Add just_check field to glean UserQueryOptions

Summary:
Add a just_check option to UserQueryOption, to allow a result to be returned after compilation (without actually query the db), so we can syntax-check a query.

**Next steps** will add to daiquery UI, so we can get syntax error highlighting in the editor while the query is written

Reviewed By: malanka

Differential Revision: D64957730

fbshipit-source-id: 5611d29113340860ccbc0fca53707479e1950081

glean/db/Glean/Query/UserQuery.hs

@@ -93,6 +93,7 @@ import Glean.Schema.Util
 import Glean.Util.Observed as Observed
 import Glean.Query.Typecheck
 import Glean.Bytecode.SysCalls (userQuerySysCalls)
+import Glean.Types (UserQueryCont)
 
 -- NOTE: We keep the public interface monomorphic, at least for now.
 
@@ -599,7 +600,6 @@ userQueryWrites env odb config bounds lookup repo pred q = do
     minus = Map.unionWith (-)
     hasFacts pid m = maybe False (> 0) $ Map.lookup pid m
 
-
 userQueryImpl
   :: Database.Env
   -> OpenDB s
@@ -619,7 +619,7 @@ userQueryImpl
   bounds
   lookup
   repo
-  Thrift.UserQuery{..} = do
+  query@Thrift.UserQuery{..} = do
     let opts = fromMaybe def userQuery_options
 
     case Thrift.userQueryOptions_syntax opts of
@@ -628,22 +628,25 @@ userQueryImpl
         "query syntax not supported: " <> Text.pack (show other)
 
     let
-      schema@DbSchema{..} = odbSchema odb
-      opts = fromMaybe def userQuery_options
+      schema = odbSchema odb
       stored = Thrift.userQueryOptions_store_derived_facts opts
       debug = Thrift.userQueryOptions_debug opts
 
     schemaVersion <-
       schemaVersionForQuery schema config userQuery_schema_id
-    trans <- transformationsForQuery schema schemaVersion
 
-    (returnType, compileTime, irDiag, cont) <-
+    compileInfo <-
       case Thrift.userQueryOptions_continuation opts of
         Just ucont
           | Just retTy <- Thrift.userQueryCont_returnType ucont -> do
           (compileTime, _, returnType) <-
             timeIt $ compileType schema schemaVersion retTy
-          return (returnType, compileTime, [], Right ucont)
+          return CompileInfo {
+            returnType = returnType,
+            compileTime = compileTime,
+            irDiag = [],
+            cont = Right ucont
+          }
 
         -- This is either a new query or the continuation of a query
         -- that returns a temporary predicate.
@@ -666,10 +669,55 @@ userQueryImpl
               Just c -> Right c
               Nothing -> Left query
 
-          return (ty, compileTime, irDiag, cont)
+          return CompileInfo {
+            returnType = ty,
+            compileTime = compileTime,
+            irDiag = irDiag,
+            cont = cont
+          }
+
+    if Thrift.userQueryOptions_just_check opts then do
+      return emptyResult
+    else do
+      runQuery env odb config  bounds lookup repo compileInfo query
+
+data CompileInfo = CompileInfo {
+  returnType :: Type,
+  compileTime :: Double,
+  irDiag :: [Text],
+  cont :: Either CodegenQuery UserQueryCont
+}
 
+runQuery
+  :: Database.Env
+  -> OpenDB s
+  -> ServerConfig.Config
+  -> Boundaries
+  -> Lookup
+  -> Thrift.Repo
+  -> CompileInfo
+  -> Thrift.UserQuery
+  -> IO (Results Stats Thrift.Fact)
+runQuery
+  env
+  odb
+  config
+  bounds
+  lookup
+  repo
+  CompileInfo{..}
+  Thrift.UserQuery{..} = do
     vlog 2 $ "return type: " <> show (displayDefault returnType)
 
+    let
+      schema@DbSchema{..} = odbSchema odb
+      opts = fromMaybe def userQuery_options
+      stored = Thrift.userQueryOptions_store_derived_facts opts
+
+    schemaVersion <-
+        schemaVersionForQuery schema config userQuery_schema_id
+    trans <- transformationsForQuery schema schemaVersion
+
     details@PredicateDetails{..} <- case returnType of
       Angle.PredicateTy (PidRef pid _) ->
         case IntMap.lookup (fromIntegral (fromPid pid)) predicatesByPid of
@@ -745,6 +793,7 @@ userQueryImpl
 
         Left query -> do
           let
+            debug = Thrift.userQueryOptions_debug opts
             bytecodeDiag sub =
               [ "bytecode:\n" <> Text.unlines
                 (disassemble "Query" userQuerySysCalls $ compiledQuerySub sub)
@@ -802,8 +851,8 @@ userQueryImpl
           }
 
     return $ if Thrift.userQueryOptions_omit_results opts
-       then withoutFacts results
-       else results
+      then withoutFacts results
+      else results
 
 transformationsForQuery
   :: DbSchema
@@ -943,6 +992,27 @@ mkQueryRuntimeOptions
         | otherwise -> ResultsOnly
     }
 
+emptyResult :: Results Stats fact
+emptyResult = Results {
+    resFacts = mempty
+  , resPredicate = Nothing
+  , resNestedFacts = mempty
+  , resCont = Nothing
+  , resStats = Stats {
+      statFactCount = 0
+    , statResultCount = 0
+    , statFullScans = []
+    }
+  , resDiags = []
+  , resWriteHandle = Nothing
+  , resFactsSearched = Nothing
+  , resType = Nothing
+  , resBytecodeSize = Nothing
+  , resCompileTime = Nothing
+  , resCodegenTime = Nothing
+  , resExecutionTime = Nothing
+  }
+
 
 {- Note [Writing derived facts]
 

glean/hs/Glean/Query/Thrift/Internal.hs

@@ -31,6 +31,7 @@ module Glean.Query.Thrift.Internal
   , showUserQueryStats
   , displayQuery
   , decodeResults
+  , justCheck
   ) where
 
 import Control.Exception
@@ -215,6 +216,12 @@ store (Query q) = Query q'
   q' = q { userQuery_options = Just (fromMaybe def (userQuery_options q))
     { userQueryOptions_store_derived_facts = True } }
 
+justCheck :: Query a -> Query a
+justCheck (Query q) = Query q'
+  where
+  q' = q { userQuery_options = Just (fromMaybe def (userQuery_options q))
+  { userQueryOptions_just_check = True } }
+
 reportUserQueryStats :: Thrift.UserQueryStats -> IO ()
 reportUserQueryStats stats =
   vlog 1 $ showUserQueryStats stats

glean/if/glean.thrift

@@ -510,6 +510,9 @@ struct UserQueryOptions {
   // A more fine-grained alternative to recursive = true. Only
   // fields of a predicate in the list will be fetched.
   14: list<SourcePredicate> expand_predicates;
+
+  // if true, the query will be compiled, but no facts will be retrieved
+  15: bool just_check = false;
 }
 
 struct QueryDebugOptions {

glean/test/tests/Angle/MiscTest.hs

@@ -46,6 +46,7 @@ main = withUnitTest $ testRunner $ TestList
   , TestLabel "limitBytes" limitTest
   , TestLabel "fullScans" fullScansTest
   , TestLabel "newold" $ newOldTest id
+  , TestLabel "justCheck" justCheckTest
   ]
 
 newOldTest :: (forall a . Query a -> Query a) -> Test
@@ -421,6 +422,22 @@ limitTest = dbTestCase $ \env repo -> do
     Angle.query $ predicate @Glean.Test.Edge wild
   assertBool "limitBytes" (length results == 2 && truncated)
 
+justCheckTest :: Test
+justCheckTest = dbTestCase $ \env repo -> do
+  results <- runQuery_ env repo $ justCheck $ Angle.query $
+    predicate @Cxx.Name wild
+  assertEqual "just check" 0 (length results)
+
+  results <- try $ runQuery_ env repo $ justCheck $ angleData @Text
+    [s|
+      Cxx1.Name X
+    |]
+  assertBool "just check - bad query" $
+    case results of
+      Left (BadQuery _) -> True
+      _ -> False
+
+
 fullScansTest :: Test
 fullScansTest = TestList $
   [ TestLabel "no full scans" $ TestCase $ withTestDB [] $ \env repo -> do