Preserve tmux window zoom when opening a floating pane

- Use new-pane -A on tmux 3.8+ to keep floating pane above zoomed pane
- Detect -A from new-pane usage; keep unzoom fallback for 3.7

Fix #4927
Fix junegunn/fzf.vim#1625

Co-authored-by: Jere Viikari <jere.viikari@gmail.com>

CHANGELOG.md

@@ -9,6 +9,8 @@ CHANGELOG
 - Fixed `focus` event not triggered after `reload` when the new item is at the same position as the previous one (#4930)
     - With `--id-nth`, the event is not triggered if the focus moves directly from an item to another item with the same key
     - A `focus` binding that runs `reload` now triggers itself again after each reload, unless `--id-nth` is set and the key does not change
+- Fixed `--popup` unzooming the window when opened over a zoomed pane on tmux 3.8 or above (#4927, junegunn/fzf.vim#1625)
+    - On tmux 3.7, the window is still unzoomed, as tmux 3.7b crashes when a floating pane is created over a zoomed window
 
 0.74.4
 ------

src/tmux.go

@@ -5,14 +5,19 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"regexp"
 	"strings"
 
 	"github.com/junegunn/fzf/src/tui"
 )
 
+// The flag group of new-pane usage includes -A (tmux 3.8 or above)
+var tmuxOverZoomFlag = regexp.MustCompile(`new-pane.*\[-[[:alpha:]]*A`)
+
 // Returns the size of the current window if the tmux server supports
-// floating panes (tmux 3.7 or above)
-func tmuxFloatingPaneInfo() (int, int, bool) {
+// floating panes (tmux 3.7 or above), and whether a floating pane can stay
+// above a zoomed pane
+func tmuxFloatingPaneInfo() (int, int, bool, bool) {
 	// TMUX_PANE is not set when fzf is not started from within a pane
 	// (e.g. 'bind-key 0 run-shell "fzf --popup"'). Do not use a floating
 	// pane there; a blocking run-shell suspends key processing for the
@@ -25,7 +30,7 @@ func tmuxFloatingPaneInfo() (int, int, bool) {
 	//   https://github.com/tmux/tmux/issues/5384
 	target := os.Getenv("TMUX_PANE")
 	if target == "" {
-		return 0, 0, false
+		return 0, 0, false, false
 	}
 	// A single invocation for both checks. Cannot rely on the exit status;
 	// tmux versions before 3.7 exit normally with empty output for an
@@ -33,17 +38,17 @@ func tmuxFloatingPaneInfo() (int, int, bool) {
 	out, err := exec.Command("tmux", "display-message", "-p", "-t", target,
 		"#{window_width} #{window_height}", ";", "list-commands", "new-pane").Output()
 	if err != nil || !strings.Contains(string(out), "new-pane") {
-		return 0, 0, false
+		return 0, 0, false, false
 	}
 	var width, height int
 	if _, err := fmt.Sscanf(string(out), "%d %d", &width, &height); err != nil {
-		return 0, 0, false
+		return 0, 0, false, false
 	}
 	// The window is too small to fit a floating pane of the minimum size
 	if width < 3 || height < 3 {
-		return 0, 0, false
+		return 0, 0, false, false
 	}
-	return width, height, true
+	return width, height, tmuxOverZoomFlag.Match(out), true
 }
 
 // tmux ends a command at an argument ending in ';', so a trailing one is
@@ -85,7 +90,7 @@ func tmuxDim(spec sizeSpec, window int) int {
 	return max(3, min(dim, window))
 }
 
-func runTmuxFloatingPane(argStr string, dir string, windowWidth int, windowHeight int, opts *Options) (int, error) {
+func runTmuxFloatingPane(argStr string, dir string, windowWidth int, windowHeight int, overZoom bool, opts *Options) (int, error) {
 	// Unlike display-popup, the size of a floating pane does not account for
 	// the border around it, and the position is that of the content area. To
 	// stay consistent with popups, treat the requested size as the total
@@ -166,13 +171,15 @@ func runTmuxFloatingPane(argStr string, dir string, windowWidth int, windowHeigh
 		}
 		paneCmd := fmt.Sprintf("%s%s %s; echo $? > %s; tmux wait-for -S %s",
 			setup, escapeSingleQuote(sh), escapeSingleQuote(temp), code, signal)
-		// Unzoom the window first; creating a floating pane over a zoomed
-		// window crashes the tmux server on 3.7b, and newer versions of
-		// tmux unzoom the window anyway.
 		target := os.Getenv("TMUX_PANE")
-		newPane := fmt.Sprintf(
-			"tmux if -F -t %s '#{window_zoomed_flag}' %s ';' new-pane -P -F '#{pane_id}' -t %s -c %s -x %d -y %d -X %d -Y %d %s -c %s",
-			escapeSingleQuote(target), escapeSingleQuote("resize-pane -Z -t "+target),
+		newPane := "tmux new-pane -A"
+		if !overZoom {
+			// Unzoom the window first; creating a floating pane over a
+			// zoomed window crashes the tmux server on 3.7b
+			newPane = fmt.Sprintf("tmux if -F -t %s '#{window_zoomed_flag}' %s ';' new-pane",
+				escapeSingleQuote(target), escapeSingleQuote("resize-pane -Z -t "+target))
+		}
+		newPane += fmt.Sprintf(" -P -F '#{pane_id}' -t %s -c %s -x %d -y %d -X %d -Y %d %s -c %s",
 			escapeSingleQuote(target), escapeSingleQuote(dir), width-2, height-2, x, y,
 			escapeSingleQuote(sh), escapeSingleQuote(paneCmd))
 
@@ -222,10 +229,10 @@ func runTmux(args []string, opts *Options) (int, error) {
 	// popup is used instead so that the fzf-drawn border is the only border
 	// shown; the native border of a tmux floating pane cannot be removed.
 	if nativeBorder(opts) {
-		if windowWidth, windowHeight, ok := tmuxFloatingPaneInfo(); ok {
+		if windowWidth, windowHeight, overZoom, ok := tmuxFloatingPaneInfo(); ok {
 			opts.Tmux.border = true
 			argStr, dir := popupArgStr(args, opts)
-			return runTmuxFloatingPane(argStr, dir, windowWidth, windowHeight, opts)
+			return runTmuxFloatingPane(argStr, dir, windowWidth, windowHeight, overZoom, opts)
 		}
 	}