log position in debug_traceCall

[yuval99g]

Hey everyone 👋
While working with debug_traceCall on different clients, I noticed that:
In reth, the LOG entries include a position field that's a hex string, but in most cases it’s just "0x0" (i.e., zero or empty).
In contrast, geth and erigon use an index field that consistently reflects the log's sequence within the call.
I'm curious:
Why does reth return position as hex?
Why is it often just "0x" — is this a placeholder, or is it expected behavior?
Is there a plan to align this with other clients, or make it more consistent?
Any insight would be helpful — trying to build tooling that works across clients and currently reth's output makes it tricky to correlate logs with trace steps.

Adding down here an example for debug_traceCall with callTracer and the response
Thanks in advance!

{"jsonrpc": "2.0", "method": "debug_traceTransaction", "params": ["0xd28020ca00594e44834fd9e5cbf6f869c7d5cc89f9538cff652aa697aef94023", {"tracer": "callTracer", "tracerConfig": {"withLog": true, "onlyTopCall": false}}], "id": 25}

{ "jsonrpc": "2.0", "id": 25, "result": { "from": "0x575a45f4361e937551b05f5287e21069532b2f0e", "gas": "0x5099d", "gasUsed": "0x2cef8", "to": "0x111111125421ca6dc452d289314280a0f8842a65", "input": "0x5816d7230000000000000000000000000000000000000000000000000000000000000040000000000000000000000000000000000000000000000000000000000000016000000000000000000000000000000000000000000000000000000000000000f4111111111117dc0aa78b770fa6a738034120c302000000000000000000000000575a45f4361e937551b05f5287e21069532b2f0e000000000000000000000000111111125421ca6dc452d289314280a0f8842a65ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff0000000000000000000000000000000000000000000000000000000066c2fe51000000000000000000000000000000000000000000000000000000000000001c1633684532843cdd2ce19e663313613c736e36dc9775a57dfd3e13bedc94c6785a5f31df80d806d917627e3cfa456115e0129c26a0fea38771e0708811a2563c000000000000000000000000000000000000000000000000000000000000000000000000000000000000040407ed23790000000000000000000000005f515f6c524b18ca30f7783fb58dd4be2e9904ec000000000000000000000000111111111117dc0aa78b770fa6a738034120c302000000000000000000000000eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee0000000000000000000000005f515f6c524b18ca30f7783fb58dd4be2e9904ec000000000000000000000000575a45f4361e937551b05f5287e21069532b2f0e00000000000000000000000000000000000000000000000098a7d9b8314c000000000000000000000000000000000000000000000000000000039529485262d60000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000012000000000000000000000000000000000000000000000000000000000000002a99ff8e77c2dd367d69b4d44ccca6a55f4c755aa63a997b04e1fa1e8ddfdb3517290171b5cb1371095775981d766de4e584a6785ed8b734f29b9197409c4b81b7100000000000000000000000000000000000000000000024b0002350001f900a0860a32ec00000000000000000000000000000000000000000000000098a7d9b8314c00000001d051201111111254eeb25477b68fb85ed929f73a960582111111111117dc0aa78b770fa6a738034120c30201043eca9c0a000000000000000000000000000000000000000066c1ad0800000000007f7d87000000000000000000000000c02aaa39b223fe8d0a0e5c4f27ead9083c756cc2000000000000000000000000111111111117dc0aa78b770fa6a738034120c302000000000000000000000000bb289bc97591f70d8216462df40ed713011b968a0000000000000000000000005f515f6c524b18ca30f7783fb58dd4be2e9904ec00000000000000000000000000000000000000000000000000039e6cee8c1b6f00000000000000000000000000000000000000000000000098a7d9b8314c0000000000000000000000000000000000000000000000000000000000000000012000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000041c854ad272435d99bf802823fab75f0246868c55338aca211d8c05ed7e5845d433799dfac832b3f7b78e31b473a7d22420cb063259ab55b92e4a099fbe413df8a1b000000000000000000000000000000000000000000000000000000000000004101c02aaa39b223fe8d0a0e5c4f27ead9083c756cc200042e1a7d4d0000000000000000000000000000000000000000000000000000000000000000c061111111125421ca6dc452d289314280a0f8842a65000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000e26b9977", "calls": [ { "from": "0x111111125421ca6dc452d289314280a0f8842a65", "gas": "0x4617f", "gasUsed": "0x4617f", "to": "0x111111111117dc0aa78b770fa6a738034120c302", "input": "0xd505accf000000000000000000000000575a45f4361e937551b05f5287e21069532b2f0e000000000000000000000000111111125421ca6dc452d289314280a0f8842a65ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff0000000000000000000000000000000000000000000000000000000066c2fe51000000000000000000000000000000000000000000000000000000000000001c1633684532843cdd2ce19e663313613c736e36dc9775a57dfd3e13bedc94c6785a5f31df80d806d917627e3cfa456115e0129c26a0fea38771e0708811a2563c", "calls": [ { "from": "0x111111111117dc0aa78b770fa6a738034120c302", "gas": "0x4420e", "gasUsed": "0xc7de", "to": "0x0000000000000000000000000000000000000001", "input": "0x39db32924474bf13e1c202b2a51758419a606c7e30999689f6c25d21909641c0000000000000000000000000000000000000000000000000000000000000001c1633684532843cdd2ce19e663313613c736e36dc9775a57dfd3e13bedc94c6785a5f31df80d806d917627e3cfa456115e0129c26a0fea38771e0708811a2563c", "logs": [ { "address": "0x0000000000000000000000000000000000000001", "topics": [ "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925", "0x000000000000000000000000575a45f4361e937551b05f5287e21069532b2f0e", "0x000000000000000000000000111111125421ca6dc452d289314280a0f8842a65" ], "data": "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "position": "0x0" } ], "type": "STATICCALL" } ], "value": "0x0", "type": "CALL" }, { "from": "0x111111125421ca6dc452d289314280a0f8842a65", "gas": "0x39b7f", "gasUsed": "0x39b7f", "to": "0x111111125421ca6dc452d289314280a0f8842a65", "input": "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", "calls": [ { "from": "0x111111125421ca6dc452d289314280a0f8842a65", "gas": "0x37edf", "gasUsed": "0x3c90", "to": "0x111111111117dc0aa78b770fa6a738034120c302", "input": "0x23b872dd000000000000000000000000575a45f4361e937551b05f5287e21069532b2f0e0000000000000000000000005f515f6c524b18ca30f7783fb58dd4be2e9904ec00000000000000000000000000000000000000000000000098a7d9b8314c0000", "output": "0x0000000000000000000000000000000000000000000000000000000000000001", "logs": [ { "address": "0x111111111117dc0aa78b770fa6a738034120c302", "topics": [ "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef", "0x000000000000000000000000575a45f4361e937551b05f5287e21069532b2f0e", "0x0000000000000000000000005f515f6c524b18ca30f7783fb58dd4be2e9904ec" ], "data": "0x00000000000000000000000000000000000000000000000098a7d9b8314c0000", "position": "0x0" }, { "address": "0x111111111117dc0aa78b770fa6a738034120c302", "topics": [ "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925", "0x000000000000000000000000575a45f4361e937551b05f5287e21069532b2f0e", "0x000000000000000000000000111111125421ca6dc452d289314280a0f8842a65" ], "data": "0xffffffffffffffffffffffffffffffffffffffffffffffff67582647ceb3ffff", "position": "0x0" } ], "value": "0x0", "type": "CALL" }, { "from": "0x111111125421ca6dc452d289314280a0f8842a65", "gas": "0x337be", "gasUsed": "0x337be", "to": "0x5f515f6c524b18ca30f7783fb58dd4be2e9904ec", "input": "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", "calls": [ { "from": "0x5f515f6c524b18ca30f7783fb58dd4be2e9904ec", "gas": "0x325c2", "gasUsed": "0x2be7c", "to": "0x0000000000000000000000000000000000000001", "input": "0xc291600c1c36a8e05b22dfa5354970cec245c3898d0b76b3c8b8670978a14805000000000000000000000000000000000000000000000000000000000000001c9ff8e77c2dd367d69b4d44ccca6a55f4c755aa63a997b04e1fa1e8ddfdb3517210171b5cb1371095775981d766de4e584a6785ed8b734f29b9197409c4b81b71", "output": "0x00000000000000000000000000000000000000000000000000039e6cee8c1b6f00000000000000000000000000000000000000000000000098a7d9b8314c0000", "type": "STATICCALL" }, { "from": "0x5f515f6c524b18ca30f7783fb58dd4be2e9904ec", "gas": "0x31732", "gasUsed": "0x17149", "to": "0x5f515f6c524b18ca30f7783fb58dd4be2e9904ec", "input": "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", "output": "0x00000000000000000000000000000000000000000000000000039e6cee8c1b6f", "calls": [ { "from": "0x5f515f6c524b18ca30f7783fb58dd4be2e9904ec", "gas": "0x30593", "gasUsed": "0x5fd9", "to": "0x111111111117dc0aa78b770fa6a738034120c302", "input": "0x095ea7b30000000000000000000000001111111254eeb25477b68fb85ed929f73a96058200000000000000000000000000000000000000000000000098a7d9b8314c0000", "output": "0x0000000000000000000000000000000000000000000000000000000000000001", "logs": [ { "address": "0x111111111117dc0aa78b770fa6a738034120c302", "topics": [ "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925", "0x0000000000000000000000005f515f6c524b18ca30f7783fb58dd4be2e9904ec", "0x0000000000000000000000001111111254eeb25477b68fb85ed929f73a960582" ], "data": "0x00000000000000000000000000000000000000000000000098a7d9b8314c0000", "position": "0x0" } ], "value": "0x0", "type": "CALL" }, { "from": "0x5f515f6c524b18ca30f7783fb58dd4be2e9904ec", "gas": "0x29bc2", "gasUsed": "0x115f9", "to": "0x1111111254eeb25477b68fb85ed929f73a960582", "input": "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", "output": "0x00000000000000000000000000000000000000000000000000039e6cee8c1b6f", "calls": [ { "from": "0x1111111254eeb25477b68fb85ed929f73a960582", "gas": "0x28987", "gasUsed": "0xa3d3", "to": "0x0000000000000000000000000000000000000001", "input": "0x44ea43f1c844fff5a9167c11d36c2f7d63c3f6229405ba8e590ee18e5c3dbce7000000000000000000000000000000000000000000000000000000000000001bc854ad272435d99bf802823fab75f0246868c55338aca211d8c05ed7e5845d433799dfac832b3f7b78e31b473a7d22420cb063259ab55b92e4a099fbe413df8a", "output": "0x00000000000000000000000000000000000000000000000000039e6cee8c1b6f00000000000000000000000000000000000000000000000098a7d9b8314c000044ea43f1c844fff5a9167c11d36c2f7d63c3f6229405ba8e590ee18e5c3dbce7", "logs": [ { "address": "0x0000000000000000000000000000000000000001", "topics": [ "0xc3b639f02b125bfa160e50739b8c44eb2d1b6908e2b6d5925c6d770f2ca78127" ], "data": "0x44ea43f1c844fff5a9167c11d36c2f7d63c3f6229405ba8e590ee18e5c3dbce700000000000000000000000000000000000000000000000000039e6cee8c1b6f", "position": "0x0" } ], "type": "STATICCALL" }, { "from": "0x1111111254eeb25477b68fb85ed929f73a960582", "gas": "0x25b44", "gasUsed": "0x3ab1", "to": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2", "input": "0x23b872dd000000000000000000000000bb289bc97591f70d8216462df40ed713011b968a0000000000000000000000005f515f6c524b18ca30f7783fb58dd4be2e9904ec00000000000000000000000000000000000000000000000000039e6cee8c1b6f", "output": "0x0000000000000000000000000000000000000000000000000000000000000001", "logs": [ { "address": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2", "topics": [ "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef", "0x000000000000000000000000bb289bc97591f70d8216462df40ed713011b968a", "0x0000000000000000000000005f515f6c524b18ca30f7783fb58dd4be2e9904ec" ], "data": "0x00000000000000000000000000000000000000000000000000039e6cee8c1b6f", "position": "0x0" } ], "value": "0x0", "type": "CALL" }, { "from": "0x1111111254eeb25477b68fb85ed929f73a960582", "gas": "0x21f98", "gasUsed": "0x29d0", "to": "0x111111111117dc0aa78b770fa6a738034120c302", "input": "0x23b872dd0000000000000000000000005f515f6c524b18ca30f7783fb58dd4be2e9904ec000000000000000000000000bb289bc97591f70d8216462df40ed713011b968a00000000000000000000000000000000000000000000000098a7d9b8314c0000", "output": "0x0000000000000000000000000000000000000000000000000000000000000001", "logs": [ { "address": "0x111111111117dc0aa78b770fa6a738034120c302", "topics": [ "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef", "0x0000000000000000000000005f515f6c524b18ca30f7783fb58dd4be2e9904ec", "0x000000000000000000000000bb289bc97591f70d8216462df40ed713011b968a" ], "data": "0x00000000000000000000000000000000000000000000000098a7d9b8314c0000", "position": "0x0" }, { "address": "0x111111111117dc0aa78b770fa6a738034120c302", "topics": [ "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925", "0x0000000000000000000000005f515f6c524b18ca30f7783fb58dd4be2e9904ec", "0x0000000000000000000000001111111254eeb25477b68fb85ed929f73a960582" ], "data": "0x0000000000000000000000000000000000000000000000000000000000000000", "position": "0x0" } ], "value": "0x0", "type": "CALL" } ], "value": "0x0", "type": "CALL" } ], "value": "0x0", "type": "CALL" }, { "from": "0x5f515f6c524b18ca30f7783fb58dd4be2e9904ec", "gas": "0x201b7", "gasUsed": "0x2406", "to": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2", "input": "0x2e1a7d4d00000000000000000000000000000000000000000000000000039e6cee8c1b6f", "calls": [ { "from": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2", "gas": "0x8fc", "gasUsed": "0x52", "to": "0x5f515f6c524b18ca30f7783fb58dd4be2e9904ec", "input": "0x", "value": "0x39e6cee8c1b6f", "type": "CALL" } ], "logs": [ { "address": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2", "topics": [ "0x7fcf532c15f0a6db0bd6d0e038bea71d30d808c7d98cb3bf7268a95bf5081b65", "0x0000000000000000000000005f515f6c524b18ca30f7783fb58dd4be2e9904ec" ], "data": "0x00000000000000000000000000000000000000000000000000039e6cee8c1b6f", "position": "0x1" } ], "value": "0x0", "type": "CALL" }, { "from": "0x5f515f6c524b18ca30f7783fb58dd4be2e9904ec", "gas": "0x1c13b", "gasUsed": "0x9a", "to": "0x111111125421ca6dc452d289314280a0f8842a65", "input": "0x", "value": "0x39e6cee8c1b6f", "type": "CALL" } ], "value": "0x0", "type": "CALL" }, { "from": "0x111111125421ca6dc452d289314280a0f8842a65", "gas": "0x1c84", "gasUsed": "0x1e5b9", "to": "0x575a45f4361e937551b05f5287e21069532b2f0e", "input": "0x", "output": "0x00000000000000000000000000000000000000000000000000039e6cee8c1b6f00000000000000000000000000000000000000000000000098a7d9b8314c0000", "value": "0x39e6cee8c1b6f", "type": "CALL" } ], "value": "0x0", "type": "DELEGATECALL" } ], "value": "0x0", "type": "CALL" } }

[mattsse]

which version is that?

when is it "0x" or did you mean 0x0, can't find this in your example.

tbh not exactly sure what

// Position of the log relative to subcalls within the same trace

means, what's the expected behaviour here?

the log's sequence within the call.

can you elaborate on what this means exactly?

because looking at this

https://github.com/ethereum/go-ethereum/blob/16117eb7cddc4584865af106d2332aa89f387d3d/eth/tracers/native/call.go#L253-L253

this tracks the number of subcalls at the time of the log?

so not clear to me what value this should be set to.

this is what we currently record

https://github.com/paradigmxyz/revm-inspectors/blob/557abd1a72fcef1ee610f79eec3c4371c20fcdc6/src/tracing/mod.rs#L581-L581

[yuval99g]

which version is that?

1.5.1

[mattsse]

@yuval99g sorry, but I cant find where geth is including an index field

https://github.com/ethereum/go-ethereum/blob/16117eb7cddc4584865af106d2332aa89f387d3d/eth/tracers/internal/tracetest/calltrace_test.go#L41-L47

index does make sense as the index of the log in this transaction, but the position value is

https://github.com/ethereum/go-ethereum/blob/a56558d0920b74b6553185de4aff79c3de534e01/eth/tracers/native/call.go#L45-L47

so I'm skeptical that geth returns index, because I cant find this in the implementation

[mattsse]

@yuval99g we could however easily add the index field, but would still like to confirm if geth really includes this

[yuval99g]

sorry for the confusion but after i found that index is only exist in erigon. i still think it will be good to have this field

[mattsse]

can easily add this soon

[mattsse]

alloy-rs/alloy#2747