Reduce Nix support

This removes the support for:
- Dev shells with pre-built packages
- Building binaries

These have been almost continually broken, and nobody is really
maintaining them. Better to just do the simple thing we can do reliably,
which is to provide dev shells.

Closes #3800

Author: michaelpj

.github/workflows/nix.yml

@@ -18,7 +18,6 @@ jobs:
     runs-on: ubuntu-latest
     outputs:
       should_skip_develop: ${{ steps.skip_check.outputs.should_skip }}
-      should_skip_build: ${{ steps.skip_check_no_nix.outputs.should_skip }}
     steps:
       - id: skip_check
         uses: fkirc/skip-duplicate-actions@v5.3.1
@@ -35,11 +34,6 @@ jobs:
                          , ".gitlab-ci.yaml"
                          , ".gitlab/**"
                          ]'
-      - id: skip_check_no_nix
-        uses: fkirc/skip-duplicate-actions@v5.3.1
-        with:
-          cancel_others: false
-          paths: '[ "**.nix" ]'
 
   # Enter the development shell and run `cabal build`
   develop:
@@ -63,66 +57,15 @@ jobs:
     - uses: cachix/cachix-action@v12
       with:
         name: haskell-language-server
-        # Disable pushing, we will do that in job `build`
-        skipPush: true
+        authToken: ${{ secrets.HLS_CACHIX_AUTH_TOKEN }}
     - run: |
         nix develop --print-build-logs --command cabal update
         nix develop --print-build-logs --command cabal build
 
-  # Build and then push HLS binaries with developmet shell to cachix
-  # This job runs when
-  #   1. PRs are merged to master (runs on master)
-  #   2. Nix files are changed (runs on PR)
-  build:
-    needs: pre_job
-    runs-on: ${{ matrix.os }}
-    env:
-      HAS_TOKEN: ${{ secrets.HLS_CACHIX_AUTH_TOKEN != '' }}
-    if: (needs.pre_job.outputs.should_skip_build != 'true' && needs.pre_job.outputs.should_skip_pr != 'true') || (github.repository_owner == 'haskell' && github.ref == 'refs/heads/master')
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [ubuntu-latest, macOS-latest]
-
-    steps:
-    - uses: actions/checkout@v3
-
-    - uses: cachix/install-nix-action@v23
-      with:
-        extra_nix_config: |
-          experimental-features = nix-command flakes
-        nix_path: nixpkgs=channel:nixos-unstable
-    - uses: cachix/cachix-action@v12
-      with:
-        name: haskell-language-server
-        authToken: ${{ secrets.HLS_CACHIX_AUTH_TOKEN }}
-    - name: Build development shell
-      run: nix develop --print-build-logs --profile dev
-    - name: Build all development shell (without nix dependencies)
-      run: nix develop --print-build-logs .#all-simple-dev-shells --profile dev
-    # We only build nix dev shell for current GHC version because some are
-    # failing with different GHC version on darwin.
-    - name: Build development shell with nix dependencies for current GHC version
-      if: matrix.os == 'macOS-latest'
-      run: nix develop --print-build-logs .#haskell-language-server-dev-nix --profile dev
-    - name: Build development shells with nix dependencies
-      if: matrix.os == 'ubuntu-latest'
-      run: nix develop --print-build-logs .#all-nix-dev-shells --profile dev
-    - name: Push development shell
-      if: ${{ env.HAS_TOKEN == 'true' }}
-      run: cachix push haskell-language-server dev
-    - name: Build binaries
-      run: nix build --print-build-logs
-    - name: Build all binaries
-      run: nix build --print-build-logs .#all-haskell-language-server
-    - name: Push binaries
-      if: ${{ env.HAS_TOKEN == 'true' }}
-      run: nix path-info --json | jq -r '.[].path' | cachix push haskell-language-server
-
   nix_post_job:
     if: always()
     runs-on: ubuntu-latest
-    needs: [pre_job, develop, build]
+    needs: [pre_job, develop]
     steps:
       - run: |
           echo "jobs info: ${{ toJSON(needs) }}"

configuration-ghc-90.nix

@@ -50,16 +50,11 @@ $ cabal build
 If you are using nix 2.4 style command (enabled by `experimental-features = nix-command`),
 you can use `nix develop` instead of `nix-shell` to enter the development shell. To enter the shell with specific GHC versions:
 
-* `nix develop` or `nix develop .#haskell-language-server-dev` - default GHC version
-* `nix develop .#haskell-language-server-901-dev` - GHC 9.0.1 (substitute GHC version as appropriate)
+* `nix develop` - default GHC version
+* `nix develop .#shell-ghc90` - GHC 9.0.1 (substitute GHC version as appropriate)
 
 If you are looking for a Nix expression to create haskell-language-server binaries, see https://github.com/haskell/haskell-language-server/issues/122
 
-To create binaries:
-
-* `nix build` or `nix build .#haskell-language-server` - default GHC version
-* `nix build .#haskell-language-server-901` - GHC 9.0.1 (substitute GHC version as appropriate)
-
 ## Testing
 
 The tests make use of the [Tasty](https://github.com/feuerbach/tasty) test framework.