Allow self-install to update running executables (#20)

* Allow self-install to update running executables

* Update snapshot, no fast-fail, rust-version field

.github/workflows/ci.yml

@@ -15,6 +15,7 @@ jobs:
     runs-on: ubuntu-latest
 
     strategy:
+      fail-fast: false
       matrix:
         rust_version: [stable, 1.58.0]
 

Cargo.toml

@@ -2,6 +2,7 @@
 name = "aftman"
 description = "Aftman is a command line toolchain manager"
 version = "0.2.4"
+rust-version = "1.58.0"
 license = "MIT"
 edition = "2021"
 repository = "https://github.com/LPGhatguy/aftman"
@@ -24,6 +25,7 @@ semver = { version = "1.0.4", features = ["serde"] }
 serde = { version = "1.0.129", features = ["derive"] }
 serde_json = "1.0.67"
 structopt = "0.3.22"
+tempfile = "3.3.0"
 toml = "0.5.8"
 toml_edit = "0.14.4"
 zip = "0.5.13"

src/tool_storage.rs

@@ -78,21 +78,51 @@ impl ToolStorage {
         Ok(code)
     }
 
+    /// Update all executables managed by Aftman, which might include Aftman
+    /// itself.
     pub fn update_links(&self) -> anyhow::Result<()> {
         let self_path =
             current_exe().context("Failed to discover path to the Aftman executable")?;
+        let self_name = self_path.file_name().unwrap();
 
         log::info!("Updating all Aftman binaries...");
 
+        // Copy our current executable into a temp directory. That way, if it
+        // ends up replaced by this process, we'll still have the file that
+        // we're supposed to be copying.
+        log::debug!("Copying own executable into temp dir");
+        let source_dir = tempfile::tempdir()?;
+        let source_path = source_dir.path().join(self_name);
+        fs_err::copy(&self_path, &source_path)?;
+        let self_path = source_path;
+
+        let junk_dir = tempfile::tempdir()?;
+        let aftman_name = format!("aftman{EXE_SUFFIX}");
+        let mut found_aftman = false;
+
         for entry in fs_err::read_dir(&self.bin_dir)? {
             let entry = entry?;
             let path = entry.path();
+            let name = path.file_name().unwrap().to_str().unwrap();
+
+            if name == aftman_name {
+                found_aftman = true;
+            }
+
+            log::debug!("Updating {:?}", name);
 
+            // Copy the executable into a temp directory so that we can replace
+            // it even if it's currently running.
+            fs_err::rename(&path, junk_dir.path().join(name))?;
             fs_err::copy(&self_path, path)?;
         }
 
-        let aftman_path = self.bin_dir.join(format!("aftman{}", EXE_SUFFIX));
-        fs_err::copy(&self_path, aftman_path)?;
+        // If we didn't find and update Aftman already, install it.
+        if !found_aftman {
+            log::info!("Installing Aftman...");
+            let aftman_path = self.bin_dir.join(aftman_name);
+            fs_err::copy(&self_path, aftman_path)?;
+        }
 
         log::info!("Updated Aftman binaries successfully!");
 

tests/snapshots/ui__self-install stderr.snap

@@ -4,5 +4,6 @@ assertion_line: 10
 expression: output.stderr
 ---
 [INFO  aftman::tool_storage] Updating all Aftman binaries...
+[INFO  aftman::tool_storage] Installing Aftman...
 [INFO  aftman::tool_storage] Updated Aftman binaries successfully!