TEP-0075: Validate Pipeline object variables in value, matrix and when

Besides task steps, Parameter variables can be used as the value of
a param, matrix or when expression.

Those validations regarding object type are added:
- The whole object value can only be used when providing values
for other object param. example:
```
params:
- name: arg
  value: $(params.myObject[*])
```
- Individual object attributes should be used in all other cases
(string/array val, matrix and when expression).

pkg/apis/pipeline/v1beta1/param_types.go

@@ -284,23 +284,32 @@ func ArrayReference(a string) string {
 	return strings.TrimSuffix(strings.TrimPrefix(a, "$("+ParamsPrefix+"."), "[*])")
 }
 
-func validatePipelineParametersVariablesInTaskParameters(params []Param, prefix string, paramNames sets.String, arrayParamNames sets.String) (errs *apis.FieldError) {
+// validatePipelineParametersVariablesInTaskParameters validates param value that
+// may contain the reference(s) to other params to make sure those references are used appropriately.
+func validatePipelineParametersVariablesInTaskParameters(params []Param, prefix string, paramNames sets.String, arrayParamNames sets.String, objectParamNameKeys map[string][]string) (errs *apis.FieldError) {
 	for _, param := range params {
-		if param.Value.Type == ParamTypeString {
-			errs = errs.Also(validateStringVariable(param.Value.StringVal, prefix, paramNames, arrayParamNames).ViaFieldKey("params", param.Name))
-		} else {
+		switch param.Value.Type {
+		case ParamTypeArray:
 			for idx, arrayElement := range param.Value.ArrayVal {
-				errs = errs.Also(validateArrayVariable(arrayElement, prefix, paramNames, arrayParamNames).ViaFieldIndex("value", idx).ViaFieldKey("params", param.Name))
+				errs = errs.Also(validateArrayVariable(arrayElement, prefix, paramNames, arrayParamNames, objectParamNameKeys).ViaFieldIndex("value", idx).ViaFieldKey("params", param.Name))
 			}
+		case ParamTypeObject:
+			for key, val := range param.Value.ObjectVal {
+				errs = errs.Also(validateStringVariable(val, prefix, paramNames, arrayParamNames, objectParamNameKeys).ViaFieldKey("properties", key).ViaFieldKey("params", param.Name))
+			}
+		default:
+			errs = errs.Also(validateParamStringValue(param, prefix, paramNames, arrayParamNames, objectParamNameKeys))
 		}
 	}
 	return errs
 }
 
-func validatePipelineParametersVariablesInMatrixParameters(matrix []Param, prefix string, paramNames sets.String, arrayParamNames sets.String) (errs *apis.FieldError) {
+// validatePipelineParametersVariablesInMatrixParameters validates matrix param value
+// that may contain the reference(s) to other params to make sure those references are used appropriately.
+func validatePipelineParametersVariablesInMatrixParameters(matrix []Param, prefix string, paramNames sets.String, arrayParamNames sets.String, objectParamNameKeys map[string][]string) (errs *apis.FieldError) {
 	for _, param := range matrix {
 		for idx, arrayElement := range param.Value.ArrayVal {
-			errs = errs.Also(validateArrayVariable(arrayElement, prefix, paramNames, arrayParamNames).ViaFieldIndex("value", idx).ViaFieldKey("matrix", param.Name))
+			errs = errs.Also(validateArrayVariable(arrayElement, prefix, paramNames, arrayParamNames, objectParamNameKeys).ViaFieldIndex("value", idx).ViaFieldKey("matrix", param.Name))
 		}
 	}
 	return errs
@@ -328,12 +337,41 @@ func validateParameterInOneOfMatrixOrParams(matrix []Param, params []Param) (err
 	return errs
 }
 
-func validateStringVariable(value, prefix string, stringVars sets.String, arrayVars sets.String) *apis.FieldError {
+// validateParamStringValue validates the param value field of string type
+// that may contain references to other isolated array/object params other than string param.
+func validateParamStringValue(param Param, prefix string, paramNames sets.String, arrayVars sets.String, objectParamNameKeys map[string][]string) (errs *apis.FieldError) {
+	stringValue := param.Value.StringVal
+
+	isIsolated, errs := substitution.ValidateWholeArrayOrObjectRefInStringVariable(param.Name, stringValue, prefix, paramNames)
+	if isIsolated {
+		return errs
+	}
+
+	// if the provided param value is string literal and/or contains multiple variables
+	// valid example: "$(params.myString) and another $(params.myObject.key1)"
+	// invalid example: "$(params.myString) and another $(params.myObject[*])"
+	return validateStringVariable(stringValue, prefix, paramNames, arrayVars, objectParamNameKeys).ViaFieldKey("params", param.Name)
+}
+
+// validateStringVariable validates the normal string fields that can only accept references to string param or individual keys of object param
+func validateStringVariable(value, prefix string, stringVars sets.String, arrayVars sets.String, objectParamNameKeys map[string][]string) *apis.FieldError {
 	errs := substitution.ValidateVariableP(value, prefix, stringVars)
+	errs = errs.Also(validateObjectVariable(value, prefix, objectParamNameKeys))
 	return errs.Also(substitution.ValidateVariableProhibitedP(value, prefix, arrayVars))
 }
 
-func validateArrayVariable(value, prefix string, stringVars sets.String, arrayVars sets.String) *apis.FieldError {
+func validateArrayVariable(value, prefix string, stringVars sets.String, arrayVars sets.String, objectParamNameKeys map[string][]string) *apis.FieldError {
 	errs := substitution.ValidateVariableP(value, prefix, stringVars)
+	errs = errs.Also(validateObjectVariable(value, prefix, objectParamNameKeys))
 	return errs.Also(substitution.ValidateVariableIsolatedP(value, prefix, arrayVars))
 }
+
+func validateObjectVariable(value, prefix string, objectParamNameKeys map[string][]string) (errs *apis.FieldError) {
+	objectNames := sets.NewString()
+	for objectParamName, keys := range objectParamNameKeys {
+		objectNames.Insert(objectParamName)
+		errs = errs.Also(substitution.ValidateVariableP(value, fmt.Sprintf("%s\\.%s", prefix, objectParamName), sets.NewString(keys...)))
+	}
+
+	return errs.Also(substitution.ValidateEntireVariableProhibitedP(value, prefix, objectNames))
+}

pkg/apis/pipeline/v1beta1/pipeline_validation.go

@@ -128,6 +128,7 @@ func validatePipelineWorkspacesUsage(wss []PipelineWorkspaceDeclaration, pts []P
 func validatePipelineParameterVariables(ctx context.Context, tasks []PipelineTask, params []ParamSpec) (errs *apis.FieldError) {
 	parameterNames := sets.NewString()
 	arrayParameterNames := sets.NewString()
+	objectParameterNameKeys := map[string][]string{}
 
 	// validates all the types within a slice of ParamSpecs
 	errs = errs.Also(ValidateParameterTypes(ctx, params).ViaField("params"))
@@ -141,16 +142,21 @@ func validatePipelineParameterVariables(ctx context.Context, tasks []PipelineTas
 		if p.Type == ParamTypeArray {
 			arrayParameterNames.Insert(p.Name)
 		}
-	}
 
-	return errs.Also(validatePipelineParametersVariables(tasks, "params", parameterNames, arrayParameterNames))
+		if p.Type == ParamTypeObject {
+			for k := range p.Properties {
+				objectParameterNameKeys[p.Name] = append(objectParameterNameKeys[p.Name], k)
+			}
+		}
+	}
+	return errs.Also(validatePipelineParametersVariables(tasks, "params", parameterNames, arrayParameterNames, objectParameterNameKeys))
 }
 
-func validatePipelineParametersVariables(tasks []PipelineTask, prefix string, paramNames sets.String, arrayParamNames sets.String) (errs *apis.FieldError) {
+func validatePipelineParametersVariables(tasks []PipelineTask, prefix string, paramNames sets.String, arrayParamNames sets.String, objectParamNameKeys map[string][]string) (errs *apis.FieldError) {
 	for idx, task := range tasks {
-		errs = errs.Also(validatePipelineParametersVariablesInTaskParameters(task.Params, prefix, paramNames, arrayParamNames).ViaIndex(idx))
-		errs = errs.Also(validatePipelineParametersVariablesInMatrixParameters(task.Matrix, prefix, paramNames, arrayParamNames).ViaIndex(idx))
-		errs = errs.Also(task.WhenExpressions.validatePipelineParametersVariables(prefix, paramNames, arrayParamNames).ViaIndex(idx))
+		errs = errs.Also(validatePipelineParametersVariablesInTaskParameters(task.Params, prefix, paramNames, arrayParamNames, objectParamNameKeys).ViaIndex(idx))
+		errs = errs.Also(validatePipelineParametersVariablesInMatrixParameters(task.Matrix, prefix, paramNames, arrayParamNames, objectParamNameKeys).ViaIndex(idx))
+		errs = errs.Also(task.WhenExpressions.validatePipelineParametersVariables(prefix, paramNames, arrayParamNames, objectParamNameKeys).ViaIndex(idx))
 	}
 	return errs
 }