Automatically set /dev/tty as STDIN on execute action

https://github.com/junegunn/fzf/issues/1360#issuecomment-788178140

  # Redirect /dev/tty to suppress "Vim: Warning: Input is not from a terminal"
  ls | fzf --bind "enter:execute(vim {} < /dev/tty)"

  # With this change, we can omit "< /dev/tty" part
  ls | fzf --bind "enter:execute(vim {})"

src/terminal.go

@@ -1723,7 +1723,7 @@ func (t *Terminal) executeCommand(template string, forcePlus bool, background bo
 	command := t.replacePlaceholder(template, forcePlus, string(t.input), list)
 	cmd := util.ExecCommand(command, false)
 	if !background {
-		cmd.Stdin = os.Stdin
+		cmd.Stdin = tui.TtyIn()
 		cmd.Stdout = os.Stdout
 		cmd.Stderr = os.Stderr
 		t.tui.Pause(true)

src/tui/ttyname_unix.go

@@ -4,6 +4,7 @@ package tui
 
 import (
 	"io/ioutil"
+	"os"
 	"syscall"
 )
 
@@ -29,3 +30,18 @@ func ttyname() string {
 	}
 	return ""
 }
+
+// TtyIn returns terminal device to be used as STDIN, falls back to os.Stdin
+func TtyIn() *os.File {
+	in, err := os.OpenFile(consoleDevice, syscall.O_RDONLY, 0)
+	if err != nil {
+		tty := ttyname()
+		if len(tty) > 0 {
+			if in, err := os.OpenFile(tty, syscall.O_RDONLY, 0); err == nil {
+				return in
+			}
+		}
+		return os.Stdin
+	}
+	return in
+}

src/tui/ttyname_windows.go

@@ -2,6 +2,13 @@
 
 package tui
 
+import "os"
+
 func ttyname() string {
 	return ""
 }
+
+// TtyIn on Windows returns os.Stdin
+func TtyIn() *os.File {
+	return os.Stdin
+}