fix(renderer): restore tab stops if hard tabs are enabled (#1677)

aymanbagabas · web-flow · commit ac355fe194c3 · 2026-04-13T10:28:52.000-04:00
When hard tabs are enabled, we optimize rendering by using actual tab characters instead of spaces. This requires us to set tab stops every 8 columns at the beginning of the rendering process. Fixes: #1614
diff --git a/cursed_renderer.go b/cursed_renderer.go
@@ -61,7 +61,11 @@ func (s *cursedRenderer) setOptimizations(hardTabs, backspace, mapnl bool) {
 	s.hardTabs = hardTabs
 	s.backspace = backspace
 	s.mapnl = mapnl
-	s.scr.SetTabStops(s.width)
+	if s.hardTabs {
+		s.scr.SetTabStops(s.width)
+	} else {
+		s.scr.SetTabStops(-1)
+	}
 	s.scr.SetBackspace(s.backspace)
 	s.scr.SetMapNewline(s.mapnl)
 	s.mu.Unlock()
@@ -275,6 +279,11 @@ func (s *cursedRenderer) flush(closing bool) error {
 		}
 	}
 
+	// Restore tab stops if we have tab optimizations enabled.
+	if s.starting && s.hardTabs {
+		_, _ = s.scr.WriteString(ansi.SetTabEvery8Columns)
+	}
+
 	if !s.starting && !closing && s.lastView != nil && viewEquals(s.lastView, &view) && frameArea == s.cellbuf.Bounds() {
 		// No changes, nothing to do.
 		return nil
@@ -587,7 +596,11 @@ func reset(s *cursedRenderer) {
 	scr.SetColorProfile(s.profile)
 	scr.SetRelativeCursor(true) // Always start in inline mode
 	scr.SetFullscreen(false)    // Always start in inline mode
-	scr.SetTabStops(s.width)
+	if s.hardTabs {
+		scr.SetTabStops(s.width)
+	} else {
+		scr.SetTabStops(-1)
+	}
 	scr.SetBackspace(s.backspace)
 	scr.SetMapNewline(s.mapnl)
 	scr.SetScrollOptim(runtime.GOOS != "windows") // disable scroll optimization on Windows due to bugs in some terminals
diff --git a/testdata/TestViewModel/altscreen_autoexit.golden b/testdata/TestViewModel/altscreen_autoexit.golden
@@ -1 +1 @@
-[>4m[=0;1u[?1049h[?25l[?2004h[>4;2m[=1;1u[H[2Jsuccess[>4m[=0;1u[24d[?1049l[?25h[?2004l[?2026$p[?2027$p
+[>4m[=0;1u[?1049h[?25l[?2004h[>4;2m[=1;1u[H[2Jsuccess[>4m[=0;1u[24;1H[?1049l[?25h[?2004l[?2026$p[?2027$p

Original file line number	Diff line number	Diff line change
`@@ -1 +1 @@`
`1`		`-[>4m[=0;1u[?1049h[?25l[?2004h[>4;2m[=1;1u[H[2Jsuccess[>4m[=0;1u[24d[?1049l[?25h[?2004l[?2026$p[?2027$p`
	`1`	`+[>4m[=0;1u[?1049h[?25l[?2004h[>4;2m[=1;1u[H[2Jsuccess[>4m[=0;1u[24;1H[?1049l[?25h[?2004l[?2026$p[?2027$p`