graphql-engine/server/src-lib/Hasura/Backends/Postgres/Translate/BoolExp.hs
Auke Booij fe8eabff19 server: fix the nullability of object relationships (fix hasura/graphql-engine#7201)
When adding object relationships, we set the nullability of the generated GraphQL field based on whether the database backend enforces that the referenced data always exists. For manual relationships (corresponding to `manual_configuration`), the database backend is unaware of any relationship between data, and hence such fields are always set to be nullable.

For relationships generated from foreign key constraints (corresponding to `foreign_key_constraint_on`), we distinguish between two cases:

1. The "forward" object relationship from a referencing table (i.e. which has the foreign key constraint) to a referenced table. This should be set to be non-nullable when all referencing columns are non-nullable. But in fact, it used to set it to be non-nullable if *any* referencing column is non-nullable, which is only correct in Postgres when `MATCH FULL` is set (a flag we don't consider). This fixes that by changing a boolean conjunction to a disjunction.
2. The "reverse" object relationship from a referenced table to a referencing table which has the foreign key constraint. This should always be set to be nullable. But in fact, it used to always be set to non-nullable, as was reported in hasura/graphql-engine#7201. This fixes that.

Moreover, we have moved the computation of the nullability from `Hasura.RQL.DDL.Relationship` to `Hasura.GraphQL.Schema.Select`: this nullability used to be passed through the `riIsNullable` field of `RelInfo`, but for array relationships this information is not actually used, and moreover the remaining fields of `RelInfo` are already enough to deduce the nullability.

This also adds regression tests for both (1) and (2) above.

https://github.com/hasura/graphql-engine-mono/pull/2159

GitOrigin-RevId: 617f12765614f49746d18d3368f41dfae2f3e6ca
2021-08-26 15:27:34 +00:00

315 lines
13 KiB
Haskell

{-# LANGUAGE PartialTypeSignatures #-}
module Hasura.Backends.Postgres.Translate.BoolExp
( toSQLBoolExp
, getBoolExpDeps
, annBoolExp
, BoolExpRHSParser(..)
) where
import Hasura.Prelude
import qualified Data.HashMap.Strict as M
import qualified Hasura.Backends.Postgres.SQL.DML as S
import Hasura.Backends.Postgres.SQL.Types hiding (TableName)
import Hasura.Backends.Postgres.Types.BoolExp
import Hasura.Base.Error
import Hasura.RQL.Types
import Hasura.SQL.Types
-- | Context to parse a RHS value in a boolean expression
data BoolExpRHSParser (b :: BackendType) m v
= BoolExpRHSParser
{ _berpValueParser :: !(ValueParser b m v) -- ^ Parse a JSON value with enforcing a column type
, _berpSessionValue :: !v -- ^ Required for a computed field SQL function with session argument
}
-- This convoluted expression instead of col = val
-- to handle the case of col : null
equalsBoolExpBuilder :: SQLExpression ('Postgres pgKind) -> SQLExpression ('Postgres pgKind) -> S.BoolExp
equalsBoolExpBuilder qualColExp rhsExp =
S.BEBin S.OrOp (S.BECompare S.SEQ qualColExp rhsExp)
(S.BEBin S.AndOp
(S.BENull qualColExp)
(S.BENull rhsExp))
notEqualsBoolExpBuilder :: SQLExpression ('Postgres pgKind) -> SQLExpression ('Postgres pgKind) -> S.BoolExp
notEqualsBoolExpBuilder qualColExp rhsExp =
S.BEBin S.OrOp (S.BECompare S.SNE qualColExp rhsExp)
(S.BEBin S.AndOp
(S.BENotNull qualColExp)
(S.BENull rhsExp))
annBoolExp
:: (QErrM m, TableCoreInfoRM b m, BackendMetadata b)
=> BoolExpRHSParser b m v
-> TableName b
-> FieldInfoMap (FieldInfo b)
-> GBoolExp b ColExp
-> m (AnnBoolExp b v)
annBoolExp rhsParser rootTable fim boolExp =
case boolExp of
BoolAnd exps -> BoolAnd <$> procExps exps
BoolOr exps -> BoolOr <$> procExps exps
BoolNot e -> BoolNot <$> annBoolExp rhsParser rootTable fim e
BoolExists (GExists refqt whereExp) ->
withPathK "_exists" $ do
refFields <- withPathK "_table" $ askFieldInfoMapSource refqt
annWhereExp <- withPathK "_where" $ annBoolExp rhsParser rootTable refFields whereExp
return $ BoolExists $ GExists refqt annWhereExp
BoolFld fld -> BoolFld <$> annColExp rhsParser rootTable fim fld
where
procExps = mapM (annBoolExp rhsParser rootTable fim)
annColExp
:: (QErrM m, TableCoreInfoRM b m, BackendMetadata b)
=> BoolExpRHSParser b m v
-> TableName b
-> FieldInfoMap (FieldInfo b)
-> ColExp
-> m (AnnBoolExpFld b v)
annColExp rhsParser rootTable colInfoMap (ColExp fieldName colVal) = do
colInfo <- askFieldInfo colInfoMap fieldName
case colInfo of
FIColumn pgi -> AVColumn pgi <$> parseBoolExpOperations (_berpValueParser rhsParser) rootTable colInfoMap (ColumnReferenceColumn pgi) colVal
FIRelationship relInfo -> do
relBoolExp <- decodeValue colVal
relFieldInfoMap <- askFieldInfoMapSource $ riRTable relInfo
annRelBoolExp <- annBoolExp rhsParser rootTable relFieldInfoMap $ unBoolExp relBoolExp
return $ AVRelationship relInfo annRelBoolExp
FIComputedField ComputedFieldInfo{..} -> do
let ComputedFieldFunction{..} = _cfiFunction
case toList _cffInputArgs of
[] -> do
let hasuraSession = _berpSessionValue rhsParser
sessionArgPresence = mkSessionArgumentPresence hasuraSession _cffSessionArgument _cffTableArgument
AVComputedField . AnnComputedFieldBoolExp _cfiXComputedFieldInfo _cfiName _cffName sessionArgPresence
<$> case _cfiReturnType of
CFRScalar scalarType -> CFBEScalar
<$> parseBoolExpOperations (_berpValueParser rhsParser) rootTable colInfoMap (ColumnReferenceComputedField _cfiName scalarType) colVal
CFRSetofTable table -> do
tableBoolExp <- decodeValue colVal
tableFieldInfoMap <- askFieldInfoMapSource table
annTableBoolExp <- annBoolExp rhsParser table tableFieldInfoMap $ unBoolExp tableBoolExp
pure $ CFBETable table annTableBoolExp
_ -> throw400 UnexpectedPayload
"Computed columns with input arguments can not be part of the where clause"
-- TODO Rakesh (from master)
FIRemoteRelationship{} ->
throw400 UnexpectedPayload "remote field unsupported"
toSQLBoolExp
:: forall pgKind
. Backend ('Postgres pgKind)
=> S.Qual
-> AnnBoolExpSQL ('Postgres pgKind)
-> S.BoolExp
toSQLBoolExp tq e =
evalState (convBoolRhs' tq e) 0
convBoolRhs'
:: forall pgKind
. Backend ('Postgres pgKind)
=> S.Qual
-> AnnBoolExpSQL ('Postgres pgKind)
-> State Word64 S.BoolExp
convBoolRhs' tq =
foldBoolExp (convColRhs tq)
convColRhs
:: forall pgKind
. Backend ('Postgres pgKind)
=> S.Qual
-> AnnBoolExpFldSQL ('Postgres pgKind)
-> State Word64 S.BoolExp
convColRhs tableQual = \case
AVColumn colInfo opExps -> do
let colFld = fromCol @('Postgres pgKind) $ pgiColumn colInfo
bExps = map (mkFieldCompExp tableQual $ LColumn colFld) opExps
return $ foldr (S.BEBin S.AndOp) (S.BELit True) bExps
AVRelationship (RelInfo _ _ colMapping relTN _ _) nesAnn -> do
-- Convert the where clause on the relationship
curVarNum <- get
put $ curVarNum + 1
let newIdentifier = Identifier $ "_be_" <> tshow curVarNum <> "_"
<> snakeCaseQualifiedObject relTN
newIdenQ = S.QualifiedIdentifier newIdentifier Nothing
annRelBoolExp <- convBoolRhs' newIdenQ nesAnn
let backCompExp = foldr (S.BEBin S.AndOp) (S.BELit True) $
flip map (M.toList colMapping) $ \(lCol, rCol) ->
S.BECompare S.SEQ
(mkQCol (S.QualifiedIdentifier newIdentifier Nothing) rCol)
(mkQCol tableQual lCol)
innerBoolExp = S.BEBin S.AndOp backCompExp annRelBoolExp
return $ S.mkExists (S.FISimple relTN $ Just $ S.Alias newIdentifier) innerBoolExp
AVComputedField (AnnComputedFieldBoolExp _ _ function sessionArgPresence cfBoolExp) -> do
case cfBoolExp of
CFBEScalar opExps -> do
-- Convert the where clause on scalar computed field
let bExps = map (mkFieldCompExp tableQual $ LComputedField function sessionArgPresence) opExps
pure $ foldr (S.BEBin S.AndOp) (S.BELit True) bExps
CFBETable _ boolExp -> do
-- Convert the where clause on table computed field
curVarNum <- get
put $ curVarNum + 1
let newIdentifier = Identifier $ "_be_" <> tshow curVarNum <> "_"
<> snakeCaseQualifiedObject function
newIdenQ = S.QualifiedIdentifier newIdentifier Nothing
functionExp = mkComputedFieldFunctionExp tableQual function sessionArgPresence
$ Just $ S.Alias newIdentifier
S.mkExists (S.FIFunc functionExp) <$> convBoolRhs' newIdenQ boolExp
where
mkQCol q = S.SEQIdentifier . S.QIdentifier q . toIdentifier
foldExists
:: forall pgKind
. Backend ('Postgres pgKind)
=> GExists ('Postgres pgKind) (AnnBoolExpFldSQL ('Postgres pgKind))
-> State Word64 S.BoolExp
foldExists (GExists qt wh) = do
whereExp <- foldBoolExp (convColRhs (S.QualTable qt)) wh
return $ S.mkExists (S.FISimple qt Nothing) whereExp
foldBoolExp
:: forall pgKind
. Backend ('Postgres pgKind)
=> (AnnBoolExpFldSQL ('Postgres pgKind) -> State Word64 S.BoolExp)
-> AnnBoolExpSQL ('Postgres pgKind)
-> State Word64 S.BoolExp
foldBoolExp f = \case
BoolAnd bes -> do
sqlBExps <- mapM (foldBoolExp f) bes
return $ foldr (S.BEBin S.AndOp) (S.BELit True) sqlBExps
BoolOr bes -> do
sqlBExps <- mapM (foldBoolExp f) bes
return $ foldr (S.BEBin S.OrOp) (S.BELit False) sqlBExps
BoolNot notExp -> S.BENot <$> foldBoolExp f notExp
BoolExists existsExp -> foldExists existsExp
BoolFld ce -> f ce
data LHSField b
= LColumn !FieldName
| LComputedField !QualifiedFunction !(SessionArgumentPresence (SQLExpression b))
mkComputedFieldFunctionExp
:: S.Qual
-> QualifiedFunction
-> SessionArgumentPresence (SQLExpression ('Postgres pgKind))
-> Maybe S.Alias
-> S.FunctionExp
mkComputedFieldFunctionExp qual function sessionArgPresence alias =
-- "function_schema"."function_name"("qual".*)
let tableRowInput = S.SEStar $ Just qual
functionArgs = flip S.FunctionArgs mempty $ case sessionArgPresence of
SAPNotPresent -> [tableRowInput] -- No session argument
SAPFirst sessArg -> [sessArg, tableRowInput]
SAPSecond sessArg -> [tableRowInput, sessArg]
in S.FunctionExp function functionArgs $ flip S.FunctionAlias Nothing <$> alias
mkFieldCompExp
:: S.Qual -> LHSField ('Postgres pgKind) -> OpExpG ('Postgres pgKind) S.SQLExp -> S.BoolExp
mkFieldCompExp qual lhsField = mkCompExp qLhsField
where
qLhsField = case lhsField of
LColumn fieldName ->
-- "qual"."column" =
S.SEQIdentifier $ S.QIdentifier qual $ Identifier $ getFieldNameTxt fieldName
LComputedField function sessionArgPresence ->
-- "function_schema"."function_name"("qual".*) =
S.SEFunction $ mkComputedFieldFunctionExp qual function sessionArgPresence Nothing
mkQCol (col, Nothing) = S.SEQIdentifier $ S.QIdentifier qual $ toIdentifier col
mkQCol (col, Just table) = S.SEQIdentifier $ S.mkQIdentifierTable table $ toIdentifier col
mkCompExp :: SQLExpression ('Postgres pgKind) -> OpExpG ('Postgres pgKind) (SQLExpression ('Postgres pgKind)) -> S.BoolExp
mkCompExp lhs = \case
ACast casts -> mkCastsExp casts
AEQ False val -> equalsBoolExpBuilder lhs val
AEQ True val -> S.BECompare S.SEQ lhs val
ANE False val -> notEqualsBoolExpBuilder lhs val
ANE True val -> S.BECompare S.SNE lhs val
AIN val -> S.BECompareAny S.SEQ lhs val
ANIN val -> S.BENot $ S.BECompareAny S.SEQ lhs val
AGT val -> S.BECompare S.SGT lhs val
ALT val -> S.BECompare S.SLT lhs val
AGTE val -> S.BECompare S.SGTE lhs val
ALTE val -> S.BECompare S.SLTE lhs val
ALIKE val -> S.BECompare S.SLIKE lhs val
ANLIKE val -> S.BECompare S.SNLIKE lhs val
CEQ rhsCol -> S.BECompare S.SEQ lhs $ mkQCol rhsCol
CNE rhsCol -> S.BECompare S.SNE lhs $ mkQCol rhsCol
CGT rhsCol -> S.BECompare S.SGT lhs $ mkQCol rhsCol
CLT rhsCol -> S.BECompare S.SLT lhs $ mkQCol rhsCol
CGTE rhsCol -> S.BECompare S.SGTE lhs $ mkQCol rhsCol
CLTE rhsCol -> S.BECompare S.SLTE lhs $ mkQCol rhsCol
ANISNULL -> S.BENull lhs
ANISNOTNULL -> S.BENotNull lhs
ABackendSpecific op -> case op of
AILIKE val -> S.BECompare S.SILIKE lhs val
ANILIKE val -> S.BECompare S.SNILIKE lhs val
ASIMILAR val -> S.BECompare S.SSIMILAR lhs val
ANSIMILAR val -> S.BECompare S.SNSIMILAR lhs val
AREGEX val -> S.BECompare S.SREGEX lhs val
AIREGEX val -> S.BECompare S.SIREGEX lhs val
ANREGEX val -> S.BECompare S.SNREGEX lhs val
ANIREGEX val -> S.BECompare S.SNIREGEX lhs val
AContains val -> S.BECompare S.SContains lhs val
AContainedIn val -> S.BECompare S.SContainedIn lhs val
AHasKey val -> S.BECompare S.SHasKey lhs val
AHasKeysAny val -> S.BECompare S.SHasKeysAny lhs val
AHasKeysAll val -> S.BECompare S.SHasKeysAll lhs val
AAncestor val -> S.BECompare S.SContains lhs val
AAncestorAny val -> S.BECompare S.SContains lhs val
ADescendant val -> S.BECompare S.SContainedIn lhs val
ADescendantAny val -> S.BECompare S.SContainedIn lhs val
AMatches val -> S.BECompare S.SREGEX lhs val
AMatchesAny val -> S.BECompare S.SHasKey lhs val
AMatchesFulltext val -> S.BECompare S.SMatchesFulltext lhs val
ASTContains val -> mkGeomOpBe "ST_Contains" val
ASTCrosses val -> mkGeomOpBe "ST_Crosses" val
ASTEquals val -> mkGeomOpBe "ST_Equals" val
ASTIntersects val -> mkGeomOpBe "ST_Intersects" val
AST3DIntersects val -> mkGeomOpBe "ST_3DIntersects" val
ASTOverlaps val -> mkGeomOpBe "ST_Overlaps" val
ASTTouches val -> mkGeomOpBe "ST_Touches" val
ASTWithin val -> mkGeomOpBe "ST_Within" val
AST3DDWithinGeom (DWithinGeomOp r val) -> applySQLFn "ST_3DDWithin" [lhs, val, r]
ASTDWithinGeom (DWithinGeomOp r val) -> applySQLFn "ST_DWithin" [lhs, val, r]
ASTDWithinGeog (DWithinGeogOp r val sph) -> applySQLFn "ST_DWithin" [lhs, val, r, sph]
ASTIntersectsRast val -> applySTIntersects [lhs, val]
ASTIntersectsNbandGeom (STIntersectsNbandGeommin nband geommin) -> applySTIntersects [lhs, nband, geommin]
ASTIntersectsGeomNband (STIntersectsGeomminNband geommin mNband) -> applySTIntersects [lhs, geommin, withSQLNull mNband]
where
mkGeomOpBe fn v = applySQLFn fn [lhs, v]
applySQLFn f exps = S.BEExp $ S.SEFnApp f exps Nothing
applySTIntersects = applySQLFn "ST_Intersects"
withSQLNull = fromMaybe S.SENull
mkCastsExp casts =
sqlAll . flip map (M.toList casts) $ \(targetType, operations) ->
let targetAnn = S.mkTypeAnn $ CollectableTypeScalar targetType
in sqlAll $ map (mkCompExp (S.SETyAnn lhs targetAnn)) operations
sqlAll = foldr (S.BEBin S.AndOp) (S.BELit True)