Skip unnecessary packing of cache artifacts (#794)

* Skip unnecessary packing (takes 2m) when we had a successful cache hit

* Pack before testing

* Reenable benchmark CI

* Disable Windows CI

Caching is broken and stackage builds fail all the time with timeouts to
casa.fpcomplete.com

Author: pepeiborra

Diff for: .azure/linux-bench.yml

@@ -31,15 +31,15 @@ jobs:
   - bash: stack setup --stack-yaml=$STACK_YAML
     displayName: 'stack setup'
   - bash: stack build --bench --only-dependencies --stack-yaml=$STACK_YAML
-    displayName: 'stack build --only-dependencies'
-  - bash: |
-      export PATH=/opt/cabal/bin:$PATH
-      stack bench --ghc-options=-Werror  --stack-yaml=$STACK_YAML
-    displayName: 'stack bench --ghc-options=-Werror'
+    displayName: 'stack build --bench --only-dependencies'
   - bash: |
       mkdir -p .azure-cache
       tar czf .azure-cache/stack-root.tar.gz -C $HOME .stack
     displayName: "Pack cache"
+  - bash: |
+      export PATH=/opt/cabal/bin:$PATH
+      stack bench --ghc-options=-Werror  --stack-yaml=$STACK_YAML
+    displayName: 'stack bench --ghc-options=-Werror'
   - bash: |
       cat bench-hist/results.csv
     displayName: "cat results"

Diff for: .azure/linux-stack.yml

@@ -43,12 +43,13 @@ jobs:
     displayName: 'stack setup'
   - bash: stack build --only-dependencies --stack-yaml=$STACK_YAML
     displayName: 'stack build --only-dependencies'
+  - bash: |
+      mkdir -p .azure-cache
+      tar czf .azure-cache/stack-root.tar.gz -C $HOME .stack
+    displayName: "Pack cache"
+    condition: eq(variables.CACHE_RESTORED, 'false')
   - bash: |
       export PATH=/opt/cabal/bin:$PATH
       stack test --ghc-options=-Werror  --stack-yaml=$STACK_YAML || stack test --ghc-options=-Werror --stack-yaml=$STACK_YAML --ta "--rerun" || LSP_TEST_LOG_COLOR=0 LSP_TEST_LOG_MESSAGES=true LSP_TEST_LOG_STDERR=true stack test --ghc-options=-Werror --stack-yaml=$STACK_YAML --ta "--rerun"
     # ghcide stack tests are flaky, see https://github.com/digital-asset/daml/issues/2606.
     displayName: 'stack test --ghc-options=-Werror'
-  - bash: |
-      mkdir -p .azure-cache
-      tar czf .azure-cache/stack-root.tar.gz -C $HOME .stack
-    displayName: "Pack cache"

Diff for: .azure/windows-stack.yml

@@ -55,6 +55,11 @@ jobs:
         stack build --only-dependencies --stack-yaml $STACK_YAML
       fi
     displayName: 'stack build --only-dependencies'
+  - bash: |
+      mkdir -p .azure-cache
+      tar -vczf .azure-cache/stack-root.tar.gz $(cygpath $STACK_ROOT)
+      tar -vczf .azure-cache/stack-work.tar.gz .stack-work
+    displayName: "Pack cache"
   - bash: |
       if [ "$STACK_YAML" = "stack8101.yaml" ]; then
         stack test --no-run-tests --ghc-options="-Werror -fexternal-interpreter" --stack-yaml $STACK_YAML || stack test --no-run-tests --ghc-options="-Werror -fexternal-interpreter" --stack-yaml $STACK_YAML || stack test --no-run-tests --ghc-options="-Werror -fexternal-interpreter" --stack-yaml $STACK_YAML
@@ -63,8 +68,3 @@ jobs:
       fi
     displayName: 'stack test --ghc-options=-Werror'
     # TODO: run test suite when failing tests are fixed or marked as broken. See https://github.com/digital-asset/ghcide/issues/474
-  - bash: |
-      mkdir -p .azure-cache
-      tar -vczf .azure-cache/stack-root.tar.gz $(cygpath $STACK_ROOT)
-      tar -vczf .azure-cache/stack-work.tar.gz .stack-work
-    displayName: "Pack cache"

Diff for: azure-pipelines.yml

@@ -15,6 +15,5 @@ pr:
 
 jobs:
   - template: ./.azure/linux-stack.yml
-  - template: ./.azure/windows-stack.yml
-# https://github.com/haskell/ghcide/pull/801
-#   - template: ./.azure/linux-bench.yml
+#  - template: ./.azure/windows-stack.yml
+  - template: ./.azure/linux-bench.yml