1 files changed, 93 insertions, 0 deletions
diff --git a/vendor/github.com/vektah/gqlparser/validator/rules/no_fragment_cycles.go b/vendor/github.com/vektah/gqlparser/validator/rules/no_fragment_cycles.go
new file mode 100644
index 00000000..7511529b
--- /dev/null
+++ b/vendor/github.com/vektah/gqlparser/validator/rules/no_fragment_cycles.go
@@ -0,0 +1,93 @@
+package validator
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/vektah/gqlparser/ast"
+	. "github.com/vektah/gqlparser/validator"
+)
+
+func init() {
+	AddRule("NoFragmentCycles", func(observers *Events, addError AddErrFunc) {
+		visitedFrags := make(map[string]bool)
+
+		observers.OnFragment(func(walker *Walker, fragment *ast.FragmentDefinition) {
+			var spreadPath []*ast.FragmentSpread
+			spreadPathIndexByName := make(map[string]int)
+
+			var recursive func(fragment *ast.FragmentDefinition)
+			recursive = func(fragment *ast.FragmentDefinition) {
+				if visitedFrags[fragment.Name] {
+					return
+				}
+
+				visitedFrags[fragment.Name] = true
+
+				spreadNodes := getFragmentSpreads(fragment.SelectionSet)
+				if len(spreadNodes) == 0 {
+					return
+				}
+				spreadPathIndexByName[fragment.Name] = len(spreadPath)
+
+				for _, spreadNode := range spreadNodes {
+					spreadName := spreadNode.Name
+
+					cycleIndex, ok := spreadPathIndexByName[spreadName]
+
+					spreadPath = append(spreadPath, spreadNode)
+					if !ok {
+						spreadFragment := walker.Document.Fragments.ForName(spreadName)
+						if spreadFragment != nil {
+							recursive(spreadFragment)
+						}
+					} else {
+						cyclePath := spreadPath[cycleIndex : len(spreadPath)-1]
+						var fragmentNames []string
+						for _, fs := range cyclePath {
+							fragmentNames = append(fragmentNames, fs.Name)
+						}
+						var via string
+						if len(fragmentNames) != 0 {
+							via = fmt.Sprintf(" via %s", strings.Join(fragmentNames, ", "))
+						}
+						addError(
+							Message(`Cannot spread fragment "%s" within itself%s.`, spreadName, via),
+							At(spreadNode.Position),
+						)
+					}
+
+					spreadPath = spreadPath[:len(spreadPath)-1]
+				}
+
+				delete(spreadPathIndexByName, fragment.Name)
+			}
+
+			recursive(fragment)
+		})
+	})
+}
+
+func getFragmentSpreads(node ast.SelectionSet) []*ast.FragmentSpread {
+	var spreads []*ast.FragmentSpread
+
+	setsToVisit := []ast.SelectionSet{node}
+
+	for len(setsToVisit) != 0 {
+		set := setsToVisit[len(setsToVisit)-1]
+		setsToVisit = setsToVisit[:len(setsToVisit)-1]
+
+		for _, selection := range set {
+			switch selection := selection.(type) {
+			case *ast.FragmentSpread:
+				spreads = append(spreads, selection)
+			case *ast.Field:
+				setsToVisit = append(setsToVisit, selection.SelectionSet)
+			case *ast.InlineFragment:
+				setsToVisit = append(setsToVisit, selection.SelectionSet)
+			}
+		}
+	}
+
+	return spreads
+}