The -t flag now works when the tmux session already exists (fix #54)

src/tmux.rs

@@ -5,7 +5,9 @@ use super::utils::{Check, PathExt};
 use directories::BaseDirs;
 use failure::Error;
 use std::env;
+use std::io;
 use std::os::unix::process::CommandExt;
+use std::path::Path;
 use std::process::Command;
 
 pub fn run_tpm(base_dirs: &BaseDirs, terminal: &mut Terminal, dry_run: bool) -> Option<(&'static str, bool)> {
@@ -27,9 +29,35 @@ pub fn run_tpm(base_dirs: &BaseDirs, terminal: &mut Terminal, dry_run: bool) ->
     None
 }
 
+fn has_session(tmux: &Path, session_name: &str) -> Result<bool, io::Error> {
+    Ok(Command::new(tmux)
+        .args(&["has-session", "-t", session_name])
+        .spawn()?
+        .wait()?
+        .success())
+}
+
+fn run_in_session(tmux: &Path, command: &str) -> Result<(), Error> {
+    Command::new(tmux)
+        .args(&["new-window", "-a", "-t", "topgrade:1", command])
+        .spawn()?
+        .wait()?
+        .check()?;
+
+    Ok(())
+}
+
 pub fn run_in_tmux() -> ! {
     let tmux = which("tmux").expect("Could not find tmux");
+    let command = env::args().collect::<Vec<String>>().join(" ");
 
+    if has_session(&tmux, "topgrade").expect("Error launching tmux") {
+        run_in_session(&tmux, &command).expect("Error launching tmux");
+
+        let err = Command::new(tmux).args(&["attach", "-t", "topgrade"]).exec();
+
+        panic!("{:?}", err);
+    } else {
         let err = Command::new(tmux)
             .args(&[
                 "new-session",
@@ -37,7 +65,7 @@ pub fn run_in_tmux() -> ! {
                 "topgrade",
                 "-n",
                 "topgrade",
-            &env::args().collect::<Vec<String>>().join(" "),
+                &command,
                 ";",
                 "set",
                 "remain-on-exit",
@@ -47,3 +75,4 @@ pub fn run_in_tmux() -> ! {
 
         panic!("{:?}", err);
     }
+}