[component] Allow calling component.ValidateConfig at the top level

.chloggen/toplevel-component-validateconfig.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: component
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Allow `component.ValidateConfig` to recurse through all fields in a config object
+
+# One or more tracking issues or pull requests related to the change
+issues: [11524]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]

component/config.go

@@ -39,7 +39,7 @@ func validate(v reflect.Value) error {
 	switch v.Kind() {
 	case reflect.Invalid:
 		return nil
-	case reflect.Ptr:
+	case reflect.Ptr, reflect.Interface:
 		return validate(v.Elem())
 	case reflect.Struct:
 		var errs error

component/config_test.go

@@ -36,6 +36,10 @@ type configChildTypeDef struct {
 	ChildPtr *errType
 }
 
+type configChildInterface struct {
+	Child Config
+}
+
 type errConfig struct {
 	err error
 }
@@ -95,6 +99,16 @@ func TestValidateConfig(t *testing.T) {
 			cfg:      newErrType("pointer type"),
 			expected: errors.New("pointer type"),
 		},
+		{
+			name:     "child interface with nil",
+			cfg:      configChildInterface{},
+			expected: nil,
+		},
+		{
+			name:     "pointer to child interface with nil",
+			cfg:      &configChildInterface{},
+			expected: nil,
+		},
 		{
 			name:     "nil",
 			cfg:      nil,
@@ -125,6 +139,26 @@ func TestValidateConfig(t *testing.T) {
 			cfg:      &configChildStruct{ChildPtr: &errConfig{err: errors.New("child struct pointer")}},
 			expected: errors.New("child struct pointer"),
 		},
+		{
+			name:     "child interface",
+			cfg:      configChildInterface{Child: errConfig{err: errors.New("child interface")}},
+			expected: errors.New("child interface"),
+		},
+		{
+			name:     "pointer to child interface",
+			cfg:      &configChildInterface{Child: errConfig{err: errors.New("pointer to child interface")}},
+			expected: errors.New("pointer to child interface"),
+		},
+		{
+			name:     "child interface with pointer",
+			cfg:      configChildInterface{Child: &errConfig{err: errors.New("child interface with pointer")}},
+			expected: errors.New("child interface with pointer"),
+		},
+		{
+			name:     "pointer to child interface with pointer",
+			cfg:      &configChildInterface{Child: &errConfig{err: errors.New("pointer to child interface with pointer")}},
+			expected: errors.New("pointer to child interface with pointer"),
+		},
 		{
 			name:     "child slice",
 			cfg:      configChildSlice{Child: []errConfig{{}, {err: errors.New("child slice")}}},