fix #1237 remove unreachable types from generated code

api/generate.go

@@ -53,7 +53,7 @@ func Generate(cfg *config.Config, option ...Option) error {
 		}
 	}
 
-	if err := cfg.LoadSchema(); err != nil {
+	if err := cfg.LoadSchema(false); err != nil {
 		return fmt.Errorf("failed to load schema: %w", err)
 	}
 
@@ -66,7 +66,7 @@ func Generate(cfg *config.Config, option ...Option) error {
 	}
 
 	// LoadSchema again now we have everything
-	if err := cfg.LoadSchema(); err != nil {
+	if err := cfg.LoadSchema(true); err != nil {
 		return fmt.Errorf("failed to load schema: %w", err)
 	}
 

codegen/config/config.go

@@ -189,7 +189,7 @@ func (c *Config) Init() error {
 	}
 
 	if c.Schema == nil {
-		if err := c.LoadSchema(); err != nil {
+		if err := c.LoadSchema(true); err != nil {
 			return err
 		}
 	}
@@ -613,7 +613,7 @@ func (c *Config) injectBuiltins() {
 	}
 }
 
-func (c *Config) LoadSchema() error {
+func (c *Config) LoadSchema(removeUnreachable bool) error {
 	if c.Packages != nil {
 		c.Packages = &code.Packages{}
 	}
@@ -635,6 +635,10 @@ func (c *Config) LoadSchema() error {
 		schema.Types["Query"] = schema.Query
 	}
 
+	if removeUnreachable {
+		removeUnreachableTypes(schema)
+	}
+
 	c.Schema = schema
 	return nil
 }

codegen/config/remove_unreachable.go

@@ -0,0 +1,131 @@
+package config
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+
+	"github.com/vektah/gqlparser/v2/ast"
+)
+
+type reachabilityCleaner struct {
+	schema    *ast.Schema
+	reachable map[string]*ast.Definition
+	queue     []*ast.Definition
+}
+
+func (r *reachabilityCleaner) addToQueue(def *ast.Definition) {
+	// simplify error handling by acceping nil and ignoring it
+	if def == nil {
+		return
+	}
+	if _, ok := r.reachable[def.Name]; !ok {
+		r.queue = append(r.queue, def)
+	}
+	r.reachable[def.Name] = r.schema.Types[def.Name]
+}
+
+func (r *reachabilityCleaner) findReachableTypes() map[string]*ast.Definition {
+	// Mark all types reachable from the current queue of definitions as reachable
+	for len(r.queue) > 0 {
+		// pop from stack
+		currentType := r.queue[0]
+		r.queue = r.queue[1:]
+
+		referencedFromCurrent := []*ast.Definition{}
+		referencedFromCurrent = append(referencedFromCurrent, r.schema.GetPossibleTypes(currentType)...)
+		referencedFromCurrent = append(referencedFromCurrent, r.schema.GetImplements(currentType)...)
+		for _, t := range currentType.Types {
+			referencedFromCurrent = append(referencedFromCurrent, r.schema.Types[t])
+		}
+		for _, i := range currentType.Interfaces {
+			referencedFromCurrent = append(referencedFromCurrent, r.schema.Types[i])
+		}
+		for _, f := range currentType.Fields {
+			referencedFromCurrent = append(referencedFromCurrent, r.schema.Types[f.Type.Name()])
+			for _, arg := range f.Arguments {
+				referencedFromCurrent = append(referencedFromCurrent, r.schema.Types[arg.Type.Name()])
+				if arg.DefaultValue != nil {
+					referencedFromCurrent = append(referencedFromCurrent, arg.DefaultValue.Definition)
+				}
+			}
+			if f.DefaultValue != nil {
+				referencedFromCurrent = append(referencedFromCurrent, f.DefaultValue.Definition)
+			}
+		}
+		for _, def := range referencedFromCurrent {
+			if def == nil {
+				continue
+			}
+			// If this type hasn't been seen before, make sure we expand it by adding to the queue
+			r.addToQueue(def)
+			// When adding a union or enum to the queue, make sure we also add all its possible implementations
+			for _, pt := range r.schema.PossibleTypes[def.Name] {
+				r.addToQueue(pt)
+			}
+			// When adding an implementation of an interface to the queue, make sure we also add the interface it implements
+			for _, pt := range r.schema.Implements[def.Name] {
+				r.addToQueue(pt)
+			}
+		}
+	}
+
+	// Mark all double underscore types as reachable because they are used for introspection
+	for _, d := range r.schema.Types {
+		if strings.HasPrefix(d.Name, "__") {
+			r.reachable[d.Name] = d
+			for _, pt := range r.schema.PossibleTypes[d.Name] {
+				r.reachable[pt.Name] = pt
+			}
+		}
+	}
+	return r.reachable
+}
+
+func calculateAndWarnOnUnreachableTypes(reachableTypes, allTypes map[string]*ast.Definition) {
+	unreachableTypes := map[string]struct{}{}
+	for all := range allTypes {
+		unreachableTypes[all] = struct{}{}
+	}
+	for r := range reachableTypes {
+		delete(unreachableTypes, r)
+	}
+
+	if len(unreachableTypes) > 0 {
+		unreachableTypesList := []string{}
+		for t := range unreachableTypes {
+			unreachableTypesList = append(unreachableTypesList, t)
+		}
+		sort.Strings(unreachableTypesList)
+		for _, typeName := range unreachableTypesList {
+			if !allTypes[typeName].BuiltIn {
+				fmt.Printf("Warning: unreachable type: %s\n", typeName)
+			}
+		}
+	}
+}
+
+func removeUnreachableTypes(a *ast.Schema) {
+	rc := reachabilityCleaner{
+		reachable: map[string]*ast.Definition{},
+		schema:    a,
+	}
+	rc.addToQueue(a.Query)
+	rc.addToQueue(a.Mutation)
+	rc.addToQueue(a.Subscription)
+	// Entity is a fake type used in the federation plugin to generate resolver interfaces to be implemented
+	// TODO: find a better way to make sure it's considered reachable
+	rc.addToQueue(a.Types["Entity"])
+	// All directive arguments are considered reachable for now. No need to clean these up as aggressively.
+	for _, dd := range a.Directives {
+		for _, arg := range dd.Arguments {
+			rc.addToQueue(a.Types[arg.Type.Name()])
+		}
+	}
+
+	reachable := rc.findReachableTypes()
+
+	calculateAndWarnOnUnreachableTypes(reachable, a.Types)
+
+	a.Types = reachable
+}

codegen/testserver/followschema/builtinscalar.graphql

@@ -1,3 +1,6 @@
+extend type Query {
+    Map: Map!
+}
 
 """
 Since gqlgen defines default implementation for a Map scalar, this tests that the builtin is _not_

codegen/testserver/followschema/loops.graphql

@@ -1,3 +1,7 @@
+extend type Query {
+    LoopA: LoopA
+}
+
 type LoopA {
     b: LoopB!
 }

codegen/testserver/followschema/resolver.go

@@ -140,6 +140,22 @@ func (r *queryResolver) DeprecatedField(ctx context.Context) (string, error) {
 	panic("not implemented")
 }
 
+func (r *queryResolver) EmbeddedPointer(ctx context.Context) (*EmbeddedPointerModel, error) {
+	panic("not implemented")
+}
+
+func (r *queryResolver) ForcedResolver(ctx context.Context) (*ForcedResolver, error) {
+	panic("not implemented")
+}
+
+func (r *queryResolver) Status(ctx context.Context) (Status, error) {
+	panic("not implemented")
+}
+
+func (r *queryResolver) Map(ctx context.Context) (*Map, error) {
+	panic("not implemented")
+}
+
 func (r *queryResolver) Overlapping(ctx context.Context) (*OverlappingFields, error) {
 	panic("not implemented")
 }
@@ -236,6 +252,10 @@ func (r *queryResolver) Issue896a(ctx context.Context) ([]*CheckIssue896, error)
 	panic("not implemented")
 }
 
+func (r *queryResolver) LoopA(ctx context.Context) (*LoopA, error) {
+	panic("not implemented")
+}
+
 func (r *queryResolver) MapStringInterface(ctx context.Context, in map[string]interface{}) (map[string]interface{}, error) {
 	panic("not implemented")
 }
@@ -296,6 +316,10 @@ func (r *queryResolver) DefaultScalar(ctx context.Context, arg string) (string,
 	panic("not implemented")
 }
 
+func (r *queryResolver) EmbeddedDefaultScalar(ctx context.Context) (*EmbeddedDefaultScalar, error) {
+	panic("not implemented")
+}
+
 func (r *queryResolver) Slices(ctx context.Context) (*Slices, error) {
 	panic("not implemented")
 }
@@ -324,10 +348,38 @@ func (r *queryResolver) ValidType(ctx context.Context) (*ValidType, error) {
 	panic("not implemented")
 }
 
+func (r *queryResolver) ContentChild(ctx context.Context) (ContentChild, error) {
+	panic("not implemented")
+}
+
 func (r *queryResolver) VariadicModel(ctx context.Context) (*VariadicModel, error) {
 	panic("not implemented")
 }
 
+func (r *queryResolver) AsdfIt(ctx context.Context) (*AsdfIt, error) {
+	panic("not implemented")
+}
+
+func (r *queryResolver) AIt(ctx context.Context) (*AIt, error) {
+	panic("not implemented")
+}
+
+func (r *queryResolver) IIt(ctx context.Context) (*IIt, error) {
+	panic("not implemented")
+}
+
+func (r *queryResolver) XXIt(ctx context.Context) (*XXIt, error) {
+	panic("not implemented")
+}
+
+func (r *queryResolver) AbIt(ctx context.Context) (*AbIt, error) {
+	panic("not implemented")
+}
+
+func (r *queryResolver) XxIt(ctx context.Context) (*XxIt, error) {
+	panic("not implemented")
+}
+
 func (r *queryResolver) WrappedStruct(ctx context.Context) (*WrappedStruct, error) {
 	panic("not implemented")
 }