Feature/nix support

.github/workflows/build_with_nix.yml

@@ -0,0 +1,24 @@
+name: build with nix
+on:
+  pull_request:
+    branches:
+      - main
+  workflow_dispatch: {}
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+jobs:
+  build_and_test:
+    strategy:
+      matrix:
+        os: ['ubuntu-22.04', 'macos-14']
+    runs-on: ${{matrix.os}}
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v25
+    - uses: cachix/cachix-action@v15
+      with:
+        name: tket
+        signingKey: ${{ secrets.CACHIX_AUTH_TOKEN }}
+    - name: Build and test pytket-qir
+      run: nix flake check -L

.gitignore

@@ -11,3 +11,5 @@ obj
 docs/extensions
 .ipynb_checkpoints
 pytket/qir/_metadata.py
+# nix
+result

flake.nix

@@ -0,0 +1,38 @@
+{
+  description = "Pytket QIR Extension";
+  nixConfig.extra-substituters = "https://tket.cachix.org https://cache.nixos.org";
+  nixConfig.trusted-public-keys = ''
+    tket.cachix.org-1:ACdm5Zg19qPL0PpvUwTPPiIx8SEUy+D/uqa9vKJFwh0=
+    cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
+  '';
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+  inputs.tket.url = "github:CQCL/tket";
+  inputs.nixpkgs = {
+   # url = "github:nixos/nixpkgs";
+    follows = "tket/nixpkgs";
+  };
+  outputs = { self, nixpkgs, flake-utils, tket }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [
+            (self: super: {
+              inherit (tket.packages."${system}") tket pytket;
+            })
+            (import ./nix-support/pyqir.nix)
+            (import ./nix-support/pytket-qir.nix)
+          ];
+        };
+      in {
+        packages = {
+          pytket-qir = pkgs.pytket-qir;
+        };
+        devShells = {
+          default = pkgs.mkShell { buildInputs = [ pkgs.pytket-qir ]; };
+        };
+        checks = {
+          pytket-qir-tests = pkgs.pytket-qir;
+        };
+      });
+}

nix-support/README.md

@@ -0,0 +1,107 @@
+# Nix support for pytket-qir
+
+## Background
+
+Tket now comes with Nix support. What this means is that the
+steps required to launch into an environment with tket and pytket
+available on Linux x86-64 and Mac Silicon machines is a single
+invocation:
+
+```
+nix develop github:CQCL/tket
+```
+
+Currently this will build all of the necessary dependencies,
+establish the environment, and enter into a shell where
+tket and pytket are available for use. Soon we aim to add Cachix,
+so that the dependencies are served pre-built to the user.
+
+## Using pytket-qir
+
+The nix.flake in this repository is able to access tket and pytket
+from the CQCL/tket nix flake, pinned at the commit and hash noted
+in flake.lock (see the Maintenance section). It then exposes
+pytket-qir as a package, and provides a development shell containing
+pytket-qir.
+
+To launch into an environment with pytket-qir available, use
+```
+nix develop github:CQCL/pytket-qir
+```
+
+from which pytket-qir is now available
+```
+y$ nix develop github:CQCL/pytket-qir/feature/nix-support
+
+$ python3
+Python 3.11.7 (main, Dec  4 2023, 18:10:11) [GCC 13.2.0] on linux
+Type "help", "copyright", "credits" or "license" for more information.
+>>> from pytket.circuit import Circuit
+>>> from pytket.qir.conversion.api import QIRFormat, pytket_to_qir
+>>> c = Circuit(2)
+>>> c.H(0)
+[H q[0]; ]
+>>> c.H(1)
+[H q[0]; H q[1]; ]
+>>> c.CX(0, 1)
+[H q[0]; H q[1]; CX q[0], q[1]; ]
+>>> c.H(0)
+[H q[0]; H q[1]; CX q[0], q[1]; H q[0]; ]
+>>> c.H(1)
+[H q[0]; H q[1]; CX q[0], q[1]; H q[0]; H q[1]; ]
+>>> print(pytket_to_qir(c, name="example", qir_format=QIRFormat.STRING))
+; ModuleID = 'example'
+source_filename = "example"
+
+%Qubit = type opaque
+%Result = type opaque
+; ... and so on
+```
+
+This will take some time if tket has not been built on the target machine yet,
+as the necessary downloading and building will take place before the environment
+is ready. Once we get Cachix it will be much faster, as the builds will be available
+from our cache.
+
+## Quirks
+
+At the time of writing, mypy checks for `warn_unused_ignores` are disabled for
+nix-only builds, as they lead to false-positives that fail the flake checks.
+
+These are only disabled for the nix version of this repository. This is done
+in nix-support/pytket-qir.nix, and is accomplished by modifying the mypy.ini file
+at the time of copying it to the Nix store.
+
+## Maintenance
+
+When changes are made, run `nix flake check` to ensure that the nix build works.
+If errors are present, run `nix flake check -L` to see the full logs.
+
+The three nix dependencies for this repository are nixpkgs, flake-utils, and tket.
+
+To update all three, simply run:
+```
+nix flake update
+```
+and commit the updated flake.lock after verifying with `nix flake check`.
+
+Dependencies can also be updated selectively with e.g.
+
+```
+nix flake lock --update-input tket
+```
+
+pyqir is not present on the nix store, so we build it manually in nix-support/pyqir.nix.
+
+If the version needs to be updated, follow this procedure:
+1. Unset the resulting hashes with `pyqir-hash = "";` and `pytket-cargo-hash = "";`
+2. Update pyqir-version to an available tag on the qir-alliance/pyqir github
+3. Run `nix flake check`
+4. The build will fail with a hash mismatch. Use the hash it provides to replace the blank `pyqir-hash`.
+5. Run `nix flake check`
+6. The build will fail with a hash mismatch. Use the hash it provides to replace the blank `pyqir-cargo-hash`.
+7. Run `nix flake check` again. This time it should succeed.
+
+If the build fails for another reason, further investigation is required.
+It is likely down to required change in build steps for pyqir, or could be
+a breaking change in pyqir that needs addressing in pytket-qir.

nix-support/pyqir.nix

@@ -0,0 +1,45 @@
+self: super:
+let
+  lib = super.lib;
+  llvm = super.llvm_14;
+  llvm-v-major = lib.versions.major llvm.version;
+  llvm-v-minor = builtins.substring 0 1 (lib.versions.minor llvm.version);
+  pyqir-version = "0.10.0";
+  pyqir-hash = sha256:dZd+U3vyHb9rrNB90XiLn6fAbsg3Xk9Htnw5Ce/vra4=;
+  pyqir-cargo-hash = sha256:U964/0ekTVgl5CCU4xgExgFhSIP1RKocNbjScWw4BTM=;
+in
+{
+  pyqir = super.python3Packages.buildPythonPackage rec {
+    pname = "pyqir";
+    version = pyqir-version;
+    format = "pyproject";
+    src = super.fetchFromGitHub {
+      owner = "qir-alliance";
+      repo = "pyqir";
+      rev = "v${pyqir-version}";
+      sha256 = pyqir-hash;
+    };
+
+    cargoDeps = super.rustPlatform.fetchCargoTarball {
+      inherit src;
+      name = "pyqir-${pyqir-version}";
+      hash = pyqir-cargo-hash;
+    };
+
+    buildAndTestSubdir = "pyqir";
+
+    nativeBuildInputs = with super.rustPlatform; [ cargoSetupHook maturinBuildHook ];
+
+    buildInputs = [ llvm super.libxml2.dev ];
+
+    maturinBuildFlags = "-F llvm${llvm-v-major}-${llvm-v-minor}";
+
+    preConfigure = ''
+      export LLVM_SYS_${llvm-v-major}${llvm-v-minor}_PREFIX=${llvm.dev}
+    '';
+
+    pythonImportsCheck = [ "pyqir" ];
+
+    passthru.llvm = llvm;
+  };
+}

nix-support/pytket-qir.nix

@@ -0,0 +1,54 @@
+self: super:
+let
+  metadata = builtins.readFile ../_metadata.py;
+  versions =
+    builtins.match ''.*_version__ *= *["']([^"']+)["'].*'' metadata;
+  version = if builtins.length versions > 0 then
+    builtins.elemAt versions 0
+  else
+    builtins.trace "Warning: unable to find version. Defaulting to 0.0.0" "0.0.0";
+in {
+  pytket-qir = super.python3.pkgs.buildPythonPackage {
+    pname = "pytket-qir";
+    version = version;
+    src = super.stdenv.mkDerivation{
+      name = "pytket-qir-sources";
+      phases = [ "installPhase" ];
+      installPhase = ''
+        mkdir -p $out;
+        cp -r ${../pytket} $out/pytket;
+        cp -r ${../tests} $out/tests;
+
+        cp ${../setup.py} $out/setup.py;
+        cp ${../README.md} $out/README.md; # required for setup's long description
+        cp ${../pytest.ini} $out/pytest.ini;
+        cp ${../_metadata.py} $out/_metadata.py;
+
+        # on nix versions of scipy and ipython, stubs are missing.
+        # adjust mypy.ini to ignore these errors.
+        (
+          cat ${../mypy.ini};
+          cat <<EOF
+[mypy-scipy.*]
+ignore_missing_imports = True
+ignore_errors = True
+
+[mypy-IPython.display.*]
+ignore_missing_imports = True
+ignore_errors = True
+EOF
+        ) >> $out/mypy.ini;
+      '';
+    };
+    propagatedBuildInputs = [ super.pytket self.pyqir ];
+    checkInputs = with super.python3Packages; [ pytest mypy ];
+    checkPhase = ''
+      export HOME=$TMPDIR;
+
+      python -m mypy --config-file=mypy.ini --no-incremental -p pytket -p tests
+
+      cd tests;
+      python -m pytest -s .
+    '';
+  };
+}