sangria.validation.rules.OverlappingFieldsCanBeMerged.scala Maven / Gradle / Ivy
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Scala GraphQL implementation
package sangria.validation.rules
import scala.collection.mutable
import scala.language.postfixOps
import sangria.ast
import sangria.ast.AstVisitorCommand
import sangria.renderer.{QueryRenderer, SchemaRenderer}
import sangria.schema._
import sangria.validation._
import scala.collection.mutable.{ListBuffer, Set => MutableSet, ListMap => MutableMap, LinkedHashSet}
/**
* Overlapping fields can be merged
*
* A selection set is only valid if all fields (including spreading any
* fragments) either correspond to distinct response names or can be merged
* without ambiguity.
*/
class OverlappingFieldsCanBeMerged extends ValidationRule {
override def visitor(ctx: ValidationContext) = new AstValidatingVisitor {
// A memoization for when two fragments are compared "between" each other for
// conflicts. Two fragments may be compared many times, so memoizing this can
// dramatically improve the performance of this validator.
val comparedFragments = new PairSet[String]
// A cache for the "field map" and list of fragment names found in any given
// selection set. Selection sets may be asked for this information multiple
// times, so this improves the performance of this validator.
val cachedFieldsAndFragmentNames = new MutableMap[(Set[String], Vector[ast.Selection]), (MutableMap[String, ListBuffer[AstAndDef]], LinkedHashSet[String])]()
/**
* Algorithm:
*
* Conflicts occur when two fields exist in a query which will produce the same
* response name, but represent differing values, thus creating a conflict.
* The algorithm below finds all conflicts via making a series of comparisons
* between fields. In order to compare as few fields as possible, this makes
* a series of comparisons "within" sets of fields and "between" sets of fields.
*
* Given any selection set, a collection produces both a set of fields by
* also including all inline fragments, as well as a list of fragments
* referenced by fragment spreads.
*
* A) Each selection set represented in the document first compares "within" its
* collected set of fields, finding any conflicts between every pair of
* overlapping fields.
* Note: This is the *only time* that a the fields "within" a set are compared
* to each other. After this only fields "between" sets are compared.
*
* B) Also, if any fragment is referenced in a selection set, then a
* comparison is made "between" the original set of fields and the
* referenced fragment.
*
* C) Also, if multiple fragments are referenced, then comparisons
* are made "between" each referenced fragment.
*
* D) When comparing "between" a set of fields and a referenced fragment, first
* a comparison is made between each field in the original set of fields and
* each field in the the referenced set of fields.
*
* E) Also, if any fragment is referenced in the referenced selection set,
* then a comparison is made "between" the original set of fields and the
* referenced fragment (recursively referring to step D).
*
* F) When comparing "between" two fragments, first a comparison is made between
* each field in the first referenced set of fields and each field in the the
* second referenced set of fields.
*
* G) Also, any fragments referenced by the first must be compared to the
* second, and any fragments referenced by the second must be compared to the
* first (recursively referring to step F).
*
* H) When comparing two fields, if both have selection sets, then a comparison
* is made "between" both selection sets, first comparing the set of fields in
* the first selection set with the set of fields in the second.
*
* I) Also, if any fragment is referenced in either selection set, then a
* comparison is made "between" the other set of fields and the
* referenced fragment.
*
* J) Also, if two fragments are referenced in both selection sets, then a
* comparison is made "between" the two fragments.
*
*/
override val onEnter: ValidationVisit = {
case selCont: ast.SelectionContainer if selCont.selections.nonEmpty =>
val conflicts = findConflictsWithinSelectionSet(ctx.typeInfo.parentType, selCont, Set.empty)
if (conflicts.nonEmpty)
Left(conflicts.toVector.map(c => FieldsConflictViolation(c.reason.fieldName, c.reason.reason, ctx.sourceMapper, (c.fields1 ++ c.fields2) flatMap (_.location))))
else
AstVisitorCommand.RightContinue
}
def findConflictsWithinSelectionSet(parentType: Option[Type], selCont: ast.SelectionContainer, visitedFragments: Set[String]): ListBuffer[Conflict] = {
val conflicts = ListBuffer[Conflict]()
val (fieldMap, fragmentNames) = getFieldsAndFragmentNames(parentType.asInstanceOf[Option[CompositeType[_]]], selCont, visitedFragments)
// (A) Find find all conflicts "within" the fields of this selection set.
// Note: this is the *only place* `collectConflictsWithin` is called.
collectConflictsWithin(conflicts, fieldMap, visitedFragments)
val fragmentNamesList = fragmentNames.toVector
// (B) Then collect conflicts between these fields and those represented by
// each spread fragment name found.
fragmentNames.zipWithIndex foreach { case (fragmentName, idx) =>
collectConflictsBetweenFieldsAndFragment(conflicts, fieldMap, fragmentName, false, visitedFragments + fragmentName)
for (i <- (idx + 1) until fragmentNamesList.size)
collectConflictsBetweenFragments(
conflicts,
fragmentName,
fragmentNamesList(i),
visitedFragments + fragmentName,
visitedFragments + fragmentNamesList(i), false)
}
conflicts
}
// Collect all Conflicts between two collections of fields. This is similar to,
// but different from the `collectConflictsWithin` function above. This check
// assumes that `collectConflictsWithin` has already been called on each
// provided collection of fields. This is true because this validator traverses
// each individual selection set.
def collectConflictsBetween(
conflicts: ListBuffer[Conflict],
fieldMap1: MutableMap[String, ListBuffer[AstAndDef]],
fieldMap2: MutableMap[String, ListBuffer[AstAndDef]],
visitedFragments1: Set[String],
visitedFragments2: Set[String],
parentFieldsAreMutuallyExclusive: Boolean): Unit = {
// A field map is a keyed collection, where each key represents a response
// name and the value at that key is a list of all fields which provide that
// response name. For any response name which appears in both provided field
// maps, each field from the first field map must be compared to every field
// in the second field map to find potential conflicts.
fieldMap1.keys foreach { outputName =>
fieldMap2.get(outputName) match {
case Some(fields2) =>
val fields1 = fieldMap1(outputName)
for {
f1 <- fields1
f2 <- fields2
} findConflict(outputName, f1, f2, visitedFragments1, visitedFragments2, parentFieldsAreMutuallyExclusive) foreach (conflicts += _)
case None => // It's ok, do nothing
}
}
}
// Collect all Conflicts "within" one collection of fields.
def collectConflictsWithin(conflicts: ListBuffer[Conflict], fieldMap: MutableMap[String, ListBuffer[AstAndDef]], visitedFragments: Set[String]): Unit = {
// A field map is a keyed collection, where each key represents a response
// name and the value at that key is a list of all fields which provide that
// response name. For every response name, if there are multiple fields, they
// must be compared to find a potential conflict.
fieldMap.keys foreach { outputName =>
val fields = fieldMap(outputName)
if (fields.size > 1)
for {
i <- 0 until fields.size
j <- (i + 1) until fields.size
} findConflict(outputName, fields(i), fields(j), visitedFragments, visitedFragments, false) foreach (conflicts += _)
}
}
def getFieldsAndFragmentNames(
parentType: Option[CompositeType[_]],
selCont: ast.SelectionContainer,
visitedFragments: Set[String]): (MutableMap[String, ListBuffer[AstAndDef]], LinkedHashSet[String]) = {
val cacheKey = visitedFragments -> selCont.selections
cachedFieldsAndFragmentNames.get(cacheKey) match {
case Some(cached) => cached
case None =>
val astAndDefs = MutableMap[String, ListBuffer[AstAndDef]]()
val fragmentNames = mutable.LinkedHashSet[String]()
collectFieldsAndFragmentNames(parentType, selCont, astAndDefs, fragmentNames, visitedFragments)
val cached = astAndDefs -> fragmentNames
cachedFieldsAndFragmentNames(cacheKey) = cached
cached
}
}
// Given a reference to a fragment, return the represented collection of fields
// as well as a list of nested fragment names referenced via fragment spreads.
def getReferencedFieldsAndFragmentNames(fragment: ast.FragmentDefinition, visitedFragments: Set[String]): (MutableMap[String, ListBuffer[AstAndDef]], LinkedHashSet[String]) = {
cachedFieldsAndFragmentNames.get(visitedFragments -> fragment.selections) match {
case Some(cached) => cached
case None =>
val fragmentType = ctx.schema.getOutputType(fragment.typeCondition, true).asInstanceOf[Option[CompositeType[_]]]
getFieldsAndFragmentNames(fragmentType, fragment, visitedFragments)
}
}
def collectFieldsAndFragmentNames(
parentType: Option[OutputType[_]],
selCont: ast.SelectionContainer,
astAndDefs: MutableMap[String, ListBuffer[AstAndDef]],
fragmentNames: MutableSet[String],
visitedFragments: Set[String]): Unit = {
selCont.selections foreach {
case field: ast.Field =>
val fieldDef: Option[Field[_, _]] = parentType flatMap {
case obj: ObjectLikeType[_, _] => obj.getField(ctx.schema, field.name).headOption
case _ => None
}
val astAndDef = astAndDefs.get(field.outputName) match {
case Some(list) => list
case None =>
val list = ListBuffer.empty[AstAndDef]
astAndDefs(field.outputName) = list
list
}
astAndDef += AstAndDef(field, parentType, fieldDef)
case fragment: ast.FragmentSpread if visitedFragments contains fragment.name =>
// This means a fragment spread in itself. We're going to infinite loop
// if we try and collect all fields. Pretend we did not index that fragment
case fragment: ast.FragmentSpread =>
fragmentNames += fragment.name
case fragment: ast.InlineFragment =>
val inlineFragmentType = fragment.typeCondition flatMap (ctx.schema.getOutputType(_, true)) orElse parentType
collectFieldsAndFragmentNames(inlineFragmentType, fragment, astAndDefs, fragmentNames, visitedFragments)
}
}
def findConflict(
outputName: String,
fieldInfo1: AstAndDef,
fieldInfo2: AstAndDef,
visitedFragments1: Set[String],
visitedFragments2: Set[String],
parentFieldsAreMutuallyExclusive: Boolean): Option[Conflict] = {
val AstAndDef(ast1, parentType1, def1) = fieldInfo1
val AstAndDef(ast2, parentType2, def2) = fieldInfo2
// If it is known that two fields could not possibly apply at the same
// time, due to the parent types, then it is safe to permit them to diverge
// in aliased field or arguments used as they will not present any ambiguity
// by differing.
// It is known that two parent types could never overlap if they are
// different Object types. Interface or Union types might overlap - if not
// in the current state of the schema, then perhaps in some future version,
// thus may not safely diverge.
val areMutuallyExclusive = parentFieldsAreMutuallyExclusive || ((parentType1, parentType2) match {
case (Some(pt1: ObjectType[_, _]), Some(pt2: ObjectType[_, _])) if pt1.name != pt2.name => true
case _ => false
})
if (!areMutuallyExclusive && ast1.name != ast2.name)
Some(Conflict(ConflictReason(outputName, Left(s"'${ast1.name}' and '${ast2.name}' are different fields")), ast1 :: Nil, ast2 :: Nil))
else if (!areMutuallyExclusive && !sameArguments(ast1.arguments, ast2.arguments))
Some(Conflict(ConflictReason(outputName, Left("they have differing arguments")), ast1 :: Nil, ast2 :: Nil))
else {
val typeRes = for {
field1 <- def1
field2 <- def2
} yield if (doTypesConflict(field1.fieldType, field2.fieldType)) {
val type1 = SchemaRenderer.renderTypeName(field1.fieldType)
val type2 = SchemaRenderer.renderTypeName(field2.fieldType)
Some(Conflict(ConflictReason(outputName, Left(s"they return conflicting types '$type1' and '$type2'")), ast1 :: Nil, ast2 :: Nil))
} else None
typeRes.flatten match {
case s @ Some(_) => s
case None =>
val type1 = def1 map (d => d.fieldType.namedType)
val type2 = def2 map (d => d.fieldType.namedType)
val conflicts = findConflictsBetweenSubSelectionSets(
areMutuallyExclusive,
type1.asInstanceOf[Option[CompositeType[_]]],
ast1,
type2.asInstanceOf[Option[CompositeType[_]]],
ast2,
visitedFragments1,
visitedFragments2)
subfieldConflicts(conflicts.toSeq, outputName, ast1, ast2)
}
}
}
// Find all conflicts found between two selection sets, including those found
// via spreading in fragments. Called when determining if conflicts exist
// between the sub-fields of two overlapping fields.
def findConflictsBetweenSubSelectionSets(
areMutuallyExclusive: Boolean,
parentType1: Option[CompositeType[_]],
selCont1: ast.SelectionContainer,
parentType2: Option[CompositeType[_]],
selCont2: ast.SelectionContainer,
visitedFragments1: Set[String],
visitedFragments2: Set[String]): ListBuffer[Conflict] = {
val conflicts = ListBuffer[Conflict]()
val (fieldMap1, fragmentNames1) = getFieldsAndFragmentNames(parentType1, selCont1, visitedFragments1)
val (fieldMap2, fragmentNames2) = getFieldsAndFragmentNames(parentType2, selCont2, visitedFragments2)
// (H) First, collect all conflicts between these two collections of field.
collectConflictsBetween(conflicts, fieldMap1, fieldMap2, visitedFragments1, visitedFragments2, areMutuallyExclusive)
// (I) Then collect conflicts between the first collection of fields and
// those referenced by each fragment name associated with the second.
fragmentNames2 foreach (fragmentName =>
collectConflictsBetweenFieldsAndFragment(conflicts, fieldMap1, fragmentName, areMutuallyExclusive, visitedFragments2 + fragmentName))
// (I) Then collect conflicts between the second collection of fields and
// those referenced by each fragment name associated with the first.
fragmentNames1 foreach (fragmentName =>
collectConflictsBetweenFieldsAndFragment(conflicts, fieldMap2, fragmentName, areMutuallyExclusive, visitedFragments1 + fragmentName))
// (J) Also collect conflicts between any fragment names by the first and
// fragment names by the second. This compares each item in the first set of
// names to each item in the second set of names.
for {
fragmentName1 <- fragmentNames1
fragmentName2 <- fragmentNames2
} collectConflictsBetweenFragments(conflicts, fragmentName1, fragmentName2, visitedFragments1 + fragmentName1, visitedFragments2 + fragmentName2, areMutuallyExclusive)
conflicts
}
// Collect all conflicts found between two fragments, including via spreading in
// any nested fragments.
def collectConflictsBetweenFragments(
conflicts: ListBuffer[Conflict],
fragmentName1: String,
fragmentName2: String,
visitedFragments1: Set[String],
visitedFragments2: Set[String],
areMutuallyExclusive: Boolean): Unit = {
(ctx.doc.fragments.get(fragmentName1), ctx.doc.fragments.get(fragmentName2)) match {
case (None, _) | (_, None) => // do nothing
case (Some(f1), Some(f2)) if f1.name == f2.name =>
// No need to compare a fragment to itself.
case (Some(f1), Some(f2)) if comparedFragments.contains(f1.name, f2.name, areMutuallyExclusive) =>
// Memoize so two fragments are not compared for conflicts more than once.
case (Some(f1), Some(f2)) =>
comparedFragments.add(f1.name, f2.name, areMutuallyExclusive)
val (fieldMap1, fragmentNames1) = getReferencedFieldsAndFragmentNames(f1, visitedFragments1)
val (fieldMap2, fragmentNames2) = getReferencedFieldsAndFragmentNames(f2, visitedFragments2)
// (F) First, collect all conflicts between these two collections of fields
// (not including any nested fragments).
collectConflictsBetween(conflicts, fieldMap1, fieldMap2, visitedFragments1, visitedFragments2, areMutuallyExclusive)
// (G) Then collect conflicts between the first fragment and any nested
// fragments spread in the second fragment.
fragmentNames2 foreach (fragmentName =>
collectConflictsBetweenFragments(conflicts, fragmentName1, fragmentName, visitedFragments1, visitedFragments2 + fragmentName, areMutuallyExclusive))
// (G) Then collect conflicts between the first fragment and any nested
// fragments spread in the second fragment.
fragmentNames1 foreach (fragmentName =>
collectConflictsBetweenFragments(conflicts, fragmentName, fragmentName2, visitedFragments1 + fragmentName, visitedFragments2, areMutuallyExclusive))
}
}
def collectConflictsBetweenFieldsAndFragment(
conflicts: ListBuffer[Conflict],
fieldMap: MutableMap[String, ListBuffer[AstAndDef]],
fragmentName: String,
areMutuallyExclusive: Boolean,
visitedFragments: Set[String]): Unit = {
ctx.doc.fragments.get(fragmentName) match {
case Some(fragment) =>
val (fieldMap2, fragmentNames2) = getReferencedFieldsAndFragmentNames(fragment, visitedFragments)
// (D) First collect any conflicts between the provided collection of fields
// and the collection of fields represented by the given fragment.
collectConflictsBetween(conflicts, fieldMap, fieldMap2, visitedFragments, visitedFragments, areMutuallyExclusive)
// (E) Then collect any conflicts between the provided collection of fields
// and any fragment names found in the given fragment.
fragmentNames2 foreach (fragmentName =>
collectConflictsBetweenFieldsAndFragment(conflicts, fieldMap, fragmentName, areMutuallyExclusive, visitedFragments + fragmentName))
case None => // do nothing
}
}
// Given a series of Conflicts which occurred between two sub-fields, generate a single Conflict.
def subfieldConflicts(conflicts: Seq[Conflict], outputName: String, ast1: ast.Field, ast2: ast.Field): Option[Conflict] =
if (conflicts.nonEmpty)
Some(Conflict(ConflictReason(outputName, Right(conflicts map (_.reason) toVector)),
conflicts.foldLeft(ast1 :: Nil){case (acc, Conflict(_, fields, _)) => acc ++ fields},
conflicts.foldLeft(ast2 :: Nil){case (acc, Conflict(_, _, fields)) => acc ++ fields}))
else
None
// Two types conflict if both types could not apply to a value simultaneously.
// Composite types are ignored as their individual field types will be compared
// later recursively. However List and Non-Null types must match.
def doTypesConflict(type1: OutputType[_], type2: OutputType[_]): Boolean = (type1, type2) match {
case (ListType(ot1), ListType(ot2)) => doTypesConflict(ot1, ot2)
case (ListType(_), _) | (_, ListType(_)) => true
case (OptionType(ot1), OptionType(ot2)) => doTypesConflict(ot1, ot2)
case (OptionType(_), _) | (_, OptionType(_)) => true
case (nt1: LeafType, nt2: Named) => nt1.name != nt2.name
case (nt1: Named, nt2: LeafType) => nt1.name != nt2.name
case _ => false
}
def sameArguments(args1: Vector[ast.Argument], args2: Vector[ast.Argument]) =
if (args1.size != args2.size) false
else args1.forall { a1 =>
args2.find(_.name == a1.name) match {
case Some(a2) => sameValue(a1.value, a2.value)
case None => false
}
}
def sameValue(v1: ast.Value, v2: ast.Value) =
QueryRenderer.render(v1, QueryRenderer.Compact) == QueryRenderer.render(v2, QueryRenderer.Compact)
}
}
case class Conflict(reason: ConflictReason, fields1: List[ast.Field], fields2: List[ast.Field])
case class ConflictReason(fieldName: String, reason: Either[String, Vector[ConflictReason]])
case class AstAndDef(astField: ast.Field, tpe: Option[OutputType[_]], field: Option[Field[_, _]])
/**
* A way to keep track of pairs of things when the ordering of the pair does
* not matter. We do this by maintaining a sort of double adjacency sets.
*/
private class PairSet[T] {
private val data = MutableMap[(T, T), Boolean]()
def contains(a: T, b: T, areMutuallyExclusive: Boolean) =
data get (a -> b) match {
case None => false
// areMutuallyExclusive being false is a superset of being true,
// hence if we want to know if this PairSet "has" these two with no
// exclusivity, we have to ensure it was added as such.
case Some(res) if !areMutuallyExclusive => !res
case Some(_) => true
}
def add(a: T, b: T, areMutuallyExclusive: Boolean) = {
addPair(a, b, areMutuallyExclusive)
addPair(b, a, areMutuallyExclusive)
}
private def addPair(a: T, b: T, areMutuallyExclusive: Boolean) =
data(a -> b) = areMutuallyExclusive
}