Test external commands with nightly GHC

Fixes #231

Author: alt-romes

.github/workflows/debugger.yaml

@@ -77,12 +77,12 @@ jobs:
     continue-on-error: ${{ inputs.is-release == false }}
     strategy:
       matrix:
-        version: [9.14.1] #, latest-nightly] disable nightly while its broken
+        version: [9.14.1, 9.15.20260330]
         include:
-          # - channel: https://ghc.gitlab.haskell.org/ghcup-metadata/ghcup-nightlies-0.0.7.yaml
-          #   version: latest-nightly
           - channel: https://raw.githubusercontent.com/haskell/ghcup-metadata/refs/heads/develop/ghcup-prereleases-0.0.9.yaml
             version: 9.14.1
+          - channel: https://gitlab.haskell.org/ghc/ghcup-metadata/-/raw/updates/ghcup-nightlies-0.0.7.yaml
+            version: 9.15.20260330
     steps:
       - uses: actions/checkout@v4
         with:
@@ -123,6 +123,14 @@ jobs:
           (cd ${{ runner.temp }}/dist && tar xzf "haskell-debugger-view-${{env.haskellDebuggerViewVersion}}.tar.gz")
           (cd ${{ runner.temp }}/dist && cd haskell-debugger-${{env.haskellDebuggerVersion}} && echo 'packages: . ../haskell-debugger-view-${{env.haskellDebuggerViewVersion}}' > cabal.project)
 
+      - name: Configure head.hackage for nightly
+        if: matrix.version == '9.15.20260330'
+        working-directory: ${{ runner.temp }}/dist/haskell-debugger-${{ env.haskellDebuggerVersion }}
+        run: |
+          curl --proto '=https' --tlsv1.2 -fsSL https://ghc.gitlab.haskell.org/head.hackage/cabal.project >> cabal.project.local
+          echo 'constraints: hashable >= 1.4.7.0' >> cabal.project.local
+          cabal update
+
       - name: Build and Run integration tests
         run: |
           echo "Using haskell-debugger-view from hackage: ${{env.USE_HASKELL_DEBUGGER_VIEW_FROM_HACKAGE}}"
@@ -143,12 +151,12 @@ jobs:
     strategy:
       matrix:
         runner: [ubuntu-latest, macOS-latest] # windows-latest is broken, see #246
-        version: [9.14.1] #, latest-nightly] disable nightly while its broken
+        version: [9.14.1, 9.15.20260330]
         include:
-          # - channel: https://ghc.gitlab.haskell.org/ghcup-metadata/ghcup-nightlies-0.0.7.yaml
-          #   version: latest-nightly
           - channel: https://raw.githubusercontent.com/haskell/ghcup-metadata/refs/heads/develop/ghcup-prereleases-0.0.9.yaml
             version: 9.14.1
+          - channel: https://gitlab.haskell.org/ghc/ghcup-metadata/-/raw/updates/ghcup-nightlies-0.0.7.yaml
+            version: 9.15.20260330
     steps:
       - uses: actions/checkout@v4
         with:
@@ -161,6 +169,13 @@ jobs:
           cabal-version: 3.14
           ghcup-release-channel: ${{ matrix.channel }}
 
+      - name: Configure head.hackage for nightly
+        if: matrix.version == '9.15.20260330'
+        run: |
+          curl --proto '=https' --tlsv1.2 -fsSL https://ghc.gitlab.haskell.org/head.hackage/cabal.project >> cabal.project.local
+          echo 'constraints: hashable >= 1.4.7.0' >> cabal.project.local
+          cabal update
+
       - name: Configure the build
         run: |
           cabal configure --enable-tests --enable-benchmarks --disable-documentation