As best I can tell, Nix enthusiasts think that this is an XY problem and that I shouldn't want to pin individual tools/packages to arbitrary versions. But the thing is that I am a rude barbarian who very much does want to do this, however philosophically misguided it might be.
The downside is that flake inputs refer to other flakes, not individual packages, so if you update the nixpkgs input it will upgrade all of your packages at once. For some packages such as Python, nixpkgs tracks multiple major versions so you can loosely pin to that version. You can also include nixpkgs as an input multiple times under different git tags/commits and only use that input for some of your packages to effectively pin them. You could keep using one nixpkgs but override the package's source to build it for a specific version/commit, but this setup could break in the future, because the derivation (and therefore build instructions) will keep evolving while your package's version will not. Or, if you really wanted to, you could straight up just copy the derivation from nixpkgs into your local repository and use that instead.
Nix is quite flexible so there's more options than just these, it just takes a little getting used to to find out what's possible. I don't use devenv myself, but some quick googling reveals it works just fine with flakes, so I would try that to see if it suits your needs.
> How do I set up my development environment using devenv.sh to pin nodejs to 24.14.0?
If I understand your response correctly, I can't do this in any very practical way.
{ pkgs }:
pkgs.mkShell {
nativeBuildInputs = with pkgs; [
# build tools
cmake
ninja
gnumake
pkg-config
];
buildInputs = with pkgs; [
# java
jdk8
# compilers
gcc
clang
llvmPackages.libcxx
# libraries
capstone
icu
openssl_3
libusb1
libftdi
zlib
# scripting
(python3.withPackages (ps: with ps; [
requests
pyelftools
]))
];
# capstone headers are in include/capstone/ but blutter expects include/
shellHook = ''
export CPATH="${pkgs.capstone}/include/capstone:$CPATH"
export CPLUS_INCLUDE_PATH="${pkgs.capstone}/include/capstone:$CPLUS_INCLUDE_PATH"
'';
}