Reject operation or argument names that are Go keywords

docs/CHANGELOG.md

@@ -33,6 +33,8 @@ When releasing a new version:
 
 ### Bug fixes:
 
+- genqlient now explicitly rejects argument, operation, and type names which are Go keywords, rather than failing with an opaque error.
+
 ## v0.4.0
 
 Version 0.4.0 adds several new configuration options, as well as additional methods to simplify the use of interfaces.

generate/convert.go

@@ -164,6 +164,10 @@ func (g *generator) convertArguments(
 	name := "__" + operation.Name + "Input"
 	fields := make([]*goStructField, len(operation.VariableDefinitions))
 	for i, arg := range operation.VariableDefinitions {
+		if goKeywords[arg.Variable] {
+			return nil, errorf(arg.Position, "variable name must not be a go keyword")
+		}
+
 		_, options, err := g.parsePrecedingComment(arg, nil, arg.Position, queryOptions)
 		if err != nil {
 			return nil, err
@@ -317,6 +321,9 @@ func (g *generator) convertDefinition(
 	// Determine the name to use for this type.
 	var name string
 	if options.TypeName != "" {
+		if goKeywords[options.TypeName] {
+			return nil, errorf(pos, "typename option must not be a go keyword")
+		}
 		// If the user specified a name, use it!
 		name = options.TypeName
 		if namePrefix != nil && namePrefix.head == name && namePrefix.tail == nil {

generate/generate.go

@@ -232,6 +232,8 @@ func (g *generator) preprocessQueryDocument(doc *ast.QueryDocument) {
 func (g *generator) addOperation(op *ast.OperationDefinition) error {
 	if op.Name == "" {
 		return errorf(op.Position, "operations must have operation-names")
+	} else if goKeywords[op.Name] {
+		return errorf(op.Position, "operation name must not be a go keyword")
 	}
 
 	queryDoc := &ast.QueryDocument{

generate/testdata/errors/KeywordArgumentName.graphql

@@ -0,0 +1,3 @@
+query KeywordArgumentName($type: String) {
+  f(type: $type)
+}

generate/testdata/errors/KeywordArgumentName.schema.graphql

@@ -0,0 +1 @@
+type Query { f(type: String): String }

generate/testdata/errors/KeywordOperationName.graphql

@@ -0,0 +1 @@
+query type { f }

generate/testdata/errors/KeywordOperationName.schema.graphql

@@ -0,0 +1 @@
+type Query { f: String }

generate/testdata/errors/KeywordTypeName.graphql

@@ -0,0 +1,6 @@
+query KeywordTypeName {
+  # @genqlient(typename: "type")
+  f {
+    g
+  }
+}

generate/testdata/errors/KeywordTypeName.schema.graphql

@@ -0,0 +1,2 @@
+type Query { f: T }
+type T { g: String }

generate/testdata/snapshots/TestGenerateErrors-KeywordArgumentName-graphql

@@ -0,0 +1 @@
+testdata/errors/KeywordArgumentName.graphql:1: variable name must not be a go keyword

generate/testdata/snapshots/TestGenerateErrors-KeywordOperationName-graphql

@@ -0,0 +1 @@
+testdata/errors/KeywordOperationName.graphql:1: operation name must not be a go keyword

generate/testdata/snapshots/TestGenerateErrors-KeywordTypeName-graphql

@@ -0,0 +1 @@
+testdata/errors/KeywordTypeName.schema.graphql:1: typename option must not be a go keyword

generate/util.go

@@ -46,3 +46,32 @@ func goConstName(s string) string {
 		return ret
 	}, s)
 }
+
+// https://go.dev/ref/spec#Keywords
+var goKeywords = map[string]bool{
+	"break":       true,
+	"default":     true,
+	"func":        true,
+	"interface":   true,
+	"select":      true,
+	"case":        true,
+	"defer":       true,
+	"go":          true,
+	"map":         true,
+	"struct":      true,
+	"chan":        true,
+	"else":        true,
+	"goto":        true,
+	"package":     true,
+	"switch":      true,
+	"const":       true,
+	"fallthrough": true,
+	"if":          true,
+	"range":       true,
+	"type":        true,
+	"continue":    true,
+	"for":         true,
+	"import":      true,
+	"return":      true,
+	"var":         true,
+}