lix/doc/manual/rl-next/rename-lixexpr.md
jade c97e17144e packaging: rename nixexpr -> lixexpr and so on
This breaks downstreams linking to us on purpose to make sure that if
someone is linking to Lix they're doing it on purpose and crucially not
mixing up Nix and Lix versions in compatibility code.

We still need to fix the internal includes to follow the same schema so
we can drop the single-level include system entirely. However, this
requires a little more effort.

This adds pkg-config for libfetchers and config.h.

Migration path:
expr.hh      -> lix/libexpr/expr.hh
nix/config.h -> lix/config.h

To apply this migration automatically, remove all `<nix/>` from
includes, so: `#include <nix/expr.hh>` -> `#include <expr.hh>`. Then,
the correct paths will be resolved from the tangled mess, and the
clang-tidy automated fix will work.

Then run the following for out of tree projects:

```
lix_root=$HOME/lix
(cd $lix_root/clang-tidy && nix develop -c 'meson setup build && ninja -C build')
run-clang-tidy -checks='-*,lix-fixincludes' -load=$lix_root/clang-tidy/build/liblix-clang-tidy.so -p build/ -fix src
```

Related: lix-project/nix-eval-jobs#5
Fixes: lix-project/lix#279
Change-Id: I7498e903afa6850a731ef8ce77a70da6b2b46966
2024-05-23 16:45:23 -06:00

32 lines
1.3 KiB
Markdown

---
synopsis: Rename all the libraries nixexpr, nixstore, etc to lixexpr, lixstore, etc
credits: jade
category: Breaking Changes
---
The Lix C++ API libraries have had the following changes:
- Includes moved from `include/nix/` to `include/lix/`
- `pkg-config` files renamed from `nix-expr` to `lix-expr` and so on.
- Libraries renamed from `libnixexpr.so` to `liblixexpr.so` and so on.
There are other changes between Nix 2.18 and Lix, since these APIs are not
stable. However, this change in particular is a deliberate compatibility break
to force downstreams linking to Lix to specifically handle Lix and avoid Lix
accidentally getting ensnared in compatibility code for newer CppNix.
Migration path:
- expr.hh -> lix/libexpr/expr.hh
- nix/config.h -> lix/config.h
To apply this migration automatically, remove all `<nix/>` from includes, so `#include <nix/expr.hh>` -> `#include <expr.hh>`.
Then, the correct paths will be resolved from the tangled mess, and the clang-tidy automated fix will work.
Then run the following for out of tree projects:
```console
lix_root=$HOME/lix
(cd $lix_root/clang-tidy && nix develop -c 'meson setup build && ninja -C build')
run-clang-tidy -checks='-*,lix-fixincludes' -load=$lix_root/clang-tidy/build/liblix-clang-tidy.so -p build/ -fix src
```