10.2.0 release (#213)

src/steps/tmux.rs

@@ -1,16 +1,22 @@
+use std::env;
+use std::path::PathBuf;
+use std::process::Command;
+
+use color_eyre::eyre::eyre;
+use color_eyre::eyre::Context;
+use color_eyre::eyre::Result;
+use directories::BaseDirs;
+
+use crate::command::CommandExt;
 use crate::executor::RunType;
 use crate::terminal::print_separator;
 use crate::{
     execution_context::ExecutionContext,
-    utils::{which, Check, PathExt},
+    utils::{which, PathExt},
 };
-use anyhow::Result;
-use directories::BaseDirs;
-use std::env;
-use std::io;
-use std::os::unix::process::CommandExt;
-use std::path::PathBuf;
-use std::process::{exit, Command};
+
+#[cfg(unix)]
+use std::os::unix::process::CommandExt as _;
 
 pub fn run_tpm(base_dirs: &BaseDirs, run_type: RunType) -> Result<()> {
     let tpm = base_dirs
@@ -20,7 +26,7 @@ pub fn run_tpm(base_dirs: &BaseDirs, run_type: RunType) -> Result<()> {
 
     print_separator("tmux plugins");
 
-    run_type.execute(tpm).arg("all").check_run()
+    run_type.execute(tpm).arg("all").status_checked()
 }
 
 struct Tmux {
@@ -44,73 +50,130 @@ impl Tmux {
         command
     }
 
-    fn has_session(&self, session_name: &str) -> Result<bool, io::Error> {
+    fn has_session(&self, session_name: &str) -> Result<bool> {
         Ok(self
             .build()
             .args(["has-session", "-t", session_name])
-            .output()?
+            .output_checked_with(|_| Ok(()))?
             .status
             .success())
     }
 
-    fn new_session(&self, session_name: &str) -> Result<bool, io::Error> {
-        Ok(self
+    /// Create a new tmux session with the given name, running the given command.
+    /// The command is passed to `sh` (see "shell-command arguments are sh(1) commands" in the
+    /// `tmux(1)` man page).
+    fn new_session(&self, session_name: &str, window_name: &str, command: &str) -> Result<()> {
+        let _ = self
             .build()
-            .args(["new-session", "-d", "-s", session_name, "-n", "dummy"])
-            .spawn()?
-            .wait()?
-            .success())
+            // `-d`: initial size comes from the global `default-size` option (instead
+            //       of passing `-x` and `-y` arguments.
+            //       (What do those even do?)
+            // `-s`: session name
+            // `-n`: window name (always `topgrade`)
+            .args(["new-session", "-d", "-s", session_name, "-n", window_name, command])
+            .output_checked()?;
+        Ok(())
     }
 
-    fn run_in_session(&self, command: &str) -> Result<()> {
-        self.build()
-            .args(["new-window", "-t", "topgrade", command])
-            .spawn()?
-            .wait()?
-            .check()?;
+    /// Like [`new_session`] but it appends a digit to the session name (if necessary) to
+    /// avoid duplicate session names.
+    ///
+    /// The session name is returned.
+    fn new_unique_session(&self, session_name: &str, window_name: &str, command: &str) -> Result<String> {
+        let mut session = session_name.to_owned();
+        for i in 1.. {
+            if !self
+                .has_session(&session)
+                .context("Error determining if a tmux session exists")?
+            {
+                self.new_session(&session, window_name, command)
+                    .context("Error running Topgrade in tmux")?;
+                return Ok(session);
+            }
+            session = format!("{session_name}-{i}");
+        }
+        unreachable!()
+    }
 
-        Ok(())
+    /// Create a new window in the given tmux session, running the given command.
+    fn new_window(&self, session_name: &str, window_name: &str, command: &str) -> Result<()> {
+        self.build()
+            // `-d`: initial size comes from the global `default-size` option (instead
+            //       of passing `-x` and `-y` arguments.
+            //       (What do those even do?)
+            // `-s`: session name
+            // `-n`: window name
+            .args([
+                "new-window",
+                "-a",
+                "-t",
+                &format!("{session_name}:{window_name}"),
+                "-n",
+                window_name,
+                command,
+            ])
+            .env_remove("TMUX")
+            .status_checked()
+    }
+
+    fn window_indices(&self, session_name: &str) -> Result<Vec<usize>> {
+        self.build()
+            .args(["list-windows", "-F", "#{window_index}", "-t", session_name])
+            .output_checked_utf8()?
+            .stdout
+            .lines()
+            .map(|l| l.parse())
+            .collect::<Result<Vec<usize>, _>>()
+            .context("Failed to compute tmux windows")
     }
 }
 
-pub fn run_in_tmux(args: Vec<String>) -> ! {
+pub fn run_in_tmux(args: Vec<String>) -> Result<()> {
     let command = {
         let mut command = vec![
             String::from("env"),
             String::from("TOPGRADE_KEEP_END=1"),
             String::from("TOPGRADE_INSIDE_TMUX=1"),
         ];
+        // TODO: Should we use `topgrade` instead of the first argument here, which may be
+        // a local path?
         command.extend(env::args());
         shell_words::join(command)
     };
 
     let tmux = Tmux::new(args);
 
-    if !tmux.has_session("topgrade").expect("Error detecting a tmux session") {
-        tmux.new_session("topgrade").expect("Error creating a tmux session");
-    }
-
-    tmux.run_in_session(&command).expect("Error running Topgrade in tmux");
-    tmux.build()
-        .args(["kill-window", "-t", "topgrade:dummy"])
-        .output()
-        .expect("Error killing the dummy tmux window");
+    // Find an unused session and run `topgrade` in it with the current command's arguments.
+    let session_name = "topgrade";
+    let window_name = "topgrade";
+    let session = tmux.new_unique_session(session_name, window_name, &command)?;
 
+    // Only attach to the newly-created session if we're not currently in a tmux session.
     if env::var("TMUX").is_err() {
-        let err = tmux.build().args(["attach", "-t", "topgrade"]).exec();
-        panic!("{:?}", err);
+        let err = tmux.build().args(["attach-session", "-t", &session]).exec();
+        Err(eyre!("{err}")).context("Failed to `execvp(3)` tmux")
     } else {
         println!("Topgrade launched in a new tmux session");
-        exit(0);
+        Ok(())
     }
 }
 
-pub fn run_command(ctx: &ExecutionContext, command: &str) -> Result<()> {
-    Tmux::new(ctx.config().tmux_arguments()?)
-        .build()
-        .args(["new-window", "-a", "-t", "topgrade:1", command])
-        .env_remove("TMUX")
-        .spawn()?
-        .wait()?
-        .check()
+pub fn run_command(ctx: &ExecutionContext, window_name: &str, command: &str) -> Result<()> {
+    let tmux = Tmux::new(ctx.config().tmux_arguments()?);
+
+    match ctx.get_tmux_session() {
+        Some(session_name) => {
+            let indices = tmux.window_indices(&session_name)?;
+            let last_window = indices
+                .iter()
+                .last()
+                .ok_or_else(|| eyre!("tmux session {session_name} has no windows"))?;
+            tmux.new_window(&session_name, &format!("{last_window}"), command)?;
+        }
+        None => {
+            let name = tmux.new_unique_session("topgrade", window_name, command)?;
+            ctx.set_tmux_session(name);
+        }
+    }
+    Ok(())
 }