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Remove cmake-era setup from the Nix shells and CONTRIBUTING.md #38543

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Remove cmake-era setup from the Nix shells and CONTRIBUTING.md #38543

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Remove cmake-era setup from the Nix shells and CONTRIBUTING.md
robobun Aug 14, 2026
7d2ede3
ci: retrigger
robobun Aug 14, 2026
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11 changes: 4 additions & 7 deletions CONTRIBUTING.md
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Original file line number Diff line number Diff line change
Expand Up @@ -8,9 +8,6 @@ A Nix flake is provided as an alternative to manual dependency installation:

```bash
nix develop
# or explicitly use the pure shell
# nix develop .#pure
export CMAKE_SYSTEM_PROCESSOR=$(uname -m)
bun bd
```

Expand Down Expand Up @@ -150,7 +147,7 @@ $ export PATH="$PATH:/usr/lib/llvm21/bin"

## Building Bun

After cloning the repository, run the following command to build. This may take a while as it will clone submodules and build dependencies.
After cloning the repository, run the following command to build. This may take a while as it downloads and builds dependencies.

```bash
$ bun run build
Expand Down Expand Up @@ -305,15 +302,15 @@ Note that if you make changes to our [WebKit fork](https://github.com/oven-sh/We

The Clang compiler typically uses the `libstdc++` C++ standard library by default. `libstdc++` is the default C++ Standard Library implementation provided by the GNU Compiler Collection (GCC). While Clang may link against the `libc++` library, this requires explicitly providing the `-stdlib` flag when running Clang.

Bun relies on C++20 features like `std::span`, which are not available in GCC versions lower than 11. GCC 10 doesn't have all of the C++20 features implemented. As a result, running `make setup` may fail with the following error:
Bun relies on C++20 features like `std::span`, which are not available in GCC versions lower than 11. GCC 10 doesn't have all of the C++20 features implemented. As a result, running `bun run build` may fail with the following error:

```
fatal error: 'span' file not found
#include <span>
^~~~~~
```

The issue may manifest when initially running `bun setup` as Clang being unable to compile a simple program:
The issue may manifest when initially running `bun run build` as Clang being unable to compile a simple program:

```
The C++ compiler
Expand Down Expand Up @@ -363,7 +360,7 @@ $ xcode-select --install
Bun defaults to linking `libatomic` statically, as not all systems have it. If you are building on a distro that does not have a static libatomic available, you can run the following command to enable dynamic linking:

```bash
$ bun run build -DUSE_STATIC_LIBATOMIC=OFF
$ bun run build --static-libatomic=off
```

The built version of Bun may not work on other systems if compiled this way.
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9 changes: 0 additions & 9 deletions flake.nix
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Expand Up @@ -139,11 +139,6 @@
export CXX="${pkgs.lib.getExe' clang "clang++"}"
export AR="${llvm}/bin/llvm-ar"
export RANLIB="${llvm}/bin/llvm-ranlib"
export CMAKE_C_COMPILER="$CC"
export CMAKE_CXX_COMPILER="$CXX"
export CMAKE_AR="$AR"
export CMAKE_RANLIB="$RANLIB"
export CMAKE_SYSTEM_PROCESSOR="$(uname -m)"
export TMPDIR="''${TMPDIR:-/tmp}"
'' + pkgs.lib.optionalString pkgs.stdenv.isLinux ''
export LD="${pkgs.lib.getExe' lld "ld.lld"}"
Expand All @@ -166,10 +161,6 @@
echo " bun bd test <test-file> # Run tests"
echo "====================================="
'';

# Additional environment variables
CMAKE_BUILD_TYPE = "Debug";
ENABLE_CCACHE = "1";
};
}
);
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5 changes: 0 additions & 5 deletions shell.nix
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Expand Up @@ -81,11 +81,6 @@ pkgs.mkShell rec {
export CXX="${pkgs.lib.getExe' pkgs.clang_21 "clang++"}"
export AR="${pkgs.llvm_21}/bin/llvm-ar"
export RANLIB="${pkgs.llvm_21}/bin/llvm-ranlib"
export CMAKE_C_COMPILER="$CC"
export CMAKE_CXX_COMPILER="$CXX"
export CMAKE_AR="$AR"
export CMAKE_RANLIB="$RANLIB"
export CMAKE_SYSTEM_PROCESSOR=$(uname -m)
export TMPDIR=''${TMPDIR:-/tmp}
'' + pkgs.lib.optionalString pkgs.stdenv.isLinux ''
export LD="${pkgs.lib.getExe' pkgs.lld_21 "ld.lld"}"
Expand Down