From e7959ecc5d9f72485d98827e6aaa7e1db9d907a3 Mon Sep 17 00:00:00 2001
From: Talia Stocks <928827+taliastocks@users.noreply.github.com>
Date: Fri, 14 Mar 2025 12:03:45 -0400
Subject: [PATCH] Update hook_impl.py

Attempt to fix https://github.com/pre-commit/pre-commit/issues/2424, which has incorrectly been marked as a duplicate of https://github.com/pre-commit/pre-commit/issues/860
---
 pre_commit/commands/hook_impl.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/pre_commit/commands/hook_impl.py b/pre_commit/commands/hook_impl.py
index 49a80b7b..c5d20169 100644
--- a/pre_commit/commands/hook_impl.py
+++ b/pre_commit/commands/hook_impl.py
@@ -113,6 +113,10 @@ def _rev_exists(rev: str) -> bool:
     return not subprocess.call(('git', 'rev-list', '--quiet', rev))
 
 
+def _is_ancestor(ancestor: str, rev: str):
+    return not subprocess.call(('git', 'merge-base', '--is-ancestor', ancestor, rev))
+
+
 def _pre_push_ns(
         color: bool,
         args: Sequence[str],
@@ -126,7 +130,7 @@ def _pre_push_ns(
         local_branch, local_sha, remote_branch, remote_sha = parts
         if local_sha == Z40:
             continue
-        elif remote_sha != Z40 and _rev_exists(remote_sha):
+        elif remote_sha != Z40 and _rev_exists(remote_sha) and _is_ancestor(remote_sha, local_sha):
             return _ns(
                 'pre-push', color,
                 from_ref=remote_sha, to_ref=local_sha,