feat: Extract correct type and value from top-most error

Author: kamilogorek

Diff for: client.go

@@ -298,11 +298,17 @@ func (client *Client) eventFromException(exception error, level Level) *Event {
 		stacktrace = NewStacktrace()
 	}
 
+	cause := exception
+	// Handle wrapped errors for github.com/pingcap/errors and github.com/pkg/errors
+	if ex, ok := exception.(interface{ Cause() error }); ok {
+		cause = ex.Cause()
+	}
+
 	event := NewEvent()
 	event.Level = level
 	event.Exception = []Exception{{
-		Value:      exception.Error(),
-		Type:       reflect.TypeOf(exception).String(),
+		Value:      cause.Error(),
+		Type:       reflect.TypeOf(cause).String(),
 		Stacktrace: stacktrace,
 	}}
 	return event

Diff for: client_test.go

@@ -3,6 +3,8 @@ package sentry
 import (
 	"errors"
 	"testing"
+
+	pkgErrors "github.com/pkg/errors"
 )
 
 func TestNewClientAllowsEmptyDSN(t *testing.T) {
@@ -58,6 +60,7 @@ func TestCaptureMessageShouldSucceedWithoutNilScope(t *testing.T) {
 func TestCaptureExceptionShouldSendEventWithProvidedError(t *testing.T) {
 	client, scope, transport := setupClientTest()
 	client.CaptureException(errors.New("custom error"), nil, scope)
+	assertEqual(t, transport.lastEvent.Exception[0].Type, "*errors.errorString")
 	assertEqual(t, transport.lastEvent.Exception[0].Value, "custom error")
 }
 
@@ -67,6 +70,21 @@ func TestCaptureExceptionShouldNotFailWhenPassedNil(t *testing.T) {
 	assertEqual(t, transport.lastEvent.Message, "Called CaptureException with nil value")
 }
 
+type customErr struct{}
+
+func (e *customErr) Error() string {
+	return "wat"
+}
+
+func TestCaptureExceptionShouldExtractCorrectTypeAndValueForWrappedErrors(t *testing.T) {
+	client, scope, transport := setupClientTest()
+	cause := &customErr{}
+	err := pkgErrors.WithStack(cause)
+	client.CaptureException(err, nil, scope)
+	assertEqual(t, transport.lastEvent.Exception[0].Type, "*sentry.customErr")
+	assertEqual(t, transport.lastEvent.Exception[0].Value, "wat")
+}
+
 func TestCaptureEventShouldSendEventWithProvidedError(t *testing.T) {
 	client, scope, transport := setupClientTest()
 	event := NewEvent()