Reworked Nix flake CI

The old CI did not run the Nix tests (it was silently failing). This
resolves that and also removes the publishing of Nix to Cachix as the
dependencies should be cached by the dependants themselves, and not the
starter projects.

Author: jaschutte

.ci/publish.sh

@@ -51,4 +51,4 @@ git add -A
 git commit -m "Automated push from clash-lang/stack-templates"
 
 # Push
-git push -f
+git push --force origin main

.ci/publish_nix.sh

@@ -5,25 +5,27 @@ IFS=$'\n\t'
 
 cd "$(git rev-parse --show-toplevel)"
 
-for project in *.hsfiles; do
-    nix-shell --pure --packages stack --run "stack new inst \"${project}\""
 
-    cd inst
+for project in projects-nix/*; do
+    # Copy the directory and resolve symlinks
+    # The reason we copy the directory rather than invoking `nix init ...` is because nix init does
+    # not resolve symlinks. However these symlinks *are* resolved as soon as it gets copied over to
+    # `clash-starters`. So to 'mimick' the behaviour of `nix init` we just copy over the directory.
+    cp -rL "$project" ci-project
+    # If files aren't referenced by git, Nix gets very confused
+    # This is not needed outside of a git repository, but since the files get copied over in a
+    # git repository, we need to do this
+    git add -A
+    cd ci-project
 
-    if [[ -f "shell.nix" ]]; then
-        # Build and test with nix. Note that nix-build already runs the tests,
-        # but we'd also like to be able to run them using just cabal in a shell.
-        nix-build
-        if [[ ${project} != "deca.hsfiles" ]]; then
-            nix-shell --pure --run "cabal run clash -- Example.Project --vhdl"
-        else
-            nix-shell --pure --run "cabal run clash -- DECA --vhdl"
-        fi
-        nix-shell --pure --run "cabal run doctests"
-        nix-shell --pure --run "cabal run test-library"
-    fi
+    # Test
+    nix build . --accept-flake-config
+    nix develop . --accept-flake-config -c cabal update
+    # The `nix run` is supposed to run inside of `nix develop`
+    nix develop . --accept-flake-config -c nix run . --accept-flake-config
+    nix develop . --accept-flake-config -c cabal run doctests
+    nix develop . --accept-flake-config -c cabal run test-library
 
     # Clean up
-    cd ..
-    rm -rf inst
+    rm -rf ./ci-project
 done

.ci/test_projects_nix.sh

@@ -207,34 +207,3 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y git ssh zip gzip tar coreutils haskell-stack
           .ci/publish.sh
-
-  # Push to Cachix
-  publish-nix:
-    name: Publish Nix
-    if: github.ref == 'refs/heads/master'
-    needs:
-      - all
-    runs-on: ubuntu-22.04
-    environment: master
-
-    env:
-      CACHIX_AUTH_TOKEN: ${{ secrets.CACHIX_AUTH_TOKEN }}
-
-    steps:
-      - uses: actions/checkout@v4
-      - uses: cachix/install-nix-action@v30
-        with:
-          nix_path: nixpkgs=channel:nixos-23.05
-
-      - name: Checkout
-        uses: actions/checkout@v4
-
-      - name: Enable cachix
-        run: |
-          nix-env -iA cachix -f https://cachix.org/api/v1/install
-          cachix use clash-lang
-
-      - name: Push to cachix
-        if: github.ref == 'refs/heads/master'
-        run: |
-          .ci/publish_nix.sh

.github/workflows/ci.yml

@@ -6,8 +6,8 @@
   };
   nixConfig = {
     extra-substituters = [ "https://clash-lang.cachix.org" ];
-    trusted-substituters = [ "https://clash-lang.cachix.org" ];
-    trusted-public-keys = [ "clash-lang.cachix.org-1:/2N1uka38B/heaOAC+Ztd/EWLmF0RLfizWgC5tamCBg=" ];
+    extra-trusted-substituters = [ "https://clash-lang.cachix.org" ];
+    extra-trusted-public-keys = [ "clash-lang.cachix.org-1:/2N1uka38B/heaOAC+Ztd/EWLmF0RLfizWgC5tamCBg=" ];
   };
   outputs = { self, nixpkgs, flake-utils, clash-compiler }:
     flake-utils.lib.eachDefaultSystem (system: