Self rename in Windows (fix #458) (#460)

config.example.toml

@@ -66,5 +66,9 @@
 
 #[windows]
 # Manually select Windows updates
-# accept_all_updates = false
+#accept_all_updates = false
 
+# Causes Topgrade to rename itself during the run to allow package managers 
+# to upgrade it. Use this only if you installed Topgrade by using a package
+# manager such as Scoop to Cargo
+#self_rename = true

src/config.rs

@@ -126,6 +126,7 @@ pub struct Vagrant {
 #[serde(deny_unknown_fields)]
 pub struct Windows {
     accept_all_updates: Option<bool>,
+    self_rename: Option<bool>,
 }
 
 #[derive(Deserialize, Default, Debug)]
@@ -505,6 +506,16 @@ impl Config {
         .unwrap_or(true)
     }
 
+    /// Whether to self rename the Topgrade executable during the run
+    #[allow(dead_code)]
+    pub fn self_rename(&self) -> bool {
+        self.config_file
+            .windows
+            .as_ref()
+            .and_then(|w| w.self_rename)
+            .unwrap_or(false)
+    }
+
     /// Whether Brew cask should be greedy
     #[allow(dead_code)]
     pub fn brew_cask_greedy(&self) -> bool {

src/main.rs

@@ -6,6 +6,8 @@ mod execution_context;
 mod executor;
 mod report;
 mod runner;
+#[cfg(windows)]
+mod self_renamer;
 #[cfg(feature = "self-update")]
 mod self_update;
 mod steps;
@@ -92,6 +94,16 @@ fn run() -> Result<()> {
         }
     }
 
+    #[cfg(windows)]
+    let _self_rename = if config.self_rename() {
+        Some(crate::self_renamer::SelfRenamer::create()?)
+    } else {
+        None
+    };
+
+    let mut s = String::new();
+    std::io::stdin().read_line(&mut s)?;
+
     if let Some(commands) = config.pre_commands() {
         for (name, command) in commands {
             generic::run_custom_command(&name, &command, &ctx)?;

src/self_renamer.rs

@@ -0,0 +1,43 @@
+#![cfg(windows)]
+
+use anyhow::Result;
+use log::{debug, error};
+use std::{env::current_exe, fs, path::PathBuf};
+
+pub struct SelfRenamer {
+    exe_path: PathBuf,
+    temp_path: PathBuf,
+}
+
+impl SelfRenamer {
+    pub fn create() -> Result<Self> {
+        let tempdir = tempfile::tempdir()?;
+        let temp_path = tempdir.path().join("topgrade.exe");
+        let exe_path = current_exe()?;
+
+        debug!("Current exe in {:?}. Moving it to {:?}", exe_path, temp_path);
+
+        fs::rename(&exe_path, &temp_path)?;
+
+        Ok(SelfRenamer { exe_path, temp_path })
+    }
+}
+
+impl Drop for SelfRenamer {
+    fn drop(&mut self) {
+        if self.exe_path.exists() {
+            debug!("{:?} exists. Topgrade was probably upgraded", self.exe_path);
+            return;
+        }
+
+        match fs::rename(&self.temp_path, &self.exe_path) {
+            Ok(_) => debug!("Moved topgrade back from {:?} to {:?}", self.temp_path, self.exe_path),
+            Err(e) => error!(
+                "Could not move Topgrade from {} back to {}: {}",
+                self.temp_path.display(),
+                self.exe_path.display(),
+                e
+            ),
+        }
+    }
+}