How to change Bitcoin Core to allow MAX_STANDARD_TX_WEIGHT to be greater than 400000?

Question

I am trying to create a transaction and I saw this issue here: https://github.com/bitcoin/bitcoin/issues/27490

I downloaded Bitcoin core source and started to compile following the documentation, then I changed on this file bitcoin/src/policy/policy.h to this new value {800000} like this:

astatic constexpr int32_t MAX_STANDARD_TX_WEIGHT{800000};

But When I am using make, I get this error

  CXX      libbitcoin_node_a-blockencodings.o
  In file included from ./txmempool.h:18,
             from blockencodings.cpp:15:
 ./policy/packages.h:25:34: error: static assertion failed
  25 | static_assert(MAX_PACKAGE_WEIGHT >= MAX_STANDARD_TX_WEIGHT);
  |               ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

How to solve this to allow this new value? Just to clarify, I am trying to create an Inscription using Ordinals theory.

Thanks so much for any help!

Answer 1

MAX_PACKAGE_WEIGHT is statically checked to be at least MAX_STANDARD_TX_WEIGHT:

static constexpr uint32_t MAX_PACKAGE_WEIGHT = 404'000;
static_assert(MAX_PACKAGE_WEIGHT >= MAX_STANDARD_TX_WEIGHT);

If you want to increase MAX_STANDARD_TX_WEIGHT beyond 404000, you'll also need to increase MAX_PACKAGE_WEIGHT, in your case for example to 804000.

Note that changing your own node's standardness rules is usually not enough to relay your non-standard transaction to a miner willing to include it in a block.

Answer 2

just wanted to put here what I did in case anyone later intend to try the same.

Here is what I changed:

Files: src/policy/packages.h
       src/policy/policy.h
       

file /src/policy/packages.h
...static constexpr uint32_t MAX_PACKAGE_WEIGHT = 808'000;

file /src/policy/policy.h
...static constexpr int32_t MAX_STANDARD_TX_WEIGHT{800000};
...static constexpr unsigned int DEFAULT_ANCESTOR_SIZE_LIMIT_KVB{201}; /** default is 101 */
...static constexpr unsigned int DEFAULT_DESCENDANT_SIZE_LIMIT_KVB{201};

See ya!!