fix(dates): keep a date on its own day where local midnight is skipped

go.mod

@@ -2,7 +2,7 @@ module github.com/ryanlewis/things-cli
 
 go 1.26.0
 
-toolchain go1.26.9
+toolchain go1.26.10
 
 require (
 	charm.land/lipgloss/v2 v2.0.6

internal/model/model.go

@@ -203,7 +203,19 @@ func (d ThingsDate) Date() (year int, month time.Month, day int) {
 
 func (d ThingsDate) ToTime() time.Time {
 	year, month, day := d.Date()
-	return time.Date(year, month, day, 0, 0, 0, 0, time.Local)
+	return DayStart(year, month, day)
+}
+
+// DayStart is the first instant of the given local day. That is midnight,
+// except where a daylight-saving change skips it (Santiago, Havana, Beirut):
+// time.Date then answers with the evening of the day before, so it steps
+// forward to the first hour that is on the day.
+func DayStart(year int, month time.Month, day int) time.Time {
+	t := time.Date(year, month, day, 0, 0, 0, 0, time.Local)
+	for h := 1; t.Day() != day && h < 24; h++ {
+		t = time.Date(year, month, day, h, 0, 0, 0, time.Local)
+	}
+	return t
 }
 
 func ThingsDateFromTime(t time.Time) ThingsDate {

internal/model/model_test.go

@@ -571,3 +571,30 @@ func TestReminderText(t *testing.T) {
 		}
 	}
 }
+
+// Santiago's clocks go from 23:59 on 5 Sep 2026 straight to 01:00 on 6 Sep, so
+// local midnight on the 6th does not exist. time.Date then answers with the
+// evening of the 5th, and a date built from it printed a day early.
+func TestThingsDateSkippedMidnight(t *testing.T) {
+	loc, err := time.LoadLocation("America/Santiago")
+	if err != nil {
+		t.Skipf("no tzdata: %v", err)
+	}
+	old := time.Local
+	time.Local = loc
+	t.Cleanup(func() { time.Local = old })
+
+	d := ThingsDateFromTime(time.Date(2026, 9, 6, 12, 0, 0, 0, loc))
+	if got := d.String(); got != "2026-09-06" {
+		t.Errorf("String() = %q, want 2026-09-06", got)
+	}
+	if got := d.AddDays(1).String(); got != "2026-09-07" {
+		t.Errorf("AddDays(1) = %q, want 2026-09-07", got)
+	}
+	if got := d.AddDays(-1).String(); got != "2026-09-05" {
+		t.Errorf("AddDays(-1) = %q, want 2026-09-05", got)
+	}
+	if y, m, day := d.ToTime().Date(); y != 2026 || m != time.September || day != 6 {
+		t.Errorf("ToTime() = %v, want a time on 2026-09-06", d.ToTime())
+	}
+}

internal/things/dates.go

@@ -7,6 +7,8 @@ import (
 	"strconv"
 	"strings"
 	"time"
+
+	"github.com/ryanlewis/things-cli/internal/model"
 )
 
 var whenKeywords = []string{"today", "tomorrow", "evening", "anytime", "someday"}
@@ -366,13 +368,13 @@ func ParseListDate(flag, s string) (time.Time, error) {
 		return time.Time{}, fmt.Errorf("--%s: date is empty", flag)
 	}
 	if t, ok := parseISO8601(v); ok {
-		return time.Date(t.Year(), t.Month(), t.Day(), 0, 0, 0, 0, time.Local), nil
+		return model.DayStart(t.Year(), t.Month(), t.Day()), nil
 	}
-	t, err := time.ParseInLocation("2006-01-02", v, time.Local)
+	t, err := time.Parse("2006-01-02", v)
 	if err != nil {
 		return time.Time{}, fmt.Errorf("--%s: invalid date %q (expected YYYY-MM-DD)", flag, v)
 	}
-	return t, nil
+	return model.DayStart(t.Year(), t.Month(), t.Day()), nil
 }
 
 // NormalizeDeadline validates and canonicalises a --deadline value. The URL

internal/things/dates_test.go

@@ -300,3 +300,25 @@ func TestResolveWhen(t *testing.T) {
 		}
 	}
 }
+
+// Local midnight on 6 Sep 2026 does not exist in Santiago, so a --on date
+// built at midnight came out as the 5th and the filter matched the wrong day.
+func TestParseListDateSkippedMidnight(t *testing.T) {
+	loc, err := time.LoadLocation("America/Santiago")
+	if err != nil {
+		t.Skipf("no tzdata: %v", err)
+	}
+	old := time.Local
+	time.Local = loc
+	t.Cleanup(func() { time.Local = old })
+
+	for _, in := range []string{"2026-09-06", "2026-09-06T10:00:00Z"} {
+		got, err := ParseListDate("on", in)
+		if err != nil {
+			t.Fatalf("ParseListDate(%q): %v", in, err)
+		}
+		if y, m, d := got.Date(); y != 2026 || m != time.September || d != 6 {
+			t.Errorf("ParseListDate(%q) = %v, want a time on 2026-09-06", in, got)
+		}
+	}
+}