Introduce ctxutil.GetMapKeyName()

Author: rockdaboot

pkg/ottl/contexts/internal/ctxprofile/profile.go

@@ -454,7 +454,7 @@ func accessAttributesKey[K Context](key []ottl.Key[K]) ottl.StandardGetSetter[K]
 			return ctxutil.GetMapValue[K](ctx, tCtx, pprofile.FromAttributeIndices(tCtx.GetProfile().AttributeTable(), tCtx.GetProfile()), key)
 		},
 		Setter: func(ctx context.Context, tCtx K, val any) error {
-			newKey, err := key[0].String(ctx, tCtx)
+			newKey, err := ctxutil.GetMapKeyName(ctx, tCtx, key)
 			if err != nil {
 				return err
 			}

pkg/ottl/contexts/internal/ctxutil/map.go

@@ -14,21 +14,10 @@ import (
 )
 
 func GetMapValue[K any](ctx context.Context, tCtx K, m pcommon.Map, keys []ottl.Key[K]) (any, error) {
-	if len(keys) == 0 {
-		return nil, errors.New("cannot get map value without keys")
-	}
-
-	s, err := keys[0].String(ctx, tCtx)
+	s, err := GetMapKeyName(ctx, tCtx, keys)
 	if err != nil {
 		return nil, err
 	}
-	if s == nil {
-		resString, err := FetchValueFromExpression[K, string](ctx, tCtx, keys[0])
-		if err != nil {
-			return nil, fmt.Errorf("unable to resolve a string index in map: %w", err)
-		}
-		s = resString
-	}
 
 	val, ok := m.Get(*s)
 	if !ok {
@@ -39,21 +28,10 @@ func GetMapValue[K any](ctx context.Context, tCtx K, m pcommon.Map, keys []ottl.
 }
 
 func SetMapValue[K any](ctx context.Context, tCtx K, m pcommon.Map, keys []ottl.Key[K], val any) error {
-	if len(keys) == 0 {
-		return errors.New("cannot set map value without key")
-	}
-
-	s, err := keys[0].String(ctx, tCtx)
+	s, err := GetMapKeyName(ctx, tCtx, keys)
 	if err != nil {
 		return err
 	}
-	if s == nil {
-		resString, err := FetchValueFromExpression[K, string](ctx, tCtx, keys[0])
-		if err != nil {
-			return fmt.Errorf("unable to resolve a string index in map: %w", err)
-		}
-		s = resString
-	}
 
 	currentValue, ok := m.Get(*s)
 	if !ok {
@@ -62,6 +40,24 @@ func SetMapValue[K any](ctx context.Context, tCtx K, m pcommon.Map, keys []ottl.
 	return SetIndexableValue[K](ctx, tCtx, currentValue, val, keys[1:])
 }
 
+func GetMapKeyName[K any](ctx context.Context, tCtx K, keys []ottl.Key[K]) (*string, error) {
+	if len(keys) == 0 {
+		return nil, errors.New("empty keys")
+	}
+
+	resolvedKey, err := keys[0].String(ctx, tCtx)
+	if err != nil {
+		return nil, err
+	}
+	if resolvedKey == nil {
+		resolvedKey, err = FetchValueFromExpression[K, string](ctx, tCtx, keys[0])
+		if err != nil {
+			return nil, fmt.Errorf("unable to resolve a string index in map: %w", err)
+		}
+	}
+	return resolvedKey, nil
+}
+
 func FetchValueFromExpression[K any, T int64 | string](ctx context.Context, tCtx K, key ottl.Key[K]) (*T, error) {
 	p, err := key.ExpressionGetter(ctx, tCtx)
 	if err != nil {

pkg/ottl/contexts/internal/ctxutil/map_test.go

@@ -389,3 +389,60 @@ func Test_GetMap(t *testing.T) {
 		})
 	}
 }
+
+func Test_GetMapKeyName(t *testing.T) {
+	getSetter := &ottl.StandardGetSetter[any]{
+		Getter: func(_ context.Context, _ any) (any, error) {
+			return nil, nil
+		},
+	}
+	tests := []struct {
+		name string
+		keys []ottl.Key[any]
+		err  error
+		key  string
+	}{
+		{
+			name: "empty keys",
+			keys: []ottl.Key[any]{},
+			err:  errors.New("empty keys"),
+		},
+		{
+			name: "first key not a string",
+			keys: []ottl.Key[any]{
+				&pathtest.Key[any]{
+					I: ottltest.Intp(0),
+					G: getSetter,
+				},
+			},
+			err: errors.New("unable to resolve a string index in map: could not resolve key for map/slice, expecting 'string' but got '<nil>'"),
+		},
+		{
+			name: "first key not initialized",
+			keys: []ottl.Key[any]{
+				&pathtest.Key[any]{},
+			},
+			err: errors.New("unable to resolve a string index in map: invalid key type"),
+		},
+		{
+			name: "valid",
+			keys: []ottl.Key[any]{
+				&pathtest.Key[any]{
+					S: ottltest.Strp("string"),
+				},
+			},
+			key: "string",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			resolvedKey, err := ctxutil.GetMapKeyName[any](context.Background(), nil, tt.keys)
+			if tt.err != nil {
+				assert.Equal(t, tt.err.Error(), err.Error())
+				return
+			}
+			assert.Equal(t, tt.key, *resolvedKey)
+		})
+	}
+}