Pixi backend

.github/workflows/tests.yml

@@ -22,7 +22,7 @@ jobs:
       matrix:
         version:
           - '1'
-          - '1.6'
+          - '1.9'
         os:
           - ubuntu-latest
           - macOS-latest
@@ -40,15 +40,23 @@ jobs:
             os: ubuntu-latest
             arch: x64
             backend: 'Null'
+          - version: '1'
+            os: ubuntu-latest
+            arch: x64
+            backend: SystemPixi
     steps:
       - uses: actions/checkout@v3
+      - uses: prefix-dev/setup-pixi@v0
+        if: ${{ matrix.backend == 'SystemPixi' }}
+        with:
+          run-install: false
       - uses: julia-actions/setup-julia@v1
         with:
           version: ${{ matrix.version }}
           arch: ${{ matrix.arch }}
       - uses: julia-actions/cache@v1
       - uses: julia-actions/julia-downgrade-compat@v1
-        if: ${{ matrix.version == '1.6' }}
+        if: ${{ matrix.version == '1.9' }}
         with:
           skip: Markdown,Pkg,TOML,Aqua,Test,TestItemRunner,OpenSSL_jll
       - uses: julia-actions/julia-buildpkg@v1

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## Unreleased
+* Add `SystemPixi` backend to allow using [Pixi](https://pixi.sh/latest/) to install packages.
+
 ## 0.2.24 (2024-11-08)
 * Add `pip_backend` preference to choose between `pip` and `uv`.
 * Add `libstdcxx_ng_version` preference to override automatic version bounds.

Project.toml

@@ -15,16 +15,16 @@ TOML = "fa267f1f-6049-4f14-aa54-33bafae1ed76"
 [compat]
 Aqua = "0 - 999"
 JSON3 = "1.9"
-Markdown = "1.6"
+Markdown = "1"
 MicroMamba = "0.1.4"
 OpenSSL_jll = "0 - 999"
 Pidfile = "1.3"
-Pkg = "1.6"
+Pkg = "1.9"
 Preferences = "1.3"
 Test = "1"
 TestItemRunner = "0 - 999"
 TOML = "1"
-julia = "1.6"
+julia = "1.9"
 
 [extras]
 Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"

README.md

@@ -157,7 +157,7 @@ in more detail.
 
 | Preference | Environment variable | Description |
 | ---------- | -------------------- | ----------- |
-| `backend` | `JULIA_CONDAPKG_BACKEND` | One of `MicroMamba`, `System`, `Current` or `Null` |
+| `backend` | `JULIA_CONDAPKG_BACKEND` | One of `MicroMamba`, `System`, `Current`, `SystemPixi` or `Null` |
 | `exe` | `JULIA_CONDAPKG_EXE` | Path to the Conda executable. |
 | `offline` | `JULIA_CONDAPKG_OFFLINE` | When `true`, work in offline mode. |
 | `env` | `JULIA_CONDAPKG_ENV` | Path to the Conda environment to use. |
@@ -184,6 +184,8 @@ by setting the `backend` preference to one of the following values:
   [MicroMamba.jl](https://github.com/JuliaPy/MicroMamba.jl).
 - `System`: Use a pre-installed Conda. If the `exe` preference is set, that is used.
   Otherwise we look for `conda`, `mamba` or `micromamba` in your `PATH`.
+- `SystemPixi`: Use a pre-installed [Pixi](https://pixi.sh). If the `exe` preference
+  is set, that is used. Otherwise we look for `pixi` in your `PATH`.
 - `Current`: Use the currently activated Conda environment instead of creating a new one.
   This backend will only ever install packages, never uninstall. The Conda executable used
   is the same as for the System backend. Similar to the default behaviour of

src/CondaPkg.jl

@@ -29,6 +29,7 @@ end
     # backend
     backend::Symbol = :NotSet
     condaexe::String = ""
+    pixiexe::String = ""
     # resolve
     resolved::Bool = false
     load_path::Vector{String} = String[]

src/PkgREPL.jl

@@ -338,8 +338,11 @@ const gc_spec = Pkg.REPLMode.CommandSpec(
 function run(args)
     try
         CondaPkg.withenv() do
-            if args[1] == "conda"
+            b = CondaPkg.backend()
+            if b in CondaPkg.CONDA_BACKENDS && args[1] == "conda"
                 Base.run(CondaPkg.conda_cmd(args[2:end]))
+            elseif b in CondaPkg.PIXI_BACKENDS && args[1] == "pixi"
+                Base.run(CondaPkg.pixi_cmd(args[2:end]))
             else
                 Base.run(Cmd(args))
             end

src/backend.jl

@@ -1,3 +1,12 @@
+"""All valid backends."""
+const ALL_BACKENDS = (:MicroMamba, :Null, :System, :Current, :SystemPixi)
+
+"""All backends that use a Conda/Mamba installer."""
+const CONDA_BACKENDS = (:MicroMamba, :System, :Current)
+
+"""All backends that use a Pixi installer."""
+const PIXI_BACKENDS = (:SystemPixi,)
+
 function backend()
     if STATE.backend == :NotSet
         backend = getpref(String, "backend", "JULIA_CONDAPKG_BACKEND", "")
@@ -27,24 +36,44 @@ function backend()
                     error("not an executable: $exe")
                 end
             end
+        elseif backend == "SystemPixi"
+            ok = false
+            exe2 = Sys.which(exe == "" ? "pixi" : exe)
+            if exe2 === nothing
+                if exe == ""
+                    error("could not find a pixi executable")
+                else
+                    error("not an executable: $exe")
+                end
+            end
+            STATE.backend = :SystemPixi
+            STATE.pixiexe = exe2
         else
             error("invalid backend: $backend")
         end
     end
+    @assert STATE.backend in ALL_BACKENDS
     STATE.backend
 end
 
 function conda_cmd(args = ``; io::IO = stderr)
     b = backend()
     if b == :MicroMamba
         MicroMamba.cmd(args, io = io)
-    elseif b in (:System, :Current)
+    elseif b in CONDA_BACKENDS
+        STATE.condaexe == "" && error("this is a bug")
         `$(STATE.condaexe) $args`
-    elseif b == :Null
-        error(
-            "Can not run conda command when backend is Null. Manage conda actions outside of julia.",
-        )
     else
-        @assert false
+        error("Cannot run conda when backend is $b.")
+    end
+end
+
+function pixi_cmd(args = ``; io::IO = stderr)
+    b = backend()
+    if b in PIXI_BACKENDS
+        STATE.pixiexe == "" && error("this is a bug")
+        `$(STATE.pixiexe) $args`
+    else
+        error("Cannot run pixi when backend is $b.")
     end
 end

src/deps.jl

@@ -114,15 +114,31 @@ function read_parsed_deps(file)
 end
 
 function current_packages()
-    cmd = conda_cmd(`list -p $(envdir()) --json`)
-    pkglist = JSON3.read(cmd)
+    b = backend()
+    if b in CONDA_BACKENDS
+        cmd = conda_cmd(`list -p $(envdir()) --json`)
+        pkglist = JSON3.read(cmd)
+    elseif b in PIXI_BACKENDS
+        cmd =
+            pixi_cmd(`list --manifest-path $(joinpath(STATE.meta_dir, "pixi.toml")) --json`)
+        pkglist = JSON3.read(cmd)
+        pkglist = [pkg for pkg in pkglist if pkg.kind == "conda"]
+    end
     Dict(normalise_pkg(pkg.name) => pkg for pkg in pkglist)
 end
 
 function current_pip_packages()
-    pkglist = withenv() do
-        cmd = `$(which("pip")) list --format=json`
-        JSON3.read(cmd)
+    b = backend()
+    if b in CONDA_BACKENDS
+        pkglist = withenv() do
+            cmd = `$(which("pip")) list --format=json`
+            JSON3.read(cmd)
+        end
+    elseif b in PIXI_BACKENDS
+        cmd =
+            pixi_cmd(`list --manifest-path $(joinpath(STATE.meta_dir, "pixi.toml")) --json`)
+        pkglist = JSON3.read(cmd)
+        pkglist = [pkg for pkg in pkglist if pkg.kind == "pypi"]
     end
     Dict(normalise_pip_pkg(pkg.name) => pkg for pkg in pkglist)
 end

src/env.jl

@@ -119,9 +119,13 @@ end
 Remove unused packages and caches.
 """
 function gc(; io::IO = stderr)
-    backend() == :Null && return
-    resolve()
-    cmd = conda_cmd(`clean -y --all`, io = io)
-    _run(io, cmd, "Removing unused caches")
+    b = backend()
+    if b in CONDA_BACKENDS
+        resolve()
+        cmd = conda_cmd(`clean -y --all`, io = io)
+        _run(io, cmd, "Removing unused caches")
+    else
+        _log(io, "GC does nothing with the $b backend.")
+    end
     return
 end

src/meta.jl

@@ -4,14 +4,15 @@ information about the most recent resolve.
 """
 
 # increment whenever the metadata format changes
-const META_VERSION = 13
+const META_VERSION = 14
 
 @kwdef mutable struct Meta
     timestamp::Float64
     conda_env::String
     load_path::Vector{String}
     extra_path::Vector{String}
     version::VersionNumber
+    backend::Symbol
     packages::Vector{PkgSpec}
     channels::Vector{ChannelSpec}
     pip_packages::Vector{PipPkgSpec}
@@ -26,6 +27,7 @@ function read_meta(io::IO)
             load_path = read_meta(io, Vector{String}),
             extra_path = read_meta(io, Vector{String}),
             version = read_meta(io, VersionNumber),
+            backend = read_meta(io, Symbol),
             packages = read_meta(io, Vector{PkgSpec}),
             channels = read_meta(io, Vector{ChannelSpec}),
             pip_packages = read_meta(io, Vector{PipPkgSpec}),
@@ -43,6 +45,9 @@ function read_meta(io::IO, ::Type{String})
     end
     String(bytes)
 end
+function read_meta(io::IO, ::Type{Symbol})
+    Symbol(read_meta(io, String))
+end
 function read_meta(io::IO, ::Type{Vector{T}}) where {T}
     len = read(io, Int)
     ans = Vector{T}()
@@ -81,6 +86,7 @@ function write_meta(io::IO, meta::Meta)
     write_meta(io, meta.load_path)
     write_meta(io, meta.extra_path)
     write_meta(io, meta.version)
+    write_meta(io, meta.backend)
     write_meta(io, meta.packages)
     write_meta(io, meta.channels)
     write_meta(io, meta.pip_packages)
@@ -93,6 +99,9 @@ function write_meta(io::IO, x::String)
     write(io, convert(Int, sizeof(x)))
     write(io, x)
 end
+function write_meta(io::IO, x::Symbol)
+    write_meta(io, String(x))
+end
 function write_meta(io::IO, x::Vector)
     write(io, convert(Int, length(x)))
     for item in x