fix: return error in LoadMatching (#8234)

Signed-off-by: Vishal Choudhary <sendtovishalchoudhary@gmail.com>
Co-authored-by: Charles-Edouard Brétéché <charles.edouard@nirmata.com>

pkg/engine/context/deferred.go

@@ -145,7 +145,7 @@ func (d *deferredLoaders) LoadMatching(query string, level int) error {
 
 	for l, idx := d.match(query, level, index); l != nil; l, idx = d.match(query, level, index) {
 		if err := d.loadData(l, idx); err != nil {
-			return nil
+			return err
 		}
 	}
 

pkg/engine/context/deferred_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/pkg/errors"
 	"gotest.tools/assert"
 )
 
@@ -441,3 +442,56 @@ func TestDeferredNotHiddenOrdered(t *testing.T) {
 	assert.NilError(t, err)
 	assert.Equal(t, "baz", val)
 }
+
+type invalidLoader struct {
+	name      string
+	level     int
+	value     interface{}
+	query     string
+	hasLoaded bool
+	ctx       *context
+}
+
+func (il *invalidLoader) Name() string {
+	return il.name
+}
+
+func (il *invalidLoader) SetLevel(lvl int) {
+	il.level = lvl
+}
+
+func (il *invalidLoader) GetLevel() int {
+	return il.level
+}
+
+func (il *invalidLoader) HasLoaded() bool {
+	return il.hasLoaded
+}
+
+func (il *invalidLoader) LoadData() error {
+	return errors.New("failed to load data")
+}
+
+func addInvalidDeferredLoader(ctx *context, name string, value interface{}, query string) (*invalidLoader, error) {
+	loader := &invalidLoader{
+		name:  name,
+		value: value,
+		ctx:   ctx,
+		query: query,
+	}
+
+	d, err := NewDeferredLoader(name, loader, logger)
+	if err != nil {
+		return loader, err
+	}
+
+	ctx.AddDeferredLoader(d)
+	return loader, nil
+}
+
+func TestDeferredLoadMatchingError(t *testing.T) {
+	ctx := newContext()
+	addInvalidDeferredLoader(ctx, "value", "0", "value")
+	err := ctx.deferred.LoadMatching("value", len(ctx.jsonRawCheckpoints))
+	assert.ErrorContains(t, err, `failed to load data`)
+}