Merge pull request #29 from ndmitchell/patch-1

#26, test GHC 8.4

Author: cocreature

azure-pipelines.yml

@@ -57,3 +57,47 @@ jobs:
                --data "{\"text\":\"<!here> *FAILED* $(Agent.JobName): <https://dev.azure.com/digitalasset/ghcide/_build/results?buildId=$(Build.BuildId)|$MESSAGE>\n\"}" \
                $(Slack.URL)
         condition: and(failed(), eq(variables['Build.SourceBranchName'], 'master'))
+  - job: ghcide_stack_84
+    timeoutInMinutes: 60
+    pool:
+      vmImage: 'ubuntu-latest'
+    steps:
+      - checkout: self
+      - task: CacheBeta@0
+        inputs:
+          key: stack-cache-v1 | $(Agent.OS) | $(Build.SourcesDirectory)/stack84.yaml | $(Build.SourcesDirectory)/ghcide.cabal
+          path: .azure-cache
+          cacheHitVar: CACHE_RESTORED
+        displayName: "Cache stack artifacts"
+      - bash: |
+          mkdir -p ~/.stack
+          tar xzf .azure-cache/stack-root.tar.gz -C $HOME
+        displayName: "Unpack cache"
+        condition: eq(variables.CACHE_RESTORED, 'true')
+      - bash: |
+          ./fmt.sh
+        displayName: "HLint via ./fmt.sh"
+      - bash: |
+          sudo apt-get install -y g++ gcc libc6-dev libffi-dev libgmp-dev make zlib1g-dev
+          curl -sSL https://get.haskellstack.org/ | sh
+        displayName: 'Install Stack'
+      - bash: stack setup --stack-yaml=stack84.yaml
+        displayName: 'stack setup --stack-yaml=stack84.yaml'
+      - bash: stack build --only-dependencies --stack-yaml=stack84.yaml
+        displayName: 'stack build --only-dependencies --stack-yaml=stack84.yaml'
+      - bash: stack test --stack-yaml=stack84.yaml || stack test --stack-yaml=stack84.yaml || stack test --stack-yaml=stack84.yaml
+        # ghcide stack tests are flaky, see https://github.com/digital-asset/daml/issues/2606.
+        displayName: 'stack test --stack-yaml=stack84.yaml'
+      - bash: |
+          mkdir -p .azure-cache
+          tar czf .azure-cache/stack-root.tar.gz -C $HOME .stack
+        displayName: "Pack cache"
+      - bash: |
+          set -euo pipefail
+          MESSAGE=$(git log --pretty=format:%s -n1)
+          curl -XPOST \
+               -i \
+               -H 'Content-type: application/json' \
+               --data "{\"text\":\"<!here> *FAILED* $(Agent.JobName): <https://dev.azure.com/digitalasset/ghcide/_build/results?buildId=$(Build.BuildId)|$MESSAGE>\n\"}" \
+               $(Slack.URL)
+        condition: and(failed(), eq(variables['Build.SourceBranchName'], 'master'))