feat: use self_replace to delete self

axoupdater/Cargo.toml

@@ -35,3 +35,6 @@ tokio = { version = "1.36.0", features = ["full"], optional = true }
 # errors
 miette = "7.2.0"
 thiserror = "1.0.58"
+
+[target.'cfg(windows)'.dependencies]
+self-replace = "1.5.0"

axoupdater/src/errors.rs

@@ -159,4 +159,11 @@ pub enum AxoupdateError {
         /// to the terminal when running the installer.
         stderr: Option<String>,
     },
+
+    /// self_replace/self_delete failed
+    #[error(
+        "Cleaning up the previous version failed; a copy of the old version has been left behind."
+    )]
+    #[diagnostic(help("This probably isn't your fault; please open an issue at https://github.com/axodotdev/axoupdater!"))]
+    CleanupFailed {},
 }

axoupdater/src/lib.rs

@@ -13,12 +13,16 @@ pub use release::*;
 
 use std::{
     env::{self, args},
+    ffi::OsStr,
     process::Stdio,
 };
 
 #[cfg(unix)]
 use std::{fs::File, os::unix::fs::PermissionsExt};
 
+#[cfg(windows)]
+use self_replace;
+
 use axoasset::LocalAsset;
 use axoprocess::Cmd;
 pub use axotag::Version;
@@ -453,34 +457,21 @@ impl AxoUpdater {
             installer_path
         };
 
-        // Before we update, move ourselves to a temporary directory.
+        // Before we update, rename ourselves to a temporary name.
         // This is necessary because Windows won't let an actively-running
         // executable be overwritten.
         // If the update fails, we'll move it back to where it was before
         // we began the update process.
-        // NOTE: this TempDir needs to be held alive for the whole function.
-        let temp_root;
-        let to_restore = if cfg!(target_family = "windows") {
-            // If we know the install prefix, place the temporary directory for
-            // the executable there. This is because the `rename` syscall can't
-            // rename an executable across filesystem bounds, and there's a
-            // chance the system temporary directory could be on a different
-            // drive than the executable is.
-            // (A copy-and-delete move won't work because Windows won't let us
-            // delete a running executable - the same reason we're moving it out
-            // of the way to begin with!)
-            // See https://github.com/axodotdev/axoupdater/issues/120.
-            temp_root = if let Ok(prefix) = self.install_prefix_root() {
-                TempDir::new_in(prefix)?
-            } else {
-                TempDir::new()?
-            };
-            let old_path = std::env::current_exe()?;
-            let old_filename = old_path.file_name().expect("current binary has no name!?");
-            let ourselves = temp_root.path().join(old_filename);
-            std::fs::rename(&old_path, &ourselves)?;
+        let old_path;
+        let to_restore = if cfg!(windows) {
+            old_path = std::env::current_exe()?;
+            let filename = old_path.file_name();
+            let old_filename = filename.expect("current binary has no name!?");
 
-            Some((ourselves, old_path))
+            let mut new_filename = old_filename.to_os_string();
+            new_filename.push(OsStr::new(".__selfdelete__.exe"));
+
+            Some((new_filename, old_filename))
         } else {
             None
         };
@@ -550,6 +541,9 @@ impl AxoUpdater {
             if let Some((ourselves, old_path)) = to_restore {
                 std::fs::rename(ourselves, old_path)?;
             }
+        } else {
+            #[cfg(windows)]
+            self_replace::self_delete().map_err(|_| AxoupdateError::CleanupFailed {})?;
         }
 
         // Return the original AxoprocessError if we failed to launch