Query failing with "negative substring length not allowed" #55

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1. bitjson commented on Feb 24, 2023

   

   bitjson

   on Feb 24, 2023

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   Thanks for opening an issue! On the demo instance, that returns:

   {
     "errors": [
       {
         "extensions": {
           "code": "data-exception",
           "path": "$"
         },
         "message": "negative substring length not allowed"
       }
     ]
   }

   That's an error coming back from Postgres. To figure it out, we'd need to run the query in the Hasura console and use the analyze button to get the actual Postgres query being run, then figure out where the error is actually happening.

   I'd guess it's because you're filtering by redeem_bytecode_pattern, which is itself a computed property. So if the other conditions take your limit 1 query down to 0, it's running that function on nothing, and somewhere inside there it "works" until a substring function is called with a negative integer.

   I'd guess redeem_bytecode_pattern just needs to return early before doing the invalid operation. I can't prioritize figuring this out myself, but I'd be happy to take a PR!
2. bitjson

   added

   good first issueGood for newcomersGood for newcomers

   on Feb 24, 2023
3. A60AB5450353F40E commented on Feb 24, 2023

   

   A60AB5450353F40E

   on Feb 24, 2023

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   Thing is, other conditions don't limit it to 0. For example if you change to limit: 2 then it returns a proper result.
   If you change the block height range to something that hasn't been mined yet, then you get a proper empty array as result, with both limit: 1 and limit: 2.
4. A60AB5450353F40E commented on Mar 1, 2023

   

   A60AB5450353F40E

   on Mar 1, 2023

   Last edited by A60AB5450353F40E

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   Also, this one which selects only 1 block trips with the same error. Change _gte and _lt heights +1 and it returns empty array proper. Commenting out the redeem_bytecode_pattern makes it return empty array, so I suspect some bug there.

   # Matches all spends from AnyHedge v0.11 contract template
   # https://gitlab.com/GeneralProtocols/anyhedge/contracts/-/blob/development/contracts/v0.11/bytecode.asm
   query {
     input(
       #limit: 10
       #offset: 0
       where: {
         transaction: {
           block_inclusions: {
             block: {
               height: { _gte: 781888, _lt: 781889 }
               accepted_by: { node: { name: { _eq: "bchn-mainnet" } } }
             }
           }
         }
         _or: [
           { unlocking_bytecode_pattern: { _eq: "40104010514d" } }
           { unlocking_bytecode_pattern: { _eq: "4141004d" } }
         ]
         redeem_bytecode_pattern: {
           _regex: "04040[2-4]0[2-4]0[2-8]0[2-8]21(17|19|23)(17|19|23)(00|51)21215c79009c637b695c7a7cad5b7a7cad6d6d6d6d6d51675c7a519dc3519d5f7a5f795779bb5d7a5d79577abb5c79587f77547f75817600a0695c79587f77547f75818c9d5c7a547f75815b799f695b795c7f77817600a0695979a35879a45c7a547f7581765c7aa2695b7aa2785a7a8b5b7aa5919b690276587a537a96a47c577a527994a4c4529d00cc7b9d00cd557a8851cc9d51cd547a8777777768"
         }
       }
     ) {
       transaction {
         block_inclusions {
           block {
             height
             timestamp
           }
         }
         inputs {
           outpoint_transaction_hash
           outpoint_index
           outpoint {
             value_satoshis
             locking_bytecode
             locking_bytecode_pattern
             transaction {
               block_inclusions {
                 block {
                   height
                   timestamp
                 }
               }
             }
           }
           unlocking_bytecode
           unlocking_bytecode_pattern
           redeem_bytecode_pattern
         }
       }
     }
   }
   
5. A60AB5450353F40E commented on Mar 27, 2023

   

   A60AB5450353F40E

   on Mar 27, 2023

   Last edited by A60AB5450353F40E

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   Replacing regex with like fails on some blocks, too:

   Query

   # Matches all spends from AnyHedge v0.11 contract template
   # https://gitlab.com/GeneralProtocols/anyhedge/contracts/-/blob/development/contracts/v0.11/bytecode.asm
   query {
     input(
       #limit: 0
       #offset: 0
       where: {
         transaction: {
           block_inclusions: {
             block: {
               height: { _gte: 785576, _lt: 785577 }
               accepted_by: { node: { name: { _like: "%mainnet" } } }
             }
           }
         }
         _or: [
           { unlocking_bytecode_pattern: { _eq: "40104010514d" } }
           { unlocking_bytecode_pattern: { _eq: "4141004d" } }
         ]
         redeem_bytecode_pattern: {
           #_regex: "04040[2-4]0[2-4]0[2-8]0[2-8]21(17|19|23)(17|19|23)(00|51)21215c79009c637b695c7a7cad5b7a7cad6d6d6d6d6d51675c7a519dc3519d5f7a5f795779bb5d7a5d79577abb5c79587f77547f75817600a0695c79587f77547f75818c9d5c7a547f75815b799f695b795c7f77817600a0695979a35879a45c7a547f7581765c7aa2695b7aa2785a7a8b5b7aa5919b690276587a537a96a47c577a527994a4c4529d00cc7b9d00cd557a8851cc9d51cd547a8777777768"
           _like: "%21215c79009c637b695c7a7cad5b7a7cad6d6d6d6d6d51675c7a519dc3519d5f7a5f795779bb5d7a5d79577abb5c79587f77547f75817600a0695c79587f77547f75818c9d5c7a547f75815b799f695b795c7f77817600a0695979a35879a45c7a547f7581765c7aa2695b7aa2785a7a8b5b7aa5919b690276587a537a96a47c577a527994a4c4529d00cc7b9d00cd557a8851cc9d51cd547a8777777768"
         }
       }
     ) {
       transaction {
         block_inclusions {
           block {
             height
             timestamp
           }
         }
         inputs {
           outpoint_transaction_hash
           outpoint_index
           outpoint {
             value_satoshis
             locking_bytecode
             locking_bytecode_pattern
             transaction {
               block_inclusions {
                 block {
                   height
                   timestamp
                 }
               }
             }
           }
           unlocking_bytecode
           unlocking_bytecode_pattern
           redeem_bytecode_pattern
         }
       }
     }
   }
   

   Result

   {
     "errors": [
       {
         "extensions": {
           "code": "data-exception",
           "path": "$"
         },
         "message": "negative substring length not allowed"
       }
     ]
   }
   
6. mainnet-pat commented on Apr 6, 2025

   

   mainnet-pat

   on Apr 6, 2025

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   #70 Fixes this issue.

   However, the queries searching by unlocking_bytecode_pattern are still unusable as they scan the entire input dataset and fail to complete in statement_timeout timespan. I am not sure if it is possible to add an index for a computed field. But it could be meaningful to materialize this field as a column.
7. rnbrady

   added a commit that references this issue on May 10, 2026

   fix(sql): harden redeem bytecode parser (fixes bitauth#75 item 7, fixes

   ...

   This issue will close once commit cf64c67 is merged into the 'master' branch.

   cf64c67