| import { inspect } from '../../jsutils/inspect.mjs'; |
| import { GraphQLError } from '../../error/GraphQLError.mjs'; |
| import { isCompositeType } from '../../type/definition.mjs'; |
| import { doTypesOverlap } from '../../utilities/typeComparators.mjs'; |
| import { typeFromAST } from '../../utilities/typeFromAST.mjs'; |
| |
| /** |
| * Possible fragment spread |
| * |
| * A fragment spread is only valid if the type condition could ever possibly |
| * be true: if there is a non-empty intersection of the possible parent types, |
| * and possible types which pass the type condition. |
| */ |
| export function PossibleFragmentSpreadsRule(context) { |
| return { |
| InlineFragment(node) { |
| const fragType = context.getType(); |
| const parentType = context.getParentType(); |
| |
| if ( |
| isCompositeType(fragType) && |
| isCompositeType(parentType) && |
| !doTypesOverlap(context.getSchema(), fragType, parentType) |
| ) { |
| const parentTypeStr = inspect(parentType); |
| const fragTypeStr = inspect(fragType); |
| context.reportError( |
| new GraphQLError( |
| `Fragment cannot be spread here as objects of type "${parentTypeStr}" can never be of type "${fragTypeStr}".`, |
| { |
| nodes: node, |
| }, |
| ), |
| ); |
| } |
| }, |
| |
| FragmentSpread(node) { |
| const fragName = node.name.value; |
| const fragType = getFragmentType(context, fragName); |
| const parentType = context.getParentType(); |
| |
| if ( |
| fragType && |
| parentType && |
| !doTypesOverlap(context.getSchema(), fragType, parentType) |
| ) { |
| const parentTypeStr = inspect(parentType); |
| const fragTypeStr = inspect(fragType); |
| context.reportError( |
| new GraphQLError( |
| `Fragment "${fragName}" cannot be spread here as objects of type "${parentTypeStr}" can never be of type "${fragTypeStr}".`, |
| { |
| nodes: node, |
| }, |
| ), |
| ); |
| } |
| }, |
| }; |
| } |
| |
| function getFragmentType(context, name) { |
| const frag = context.getFragment(name); |
| |
| if (frag) { |
| const type = typeFromAST(context.getSchema(), frag.typeCondition); |
| |
| if (isCompositeType(type)) { |
| return type; |
| } |
| } |
| } |