Export compile_commands.json in standalone builds (by default) #314

pull Sjors wants to merge 2 commits into bitcoin-core:master from Sjors:2026/07/export-compile-commands changing 2 files +11 −0

Sjors commented at 11:52 AM on July 21, 2026: member
This makes the default build configuration play nicely with code editors. E.g. with Zed, looking at spawn_argv in #231:

Before: <img width="1025" height="426" alt="before" src="https://github.com/user-attachments/assets/3b9881fd-7be2-49de-9180-b8517dda0394" />

After: <img width="911" height="427" alt="after" src="https://github.com/user-attachments/assets/42bac960-3d31-4bf4-9d42-7d92b72c13a9" />

One downside of this approach is that it only just works(tm) on the build directory.

There are several alternative approaches:
1. Update documentation to recommend:
```
cmake -B build -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
ln -sf build/compile_commands.json .
```
1. Have cmake add a symlink to the source dir
2. Add a (dev) cmake preset

cmake: Export compile_commands.json by default in standalone builds

Makes clangd and other tooling work out of the box after configuring.
Only applied when libmultiprocess is the top-level project, so it does
not opt targets into a parent project's compile database when built as
a subtree.

An explicit -DCMAKE_EXPORT_COMPILE_COMMANDS=OFF or environment variable
setting still takes precedence: project() copies the environment value
into the cache, leaving the cache entry empty when neither is set, so
the default only applies to an empty value.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

a92b068742

Add .clangd pointing clangd at the build/ compile database

clangd only searches ancestor directories of a source file for
compile_commands.json, so even with CMAKE_EXPORT_COMPILE_COMMANDS
enabled it would not find the database in the build directory without
a symlink in the source directory. Point it at the build/ directory
suggested by doc/install.md and doc/usage.md.

Developers using a differently named build directory can override this
with clangd's --compile-commands-dir flag or a personal clangd user
config, which takes precedence over this file.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

fab9081bc3

DrahtBot commented at 11:52 AM on July 21, 2026: none



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ryanofsky commented at 1:41 PM on July 30, 2026: collaborator

Code review fab9081bc3a1ef37c521528b466df7d5d1c9df8c.

I think we should do something to make this less cumbersome, but I'm not sure about this approach, especially since it hardcodes the name of the build directory. The simplest thing to do would be to suggest running cmake -B build -DCMAKE_EXPORT_COMPILE_COMMANDS=ON && ln -sf build/compile_commands.json . in documentation to set this up.

But I've also been thinking it would be good to have a clearer separation in the cmake build between essential features that can't be provided externally and convenience features and maybe just enable the convenience features in a dev mode present like Bitcoin core. Sketch of this idea is: https://github.com/bitcoin-core/libmultiprocess/compare/master...ryanofsky:libmultiprocess:pr/extras (branch) which would automatically set up this editor support if dev mode is enabled while avoiding a hardcoded .clangd file, and simplifying the main cmake file instead of complicating it.
Sjors commented at 12:20 PM on July 31, 2026: member

Closing in favor of your suggested approach. I won't have time in the next two weeks to implement that though.
Sjors closed this on Jul 31, 2026

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#231 Add windows support

Export compile_commands.json in standalone builds (by default) #314

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