Address code review.

Author: Alexhuszagh

src/docker/custom.rs

@@ -205,7 +205,7 @@ impl<'a> Dockerfile<'a> {
                 "{}{package_name}:{target_triple}-{path_hash}{custom}",
                 CROSS_CUSTOM_DOCKERFILE_IMAGE_PREFIX,
                 package_name = docker_package_name(metadata),
-                path_hash = path_hash(&metadata.workspace_root, 5)?,
+                path_hash = path_hash(&metadata.workspace_root, docker::PATH_HASH_SHORT)?,
                 custom = if matches!(self, Self::File { .. }) {
                     ""
                 } else {

src/docker/remote.rs

@@ -71,7 +71,7 @@ impl<'a, 'b, 'c> ContainerDataVolume<'a, 'b, 'c> {
         let temppath = tempdir.path();
         let had_symlinks = copy_dir(src, temppath, copy_symlinks, 0, |e, _| is_cachedir(e))?;
         warn_symlinks(had_symlinks, msg_info)?;
-        self.copy_files(temppath, dst, msg_info)
+        self.copy_files(&temppath.join("."), dst, msg_info)
     }
 
     // copy files for a docker volume, for remote host support
@@ -567,7 +567,7 @@ impl QualifiedToolchain {
             .file_name()
             .expect("should be able to get toolchain name")
             .to_utf8()?;
-        let toolchain_hash = path_hash(self.get_sysroot(), 5)?;
+        let toolchain_hash = path_hash(self.get_sysroot(), PATH_HASH_SHORT)?;
         Ok(format!(
             "{VOLUME_PREFIX}{toolchain_name}-{toolchain_hash}-{commit_hash}"
         ))
@@ -577,15 +577,15 @@ impl QualifiedToolchain {
     // be generated outside a rust package and run multiple times.
     pub fn unique_container_identifier(&self, triple: &TargetTriple) -> Result<String> {
         let toolchain_id = self.unique_toolchain_identifier()?;
-        let cwd_path = path_hash(&env::current_dir()?, 5)?;
+        let cwd_path = path_hash(&env::current_dir()?, PATH_HASH_SHORT)?;
         let system_time = now_as_millis()?;
         Ok(format!("{toolchain_id}-{triple}-{cwd_path}-{system_time}"))
     }
 
     // unique identifier for a given mounted volume
     pub fn unique_mount_identifier(&self, path: &Path) -> Result<String> {
         let toolchain_id = self.unique_toolchain_identifier()?;
-        let mount_hash = path_hash(path, 10)?;
+        let mount_hash = path_hash(path, PATH_HASH_UNIQUE)?;
         Ok(format!("{toolchain_id}-{mount_hash}"))
     }
 }

src/docker/shared.rs

@@ -1443,6 +1443,13 @@ impl MountFinder {
     }
 }
 
+/// Short hash for identifiers with minimal risk of collision.
+pub const PATH_HASH_SHORT: usize = 5;
+
+/// Longer hash to minimize risk of random collisions
+/// Collision chance is ~10^-6
+pub const PATH_HASH_UNIQUE: usize = 10;
+
 fn path_digest(path: &Path) -> Result<const_sha1::Digest> {
     let buffer = const_sha1::ConstBuffer::from_slice(path.to_utf8()?.as_bytes());
     Ok(const_sha1::sha1(&buffer))