add native-border option to --tmux flag

This commit adds the `native-border` resulting in
the following:
```
--tmux[=[center|top|bottom|left|right][,SIZE[%]][,SIZE[%]][,native-border]]
```

By default, when not specified, the `-B` flag is passed to the
`tmux popup-window` command such that no border is drawn around
the tmux popup window.

When the `native-border` option is present the `-B` flag is omitted
and the popup window is drawn using the border style configured in
the tmux config file.

Fixes #4156

Signed-off-by: Andreas Auernhammer <[email protected]>

ADVANCED.md

@@ -128,7 +128,7 @@ fzf  --height 70% --tmux 70%
 You can also specify the position, width, and height of the popup window in
 the following format:
 
-* `[center|top|bottom|left|right][,SIZE[%]][,SIZE[%]]`
+* `[center|top|bottom|left|right][,SIZE[%]][,SIZE[%][,border-native]]`
 
 ```sh
 # 100% width and 60% height

README.md

@@ -343,7 +343,7 @@ fzf --height -3
 With `--tmux` option, fzf will start in a tmux popup.
 
 ```sh
-# --tmux [center|top|bottom|left|right][,SIZE[%]][,SIZE[%]]
+# --tmux [center|top|bottom|left|right][,SIZE[%]][,SIZE[%][,border-native]]
 
 fzf --tmux center         # Center, 50% width and height
 fzf --tmux 80%            # Center, 80% width and height

man/man1/fzf.1

@@ -271,7 +271,7 @@ Adaptive height has the following limitations:
 Minimum height when \fB\-\-height\fR is given in percent (default: 10).
 Ignored when \fB\-\-height\fR is not specified.
 .TP
-.BI "\-\-tmux" "[=[center|top|bottom|left|right][,SIZE[%]][,SIZE[%]]]"
+.BI "\-\-tmux" "[=[center|top|bottom|left|right][,SIZE[%]][,SIZE[%]][,border-native]]"
 Start fzf in a tmux popup (default \fBcenter,50%\fR). Requires tmux 3.3 or
 later. This option is ignored if you are not running fzf inside tmux.
 
@@ -286,7 +286,11 @@ e.g.
   fzf \-\-tmux bottom,30%
 
   # Popup on the top with 80% width and 40% height
-  fzf \-\-tmux top,80%,40%\fR
+  fzf \-\-tmux top,80%,40%
+
+  # Popup with a native window border in the center
+  # with 80% width and 50% height.
+  fzf \-\-tmux center,80%,50%,border-native\fR
 
 .TP
 .BI "\-\-layout=" "LAYOUT"

src/options.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"regexp"
+	"slices"
 	"strconv"
 	"strings"
 	"unicode"
@@ -254,6 +255,7 @@ type tmuxOptions struct {
 	height   sizeSpec
 	position windowPosition
 	index    int
+	border   bool
 }
 
 type layoutType int
@@ -309,15 +311,16 @@ func defaultTmuxOptions(index int) *tmuxOptions {
 		position: posCenter,
 		width:    sizeSpec{50, true},
 		height:   sizeSpec{50, true},
-		index:    index}
+		index:    index,
+	}
 }
 
 func parseTmuxOptions(arg string, index int) (*tmuxOptions, error) {
 	var err error
 	opts := defaultTmuxOptions(index)
 	tokens := splitRegexp.Split(arg, -1)
-	errorToReturn := errors.New("invalid tmux option: " + arg + " (expected: [center|top|bottom|left|right][,SIZE[%]][,SIZE[%]])")
-	if len(tokens) == 0 || len(tokens) > 3 {
+	errorToReturn := errors.New("invalid tmux option: " + arg + " (expected: [center|top|bottom|left|right][,SIZE[%]][,SIZE[%][,border-native]])")
+	if len(tokens) == 0 || len(tokens) > 4 {
 		return nil, errorToReturn
 	}
 
@@ -340,6 +343,15 @@ func parseTmuxOptions(arg string, index int) (*tmuxOptions, error) {
 		tokens = append([]string{"center"}, tokens...)
 	}
 
+	if i := slices.Index(tokens, "border-native"); i >= 0 {
+		// The border option, if present, is the last one
+		if i != len(tokens)-1 {
+			return nil, errorToReturn
+		}
+		tokens = slices.Delete(tokens, i, i+1)
+		opts.border = true
+	}
+
 	// One size given
 	var size1 sizeSpec
 	if len(tokens) > 1 {
@@ -650,7 +662,8 @@ func defaultOptions() *Options {
 		WalkerRoot:   []string{"."},
 		WalkerSkip:   []string{".git", "node_modules"},
 		Help:         false,
-		Version:      false}
+		Version:      false,
+	}
 }
 
 func optString(arg string, prefixes ...string) (bool, string) {
@@ -1725,7 +1738,7 @@ func strLines(str string) []string {
 }
 
 func parseSize(str string, maxPercent float64, label string) (sizeSpec, error) {
-	var spec = sizeSpec{}
+	spec := sizeSpec{}
 	var val float64
 	var err error
 	percent := strings.HasSuffix(str, "%")
@@ -1811,7 +1824,8 @@ func parseInfoStyle(str string) (infoStyle, string, error) {
 	}
 	for _, spec := range []infoSpec{
 		{"inline", infoInline},
-		{"inline-right", infoInlineRight}} {
+		{"inline-right", infoInlineRight},
+	} {
 		if strings.HasPrefix(str, spec.name+":") {
 			return spec.style, strings.ReplaceAll(str[len(spec.name)+1:], "\n", " "), nil
 		}

src/tmux.go

@@ -33,7 +33,10 @@ func runTmux(args []string, opts *Options) (int, error) {
 	// M        Both    The mouse position
 	// W        Both    The window position on the status line
 	// S        -y      The line above or below the status line
-	tmuxArgs := []string{"display-popup", "-E", "-B", "-d", dir}
+	tmuxArgs := []string{"display-popup", "-E", "-d", dir}
+	if !opts.Tmux.border {
+		tmuxArgs = append(tmuxArgs, "-B")
+	}
 	switch opts.Tmux.position {
 	case posUp:
 		tmuxArgs = append(tmuxArgs, "-xC", "-y0")