From 8b0c01d1e9afbc2fe4a12113436e9192a4e5dd33 Mon Sep 17 00:00:00 2001
From: Yuya Nishihara <yuya@tcha.org>
Date: Thu, 15 Jun 2023 17:48:20 +0900
Subject: [PATCH] git: return early from import_refs() if no commits to abandon

This saves another 150ms needed to set up binary heap with ~4000 wanted
and unwanted heads.
---
 lib/src/git.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/src/git.rs b/lib/src/git.rs
index ec569bd31..c4548bbcd 100644
--- a/lib/src/git.rs
+++ b/lib/src/git.rs
@@ -216,6 +216,9 @@ pub fn import_some_refs(
         .filter_map(|(old_git_target, _)| old_git_target.as_ref().map(|target| target.adds()))
         .flatten()
         .collect_vec();
+    if hidable_git_heads.is_empty() {
+        return Ok(());
+    }
     // We must remove non-existing commits from pinned_git_heads, as they could have
     // come from branches which were never fetched.
     let mut pinned_git_heads_set = HashSet::new();