add option to force using a pointer

generate/comments.go

@@ -50,7 +50,31 @@ type GenqlientDirective struct {
 	// value otherwise.
 	//
 	// Only applicable to arguments of nullable types.
-	Omitempty bool
+	Omitempty *bool
+
+	// If set, this argument or field will use a pointer type in Go.  Response
+	// types always use pointers, but otherwise we typically do not.
+	//
+	// This can be useful if it's a type you'll need to pass around (and want a
+	// pointer to save copies) or if you wish to distinguish between the Go
+	// zero value and null (for nullable fields).
+	Pointer *bool
+}
+
+func (g *GenqlientDirective) GetOmitempty() bool { return g.Omitempty != nil && *g.Omitempty }
+func (g *GenqlientDirective) GetPointer() bool   { return g.Pointer != nil && *g.Pointer }
+
+func setBool(dst **bool, v *ast.Value) error {
+	ei, err := v.Value(nil) // no vars allowed
+	// TODO: here and below, put positions on these errors
+	if err != nil {
+		return fmt.Errorf("invalid boolean value %v: %w", v, err)
+	}
+	if b, ok := ei.(bool); ok {
+		*dst = &b
+		return nil
+	}
+	return fmt.Errorf("expected boolean, got non-boolean value %T(%v)", ei, ei)
 }
 
 func fromGraphQL(dir *ast.Directive) (*GenqlientDirective, error) {
@@ -61,13 +85,20 @@ func fromGraphQL(dir *ast.Directive) (*GenqlientDirective, error) {
 	}
 
 	var retval GenqlientDirective
+	var err error
 	for _, arg := range dir.Arguments {
 		switch arg.Name {
+		// TODO: reflect and struct tags?
 		case "omitempty":
-			retval.Omitempty = true
+			err = setBool(&retval.Omitempty, arg.Value)
+		case "pointer":
+			err = setBool(&retval.Pointer, arg.Value)
 		default:
 			return nil, fmt.Errorf("unknown argument %v for @genqlient", arg.Name)
 		}
+		if err != nil {
+			return nil, err
+		}
 	}
 	return &retval, nil
 }
@@ -79,12 +110,12 @@ func (dir *GenqlientDirective) validate(node interface{}) error {
 		// whatever it is relevant to.
 		return nil
 	case *ast.VariableDefinition:
-		if dir.Omitempty && node.Type.NonNull {
+		if dir.Omitempty != nil && node.Type.NonNull {
 			return fmt.Errorf("omitempty may only be used on optional arguments")
 		}
 		return nil
 	case *ast.Field:
-		if dir.Omitempty {
+		if dir.Omitempty != nil {
 			return fmt.Errorf("omitempty is not appilcable to fields")
 		}
 		return nil
@@ -94,18 +125,21 @@ func (dir *GenqlientDirective) validate(node interface{}) error {
 }
 
 func (dir *GenqlientDirective) merge(other *GenqlientDirective) *GenqlientDirective {
-	if dir == nil {
-		return other
+	retval := *dir
+	if other.Omitempty != nil {
+		retval.Omitempty = other.Omitempty
+	}
+	if other.Pointer != nil {
+		retval.Pointer = other.Pointer
 	}
-	var retval GenqlientDirective
-	retval.Omitempty = dir.Omitempty || other.Omitempty
 	return &retval
 }
 
 func (g *generator) parsePrecedingComment(
 	node interface{},
 	pos *ast.Position,
 ) (comment string, directive *GenqlientDirective, err error) {
+	directive = new(GenqlientDirective)
 	var commentLines []string
 	sourceLines := strings.Split(pos.Src.Input, "\n")
 	for i := pos.Line - 1; i > 0; i-- {

generate/generate.go

@@ -61,7 +61,7 @@ type argument struct {
 	GoName      string
 	GoType      string
 	GraphQLName string
-	Omitempty   bool
+	Options     *GenqlientDirective
 }
 
 func newGenerator(config *Config, schema *ast.Schema) *generator {
@@ -117,22 +117,18 @@ func (g *generator) getArgument(
 	if err != nil {
 		return argument{}, err
 	}
-	directive = operationDirective.merge(directive)
-	omitempty := false
-	if directive != nil {
-		omitempty = directive.Omitempty
-	}
 
 	graphQLName := arg.Variable
-	goType, err := g.getTypeForInputType(opName, arg.Type)
+	goType, err := g.getTypeForInputType(
+		opName, arg.Type, directive, operationDirective)
 	if err != nil {
 		return argument{}, err
 	}
 	return argument{
 		GraphQLName: graphQLName,
 		GoName:      lowerFirst(graphQLName),
 		GoType:      goType,
-		Omitempty:   omitempty,
+		Options:     directive,
 	}, nil
 }
 
@@ -163,7 +159,7 @@ func (g *generator) addOperation(op *ast.OperationDefinition) error {
 		}
 	}
 
-	responseName, err := g.getTypeForOperation(op)
+	responseName, err := g.getTypeForOperation(op, directive)
 	if err != nil {
 		return err
 	}

generate/generate_test.go

@@ -95,8 +95,11 @@ func TestGenerate(t *testing.T) {
 				}
 
 				if string(content) != expectedContent {
-					t.Errorf("mismatch in %v\ngot:\n%v\nwant:\n%v\n",
-						filename, string(content), expectedContent)
+					t.Errorf("mismatch in %v", filename)
+					if testing.Verbose() {
+						t.Errorf("got:\n%v\nwant:\n%v\n",
+							string(content), expectedContent)
+					}
 					if update {
 						t.Log("Updating testdata dir to match")
 						err = ioutil.WriteFile(filepath.Join(dataDir, filename), content, 0o644)

generate/operation.go.tmpl

@@ -24,11 +24,13 @@ func {{.Name}}(
     {{- if .Args -}}
     variables := map[string]interface{}{
         {{range .Args -}}
-        "{{.GraphQLName}}": {{if .Omitempty}}nil{{else}}{{.GoName}}{{end}},
+        {{if not .Options.GetOmitempty -}}
+        "{{.GraphQLName}}": {{.GoName}},
+        {{end -}}
         {{end}}
     }
     {{range .Args -}}
-    {{if .Omitempty -}}
+    {{if .Options.GetOmitempty -}}
     {{/* zero_{{.GoType}} would be a better name, but {{.GoType}} would require
          munging since it might be, say, `time.Time`. */}}
     var zero_{{.GoName}} {{.GoType}}

generate/testdata/queries/Omitempty.graphql

@@ -3,9 +3,12 @@ query OmitEmptyQuery(
   $query: UserQueryInput,
   $dt: DateTime,
   $tz: String,
+  # @genqlient(omitempty: false)
+  $tzNoOmitEmpty: String,
 ) {
   user(query: $query) {
     id
   }
   maybeConvert(dt: $dt, tz: $tz)
+  convert2: maybeConvert(dt: $dt, tz: $tzNoOmitEmpty)
 }

generate/testdata/queries/Omitempty.graphql.json

@@ -2,7 +2,7 @@
   "operations": [
     {
       "operationName": "OmitEmptyQuery",
-      "query": "\nquery OmitEmptyQuery ($query: UserQueryInput, $dt: DateTime, $tz: String) {\n\tuser(query: $query) {\n\t\tid\n\t}\n\tmaybeConvert(dt: $dt, tz: $tz)\n}\n",
+      "query": "\nquery OmitEmptyQuery ($query: UserQueryInput, $dt: DateTime, $tz: String, $tzNoOmitEmpty: String) {\n\tuser(query: $query) {\n\t\tid\n\t}\n\tmaybeConvert(dt: $dt, tz: $tz)\n\tconvert2: maybeConvert(dt: $dt, tz: $tzNoOmitEmpty)\n}\n",
       "sourceLocation": "testdata/queries/Omitempty.graphql"
     }
   ]

generate/testdata/queries/Pointers.graphql

@@ -0,0 +1,20 @@
+# @genqlient(pointer: true)
+query PointersQuery(
+  $query: UserQueryInput,
+  # @genqlient(pointer: false)
+  $dt: DateTime,
+  $tz: String,
+) {
+  user(query: $query) {
+    id
+    roles
+    name
+    emails
+    # @genqlient(pointer: false)
+    emailsNoPtr: emails
+  }
+  otherUser: user(query: $query) {
+    id
+  }
+  maybeConvert(dt: $dt, tz: $tz)
+}

generate/testdata/queries/Pointers.graphql.json

@@ -0,0 +1,9 @@
+{
+  "operations": [
+    {
+      "operationName": "PointersQuery",
+      "query": "\nquery PointersQuery ($query: UserQueryInput, $dt: DateTime, $tz: String) {\n\tuser(query: $query) {\n\t\tid\n\t\troles\n\t\tname\n\t\temails\n\t\temailsNoPtr: emails\n\t}\n\totherUser: user(query: $query) {\n\t\tid\n\t}\n\tmaybeConvert(dt: $dt, tz: $tz)\n}\n",
+      "sourceLocation": "testdata/queries/Pointers.graphql"
+    }
+  ]
+}

generate/testdata/queries/PointersInline.graphql

@@ -0,0 +1,24 @@
+query PointersQuery(
+  # @genqlient(pointer: true)
+  $query: UserQueryInput,
+  # @genqlient(pointer: true)
+  $dt: DateTime,
+  $tz: String,
+) {
+  # @genqlient(pointer: true)
+  user(query: $query) {
+    id
+    roles
+    # @genqlient(pointer: true)
+    name
+    # @genqlient(pointer: true)
+    emails
+    # @genqlient(pointer: true)
+    emailsNoPtr: emails
+  }
+  # @genqlient(pointer: true)
+  otherUser: user(query: $query) {
+    id
+  }
+  maybeConvert(dt: $dt, tz: $tz)
+}