Add HLint to CI

Author: newhoggy

.github/workflows/hlint.yml

@@ -0,0 +1,101 @@
+name: HLint
+
+on:
+  push:
+  create:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+
+    env:
+      # Modify this value to "invalidate" the cabal cache.
+      CABAL_CACHE_VERSION: "2022-12-30"
+
+      HLINT_VERSION: "3.5"
+
+    steps:
+    - name: Install Haskell
+      uses: input-output-hk/setup-haskell@v1
+      id: setup-haskell
+      with:
+        ghc-version: 9.2.4
+        cabal-version: 3.8.1.0
+
+    - name: Cabal update
+      run: cabal update
+
+    - name: Get hlint
+      run: cabal get "hlint-$HLINT_VERSION"
+
+    - name: Build dry run for hlint
+      run: |
+        cd "hlint-$HLINT_VERSION"
+        cabal build all --dry-run
+
+    # For users who fork cardano-node and want to define a writable cache, then can set up their own
+    # S3 bucket then define in their forked repository settings the following secrets:
+    #
+    #   AWS_ACCESS_KEY_ID
+    #   AWS_SECRET_ACCESS_KEY
+    #   BINARY_CACHE_URI
+    #   BINARY_CACHE_REGION
+    - name: Cabal cache over S3
+      uses: action-works/cabal-cache-s3@v1
+      env:
+        AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
+        AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
+      with:
+        region: ${{ secrets.BINARY_CACHE_REGION }}
+        dist-dir: hlint-${{ env.HLINT_VERSION }}/dist-newstyle
+        store-path: ${{ steps.setup-haskell.outputs.cabal-store }}
+        threads: 16
+        archive-uri: ${{ secrets.BINARY_CACHE_URI }}/${{ env.CABAL_CACHE_VERSION }}/${{ runner.os }}
+        skip: "${{ secrets.BINARY_CACHE_URI == '' }}"
+
+    # It's important to ensure that people who fork this repository can not only successfully build in
+    # CI by default, but also have meaning cabal store caching.
+    #
+    # Because syncing with S3 requires credentials, we cannot rely on S3 for this. For this reason a
+    # https fallback is used. The https server mirrors the content of the S3 bucket. The https cabal
+    # store archive is read-only for security reasons.
+    #
+    # Users who fork this repository who want to have a writable cabal store archive are encouraged
+    # to set up their own S3 bucket.
+    - name: Cabal cache over HTTPS
+      uses: action-works/cabal-cache-s3@v1
+      with:
+        dist-dir: hlint-${{ env.HLINT_VERSION }}/dist-newstyle
+        store-path: ${{ steps.setup-haskell.outputs.cabal-store }}
+        threads: 16
+        archive-uri: https://iohk.cache.haskellworks.io/${{ env.CABAL_CACHE_VERSION }}/${{ runner.os }}
+        skip: "${{ secrets.BINARY_CACHE_URI != '' }}"
+        enable-save: false
+
+    - name: Build hlint
+      run: |
+        cd "hlint-$HLINT_VERSION"
+        cabal build all
+
+    - name: Install hlint
+      run: |
+        cd "hlint-$HLINT_VERSION"
+        cabal install exe:hlint
+
+    - name: Remove hlint build directory
+      run: rm -rf "hlint-$HLINT_VERSION"
+
+    - name: hlint installation directory
+      run: find . -name hlint
+
+    - name: Add installation directory to path
+      run: echo "PATH=$HOME/.cabal/bin:$PATH" >> $GITHUB_ENV
+
+    - uses: actions/checkout@v2
+
+    - name: Run hlint over all Haskell files
+      run: |
+        hlint . --threads=4

.hlint.yaml

@@ -6,9 +6,6 @@
 # placed as .hlint.yaml in the root of your project
 
 
-# Warnings currently triggered by your code
-- ignore: {name: "Move brackets to avoid $"}
-
 # Specify additional command line arguments
 #
 # - arguments: [--color, --cpp-simple, -XQuasiQuotes]
@@ -37,6 +34,12 @@
 # Will suggest replacing "wibbleMany [myvar]" with "wibbleOne myvar"
 # - error: {lhs: "wibbleMany [x]", rhs: wibbleOne x}
 
+# The hints are named by the string they display in warning messages.
+# For example, if you see a warning starting like
+#
+# Main.hs:116:51: Warning: Redundant ==
+#
+# You can refer to that hint with `{name: Redundant ==}` (see below).
 
 # Turn on hints that are off by default
 #
@@ -53,7 +56,7 @@
 # Ignore some builtin hints
 # - ignore: {name: Use let}
 # - ignore: {name: Use const, within: SpecialModule} # Only within certain modules
-# - ignore: {name: "Use lambda-case"}
+
 
 # Define some custom infix operators
 # - fixity: infixr 3 ~^#^~

cardano-cli/src/Cardano/CLI/Shelley/Run/Query.hs

@@ -99,9 +99,7 @@ import qualified Ouroboros.Consensus.Protocol.Praos.Common as Consensus
 import qualified Ouroboros.Consensus.HardFork.History.Qry as Qry
 import qualified Ouroboros.Network.Protocol.LocalStateQuery.Type as LocalStateQuery
 
-{- HLINT ignore "Reduce duplication" -}
-{- HLINT ignore "Use const" -}
-{- HLINT ignore "Use let" -}
+{- HLINT ignore "Move brackets to avoid $" -}
 
 data ShelleyQueryCmdError
   = ShelleyQueryCmdEnvVarSocketErr !EnvSocketError