radicle: More convenience methods to get default branch

crates/radicle/src/identity/doc.rs

@@ -737,12 +737,16 @@ impl Doc {
         Ok(proj)
     }
 
+    /// Gets the qualified reference name of the default branch,
+    /// according to the project payload in this document.
+    pub fn default_branch(&self) -> Result<git::fmt::Qualified<'_>, PayloadError> {
+        Ok(git::refs::branch(self.project()?.default_branch()))
+    }
+
     pub fn default_branch_rule(
         &self,
     ) -> Result<(rules::Pattern, rules::ValidRule), DefaultBranchRuleError> {
-        let proj = self.project()?;
+        let pattern = rules::Pattern::try_from(self.default_branch()?.to_owned())?;
-        let refname = proj.default_branch();
-        let pattern = rules::Pattern::try_from(git::refs::branch(refname).to_owned())?;
         let rule = rules::Rule::new(
             rules::ResolvedDelegates::Delegates(self.delegates.clone()),
             self.threshold,

crates/radicle/src/storage.rs

@@ -520,6 +520,12 @@ pub trait ReadRepository: Sized + ValidateRepository {
     /// Returns the [`Oid`] as well as the qualified reference name.
     fn head(&self) -> Result<(Qualified<'_>, Oid), RepositoryError>;
 
+    /// Gets the qualified reference name of the default branch of self,
+    /// according to the project payload in the identity document.
+    fn default_branch(&self) -> Result<Qualified<'_>, RepositoryError> {
+        Ok(self.identity_doc()?.default_branch()?.to_owned())
+    }
+
     /// Compute the canonical head of this repository.
     ///
     /// Ignores any existing `HEAD` reference.

crates/radicle/src/storage/git.rs

@@ -853,7 +853,7 @@ impl ReadRepository for Repository {
 
     fn canonical_head(&self) -> Result<(Qualified<'_>, Oid), RepositoryError> {
         let doc = self.identity_doc()?;
-        let refname = git::refs::branch(doc.project()?.default_branch());
+        let refname = doc.default_branch()?.to_owned();
         let crefs = match doc.canonical_refs()? {
             Some(crefs) => crefs,
             // Fallback to constructing the default branch via the project