feat(depinject): silently ignore private fields on In structs (#22438)

Co-authored-by: Julien Robert <[email protected]>

depinject/CHANGELOG.md

@@ -22,6 +22,10 @@ Each entry must include the Github issue reference in the following format:
 
 ## [Unreleased]
 
+## 1.1.0
+
+* [#22438](https://github.com/cosmos/cosmos-sdk/pull/22438) Unexported fields on `In` structs are now silently ignored instead of failing.
+
 ## 1.0.0
 
 * [#20540](https://github.com/cosmos/cosmos-sdk/pull/20540) Add support for defining `appconfig` module configuration types using `github.com/cosmos/gogoproto/proto` in addition to `google.golang.org/protobuf` so that users can use gogo proto across their stack.

depinject/binding_test.go

@@ -300,3 +300,16 @@ func TestBindingInterfaceTwoModuleScopedAndGlobalBinding(t *testing.T) {
 	IsResolvedModuleScope(t, pond, moduleC, "Marbled")
 	IsResolvedInGlobalScope(t, pond, "Marbled")
 }
+
+func TestIgnoredField(t *testing.T) {
+	t.Parallel()
+	cfg := struct {
+		depinject.In
+		TheDuck      Duck
+		privateField bool
+		AnotherDuck  Duck
+	}{}
+
+	err := depinject.Inject(depinject.Provide(ProvideMallard), &cfg)
+	require.NoError(t, err)
+}

depinject/container.go

@@ -71,6 +71,9 @@ func (c *container) call(provider *providerDescriptor, moduleKey *moduleKey) ([]
 	c.indentLogger()
 	inVals := make([]reflect.Value, len(provider.Inputs))
 	for i, in := range provider.Inputs {
+		if in.Ignored {
+			continue
+		}
 		val, err := c.resolve(in, moduleKey, loc)
 		if err != nil {
 			return nil, err

depinject/container_test.go

@@ -213,15 +213,14 @@ func TestUnexportedField(t *testing.T) {
 		"depinject.Out struct",
 	)
 
-	require.ErrorContains(t,
+	require.NoError(t,
 		depinject.Inject(
 			scenarioConfigDependency,
 			&handlers,
 			&commands,
 			&a,
 			&c,
 		),
-		"depinject.In struct",
 	)
 
 	require.ErrorContains(t,

depinject/provider_desc.go

@@ -32,6 +32,7 @@ type providerDescriptor struct {
 type providerInput struct {
 	Type     reflect.Type
 	Optional bool
+	Ignored  bool
 }
 
 type providerOutput struct {

depinject/struct_args.go

@@ -8,7 +8,7 @@ import (
 // In can be embedded in another struct to inform the container that the
 // fields of the struct should be treated as dependency inputs.
 // This allows a struct to be used to specify dependencies rather than
-// positional parameters.
+// positional parameters.  Unexpected fields will be ignored.
 //
 // Fields of the struct may support the following tags:
 //
@@ -126,6 +126,7 @@ func structArgsInTypes(typ reflect.Type) ([]providerInput, error) {
 		res = append(res, providerInput{
 			Type:     f.Type,
 			Optional: optional,
+			Ignored:  !f.IsExported(),
 		})
 	}
 	return res, nil
@@ -166,13 +167,15 @@ func buildIn(typ reflect.Type, values []reflect.Value) (reflect.Value, int, erro
 	j := 0
 	res := reflect.New(typ)
 	for i := 0; i < numFields; i++ {
+		if !res.Elem().Field(i).CanSet() {
+			// private field, skip
+			j++
+			continue
+		}
 		f := typ.Field(i)
 		if f.Type.AssignableTo(isInType) {
 			continue
 		}
-		if !res.Elem().Field(i).CanSet() {
-			return reflect.Value{}, 0, fmt.Errorf("depinject.In struct %s on package %s can't have unexported field", res.Elem().String(), f.PkgPath)
-		}
 		if !values[j].CanInterface() {
 			return reflect.Value{}, 0, fmt.Errorf("depinject.Out struct %s on package %s can't have unexported field", res.Elem().String(), f.PkgPath)
 		}