APIGOV-27289 - more informative NPE (#751)

* APIGOV-27289 - more informative NPE

* fix tests

pkg/util/exception/exception.go

@@ -1,5 +1,11 @@
 package exception
 
+import (
+	"fmt"
+	"runtime/debug"
+	"strings"
+)
+
 // Block - defines the try, catch and finally code blocks
 type Block struct {
 	Try     func()
@@ -28,8 +34,13 @@ func (block Block) Do() {
 
 	if block.Catch != nil {
 		defer func() {
-			if r := recover(); r != nil {
-				block.Catch(r.(error))
+			if obj := recover(); obj != nil {
+				err := obj.(error)
+				if strings.Contains(err.Error(), "nil pointer dereference") {
+					block.Catch(fmt.Errorf(err.Error() + ": \n " + string(debug.Stack())))
+				} else {
+					block.Catch(err)
+				}
 			}
 		}()
 	}

pkg/util/exception/exeception_test.go

@@ -2,6 +2,7 @@ package exception
 
 import (
 	"errors"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -58,3 +59,23 @@ func TestExceptionTryCatchFinallyBlock(t *testing.T) {
 	assert.Equal(t, "try_catch_finally_err", catchErr.Error())
 	assert.Equal(t, "trycatchfinally", executionOrder)
 }
+
+func TestExceptionTryCatchBlockWithNPE(t *testing.T) {
+	var catchErr error
+	var executionOrder string
+	tryCatchFinallyBlockException := Block{
+		Try: func() {
+			executionOrder = "try"
+			b := Block{}
+			b.Try()
+		},
+		Catch: func(err error) {
+			executionOrder = executionOrder + "catch"
+			catchErr = err
+		},
+	}.Do
+
+	assert.NotPanics(t, tryCatchFinallyBlockException)
+	assert.NotNil(t, catchErr)
+	assert.Equal(t, strings.Contains(catchErr.Error(), "runtime error: invalid memory address or nil pointer dereference"), true)
+}