feat: removed fallback predefined gas value for eth_estimateGas when failed to retrieve gas estimate from Mirror Node

[quiet-node]

Description

This PR fixes inconsistent error handling in eth_estimateGas by removing the fallback gas behavior that masked legitimate errors.

Problem: Previously, when the Mirror Node returned any error other than CONTRACT_REVERT_EXECUTED, the Relay would silently return a predefined fallback gas estimate. This hid real errors from users, who would then submit transactions that were guaranteed to fail on-chain.

Solution: This PR enables the Relay now properly propagates errors according to industry standards (aligned with Geth, Besu, and major providers):

• Contract reverts → code 3 (CONTRACT_REVERT)
• 400 errors (non-revert, validation failures) → code -32000 (COULD_NOT_SIMULATE_TRANSACTION)
• 429, 5xx errors → re-thrown to preserve original error context and handled at dispatch level

Related issue(s)

Fixes #4459

Testing Guide

1. Contract revert scenario:

   • Call eth_estimateGas on a contract function that reverts
   • Expected: Error with code 3 and revert message

2. Non-existent sender account:

   • Call eth_estimateGas with a from address that doesn't exist on the network
   • Expected: Error with code -32000 and message containing "Error occurred during transaction simulation"

3. Valid gas estimation:

   • Call eth_estimateGas with valid from/to addresses and valid contract call data
   • Expected: Returns gas estimate as before

Changes from original design (optional)

• Combined MirrorNodeClientError isContractReverted() & isContractRevertOpcodeExecuted() into isContractRevert(), make sure it checks for CONTRACT_REVERT_EXECUTED message explicitly
• With the new logic of CONTRACT_REVERT for eth_estimateGas, eth_call errors are also updated to align:
  • If truly CONTRACT_REVERT -> return code 3
  • If 400 from MN -> return code -32000
  • If 429, 5xx -> return re-thrown to preserve original error context and handled at dispatch level

Additional work needed (optional)

N/A

Checklist

• I've assigned an assignee to this PR and related issue(s) (if applicable)
• I've assigned a label to this PR and related issue(s) (if applicable)
• I've assigned a milestone to this PR and related issue(s) (if applicable)
• I've updated documentation (code comments, README, etc. if applicable)
• I've done sufficient testing (unit, integration, etc.)

[github-actions]

Test Results

 20 files  ±0  274 suites  +2   22m 2s ⏱️ +22s
798 tests +7  794 ✅ +8  4 💤 ±0  0 ❌  - 1 
814 runs  +7  810 ✅ +8  4 💤 ±0  0 ❌  - 1 

Results for commit e090cab. ± Comparison against base commit 2e9648a.

This pull request removes 4 and adds 11 tests. Note that renamed tests count towards both.

@release-light, @release should execute "eth_estimateGas" ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas @release-light, @release should execute "eth_estimateGas"
should execute "eth_estimateGas" with `to` filed set to null (deployment transaction) ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas should execute "eth_estimateGas" with `to` filed set to null (deployment transaction)
should execute "eth_estimateGas" with to, from, value and gas filed ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas should execute "eth_estimateGas" with to, from, value and gas filed
should execute "eth_estimateGas" with to, from, value,accessList gas filed ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas should execute "eth_estimateGas" with to, from, value,accessList gas filed

@release-light, @release should execute "eth_estimateGas" with empty object and throw error ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas @release-light, @release should execute "eth_estimateGas" with empty object and throw error
should execute "eth_estimateGas" with `to` field set to null (deployment transaction) ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas should execute "eth_estimateGas" with `to` field set to null (deployment transaction)
should execute "eth_estimateGas" with to, from, value and gas field ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas should execute "eth_estimateGas" with to, from, value and gas field
should execute "eth_estimateGas" with to, from, value, accessList and gas field ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas should execute "eth_estimateGas" with to, from, value, accessList and gas field
should throw COULD_NOT_SIMULATE_TRANSACTION error when "to" field is empty for contract call ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas Gas estimation errors (non-contract revert) should throw COULD_NOT_SIMULATE_TRANSACTION error when "to" field is empty for contract call
should throw COULD_NOT_SIMULATE_TRANSACTION error when sender account does not exist ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas Gas estimation errors (non-contract revert) should throw COULD_NOT_SIMULATE_TRANSACTION error when sender account does not exist
should throw error when eth_estimateGas is called with a contract that reverts with custom error ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas Contract call reverts during gas estimation should throw error when eth_estimateGas is called with a contract that reverts with custom error
should throw error when eth_estimateGas is called with a contract that reverts with panic error ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas Contract call reverts during gas estimation should throw error when eth_estimateGas is called with a contract that reverts with panic error
should throw error when eth_estimateGas is called with a contract that reverts with string message ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas Contract call reverts during gas estimation should throw error when eth_estimateGas is called with a contract that reverts with string message
should throw error when eth_estimateGas is called with a contract that reverts without message ‑ RPC Server Acceptance Tests Acceptance tests @api-batch-2 RPC Server Acceptance Tests eth_estimateGas Contract call reverts during gas estimation should throw error when eth_estimateGas is called with a contract that reverts without message
…

♻️ This comment has been updated with latest results.

[quiet-node]

Note for reviewers: Since estimateGas no longer falls back to predefined gas and always throws, the ESTIMATE_GAS_THROWS config no longer has any meaningful effect, so it has been removed.

[quiet-node]

Note for reviewers: These two are now consolidated into a single method, isContractRevert(), which explicitly checks for the error.message === MirrorNodeClientError.messages.CONTRACT_REVERT_EXECUTED instead of falling back to a 400 status code as before, which wasn't accurate since not all 400 errors indicate a contract revert.

[quiet-node]

Note for reviewers: Previously, this was thrown as COULD_NOT_ESTIMATE_GAS_PRICE, which was inaccurate since this method is used for eth_gasPrice, not estimation. I’ve updated it to use INTERNAL_ERROR instead, as reaching this point indicates an unexpected code issue rather than a gas-related problem from the Mirror Node.

[quiet-node]

Note for reviewers: Renamed to COULD_NOT_SIMULATE_TRANSACTION so it can be used for both eth_estimateGas and eth_call when they encounter issues submitting requests to the Mirror Node’s /call endpoint, which handles transaction simulation under the hood.

[codecov]

Codecov Report

❌ Patch coverage is 87.09677% with 4 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ices/ethService/contractService/ContractService.ts	82.60%	4 Missing ⚠️

@@            Coverage Diff             @@
##             main    #4678      +/-   ##
==========================================
- Coverage   95.47%   95.43%   -0.05%     
==========================================
  Files         129      129              
  Lines       20928    20859      -69     
  Branches     1793     1790       -3     
==========================================
- Hits        19982    19906      -76     
- Misses        926      934       +8     
+ Partials       20       19       -1     

Flag	Coverage Δ
config-service	98.82% <ø> (-0.01%)	⬇️
relay	90.89% <77.41%> (+0.01%)	⬆️
server	88.99% <ø> (ø)
ws-server	97.93% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...ckages/config-service/src/services/globalConfig.ts	100.00% <ø> (ø)
packages/relay/src/lib/errors/JsonRpcError.ts	96.93% <100.00%> (+0.02%)	⬆️
...ages/relay/src/lib/errors/MirrorNodeClientError.ts	94.87% <100.00%> (-0.31%)	⬇️
...vices/ethService/ethCommonService/CommonService.ts	95.50% <100.00%> (ø)
...ices/ethService/contractService/ContractService.ts	93.82% <82.60%> (-0.12%)	⬇️

... and 1 file with indirect coverage changes

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