Drop usage of go's log package

internal/timeperiod/timeperiod.go

@@ -2,7 +2,6 @@ package timeperiod
 
 import (
 	"github.com/teambition/rrule-go"
-	"log"
 	"time"
 )
 
@@ -46,6 +45,8 @@ func (p *TimePeriod) NextTransition(base time.Time) time.Time {
 	return transition
 }
 
+// Entry represents a single TimePeriod segment and defines its own start and end time.
+// You should initialize it by calling its Init method before using any of its other methods.
 type Entry struct {
 	Start, End time.Time
 
@@ -57,6 +58,7 @@ type Entry struct {
 }
 
 // Init initializes the rrule instance from the configured rrule string
+// Returns error when it fails to initiate an RRule instance from the configured rrule string (if any).
 func (e *Entry) Init() error {
 	if e.rrule != nil || e.RecurrenceRule == "" {
 		return nil
@@ -82,10 +84,10 @@ func (e *Entry) Init() error {
 }
 
 // Contains returns whether a point in time t is covered by this entry.
+// It panics when it's used before initializing the rrule instance while a rrule string is configured.
 func (e *Entry) Contains(t time.Time) bool {
-	err := e.Init()
-	if err != nil {
-		log.Printf("Can't initialize entry: %s", err)
+	if e.rrule == nil && e.RecurrenceRule != "" {
+		panic("time period entry not initialized")
 	}
 
 	if t.Before(e.Start) {
@@ -108,11 +110,10 @@ func (e *Entry) Contains(t time.Time) bool {
 
 // NextTransition returns the next recurrence start or end of this entry relative to the given time inclusively.
 // This function returns also time.Time's zero value if there is no transition that starts/ends at/after the
-// specified time.
+// specified time. It panics when it's used before initializing the rrule instance while a rrule string is configured.
 func (e *Entry) NextTransition(t time.Time) time.Time {
-	err := e.Init()
-	if err != nil {
-		log.Printf("Can't initialize entry: %s", err)
+	if e.rrule == nil && e.RecurrenceRule != "" {
+		panic("time period entry not initialized")
 	}
 
 	if t.Before(e.Start) {

internal/timeperiod/timeperiod_test.go

@@ -18,11 +18,11 @@ func TestEntry(t *testing.T) {
 		start := berlinTime("2023-03-01 09:00:00")
 		end := berlinTime("2023-03-01 11:00:00")
 		until := berlinTime("2023-03-03 09:00:00")
-		e := &timeperiod.Entry{
+		e := initEntry(&timeperiod.Entry{
 			Start:          start,
 			End:            end,
 			RecurrenceRule: fmt.Sprintf("FREQ=DAILY;UNTIL=%s", until.UTC().Format(rrule.DateTimeFormat)),
-		}
+		})
 
 		t.Run("TimeAtFirstRecurrenceStart", func(t *testing.T) {
 			assert.True(t, e.Contains(start))
@@ -72,11 +72,11 @@ func TestEntry(t *testing.T) {
 		t.Run("DST", func(t *testing.T) {
 			start := berlinTime("2023-03-25 01:00:00")
 			end := berlinTime("2023-03-25 02:30:00")
-			e := &timeperiod.Entry{
+			e := initEntry(&timeperiod.Entry{
 				Start:          start,
 				End:            end,
 				RecurrenceRule: "FREQ=DAILY",
-			}
+			})
 
 			assert.True(t, e.Contains(start))
 
@@ -94,11 +94,11 @@ func TestEntry(t *testing.T) {
 
 		start := berlinTime("2023-03-01 08:00:00")
 		end := berlinTime("2023-03-01 12:30:00")
-		e := &timeperiod.Entry{
+		e := initEntry(&timeperiod.Entry{
 			Start:          start,
 			End:            end,
 			RecurrenceRule: "FREQ=DAILY",
-		}
+		})
 
 		t.Run("TimeAtFirstRecurrenceStart", func(t *testing.T) {
 			assert.Equal(t, end, e.NextTransition(start))
@@ -123,11 +123,11 @@ func TestEntry(t *testing.T) {
 		t.Run("DST", func(t *testing.T) {
 			start := berlinTime("2023-03-25 01:00:00")
 			end := berlinTime("2023-03-25 02:30:00")
-			e := &timeperiod.Entry{
+			e := initEntry(&timeperiod.Entry{
 				Start:          start,
 				End:            end,
 				RecurrenceRule: "FREQ=DAILY",
-			}
+			})
 
 			assert.Equal(t, end, e.NextTransition(start), "next transition should match the first recurrence end")
 
@@ -149,13 +149,14 @@ func TestTimePeriodTransitions(t *testing.T) {
 	t.Run("WithOneEntry", func(t *testing.T) {
 		start := berlinTime("2023-03-27 09:00:00")
 		end := berlinTime("2023-03-27 17:00:00")
+
 		p := &timeperiod.TimePeriod{
 			Name: "Transition Test",
-			Entries: []*timeperiod.Entry{{
+			Entries: []*timeperiod.Entry{initEntry(&timeperiod.Entry{
 				Start:          start,
 				End:            end,
 				RecurrenceRule: "FREQ=DAILY",
-			}},
+			})},
 		}
 
 		assert.Equal(t, end, p.NextTransition(start), "next transition should match the interval end")
@@ -169,16 +170,16 @@ func TestTimePeriodTransitions(t *testing.T) {
 		p := &timeperiod.TimePeriod{
 			Name: "Transition Test",
 			Entries: []*timeperiod.Entry{
-				{
+				initEntry(&timeperiod.Entry{
 					Start:          start,
 					End:            end,
 					RecurrenceRule: "FREQ=HOURLY;BYHOUR=1,3,5,7,9,11,13,15",
-				},
-				{
+				}),
+				initEntry(&timeperiod.Entry{
 					Start:          berlinTime("2023-03-27 08:00:00"),
 					End:            berlinTime("2023-03-27 08:30:00"),
 					RecurrenceRule: "FREQ=HOURLY;BYHOUR=0,2,4,6,8,10,12,14",
-				},
+				}),
 			},
 		}
 
@@ -219,3 +220,12 @@ func berlinTime(value string) time.Time {
 
 	return t
 }
+
+func initEntry(e *timeperiod.Entry) *timeperiod.Entry {
+	err := e.Init()
+	if err != nil {
+		panic(err)
+	}
+
+	return e
+}