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Improve robustness of typechecker
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* This now correctly handles modifiers for bpchar and numeric, as well
  as correctly handling namespaces when the TypeInfo provides this
  information.
* This also cleans up imports a great deal.
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@abigailalice
abigailalice committed Aug 12, 2024
1 parent 32f9f32 commit 81a52b0
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Showing 3 changed files with 183 additions and 77 deletions.
193 changes: 118 additions & 75 deletions src/Rel8/Table/Verify.hs
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Original file line number Diff line number Diff line change
Expand Up @@ -26,54 +26,56 @@ module Rel8.Table.Verify
) where

-- base
import Prelude hiding ( filter )
import qualified Prelude as P
import Data.These
import Control.Monad
import Data.Bits (shiftR, (.&.))
import Data.Either (lefts)
import Data.Function
import Data.Functor ((<&>))
import Data.Maybe (isJust, mapMaybe)
import qualified Data.List as L

-- hasql
import Hasql.Connection
import qualified Hasql.Statement as HS

import Data.Either (lefts)
import Data.Functor.Const
import Data.Functor.Contravariant ( (>$<) )
import Data.Int ( Int16, Int64 )
import qualified Data.List as L
import Data.List.NonEmpty ( NonEmpty((:|)) )
import qualified Data.List.NonEmpty as NonEmpty
import Data.Maybe (isJust, mapMaybe)
import Data.Text ( Text )
import qualified Data.Text as T
import GHC.Generics
import Data.List.NonEmpty ( NonEmpty((:|)) )
import qualified Data.List.NonEmpty as NonEmpty
import Prelude hiding ( filter )
import qualified Prelude as P

-- containers
import qualified Data.Map as M

-- hasql
import Hasql.Connection
import qualified Hasql.Statement as HS

-- rel8
import Rel8 -- not importing this seems to cause a type error???
import Rel8.Schema.Null hiding (nullable)
import Rel8.Column ( Column )
import Rel8.Column.List ( HList )
import Rel8.Expr ( Expr )
import Rel8.Generic.Rel8able (GFromExprs, Rel8able)
import Rel8.Query ( Query )
import Rel8.Schema.HTable
import Rel8.Schema.Name ( Name(Name) )
import Rel8.Schema.Null hiding (nullable)
import qualified Rel8.Schema.Null as Null
import Rel8.Schema.Table ( TableSchema(..) )
import qualified Rel8.Statement.Run as RSR
import Rel8.Schema.Name ( Name(Name) )
import Rel8.Expr ( Expr )
import Rel8.Table ( Columns )
import Rel8.Schema.Table ( TableSchema(..) )
import Rel8.Schema.Spec
import Rel8.Schema.Result ( Result )
import Rel8.Schema.QualifiedName ( QualifiedName(..) )
import Rel8.Query ( Query )
import Rel8.Column ( Column )
import Rel8.Type.Eq ( DBEq )
import Rel8.Type ( DBType(..) )
import Rel8.Table ( Columns )
import Rel8.Table.List ( ListTable )
import Rel8.Column.List ( HList )
import Data.Functor.Const
import Rel8.Schema.HTable
import Rel8.Type.Name ( TypeName(..) )
import Rel8.Table.Serialize ( ToExprs )
import Rel8.Type ( DBType(..) )
import Rel8.Type.Eq ( DBEq )
import Rel8.Type.Name ( TypeName(..) )

-- these
import Data.These


data Relkind
Expand Down Expand Up @@ -143,6 +145,7 @@ data PGAttribute f = PGAttribute
, attname :: Column f Text
, atttypid :: Column f Oid
, attnum :: Column f Int64
, atttypmod :: Column f Int64
, attnotnull :: Column f Bool
, attndims :: Column f Int16
}
Expand All @@ -160,6 +163,7 @@ pgattribute = TableSchema
data PGType f = PGType
{ oid :: Column f Oid
, typname :: Column f Text
, typnamespace :: Column f Oid
}
deriving stock (Generic)
deriving anyclass (Rel8able)
Expand Down Expand Up @@ -218,6 +222,7 @@ deriving stock instance Show (PGTable Result)
data Attribute f = Attribute
{ attribute :: PGAttribute f
, typ :: PGType f
, namespace :: PGNamespace f
}
deriving stock (Generic)
deriving anyclass (Rel8able)
Expand Down Expand Up @@ -250,7 +255,13 @@ fetchTables = many do
each pgtype
>>= filter (\PGType{ oid = typoid } -> atttypid ==. typoid)

return Attribute{ attribute, typ }
namespace <-
each pgnamespace
>>= filter (\PGNamespace{ oid = nsoid } -> nsoid ==. typ.typnamespace)



return Attribute{ attribute, typ, namespace }

return PGTable
{ name = relname
Expand Down Expand Up @@ -322,7 +333,7 @@ checkedSchemaToTypeMap cols =


showCreateTable_helper :: String -> M.Map String TypeInfo -> String
showCreateTable_helper name typeMap = "CREATE TABLE IF NOT EXISTS " <> show name <> " ("
showCreateTable_helper name typeMap = "CREATE TABLE " <> show name <> " ("
++ L.intercalate "," (fmap go $ M.assocs typeMap)
++ "\n);"
where
Expand All @@ -339,11 +350,9 @@ showCreateTable_helper name typeMap = "CREATE TABLE IF NOT EXISTS " <> show name
showCreateTable :: Rel8able k => TableSchema (k Name) -> String
showCreateTable schema = showCreateTable_helper schema.name.name $ fmap NonEmpty.head $ schemaToTypeMap schema.columns


-- |@'safeShowCreateTable'@ shows an example CREATE TABLE statement for the table.
-- This does not show relationships like primary or foreign keys, but can still
-- be useful to see what types rel8 will expect of the underlying database
-- table.
-- |@'checkedShowCreateTable'@ shows an example CREATE TABLE statement for the
-- table. This does not show relationships like primary or foreign keys, but can
-- still be useful to see what types rel8 will expect of the underlying database.
--
-- In the event multiple columns have the same name, this will return a map of
-- names to the labels identifying the column.
Expand All @@ -352,39 +361,51 @@ checkedShowCreateTable schema = case checkedSchemaToTypeMap schema.columns of
Left e -> Left $ (fmap . fmap) (\typ -> typ.label) e
Right a -> Right $ showCreateTable_helper schema.name.name a


-- implicit casts are ok as long as they're bidirectional
checkTypeEquality :: CheckEnv -> Attribute Result -> TypeInfo -> Maybe ColumnError
checkTypeEquality env attr ty
| attrTyName == tyTyName && attrDims == tyDims = Nothing
| (attrTyName, tyTyName) `elem` env.casts && (tyTyName, attrTyName) `elem` env.casts
&& attrDims == tyDims
= Nothing
| otherwise = Just BidirectionalCastDoesNotExist
checkTypeEquality :: CheckEnv -> TypeInfo -> TypeInfo -> Maybe ColumnError
checkTypeEquality env db hs
| Prelude.and [sameDims, sameMods, toName db == toName hs || castExists]
= Nothing
| otherwise
= Just BidirectionalCastDoesNotExist
where
attrTyName = dropWhile (=='_') $ T.unpack attr.typ.typname
attrDims = fromIntegral attr.attribute.attndims
tyTyName = case ty.typeName.name of
QualifiedName a _ -> dropWhile (=='_') a
tyDims = fromIntegral ty.typeName.arrayDepth
castExists = Prelude.and
[ (toName db, toName hs) `elem` env.casts
, (toName hs, toName db) `elem` env.casts
]

sameMods, sameDims :: Bool
sameMods = db.typeName.modifiers == hs.typeName.modifiers
sameDims = db.typeName.arrayDepth == hs.typeName.arrayDepth

sameName = equalName db.typeName.name hs.typeName.name

toName :: TypeInfo -> String
toName typeInfo = case typeInfo.typeName.name of
QualifiedName name _ -> L.dropWhile (=='_') name

equalName :: QualifiedName -> QualifiedName -> Bool
equalName (QualifiedName a (Just b)) (QualifiedName a' (Just b'))
= L.dropWhile (=='_') a == L.dropWhile (=='_') a' && b == b'
equalName (QualifiedName a _) (QualifiedName a' _)
= dropWhile (=='_') a == dropWhile (=='_') a'

-- check types for a single table
compareTypes
:: CheckEnv
-> M.Map String (Attribute Result)
-> M.Map String TypeInfo
-> [ColumnDiff]
-> [ColumnInfo]
compareTypes env attrMap typeMap = fmap (uncurry go) $ M.assocs (disjointUnion attrMap typeMap)
where
go :: String -> These (Attribute Result) TypeInfo -> ColumnDiff
go name (These a b) = ColumnDiff
go :: String -> These (Attribute Result) TypeInfo -> ColumnInfo
go name (These a b) = ColumnInfo
{ name = name
, dbType = Just $ fromAttribute a
, hsType = Just $ b
, error = checkTypeEquality env a b
, error = checkTypeEquality env (fromAttribute a) b
}
go name (This a) = ColumnDiff
go name (This a) = ColumnInfo
{ name = name
, dbType = Just $ fromAttribute a
, hsType = Nothing
Expand All @@ -393,7 +414,7 @@ compareTypes env attrMap typeMap = fmap (uncurry go) $ M.assocs (disjointUnion a
then Just DbTypeIsNotNullButNotPresentInHsType
else Nothing
}
go name (That b) = ColumnDiff
go name (That b) = ColumnInfo
{ name = name
, dbType = Nothing
, hsType = Just $ b
Expand All @@ -405,12 +426,23 @@ compareTypes env attrMap typeMap = fmap (uncurry go) $ M.assocs (disjointUnion a
{ label = [T.unpack attr.attribute.attname]
, isNull = not attr.attribute.attnotnull
, typeName = TypeName
{ name = QualifiedName (T.unpack attr.typ.typname) Nothing
, modifiers = []
{ name = QualifiedName
(T.unpack attr.typ.typname)
(Just $ T.unpack attr.namespace.nspname)
, modifiers = toModifier
(T.dropWhile (=='_') attr.typ.typname)
attr.attribute.atttypmod
, arrayDepth = fromIntegral attr.attribute.attndims
}
}

toModifier :: Text -> Int64 -> [String]
toModifier "bpchar" (-1) = []
toModifier "bpchar" n = [show (n - 4)]
toModifier "numeric" (-1) = []
toModifier "numeric" n = [show $ (n - 4) `shiftR` 16, show $ (n - 4) .&. 65535]
toModifier _ _ = []

disjointUnion :: Ord k => M.Map k a -> M.Map k b -> M.Map k (These a b)
disjointUnion a b = M.unionWith go (fmap This a) (fmap That b)
where
Expand Down Expand Up @@ -441,37 +473,41 @@ pShowTable xs
lengths = fmap (maximum . fmap T.length) $ xs'


pShowErrors :: [TableDiff] -> Text
pShowErrors :: [TableInfo] -> Text
pShowErrors = T.intercalate "\n\n" . fmap go
where
go :: TableDiff -> Text
go (TableDiff {tableExists, name, columns}) = "Table: " <> T.pack name
go :: TableInfo -> Text
go (TableInfo {tableExists, name, columns}) = "Table: " <> T.pack name
<> if not tableExists then " does not exist\n" else "\n"
<> pShowTable (["Column Name", "Implied DB type", "Current DB type", "Error"] : (columns <&> \column ->
[ T.pack $ column.name
, T.pack $ maybe "" showTypeInfo column.hsType
, T.pack $ maybe "" showTypeInfo column.dbType
, T.pack $ maybe "" show column.error
]))
go (DuplicateNames {name, duplicates}) = "Table " <> T.pack name <> " has multiple columns with the same name. Using 'namesFromLabels' can ensure each column has unique names, which is the easiest way to prevent this, but may require changing names in your database to match the generated names."
<> pShowTable (["DB name", "Haskell label"] : (M.assocs duplicates <&> \(name, typs) ->
go (DuplicateNames {name, duplicates}) = mconcat
[ "Table "
, T.pack (show name)
, " has multiple columns with the same name. This is an error with the Haskell code generating an impossible schema, rather than an error in your current setup of the database itself. Using 'namesFromLabels' can ensure each column has unique names, which is the easiest way to prevent this, but may require changing names in your database to match the new generated names."
, pShowTable (["DB name", "Haskell label"] : (M.assocs duplicates <&> \(name, typs) ->
[ T.pack name
, T.intercalate " " $ fmap (\typ -> T.intercalate "/" $ fmap T.pack typ.label) $ NonEmpty.toList typs
]))
]


data TableDiff
= TableDiff
data TableInfo
= TableInfo
{ tableExists :: Bool
, name :: String
, columns :: [ColumnDiff]
, columns :: [ColumnInfo]
}
| DuplicateNames
{ name :: String
, duplicates :: M.Map String (NonEmpty.NonEmpty TypeInfo)
}
deriving (Show)
data ColumnDiff = ColumnDiff
data ColumnInfo = ColumnInfo
{ name :: String
, hsType :: Maybe TypeInfo
, dbType :: Maybe TypeInfo
Expand All @@ -485,26 +521,33 @@ data ColumnError


showTypeInfo :: TypeInfo -> String
showTypeInfo typeInfo = name
<> concat (replicate (fromIntegral typeInfo.typeName.arrayDepth) "[]")
<> if typeInfo.isNull then "" else " NOT NULL"
showTypeInfo typeInfo = concat
[ name
, if Prelude.null modifiers then "" else "(" <> L.intercalate "," modifiers <> ")"
, concat (replicate (fromIntegral typeInfo.typeName.arrayDepth) "[]")
, if typeInfo.isNull then "" else " NOT NULL"
]
where
name = case typeInfo.typeName.name of
QualifiedName a _ -> dropWhile (=='_') a
QualifiedName a Nothing -> show (dropWhile (=='_') a)
QualifiedName a (Just b) -> show b <> "." <> show (dropWhile (=='_') a)

modifiers :: [String]
modifiers = typeInfo.typeName.modifiers


verifySchema :: Rel8able k => CheckEnv -> TableSchema (k Name) -> TableDiff
verifySchema :: Rel8able k => CheckEnv -> TableSchema (k Name) -> TableInfo
verifySchema env schema = case checkedSchemaToTypeMap schema.columns of
Left dups -> DuplicateNames schema.name.name dups
Right typeMap -> go typeMap maybeTable
where
maybeTable = M.lookup schema.name.name env.schemaMap
go typeMap Nothing = TableDiff
go typeMap Nothing = TableInfo
{ tableExists = False
, name = schema.name.name
, columns = compareTypes env mempty typeMap
}
go typeMap (Just attrs) = TableDiff
go typeMap (Just attrs) = TableInfo
{ tableExists = True
, name = schema.name.name
, columns = compareTypes env (attrsToMap attrs) typeMap
Expand Down Expand Up @@ -585,15 +628,15 @@ getSchemaErrors someTables = fmap collectErrors fetchCheckEnv

-- removes each column which is valid for use by rel8, as well as each table
-- which contains only valid columns
filterErrors :: [TableDiff] -> Maybe [TableDiff]
filterErrors :: [TableInfo] -> Maybe [TableInfo]
filterErrors tables = case mapMaybe go tables of
[] -> Nothing
xs -> Just xs
where
go :: TableDiff -> Maybe TableDiff
go TableDiff {..} = case P.filter (\cd -> isJust cd.error) columns of
[] -> if tableExists then Nothing else Just $ TableDiff { name , tableExists , columns = [] }
xs -> Just $ TableDiff { name , tableExists , columns = xs }
go :: TableInfo -> Maybe TableInfo
go TableInfo {..} = case P.filter (\cd -> isJust cd.error) columns of
[] -> if tableExists then Nothing else Just $ TableInfo { name , tableExists , columns = [] }
xs -> Just $ TableInfo { name , tableExists , columns = xs }
go DuplicateNames {..} = Just (DuplicateNames {..})


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