Build backend: Preserve executable bit (#10027)

Fixes #9968

Author: konstin

crates/uv-build-backend/src/wheel.rs

@@ -596,12 +596,17 @@ impl ZipDirectoryWriter {
     }
 
     /// Add a file with the given name and return a writer for it.
-    fn new_writer<'slf>(&'slf mut self, path: &str) -> Result<Box<dyn Write + 'slf>, Error> {
-        // TODO(konsti): We need to preserve permissions, at least the executable bit.
-        self.writer.start_file(
-            path,
-            zip::write::FileOptions::default().compression_method(self.compression),
-        )?;
+    fn new_writer<'slf>(
+        &'slf mut self,
+        path: &str,
+        executable_bit: bool,
+    ) -> Result<Box<dyn Write + 'slf>, Error> {
+        // 644 is the default of the zip crate.
+        let permissions = if executable_bit { 775 } else { 664 };
+        let options = zip::write::FileOptions::default()
+            .unix_permissions(permissions)
+            .compression_method(self.compression);
+        self.writer.start_file(path, options)?;
         Ok(Box::new(&mut self.writer))
     }
 }
@@ -626,7 +631,16 @@ impl DirectoryWriter for ZipDirectoryWriter {
     fn write_file(&mut self, path: &str, file: &Path) -> Result<(), Error> {
         trace!("Adding {} from {}", path, file.user_display());
         let mut reader = BufReader::new(File::open(file)?);
-        let mut writer = self.new_writer(path)?;
+        // Preserve the executable bit, especially for scripts
+        #[cfg(unix)]
+        let executable_bit = {
+            use std::os::unix::fs::PermissionsExt;
+            file.metadata()?.permissions().mode() & 0o111 != 0
+        };
+        // Windows has no executable bit
+        #[cfg(not(unix))]
+        let executable_bit = false;
+        let mut writer = self.new_writer(path, executable_bit)?;
         let record = write_hashed(path, &mut reader, &mut writer)?;
         drop(writer);
         self.record.push(record);
@@ -644,7 +658,11 @@ impl DirectoryWriter for ZipDirectoryWriter {
         let record_path = format!("{dist_info_dir}/RECORD");
         trace!("Adding {record_path}");
         let record = mem::take(&mut self.record);
-        write_record(&mut self.new_writer(&record_path)?, dist_info_dir, record)?;
+        write_record(
+            &mut self.new_writer(&record_path, false)?,
+            dist_info_dir,
+            record,
+        )?;
 
         trace!("Adding central directory");
         self.writer.finish()?;

crates/uv/tests/it/build_backend.rs

@@ -214,3 +214,67 @@ fn built_by_uv_editable() -> Result<()> {
 
     Ok(())
 }
+
+#[cfg(unix)]
+#[test]
+fn preserve_executable_bit() -> Result<()> {
+    use std::io::Write;
+
+    let context = TestContext::new("3.12");
+
+    let project_dir = context.temp_dir.path().join("preserve_executable_bit");
+    context
+        .init()
+        .arg("--build-backend")
+        .arg("uv")
+        .arg("--preview")
+        .arg(&project_dir)
+        .assert()
+        .success();
+
+    fs_err::OpenOptions::new()
+        .write(true)
+        .append(true)
+        .open(project_dir.join("pyproject.toml"))?
+        .write_all(
+            indoc! {r#"
+            [tool.uv.build-backend.data]
+            scripts = "scripts"
+        "#}
+            .as_bytes(),
+        )?;
+
+    fs_err::create_dir(project_dir.join("scripts"))?;
+    fs_err::write(
+        project_dir.join("scripts").join("greet.sh"),
+        indoc! {r#"
+        echo "Hi from the shell"
+    "#},
+    )?;
+
+    context
+        .build_backend()
+        .arg("build-wheel")
+        .arg(context.temp_dir.path())
+        .current_dir(project_dir)
+        .assert()
+        .success();
+
+    let wheel = context
+        .temp_dir
+        .path()
+        .join("preserve_executable_bit-0.1.0-py3-none-any.whl");
+    context.pip_install().arg(wheel).assert().success();
+
+    uv_snapshot!(Command::new("greet.sh")
+        .env(EnvVars::PATH, venv_bin_path(&context.venv)), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    Hi from the shell
+
+    ----- stderr -----
+    "###);
+
+    Ok(())
+}