TEP-0075: Extract out the validation of object keys

Prior to this commit, the validation against the required and
provided keys for object type was part of the validateObjectUsage
function. That makes the purpose of validateObjectUsage confusing.

In this commit, a new helper function is created to validate that
separately. Also functions are reordered a bit to make the whole
file easier to track and read.

pkg/apis/pipeline/v1beta1/task_validation.go

@@ -325,6 +325,7 @@ func ValidateParameterVariables(steps []Step, params []ParamSpec) *apis.FieldErr
 
 	errs := validateVariables(steps, "params", parameterNames)
 	errs = errs.Also(validateArrayUsage(steps, "params", arrayParameterNames))
+	errs = errs.Also(validateObjectDefault(objectParamSpecs))
 	return errs.Also(validateObjectUsage(steps, objectParamSpecs))
 }
 
@@ -361,52 +362,6 @@ func ValidateResourcesVariables(steps []Step, resources *TaskResources) *apis.Fi
 	return validateVariables(steps, "resources.(?:inputs|outputs)", resourceNames)
 }
 
-// TODO (@chuangw6): Make sure an object param is not used as a whole when providing values for strings.
-// https://github.com/tektoncd/community/blob/main/teps/0075-object-param-and-result-types.md#variable-replacement-with-object-params
-// "When providing values for strings, Task and Pipeline authors can access
-// individual attributes of an object param; they cannot access the object
-// as whole (we could add support for this later)."
-func validateObjectUsage(steps []Step, params []ParamSpec) (errs *apis.FieldError) {
-	objectParameterNames := sets.NewString()
-	for _, p := range params {
-		// collect all names of object type params
-		objectParameterNames.Insert(p.Name)
-
-		// collect all keys for this object param
-		objectKeys := sets.NewString()
-		for key := range p.Properties {
-			objectKeys.Insert(key)
-		}
-
-		if p.Default != nil && p.Default.ObjectVal != nil {
-			errs = errs.Also(validateObjectKeysInDefault(p.Default.ObjectVal, objectKeys, p.Name))
-		}
-
-		// check if the object's key names are referenced correctly i.e. param.objectParam.key1
-		errs = errs.Also(validateVariables(steps, fmt.Sprintf("params\\.%s", p.Name), objectKeys))
-	}
-
-	return errs
-}
-
-// validate if object keys defined in properties are all provided in default
-func validateObjectKeysInDefault(defaultObject map[string]string, neededObjectKeys sets.String, paramName string) (errs *apis.FieldError) {
-	neededObjectKeysInSpec := neededObjectKeys.List()
-	providedObjectKeysInDefault := []string{}
-	for k := range defaultObject {
-		providedObjectKeysInDefault = append(providedObjectKeysInDefault, k)
-	}
-
-	missingObjectKeys := list.DiffLeft(neededObjectKeysInSpec, providedObjectKeysInDefault)
-	if len(missingObjectKeys) != 0 {
-		return &apis.FieldError{
-			Message: fmt.Sprintf("Required key(s) %s for the parameter %s are not provided in default.", missingObjectKeys, paramName),
-			Paths:   []string{fmt.Sprintf("%s.properties", paramName), fmt.Sprintf("%s.default", paramName)},
-		}
-	}
-	return nil
-}
-
 func validateArrayUsage(steps []Step, prefix string, vars sets.String) (errs *apis.FieldError) {
 	for idx, step := range steps {
 		errs = errs.Also(validateStepArrayUsage(step, prefix, vars)).ViaFieldIndex("steps", idx)
@@ -488,6 +443,69 @@ func validateStepVariables(step Step, prefix string, vars sets.String) *apis.Fie
 	return errs
 }
 
+// validateObjectDefault validates the keys of all the object params within a
+// slice of ParamSpecs are provided in default iff the default section is provided.
+func validateObjectDefault(objectParams []ParamSpec) (errs *apis.FieldError) {
+	for _, p := range objectParams {
+		errs = errs.Also(validateObjectKeys(p.Properties, p.Default, p.Name))
+	}
+	return errs
+}
+
+// validate if object keys defined in properties are all provided in its value provider iff the provider is not nil.
+func validateObjectKeys(properties map[string]PropertySpec, propertiesProvider *ArrayOrString, name string) (errs *apis.FieldError) {
+	if propertiesProvider == nil || propertiesProvider.ObjectVal == nil {
+		return nil
+	}
+
+	neededKeys := []string{}
+	providedKeys := []string{}
+
+	// collect all needed keys
+	for key := range properties {
+		neededKeys = append(neededKeys, key)
+	}
+
+	// collect all provided keys
+	for key := range propertiesProvider.ObjectVal {
+		providedKeys = append(providedKeys, key)
+	}
+
+	missings := list.DiffLeft(neededKeys, providedKeys)
+	if len(missings) != 0 {
+		return &apis.FieldError{
+			Message: fmt.Sprintf("Required key(s) %s for the parameter %s are missing in the value provider.", missings, name),
+			Paths:   []string{fmt.Sprintf("%s.properties", name), fmt.Sprintf("%s.default", name)},
+		}
+	}
+
+	return nil
+}
+
+// TODO (@chuangw6): Make sure an object param is not used as a whole when providing values for strings.
+// https://github.com/tektoncd/community/blob/main/teps/0075-object-param-and-result-types.md#variable-replacement-with-object-params
+// "When providing values for strings, Task and Pipeline authors can access
+// individual attributes of an object param; they cannot access the object
+// as whole (we could add support for this later)."
+func validateObjectUsage(steps []Step, params []ParamSpec) (errs *apis.FieldError) {
+	objectParameterNames := sets.NewString()
+	for _, p := range params {
+		// collect all names of object type params
+		objectParameterNames.Insert(p.Name)
+
+		// collect all keys for this object param
+		objectKeys := sets.NewString()
+		for key := range p.Properties {
+			objectKeys.Insert(key)
+		}
+
+		// check if the object's key names are referenced correctly i.e. param.objectParam.key1
+		errs = errs.Also(validateVariables(steps, fmt.Sprintf("params\\.%s", p.Name), objectKeys))
+	}
+
+	return errs
+}
+
 func validateTaskVariable(value, prefix string, vars sets.String) *apis.FieldError {
 	return substitution.ValidateVariableP(value, prefix, vars)
 }

pkg/apis/pipeline/v1beta1/task_validation_test.go

@@ -660,7 +660,7 @@ func TestTaskSpecValidateError(t *testing.T) {
 			Steps: validSteps,
 		},
 		expectedError: apis.FieldError{
-			Message: fmt.Sprintf("Required key(s) %s for the parameter %s are not provided in default.", []string{"key2"}, "myobjectParam"),
+			Message: fmt.Sprintf("Required key(s) %s for the parameter %s are missing in the value provider.", []string{"key2"}, "myobjectParam"),
 			Paths:   []string{"myobjectParam.properties", "myobjectParam.default"},
 		},
 	}, {