Panic MW: will now return a custom PanicStackError with stack trace when config.DisablePrintStack is set to false.

Author: aldas

middleware/recover.go

@@ -77,7 +77,7 @@ func (config RecoverConfig) ToMiddleware() (echo.MiddlewareFunc, error) {
 					if !config.DisablePrintStack {
 						stack := make([]byte, config.StackSize)
 						length := runtime.Stack(stack, !config.DisableStackAll)
-						tmpErr = fmt.Errorf("[PANIC RECOVER] %w %s", tmpErr, stack[:length])
+						tmpErr = &PanicStackError{Stack: stack[:length], Err: tmpErr}
 					}
 					err = tmpErr
 				}
@@ -86,3 +86,18 @@ func (config RecoverConfig) ToMiddleware() (echo.MiddlewareFunc, error) {
 		}
 	}, nil
 }
+
+// PanicStackError is an error type that wraps an error along with its stack trace.
+// It is returned when config.DisablePrintStack is set to false.
+type PanicStackError struct {
+	Stack []byte
+	Err   error
+}
+
+func (e *PanicStackError) Error() string {
+	return fmt.Sprintf("[PANIC RECOVER] %s %s", e.Err.Error(), e.Stack)
+}
+
+func (e *PanicStackError) Unwrap() error {
+	return e.Err
+}

middleware/recover_test.go

@@ -5,6 +5,7 @@ package middleware
 
 import (
 	"bytes"
+	"errors"
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
@@ -26,6 +27,14 @@ func TestRecover(t *testing.T) {
 	})
 	err := h(c)
 	assert.Contains(t, err.Error(), "[PANIC RECOVER] test goroutine")
+
+	var pse *PanicStackError
+	if errors.As(err, &pse) {
+		assert.Contains(t, string(pse.Stack), "middleware/recover.go")
+	} else {
+		assert.Fail(t, "not of type PanicStackError")
+	}
+
 	assert.Equal(t, http.StatusOK, rec.Code) // status is still untouched. err is returned from middleware chain
 	assert.Contains(t, buf.String(), "")     // nothing is logged
 }