PreparedStatementCacheSpec.hs

module Sharing.ByFeature.PreparedStatementCacheSpec (spec) where

import Data.Either
import Hasql.Connection qualified as Connection
import Hasql.Decoders qualified as Decoders
import Hasql.Pipeline qualified as Pipeline
import Hasql.Session qualified as Session
import Hasql.Statement qualified as Statement
import Helpers.Scripts qualified as Scripts
import Test.Hspec
import Prelude

spec :: SpecWith (Text, Word16)
spec = do
  describe "Session" do
    it "Failing statements don't cause misses in updates of the prepared statement cache" \config -> do
      Scripts.onPreparableConnection config \connection -> do
        -- Run an intentionally failing prepared statement to set the condition of the bug.
        result <- Connection.use connection do
          Session.statement
            ()
            ( Statement.preparable
                "select null"
                mempty
                (Decoders.singleRow (Decoders.column (Decoders.nonNullable Decoders.int4)))
            )
        shouldBe (isLeft result) True
        -- Run a succeeding prepared statement to see if the cache is still in a good state.
        result <- Connection.use connection do
          Session.statement
            ()
            ( Statement.preparable
                "select 1"
                mempty
                (Decoders.singleRow (Decoders.column (Decoders.nonNullable Decoders.int4)))
            )
        -- If there is an error the cache got corrupted.
        case result of
          Right _ ->
            pure ()
          Left result ->
            expectationFailure ("Unexpected error: " <> show result)

  describe "Pipeline" do
    it "Failing pipeline statements don't cause misses in updates of the prepared statement cache" \config -> do
      Scripts.onPreparableConnection config \connection -> do
        -- Run an intentionally failing prepared statement in a pipeline to set the condition of the bug.
        result <- Connection.use connection do
          Session.pipeline do
            Pipeline.statement
              ()
              ( Statement.preparable
                  "select null :: int4"
                  mempty
                  (Decoders.singleRow (Decoders.column (Decoders.nonNullable Decoders.int4)))
              )
        case result of
          Right val ->
            expectationFailure ("First statement succeeded unexpectedly: " <> show val)
          Left _ ->
            pure ()

        -- Run a succeeding prepared statement in a pipeline to see if the cache is still in a good state.
        result <- Connection.use connection do
          Session.pipeline do
            Pipeline.statement
              ()
              ( Statement.preparable
                  "select 1"
                  mempty
                  (Decoders.singleRow (Decoders.column (Decoders.nonNullable Decoders.int4)))
              )
        -- If there is an error the cache got corrupted.
        case result of
          Right _ ->
            pure ()
          Left result ->
            expectationFailure ("Unexpected error: " <> show result)