Kernel Laundry List (Bitcoin Core Dev Tech, May 2026)

A walk through roughly ten kernel-library tasks at varying stages of completion, spread across unrelated domains. The Bitcoin Core "kernel" is the extracted, reusable consensus-validation library, and this list covers the rough edges of making its API safe and ergonomic.

Themes included removing strings and translations from the kernel (annotating user-surfaceable strings rather than translating in-kernel), returning proper fatal error codes instead of strings and ensuring errors bubble up the call stack — with a debate between a clang-tidy plugin to enforce this versus using exceptions (one view being that Core, not being real-time, is a prime candidate for exceptions). Other items: bare-metal compatibility, a CheckedBlock type to prevent a class of bugs, abstract block-file reader/writer classes to run a node fully in memory (useful for fuzzing), splitting the bidirectional chainman/chainstate relationship (a step toward making AssumeUTXO a kernel client), making cs_LastBlockFile non-recursive (a step toward parallel block writes that would notably speed up SwiftSync), and removing the mempool from the kernel library. Several branches need review or new owners.