Eradicate panics

Author: runxiyu

course_types_groups.go

@@ -150,7 +150,7 @@ func populateUserCourseTypesAndGroups(
 		}
 		course, ok := _course.(*courseT)
 		if !ok {
-			panic("courses map has non-\"*courseT\" items")
+			return errType
 		}
 		thisGroupName = course.Group
 		thisTypeName = course.Type

endpoint_export_choices.go

@@ -92,7 +92,7 @@ func handleExportChoices(
 		}
 		course, ok := _course.(*courseT)
 		if !ok {
-			panic("courses map has non-\"*courseT\" items")
+			return "", -1, errType
 		}
 		if course == nil {
 			return "", -1, wrapAny(errNoSuchCourse, currentCourseID)

endpoint_index.go

@@ -58,14 +58,17 @@ func handleIndex(w http.ResponseWriter, req *http.Request) (string, int, error)
 			Courses: &_coursemap,
 		}
 	}
+	err = nil
 	courses.Range(func(key, value interface{}) bool {
 		courseID, ok := key.(int)
 		if !ok {
-			panic("courses map has non-\"int\" keys")
+			err = errType
+			return false
 		}
 		course, ok := value.(*courseT)
 		if !ok {
-			panic("courses map has non-\"*courseT\" items")
+			err = errType
+			return false
 		}
 		if department != staffDepartment {
 			if yearGroupsNumberBits[department]&course.YearGroups == 0 {
@@ -75,6 +78,9 @@ func handleIndex(w http.ResponseWriter, req *http.Request) (string, int, error)
 		(*_groups[course.Group].Courses)[courseID] = course
 		return true
 	})
+	if err != nil {
+		return "", -1, err
+	}
 
 	if department == staffDepartment {
 		StatesDereferenced := map[string]uint32{}

ws_connection.go

@@ -38,7 +38,7 @@ func handleConn(
 	c *websocket.Conn,
 	userID string,
 	department string,
-) error {
+) (reterr error) {
 	_state, ok := states[department]
 	if !ok {
 		return errNoSuchYearGroup
@@ -76,14 +76,17 @@ func handleConn(
 	usems := make(map[int]*usemT)
 
 	atomic.AddInt64(&usemCount, int64(atomic.LoadUint32(&numCourses)))
+	var err error
 	courses.Range(func(key, value interface{}) bool {
 		courseID, ok := key.(int)
 		if !ok {
-			panic("courses map has non-\"int\" keys")
+			err = errType
+			return false
 		}
 		course, ok := value.(*courseT)
 		if !ok {
-			panic("courses map has non-\"*courseT\" items")
+			err = errType
+			return false
 		}
 		usem := &usemT{} //exhaustruct:ignore
 		usem.init()
@@ -97,7 +100,8 @@ func handleConn(
 			_ = key
 			course, ok := value.(*courseT)
 			if !ok {
-				panic("courses map has non-\"*courseT\" items")
+				reterr = errType
+				return false
 			}
 			course.Usems.Delete(userID)
 			return true
@@ -137,7 +141,7 @@ func handleConn(
 
 	var userCourseGroups userCourseGroupsT = make(map[string]struct{})
 	var userCourseTypes userCourseTypesT = make(map[string]int)
-	err := populateUserCourseTypesAndGroups(
+	err = populateUserCourseTypesAndGroups(
 		newCtx,
 		&userCourseTypes,
 		&userCourseGroups,

ws_utils.go

@@ -72,7 +72,8 @@ func propagateSelectedUpdate(course *courseT) {
 		_ = key
 		usem, ok := value.(*usemT)
 		if !ok {
-			panic("Usems contains non-\"*usemT\" value")
+			slog.Error(errType.Error())
+			return false
 		}
 		usem.set()
 		return true
@@ -90,7 +91,7 @@ func sendSelectedUpdate(
 	}
 	course, ok := _course.(*courseT)
 	if !ok {
-		panic("courses map has non-\"*courseT\" items")
+		return errType
 	}
 	if course == nil {
 		return fmt.Errorf("%w: %d", errNoSuchCourse, courseID)
@@ -111,17 +112,20 @@ func propagate(yeargroup string, msg string) error {
 	if !ok {
 		return errNoSuchYearGroup
 	}
+	var err error
 	chanSubPool.Range(func(_userID, _ch interface{}) bool {
 		ch, ok := _ch.(*chan string)
 		if !ok {
-			panic("chanPool has non-\"*chan string\" key")
+			err = errType
+			return false
 		}
 		select {
 		case *ch <- msg:
 		default:
 			userID, ok := _userID.(string)
 			if !ok {
-				panic("chanPool has non-string key")
+				err = errType
+				return false
 			}
 			slog.Warn(
 				"sendq",
@@ -131,7 +135,7 @@ func propagate(yeargroup string, msg string) error {
 		}
 		return true
 	})
-	return nil
+	return err
 }
 
 func writeText(ctx context.Context, c *websocket.Conn, msg string) error {

wsmsg_choose.go

@@ -68,7 +68,7 @@ func messageChooseCourse(
 	}
 	course, ok := _course.(*courseT)
 	if !ok {
-		panic("courses map has non-\"*courseT\" items")
+		return errType
 	}
 	if course == nil {
 		return errNoSuchCourse

wsmsg_unchoose.go

@@ -63,7 +63,7 @@ func messageUnchooseCourse(
 	}
 	course, ok := _course.(*courseT)
 	if !ok {
-		panic("courses map has non-\"*courseT\" items")
+		return errType
 	}
 	if course == nil {
 		return errNoSuchCourse
@@ -94,7 +94,7 @@ func messageUnchooseCourse(
 		}
 		course, ok := _course.(*courseT)
 		if !ok {
-			panic("courses map has non-\"*courseT\" items")
+			return errType
 		}
 		if course == nil {
 			return errNoSuchCourse