eth/tracers/logger: fix legacy structLog JSON encoding#34093
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s1na merged 5 commits intoMar 31, 2026
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Fix several issues in the legacy structLog JSON format produced by the struct logger tracer: - Error field: change from string to *string so that error is truly omitted (rather than serialised as "") when there is no error. - Memory words: zero-pad each 32-byte chunk before hex-encoding so the output always matches the expected 64-character format instead of emitting a truncated hex string for partial words. - Storage/ReturnData: use hexutil.Encode / common.Hash.Hex() to produce consistent 0x-prefixed output rather than bare %x formatting. Add tests that cover the legacy JSON shape directly (TestStructLogLegacyJSONSpecFormatting), and two integration-level tracer tests verifying that refund counters and storage snapshots are captured correctly and that hard-failure vs revert return values are handled as specified.
reexec was a geth-specific, hash-scheme-only implementation detail that let callers cap how many ancestor blocks the node would re-execute to reconstruct missing historical state. It was never part of the execution API spec, and path-scheme nodes ignored it entirely. Remove Reexec from TraceConfig and StdTraceConfig so it is no longer accepted over JSON-RPC. Drop the parameter from the Backend interface (StateAtBlock, StateAtTransaction) and all the way down through EthAPIBackend and state_accessor. A local constant reexecLimit = 128 replaces the old defaultTraceReexec inside hashState, preserving the existing non-archive hash-scheme behaviour.
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ci test failed but not because of my PR 😆 |
s1na
reviewed
Mar 27, 2026
Contributor
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Generally looks good to me. I'd wait for merging until after the coming release. Given that it's breaking API output we should probably release it as part of a major version. |
Co-authored-by: Sina M <1591639+s1na@users.noreply.github.com>
fjl
reviewed
Mar 28, 2026
Use a plain string field with omitzero for the legacy structLog error field so the JSON shape stays unchanged without pointer indirection.
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Release notes
This is a breaking change for tracing APIs (debug_trace*), when using specifically the structlog (opcode) tracer. The following fields will have slightly different formatting in the response. The reason is for geth to conform to the newly established client-wide spec: ethereum/execution-apis#762.
memorywords will have the0xprefix. A word will be padded to 32-bytes.storage: keys and values will have the0xprefix.Summary
This PR fixes several correctness issues in the legacy
structLogJSON format produced byStructLogger(the default tracer behinddebug_traceTransaction), and removes the non-specreexecfield from the tracer config.Fix legacy structLog JSON encoding
stringto*stringso the"error"key is truly omitted when there is no error, rather than being serialised as""."0xaabb"instead of"0xaabb000000000000000000000000000000000000000000000000000000000000".fmt.Sprintf("%x", …)withhexutil.Encode/common.Hash.Hex()to produce consistent0x-prefixed output, matching the format expected by clients and conformance tests.Remove
reexecfrom tracer configreexecwas a geth-specific, hash-scheme-only knob that let callers cap how many ancestor blocks the node would re-execute when the requested state was not on disk. It was never part of the execution API spec and was silently ignored by path-scheme nodes.Reexec *uint64fromTraceConfigandStdTraceConfig— the field is no longer accepted over JSON-RPC.Backendinterface (StateAtBlock,StateAtTransaction) and propagated the removal down throughEthAPIBackend,state_accessor, andapi_debug.reexecLimit = 128constant instate_accessor.Tests
TestStructLogLegacyJSONSpecFormatting— unit tests directly exercising the legacy JSON shape for memory padding, storage encoding, and error omission.TestTraceTransactionRefundAndStorageSnapshots— integration test verifying thatSLOAD/SSTOREstorage snapshots and refund counters are correctly captured in a traced transaction.TestTraceTransactionFailureReturnValues— integration test verifying that a reverted transaction preserves its return data while a hard-failure (e.g.INVALID) clears it.Reference
execution-apis