Removing the check for the ottlarg struct tag

pkg/ottl/expression.go

@@ -279,15 +279,7 @@ func (g StandardFunctionGetter[K]) Get(args Arguments) (Expr[K], error) {
  }
  for i := 0; i < fArgsVal.NumField(); i++ {
  field := argsVal.Field(i)
- argIndex, err := getArgumentIndex(i, argsVal)
- if err != nil {
- return Expr[K]{}, err
- }
- fArgIndex, err := getArgumentIndex(argIndex, fArgsVal)
- if err != nil {
- return Expr[K]{}, err
- }
- fArgsVal.Field(fArgIndex).Set(field)
+ fArgsVal.Field(i).Set(field)
  }
  fn, err := g.fact.CreateFunction(g.fCtx, fArgs)
  if err != nil {

pkg/ottl/expression_test.go

@@ -688,11 +688,6 @@ func Test_FunctionGetter(t *testing.T) {
  &multipleArgsArguments{},
  functionWithStringGetter,
  ),
- createFactory[any](
- "no_struct_tag",
- &noStructTagFunctionArguments{},
- functionWithStringGetter,
- ),
  NewFactory(
  "cannot_create_function",
  &stringGetterArguments{},
@@ -751,18 +746,6 @@ func Test_FunctionGetter(t *testing.T) {
  valid: false,
  expectedErrorMsg: "incorrect number of arguments. Expected: 4 Received: 1",
  },
- {
- name: "Invalid Arguments struct tag",
- getter: StandardStringGetter[interface{}]{
- Getter: func(ctx context.Context, tCtx interface{}) (interface{}, error) {
- return nil, nil
- },
- },
- function: StandardFunctionGetter[any]{fCtx: FunctionContext{Set: componenttest.NewNopTelemetrySettings()}, fact: functions["no_struct_tag"]},
- want: "anything",
- valid: false,
- expectedErrorMsg: "no `ottlarg` struct tag on Arguments field \"StringArg\"",
- },
  {
  name: "Cannot create function",
  getter: StandardStringGetter[interface{}]{

pkg/ottl/functions.go

@@ -7,7 +7,6 @@ import (
  "errors"
  "fmt"
  "reflect"
- "strconv"
  "strings"
 )
 
@@ -47,22 +46,6 @@ func (p *Parser[K]) newFunctionCall(ed editor) (Expr[K], error) {
  return Expr[K]{exprFunc: fn}, err
 }
 
-func getArgumentIndex(index int, args reflect.Value) (int, error) {
- argsType := args.Type()
- fieldTag, ok := argsType.Field(index).Tag.Lookup("ottlarg")
- if !ok {
- return 0, fmt.Errorf("no `ottlarg` struct tag on Arguments field %q", argsType.Field(index).Name)
- }
- argNum, err := strconv.Atoi(fieldTag)
- if err != nil {
- return 0, fmt.Errorf("ottlarg struct tag on field %q is not a valid integer: %w", argsType.Field(index).Name, err)
- }
- if argNum < 0 || argNum >= args.NumField() {
- return 0, fmt.Errorf("ottlarg struct tag on field %q has value %d, but must be between 0 and %d", argsType.Field(index).Name, argNum, args.NumField())
- }
- return argNum, nil
-}
-
 func (p *Parser[K]) buildArgs(ed editor, argsVal reflect.Value) error {
  if len(ed.Arguments) != argsVal.NumField() {
  return fmt.Errorf("incorrect number of arguments. Expected: %d Received: %d", argsVal.NumField(), len(ed.Arguments))
@@ -71,12 +54,9 @@ func (p *Parser[K]) buildArgs(ed editor, argsVal reflect.Value) error {
  for i := 0; i < argsVal.NumField(); i++ {
  field := argsVal.Field(i)
  fieldType := field.Type()
- argNum, err := getArgumentIndex(i, argsVal)
- if err != nil {
- return err
- }
- argVal := ed.Arguments[argNum]
+ argVal := ed.Arguments[i]
  var val any
+ var err error
  switch {
  case strings.HasPrefix(fieldType.Name(), "FunctionGetter"):
  var name string

pkg/ottl/functions_test.go

@@ -63,31 +63,6 @@ func Test_NewFunctionCall_invalid(t *testing.T) {
  errorFunctionArguments{},
  functionThatHasAnError,
  ),
- createFactory(
- "no_struct_tag",
- &noStructTagFunctionArguments{},
- functionThatHasAnError,
- ),
- createFactory(
- "wrong_struct_tag",
- &wrongTagFunctionArguments{},
- functionThatHasAnError,
- ),
- createFactory(
- "bad_struct_tag",
- &badStructTagFunctionArguments{},
- functionThatHasAnError,
- ),
- createFactory(
- "negative_struct_tag",
- &negativeStructTagFunctionArguments{},
- functionThatHasAnError,
- ),
- createFactory(
- "out_of_bounds_struct_tag",
- &outOfBoundsStructTagFunctionArguments{},
- functionThatHasAnError,
- ),
  createFactory(
  "testing_unknown_function",
  &functionGetterArguments{},
@@ -349,61 +324,6 @@ func Test_NewFunctionCall_invalid(t *testing.T) {
  Function: "non_pointer",
  },
  },
- {
- name: "no struct tags",
- inv: editor{
- Function: "no_struct_tag",
- Arguments: []value{
- {
- String: ottltest.Strp("str"),
- },
- },
- },
- },
- {
- name: "using the wrong struct tag",
- inv: editor{
- Function: "wrong_struct_tag",
- Arguments: []value{
- {
- String: ottltest.Strp("str"),
- },
- },
- },
- },
- {
- name: "non-integer struct tags",
- inv: editor{
- Function: "bad_struct_tag",
- Arguments: []value{
- {
- String: ottltest.Strp("str"),
- },
- },
- },
- },
- {
- name: "struct tag index too low",
- inv: editor{
- Function: "negative_struct_tag",
- Arguments: []value{
- {
- String: ottltest.Strp("str"),
- },
- },
- },
- },
- {
- name: "struct tag index too high",
- inv: editor{
- Function: "out_of_bounds_struct_tag",
- Arguments: []value{
- {
- String: ottltest.Strp("str"),
- },
- },
- },
- },
  }
 
  for _, tt := range tests {
@@ -1516,26 +1436,6 @@ func functionWithEnum(Enum) (ExprFunc[interface{}], error) {
  }, nil
 }
 
-type noStructTagFunctionArguments struct {
- StringArg string
-}
-
-type badStructTagFunctionArguments struct {
- StringArg string `ottlarg:"a"`
-}
-
-type negativeStructTagFunctionArguments struct {
- StringArg string `ottlarg:"-1"`
-}
-
-type outOfBoundsStructTagFunctionArguments struct {
- StringArg string `ottlarg:"1"`
-}
-
-type wrongTagFunctionArguments struct {
- StringArg string `argument:"1"`
-}
-
 func createFactory[A any](name string, args A, fn any) Factory[any] {
  createFunction := func(fCtx FunctionContext, oArgs Arguments) (ExprFunc[any], error) {
  fArgs, ok := oArgs.(A)

pkg/ottl/ottlfuncs/func_substring.go

@@ -12,8 +12,8 @@ import (
 
 type SubstringArguments[K any] struct {
  Target ottl.StringGetter[K]
- Start int64
- Length int64
+ Start ottl.IntGetter[K]
+ Length ottl.IntGetter[K]
 }
 
 func NewSubstringFactory[K any]() ottl.Factory[K] {