From 0f0f9ff9b4cce526ac39a4140a6400b1bd7c6368 Mon Sep 17 00:00:00 2001
From: cloudhead <cloudhead@radicle.xyz>
Date: Mon, 11 Mar 2024 18:05:18 +0100
Subject: [PATCH] helper: Check for missing canonical head

Without the canonical head in the working copy, the next check will fail
with a cryptic error.
---
 radicle-remote-helper/src/push.rs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/radicle-remote-helper/src/push.rs b/radicle-remote-helper/src/push.rs
index c777610b..655a8037 100644
--- a/radicle-remote-helper/src/push.rs
+++ b/radicle-remote-helper/src/push.rs
@@ -96,6 +96,9 @@ pub enum Error {
     /// Patch is empty.
     #[error("patch commits are already included in the base branch")]
     EmptyPatch,
+    /// Missing canonical head.
+    #[error("the canonical head is missing from your working copy; please pull before pushing")]
+    MissingCanonicalHead(git::Oid),
     /// COB store error.
     #[error(transparent)]
     Cob(#[from] radicle::cob::store::Error),
@@ -257,6 +260,13 @@ pub fn run(
                             && delegates.contains(&Did::from(nid))
                             && delegates.len() > 1
                         {
+                            if let Err(e) = working.find_commit(**canonical_oid) {
+                                return if git::ext::is_not_found_err(&e) {
+                                    Err(Error::MissingCanonicalHead(*canonical_oid))
+                                } else {
+                                    Err(e.into())
+                                };
+                            }
                             let head = working.find_reference(src.as_str())?;
                             let head = head.peel_to_commit()?.id();
                             // Rollback is allowed and head is an ancestor of the canonical head.