Only handle one panic we're interested in

else, "rethrow"

so users can use functions that `panic` and have them act the way
they're expecting.

Author: msabramo

gomock/call.go

@@ -153,12 +153,23 @@ func (c *Call) Do(f interface{}) *Call {
 			}
 		}
 		defer func() {
-			if err := recover(); err != nil {
+			if r := recover(); r != nil {
+				errMsg, ok := r.(string)
+
+				// We only handle a very specific panic
+				// If it's not that one, then we "rethrow" the panic
+				// This allows users to use functions that panic in their tests
+				if !ok {
+					panic(r)
+				}
+				if !strings.Contains(errMsg, "reflect: Call using") {
+					panic(r)
+				}
 				skipFrames := 8
 				stackTraceStr := "\n\n" + currentStackTrace(skipFrames)
 				funcPC := v.Pointer()
 				file, line := runtime.FuncForPC(funcPC).FileLine(funcPC)
-				c.t.Fatalf("%s (incorrect func args at %s:%d?)%+v", err, file, line, stackTraceStr)
+				c.t.Fatalf("%s (incorrect func args at %s:%d?)%+v", errMsg, file, line, stackTraceStr)
 			}
 		}()
 		v.Call(vargs)