Reserve the width the whole reflog needs for its date column

Pad the date of every line to the width that the oldest entry in the
reflog asks for, so that the column keeps its width as the user scrolls.
This is the same treatment the commits panel's date column gets, with the
same limits; getReservedColumnWidths spells them out.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

pkg/gui/presentation/reflog_commits.go

@@ -18,8 +18,13 @@ func GetReflogCommitListDisplayStrings(commits []*models.Commit, startIdx int, e
 	}
 
 	var displayFunc func(*models.Commit, reflogCommitDisplayAttributes) []string
+	reservedDateWidth := 0
 	if fullDescription {
 		displayFunc = getFullDescriptionDisplayStringsForReflogCommit
+		// See getReservedColumnWidths for why the oldest entry alone decides
+		// how much width the date column needs.
+		reservedDateWidth = utils.StringWidth(utils.UnixToDateSmart(
+			now, commits[len(commits)-1].UnixTimestamp, timeFormat, shortTimeFormat))
 	} else {
 		displayFunc = getDisplayStringsForReflogCommit
 	}
@@ -29,12 +34,13 @@ func GetReflogCommitListDisplayStrings(commits []*models.Commit, startIdx int, e
 		cherryPicked := cherryPickedCommitHashSet.Includes(commit.Hash())
 		return displayFunc(commit,
 			reflogCommitDisplayAttributes{
-				cherryPicked:    cherryPicked,
-				diffed:          diffed,
-				parseEmoji:      parseEmoji,
-				timeFormat:      timeFormat,
-				shortTimeFormat: shortTimeFormat,
-				now:             now,
+				cherryPicked:      cherryPicked,
+				diffed:            diffed,
+				parseEmoji:        parseEmoji,
+				timeFormat:        timeFormat,
+				shortTimeFormat:   shortTimeFormat,
+				now:               now,
+				reservedDateWidth: reservedDateWidth,
 			})
 	})
 }
@@ -59,6 +65,9 @@ type reflogCommitDisplayAttributes struct {
 	timeFormat      string
 	shortTimeFormat string
 	now             time.Time
+	// The width the date column needs for the whole reflog, not just for the
+	// lines that are on screen
+	reservedDateWidth int
 }
 
 func getFullDescriptionDisplayStringsForReflogCommit(c *models.Commit, attrs reflogCommitDisplayAttributes) []string {
@@ -67,9 +76,12 @@ func getFullDescriptionDisplayStringsForReflogCommit(c *models.Commit, attrs ref
 		name = emoji.Sprint(name)
 	}
 
+	date := style.FgMagenta.Sprint(
+		utils.UnixToDateSmart(attrs.now, c.UnixTimestamp, attrs.timeFormat, attrs.shortTimeFormat))
+
 	return []string{
 		reflogHashColor(attrs.cherryPicked, attrs.diffed).Sprint(c.ShortHash()),
-		style.FgMagenta.Sprint(utils.UnixToDateSmart(attrs.now, c.UnixTimestamp, attrs.timeFormat, attrs.shortTimeFormat)),
+		utils.WithPadding(date, attrs.reservedDateWidth, utils.AlignLeft),
 		theme.DefaultTextColor.Sprint(name),
 	}
 }

pkg/gui/presentation/reflog_commits_test.go

@@ -77,14 +77,9 @@ func TestGetReflogCommitListDisplayStrings(t *testing.T) {
 			startIdx:        0,
 			endIdx:          1,
 			now:             time.Date(2020, 1, 1, 5, 3, 4, 0, time.UTC),
-			/* EXPECTED:
 			expected: formatExpected(`
 		hash1 2:03AM     commit: today
 				`),
-			ACTUAL: */
-			expected: formatExpected(`
-		hash1 2:03AM commit: today
-				`),
 		},
 	}