Replace Windows symlinks with volta run scripts

crates/volta-core/Cargo.toml

@@ -55,3 +55,4 @@ fs2 = "0.4.3"
 
 [target.'cfg(windows)'.dependencies]
 winreg = "0.52.0"
+junction = "1.1.0"

crates/volta-core/src/fs.rs

@@ -138,7 +138,7 @@ where
     D: AsRef<Path>,
 {
     #[cfg(windows)]
-    return std::os::windows::fs::symlink_dir(src, dest);
+    return junction::create(src, dest);
 
     #[cfg(unix)]
     return std::os::unix::fs::symlink(src, dest);

crates/volta-core/src/layout/mod.rs

@@ -5,7 +5,7 @@ use crate::error::{Context, ErrorKind, Fallible};
 use cfg_if::cfg_if;
 use dunce::canonicalize;
 use once_cell::sync::OnceCell;
-use volta_layout::v3::{VoltaHome, VoltaInstall};
+use volta_layout::v4::{VoltaHome, VoltaInstall};
 
 cfg_if! {
     if #[cfg(unix)] {

crates/volta-core/src/shim.rs

@@ -1,16 +1,18 @@
 //! Provides utilities for modifying shims for 3rd-party executables
 
 use std::collections::HashSet;
-use std::fs::{self, DirEntry, Metadata};
+use std::fs;
 use std::io;
 use std::path::Path;
 
 use crate::error::{Context, ErrorKind, Fallible, VoltaError};
-use crate::fs::{read_dir_eager, symlink_file};
-use crate::layout::{volta_home, volta_install};
+use crate::fs::read_dir_eager;
+use crate::layout::volta_home;
 use crate::sync::VoltaLock;
 use log::debug;
 
+pub use platform::create;
+
 pub fn regenerate_shims_for_dir(dir: &Path) -> Fallible<()> {
     // Acquire a lock on the Volta directory, if possible, to prevent concurrent changes
     let _lock = VoltaLock::acquire();
@@ -30,7 +32,8 @@ fn get_shim_list_deduped(dir: &Path) -> Fallible<HashSet<String>> {
 
     #[cfg(unix)]
     {
-        let mut shims: HashSet<String> = contents.filter_map(entry_to_shim_name).collect();
+        let mut shims: HashSet<String> =
+            contents.filter_map(platform::entry_to_shim_name).collect();
         shims.insert("node".into());
         shims.insert("npm".into());
         shims.insert("npx".into());
@@ -43,19 +46,7 @@ fn get_shim_list_deduped(dir: &Path) -> Fallible<HashSet<String>> {
     #[cfg(windows)]
     {
         // On Windows, the default shims are installed in Program Files, so we don't need to generate them here
-        Ok(contents.filter_map(entry_to_shim_name).collect())
-    }
-}
-
-fn entry_to_shim_name((entry, metadata): (DirEntry, Metadata)) -> Option<String> {
-    if metadata.file_type().is_symlink() {
-        entry
-            .path()
-            .file_stem()
-            .and_then(|stem| stem.to_str())
-            .map(|stem| stem.to_string())
-    } else {
-        None
+        Ok(contents.filter_map(platform::entry_to_shim_name).collect())
     }
 }
 
@@ -67,35 +58,11 @@ pub enum ShimResult {
     DoesntExist,
 }
 
-pub fn create(shim_name: &str) -> Fallible<ShimResult> {
-    let executable = volta_install()?.shim_executable();
-    let shim = volta_home()?.shim_file(shim_name);
-
-    #[cfg(windows)]
-    windows::create_git_bash_script(shim_name)?;
-
-    match symlink_file(executable, shim) {
-        Ok(_) => Ok(ShimResult::Created),
-        Err(err) => {
-            if err.kind() == io::ErrorKind::AlreadyExists {
-                Ok(ShimResult::AlreadyExists)
-            } else {
-                Err(VoltaError::from_source(
-                    err,
-                    ErrorKind::ShimCreateError {
-                        name: shim_name.to_string(),
-                    },
-                ))
-            }
-        }
-    }
-}
-
 pub fn delete(shim_name: &str) -> Fallible<ShimResult> {
     let shim = volta_home()?.shim_file(shim_name);
 
     #[cfg(windows)]
-    windows::delete_git_bash_script(shim_name)?;
+    platform::delete_git_bash_script(shim_name)?;
 
     match fs::remove_file(shim) {
         Ok(_) => Ok(ShimResult::Deleted),
@@ -114,28 +81,111 @@ pub fn delete(shim_name: &str) -> Fallible<ShimResult> {
     }
 }
 
-/// These methods are a (hacky) workaround for an issue with Git Bash on Windows
-/// When executing the shim symlink, Git Bash resolves the symlink first and then calls shim.exe directly
-/// This results in the shim being unable to determine which tool is being executed
-/// However, both cmd.exe and PowerShell execute the symlink correctly
-/// To fix the issue specifically in Git Bash, we write a bash script in the shim dir, with the same name as the shim
-/// minus the '.exe' (e.g. we write `ember` next to the symlink `ember.exe`)
-/// Since the file doesn't have a file extension, it is ignored by cmd.exe and PowerShell, but is detected by Bash
-/// This bash script simply calls the shim using `cmd.exe`, so that it is resolved correctly
+#[cfg(unix)]
+mod platform {
+    //! Unix-specific shim utilities
+    //!
+    //! On macOS and Linux, creating a shim involves creating a symlink to the `volta-shim`
+    //! executable. Additionally, filtering the shims from directory entries means looking
+    //! for symlinks and ignoring the actual binaries
+    use std::ffi::OsStr;
+    use std::fs::{DirEntry, Metadata};
+    use std::io;
+
+    use super::ShimResult;
+    use crate::error::{ErrorKind, Fallible, VoltaError};
+    use crate::fs::symlink_file;
+    use crate::layout::{volta_home, volta_install};
+
+    pub fn create(shim_name: &str) -> Fallible<ShimResult> {
+        let executable = volta_install()?.shim_executable();
+        let shim = volta_home()?.shim_file(shim_name);
+
+        match symlink_file(executable, shim) {
+            Ok(_) => Ok(ShimResult::Created),
+            Err(err) => {
+                if err.kind() == io::ErrorKind::AlreadyExists {
+                    Ok(ShimResult::AlreadyExists)
+                } else {
+                    Err(VoltaError::from_source(
+                        err,
+                        ErrorKind::ShimCreateError {
+                            name: shim_name.to_string(),
+                        },
+                    ))
+                }
+            }
+        }
+    }
+
+    pub fn entry_to_shim_name((entry, metadata): (DirEntry, Metadata)) -> Option<String> {
+        if metadata.file_type().is_symlink() {
+            entry
+                .path()
+                .file_stem()
+                .and_then(OsStr::to_str)
+                .map(ToOwned::to_owned)
+        } else {
+            None
+        }
+    }
+}
+
 #[cfg(windows)]
-mod windows {
+mod platform {
+    //! Windows-specific shim utilities
+    //!
+    //! On Windows, creating a shim involves creating a small .cmd script, rather than a symlink.
+    //! This allows us to create shims without requiring administrator privileges or developer
+    //! mode. Also, to support Git Bash, we create a similar script with bash syntax that doesn't
+    //! have a file extension. This allows Powershell and Cmd to ignore it, while Bash detects it
+    //! as an executable script.
+    //!
+    //! Finally, filtering directory entries to find the shim files involves looking for the .cmd
+    //! files.
+    use std::ffi::OsStr;
+    use std::fs::{write, DirEntry, Metadata};
+
+    use super::ShimResult;
     use crate::error::{Context, ErrorKind, Fallible};
     use crate::fs::remove_file_if_exists;
     use crate::layout::volta_home;
-    use std::fs::write;
 
-    const BASH_SCRIPT: &str = r#"cmd //C $0 "$@""#;
+    const SHIM_SCRIPT_CONTENTS: &str = r#"@echo off
+volta run %~n0 %*
+"#;
 
-    pub fn create_git_bash_script(shim_name: &str) -> Fallible<()> {
-        let script_path = volta_home()?.shim_git_bash_script_file(shim_name);
-        write(script_path, BASH_SCRIPT).with_context(|| ErrorKind::ShimCreateError {
-            name: shim_name.to_string(),
-        })
+    const GIT_BASH_SCRIPT_CONTENTS: &str = r#"#!/bin/bash
+volta run "$(basename $0)" "$@""#;
+
+    pub fn create(shim_name: &str) -> Fallible<ShimResult> {
+        let shim = volta_home()?.shim_file(shim_name);
+
+        write(shim, SHIM_SCRIPT_CONTENTS).with_context(|| ErrorKind::ShimCreateError {
+            name: shim_name.to_owned(),
+        })?;
+
+        let git_bash_script = volta_home()?.shim_git_bash_script_file(shim_name);
+
+        write(git_bash_script, GIT_BASH_SCRIPT_CONTENTS).with_context(|| {
+            ErrorKind::ShimCreateError {
+                name: shim_name.to_owned(),
+            }
+        })?;
+
+        Ok(ShimResult::Created)
+    }
+
+    pub fn entry_to_shim_name((entry, _): (DirEntry, Metadata)) -> Option<String> {
+        let path = entry.path();
+
+        if path.extension().is_some_and(|ext| ext == "cmd") {
+            path.file_stem()
+                .and_then(OsStr::to_str)
+                .map(ToOwned::to_owned)
+        } else {
+            None
+        }
     }
 
     pub fn delete_git_bash_script(shim_name: &str) -> Fallible<()> {

crates/volta-layout/src/lib.rs

@@ -5,6 +5,7 @@ pub mod v0;
 pub mod v1;
 pub mod v2;
 pub mod v3;
+pub mod v4;
 
 fn executable(name: &str) -> String {
     format!("{}{}", name, std::env::consts::EXE_SUFFIX)