julia.withPackages: add juliaCpuTarget option

doc/languages-frameworks/julia.section.md

@@ -67,3 +67,14 @@ nix-shell -p 'julia.withPackages ["Plots"]' --run julia
 
   This normally points at a special augmented version of the Julia [General packages registry](https://github.com/JuliaRegistries/General).
   If you want to use a bleeding-edge version to pick up the latest package updates, you can plug in a later revision than the one in Nixpkgs.
+
+* `juliaCpuTarget`: Allows you to set `JULIA_CPU_TARGET` when precompiling. Has no effect if `precompile=false`.
+
+  You may want to use this if you're building a Julia depot that will end up in a Nix cache and used on machines with
+  different CPUs.
+
+  Why? Julia will detect the CPU microarchitecture of the build machine and include this information in the precompiled
+  `*.ji` files. Starting in 1.10 Julia became more strict about checking the CPU target compatibility, so it may reject
+  your precompiled files if they were compiled on a different machine.
+  A good option to provide wide compatibility is to set this to `"generic"`, although this may reduce performance.
+  You can also set a semicolon-separated list of multiple different targets. See the Julia documentation for details.

pkgs/development/julia-modules/default.nix

@@ -1,13 +1,14 @@
-{ lib
-, callPackage
-, runCommand
+{ callPackage
 , fetchgit
 , fontconfig
 , git
+, lib
 , makeWrapper
+, python3
+, runCommand
+, system
 , writeText
 , writeTextFile
-, python3
 
 # Artifacts dependencies
 , fetchurl
@@ -23,19 +24,19 @@
 
 # Other overridable arguments
 , extraLibs ? []
-, precompile ? true
-, setDefaultDepot ? true
+, juliaCpuTarget ? null
+, makeTransitiveDependenciesImportable ? false # Used to support symbol indexing
 , makeWrapperArgs ? ""
 , packageOverrides ? {}
-, makeTransitiveDependenciesImportable ? false # Used to support symbol indexing
+, precompile ? true
+, setDefaultDepot ? true
 }:
 
 packageNames:
 
 let
   util = callPackage ./util.nix {};
 
-
   # Some Julia packages require access to Python. Provide a Nixpkgs version so it
   # doesn't try to install its own.
   pythonToUse = let
@@ -152,7 +153,7 @@ let
   # Build a Julia project and depot. The project contains Project.toml/Manifest.toml, while the
   # depot contains package build products (including the precompiled libraries, if precompile=true)
   projectAndDepot = callPackage ./depot.nix {
-    inherit closureYaml extraLibs overridesToml packageImplications precompile;
+    inherit closureYaml extraLibs juliaCpuTarget overridesToml packageImplications precompile;
     julia = juliaWrapped;
     registry = minimalRegistry;
     packageNames = if makeTransitiveDependenciesImportable

pkgs/development/julia-modules/depot.nix

@@ -9,17 +9,18 @@
 
 , closureYaml
 , extraLibs
+, juliaCpuTarget
 , overridesToml
-, packageNames
 , packageImplications
+, packageNames
 , precompile
 , registry
 }:
 
 runCommand "julia-depot" {
-    nativeBuildInputs = [curl git julia (python3.withPackages (ps: with ps; [pyyaml]))] ++ extraLibs;
-    inherit precompile registry;
-  } ''
+  nativeBuildInputs = [curl git julia (python3.withPackages (ps: with ps; [pyyaml]))] ++ extraLibs;
+  inherit precompile registry;
+} (''
   export HOME=$(pwd)
 
   echo "Building Julia depot and project with the following inputs"
@@ -42,7 +43,9 @@ runCommand "julia-depot" {
 
   # Only precompile if configured to below
   export JULIA_PKG_PRECOMPILE_AUTO=0
-
+'' + lib.optionalString (juliaCpuTarget != null) ''
+  export JULIA_CPU_TARGET="${juliaCpuTarget}"
+'' + ''
   # Prevent a warning where Julia tries to download package server info
   export JULIA_PKG_SERVER=""
 
@@ -84,11 +87,15 @@ runCommand "julia-depot" {
       Pkg.instantiate()
 
       if "precompile" in keys(ENV) && ENV["precompile"] != "0" && ENV["precompile"] != ""
+        if isdefined(Sys, :CPU_NAME)
+          println("Precompiling with CPU_NAME = " * Sys.CPU_NAME)
+        end
+
         Pkg.precompile()
       end
     end
 
     # Remove the registry to save space
     Pkg.Registry.rm("General")
   '
-''
+'')