From 1a0f61a1b9c360d39ef048775290e6d0d5b28c64 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Samuel=20G=C3=A9lineau?= <gelisam+github@gmail.com>
Date: Sun, 27 Dec 2020 16:49:32 -0500
Subject: [PATCH] GitHub Actions

---
 .github/workflows/ci.yml                      | 163 ++++++++++++++++++
 ...rted-lts.yaml => oldest-supported-lts.yaml |   0
 2 files changed, 163 insertions(+)
 create mode 100644 .github/workflows/ci.yml
 rename stack-oldest-supported-lts.yaml => oldest-supported-lts.yaml (100%)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..48503b3
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,163 @@
+name: CI
+
+on:
+  # Build every pull request, to check for regressions.
+  pull_request:
+
+  # Build when a PR is merged, to update the README's CI badge.
+  push:
+    branches: [main]
+
+  # Build once a month, to detect missing upper bounds.
+  schedule:
+    - cron: '0 0 1 * *'
+
+jobs:
+  stack:
+    name: ${{ matrix.name }}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        include:
+          # Check that the build passes with the recommended snapshot.
+          - name: stable
+            stack_yaml: "stack.yaml"
+            os: ubuntu-latest
+
+          # Check that the lower bounds are still correct by building with the
+          # lowest-supported version of everything, including our dependencies.
+          - name: oldest
+            stack_yaml: "oldest-supported-lts.yaml"
+            os: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+      if: github.event.action == 'opened' || github.event.action == 'synchronize' || github.event.ref == 'refs/heads/main'
+
+    - uses: actions/cache@v2
+      name: Cache Stack Artifacts
+      with:
+        path: |
+          ~/.stack
+          .stack-work
+        key: ${{ runner.os }}-stack-${{ hashFiles(matrix.stack_yaml) }}
+
+    - uses: haskell/actions/setup@v1
+      id: setup-haskell-stack
+      name: Setup Stack
+      with:
+        enable-stack: true
+        stack-setup-ghc: true
+        stack-no-global: true
+        ghc-version: ${{ matrix.ghc }}
+
+    - name: Build
+      run: |
+        stack --stack-yaml=${{ matrix.stack_yaml }} build --test --bench --no-run-tests --no-run-benchmarks
+
+    - name: Test
+      run: |
+        stack --stack-yaml=${{ matrix.stack_yaml }} test
+
+  cabal:
+    name: ${{ matrix.name }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        include:
+          # Check that our upper bounds are correct by building with the latest
+          # version of everything. We use cabal because it uses the latest
+          # versions of our dependencies allowed by our upper bounds.
+          - name: newest
+            ghc: latest
+            os: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+      if: github.event.action == 'opened' || github.event.action == 'synchronize' || github.event.ref == 'refs/heads/main'
+
+    - uses: haskell/actions/setup@v1
+      id: setup-haskell-cabal
+      name: Setup Cabal
+      with:
+        ghc-version: ${{ matrix.ghc }}
+        cabal-version: ${{ matrix.cabal }}
+
+    # This freeze file is regenerated on every build, so we will always test
+    # with the most recent version of our dependencies allowed by our upper
+    # bounds.
+    - name: Freeze
+      run: |
+        cabal configure --enable-tests --enable-benchmarks --test-show-details=direct
+        cabal freeze
+
+    # Only reuse the cached copy of our dependencies if our freeze file matches
+    # the cache's copy.
+    - uses: actions/cache@v2
+      name: Cache Cabal Artifacts
+      with:
+        path: |
+          ${{ steps.setup-haskell-cabal.outputs.cabal-store }}
+          dist-newstyle
+        key: ${{ runner.os }}-cabal-${{ hashFiles('cabal.project.freeze') }}
+
+    - name: Build
+      run: |
+        cabal build all
+
+    - name: Test
+      run: |
+        cabal test all
+
+  # a separate job just to check the error messages, because that requires
+  # building several failing projects and so the test framework is more complex.
+  error-messages:
+    name: Error Messages
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        include:
+          - ghc: "8.10"
+            os: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+      if: github.event.action == 'opened' || github.event.action == 'synchronize' || github.event.ref == 'refs/heads/main'
+
+    # ./test/error-messages/Test.hs is a cabal script, so we need Cabal.
+    - uses: haskell/actions/setup@v1
+      id: setup-haskell-cabal
+      name: Setup Cabal
+      with:
+        ghc-version: ${{ matrix.ghc }}
+        enable-stack: false
+
+    # ./test/error-messages/Test.hs runs some stack projects, so we also need stack.
+    - uses: haskell/actions/setup@v1
+      id: setup-haskell-stack
+      name: Setup Stack
+      with:
+        ghc-version: ${{ matrix.ghc }}
+        enable-stack: true
+
+    - uses: actions/cache@v2
+      id: cache-stack-and-cabal
+      name: Cache Stack and Cabal Artifacts
+      with:
+        # store the whole ~/.cabal, not just ~/.cabal/store, so we don't have to re-run 'cabal update'.
+        path: |
+          ~/.cabal
+          dist-newstyle
+          ~/.stack
+          **/.stack-work
+        key: ${{ runner.os }}-${{ matrix.ghc }}-error-messages-${{ hashFiles('stack.yaml') }}
+
+    # For some reason setup-haskell-cabal sometimes doesn't run 'cabal update'.
+    - name: Initialize Cabal
+      if: steps.cache-stack-and-cabal.outputs.cache-hit != 'true'
+      run: |
+        cabal update
+
+    - name: Test Error Messages
+      run: |
+        ./test/error-messages/Test.hs `pwd`
diff --git a/stack-oldest-supported-lts.yaml b/oldest-supported-lts.yaml
similarity index 100%
rename from stack-oldest-supported-lts.yaml
rename to oldest-supported-lts.yaml