Fix #2947

Cargo.toml

@@ -93,6 +93,11 @@ path = "src/main.rs"
 name = "just"
 test = false
 
+[[bin]]
+path = "src/bin/echoargs.rs"
+name = "echoargs"
+test = false
+
 # The public documentation is minimal and doesn't change between
 # platforms, so we only build them for linux on docs.rs to save
 # their build machines some cycles.

src/bin/echoargs.rs

@@ -0,0 +1,6 @@
+use std::env;
+
+fn main() {
+  let args: Vec<String> = env::args().skip(1).collect();
+  println!("{}", args.join(" "));
+}

src/command_ext.rs

@@ -1,6 +1,8 @@
 use super::*;
 
 pub(crate) trait CommandExt {
+  fn with_explicit_path(&mut self) -> &mut Command;
+
   fn export(
     &mut self,
     settings: &Settings,
@@ -19,6 +21,18 @@ pub(crate) trait CommandExt {
 }
 
 impl CommandExt for Command {
+  fn with_explicit_path(&mut self) -> &mut Command {
+    // On Windows, set child's path explicitly so that spawned executable
+    // is located on path before System32 fallback, not the other way around.
+    // https://blog.rust-lang.org/2022/01/13/Rust-1.58.0/#reduced-windows-command-search-path
+    #[cfg(windows)]
+    if let Some(path) = std::env::var_os("Path") {
+      self.env("Path", path);
+    }
+
+    self
+  }
+
   fn export(
     &mut self,
     settings: &Settings,

src/executor.rs

@@ -16,6 +16,7 @@ impl Executor<'_> {
     match self {
       Self::Command(interpreter) => {
         let mut command = Command::new(&interpreter.command.cooked);
+        command.with_explicit_path();
 
         if let Some(working_directory) = working_directory {
           command.current_dir(working_directory);

src/justfile.rs

@@ -157,7 +157,9 @@ impl<'src> Justfile<'src> {
           command.arg(binary);
           command
         } else {
-          Command::new(binary)
+          let mut command = Command::new(binary);
+          command.with_explicit_path();
+          command
         };
 
         command

src/platform/windows.rs

@@ -32,6 +32,7 @@ impl PlatformInterface for Platform {
     };
 
     let mut cmd = Command::new(command.as_ref());
+    cmd.with_explicit_path();
 
     if let Some(working_directory) = working_directory {
       cmd.current_dir(working_directory);

src/settings.rs

@@ -106,6 +106,7 @@ impl<'src> Settings<'src> {
     let (command, args) = self.shell(config);
 
     let mut cmd = Command::new(command);
+    cmd.with_explicit_path();
 
     cmd.args(args);
 

src/subcommand.rs

@@ -307,7 +307,7 @@ impl Subcommand {
       .or_else(|| env::var_os("EDITOR"))
       .unwrap_or_else(|| "vim".into());
 
-    let error = Command::new(&editor)
+    let error = Command::new(&editor).with_explicit_path()
       .current_dir(&search.working_directory)
       .arg(&search.justfile)
       .status();

tests/lib.rs

@@ -132,6 +132,8 @@ mod unstable;
 mod which_function;
 #[cfg(windows)]
 mod windows;
+#[cfg(windows)]
+mod windows_path_resolution;
 #[cfg(target_family = "windows")]
 mod windows_shell;
 mod working_directory;

tests/windows_path_resolution.rs

@@ -0,0 +1,41 @@
+use super::*;
+
+#[cfg(windows)]
+#[test]
+fn windows_path_resolution() {
+
+  // Goal: Confirm that $PATH entries are respected *before* C:\Windows\System32 when
+  // locating shell executable. This can happen when PATH is configured to prefer
+  // Git-for-Windows' bash.exe, and just must not call C:\Windows\System32\bash.exe
+  // https://github.com/casey/just/issues/2947
+
+  // Copy echoargs.exe to temp directory as where.exe, to intentionally match
+  // the name of an executable in C:\Windows\System32
+  let mut echoargs_path = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+  echoargs_path.push("target");
+  echoargs_path.push("debug");
+  echoargs_path.push("echoargs.exe");
+  let tmp = tempdir();
+  let tmp_subdir= tmp.path().join("subdir");
+  let tmp_subdir_path = tmp_subdir.as_path();
+  let exe_path = tmp_subdir_path.join("where.exe");
+  std::fs::create_dir(tmp_subdir_path).expect("Failed to create temp subdirectory");
+  std::fs::copy(&echoargs_path, &exe_path)
+    .expect("Failed to copy exe to temp directory");
+
+  // Prepend temp directory to PATH
+  let new_path = tmp_subdir_path.to_str().unwrap().to_owned() + ";" + &env::var("PATH").unwrap();
+
+  Test::with_tempdir(tmp)
+    .shell(false)
+    .env("Path", &new_path)
+    .justfile(
+      r#"
+        set shell := ['where.exe']
+        @default:
+          test_marker
+      "#,
+    )
+    .stdout("test_marker\n")
+    .run();
+}