Solidity跨合约访问成员变量在私有链失败，Remix JS VM正常

Let's break down why you're seeing this frustrating discrepancy between Remix's JavaScript VM and your private Geth 1.8.6 chain, and how to fix it.

Core Issue Analysis #

The failure happens specifically when your Parent contract calls thisChild.isUpdated()—an automatically generated getter for the Child contract's public isUpdated boolean variable. When you remove this check, everything works on both environments. This points to differences in how the two environments handle cross-contract view function calls, especially in older Geth versions.

Key Differences Between Remix JS VM and Geth 1.8.6 Private Chain #

1. EVM & Compiler Version Disparities #

• Remix's JavaScript VM typically uses a more modern EVM implementation (aligned with recent Solidity compiler versions) that handles auto-generated getter functions for public variables smoothly.
• Geth 1.8.6 is a relatively old release (circa 2018) targeting older EVM versions like Byzantium. This version has known quirks and bugs around cross-contract view function calls—specifically, how gas is estimated when accessing auto-generated getters from another contract. The node may struggle to correctly simulate this call during gas estimation, leading to the -32603 internal error.

2. Gas Estimation Logic #

• Remix's VM is a simulated environment with simplified, forgiving gas estimation logic that doesn't fully replicate the strict calculation and simulation of a real Geth node. It handles edge cases like cross-contract view calls more leniently.
• Geth 1.8.6's gas estimator can fail when computing the cost of calling a view function on a child contract, especially if that getter is auto-generated by Solidity. This failure triggers the "Invalid JSON RPC response" error you encounter.

3. Private Chain Configuration (Less Likely, But Worth Checking) #

While configuration issues are less probable here, double-check your private chain's genesis file:

• Ensure byzantiumBlock is set correctly (standard for Geth 1.8.x)
• Verify no custom gas limits or block constraints are interfering with cross-contract calls

Fixes to Try #

1. Upgrade Your Geth Node #

The most reliable fix is to upgrade to a newer Geth version (1.9.x or later). These releases include critical bug fixes for EVM behavior and gas estimation, including improvements to cross-contract view function handling, aligning much closer to Remix's VM behavior.

2. Adjust Your Code to Avoid Cross-Contract View Checks #

If upgrading isn't feasible right now, modify your logic to skip the cross-contract isUpdated check in the Parent contract:

• Track the isUpdated state directly in the Parent contract (add a mapping(uint => bool) to store whether each child is updated)
• Remove the if (thisChild.isUpdated()) condition entirely (if your business logic allows it)
• Have the Child contract emit an event when isUpdated is set, and let off-chain tools handle validation instead of on-chain checks

3. Force the Transaction (Temporary Workaround) #

Remix offers the option to "force sending" even when gas estimation fails. While this isn't a long-term solution, it can confirm whether the transaction would actually execute successfully despite the estimation error. Use this only for testing purposes.

内容的提问来源于stack exchange，提问作者3tbraden