haven't implemented Shanghai upgrades

• Using development environments with inconsistent EVM versions

• Maintaining cross-chain compatible codebases

Impact:

• Complete deployment failure on unsupported chains

• Bytecode execution failures if somehow deployed

• Fragmented deployment capabilities across ecosystems

Proof of Concept

The issue can be demonstrated by compiling with Solidity ≥0.8.20 and attempting deployment on unsupported chains (e.g., legacy testnets or non-upgraded L2s), resulting in PUSH0-related revert errors.

Chain Compatibility Check:

Recommended Mitigation

Either:

1. Downgrade to Solidity 0.8.19 (pragma solidity 0.8.19;), or

2. Explicitly set EVM version in configs: