feat: Category::to_full_name() can now be passed a full name without prefix duplication.

This is for convenience, as it can then be passed a valid partial name.

Author: Byron

gix-ref/src/fullname.rs

@@ -1,8 +1,7 @@
+use crate::{bstr::ByteVec, name::is_pseudo_ref, Category, FullName, FullNameRef, Namespace, PartialNameRef};
 use gix_object::bstr::{BStr, BString, ByteSlice};
 use std::{borrow::Borrow, path::Path};
 
-use crate::{bstr::ByteVec, name::is_pseudo_ref, Category, FullName, FullNameRef, Namespace, PartialNameRef};
-
 impl TryFrom<&str> for FullName {
     type Error = gix_validate::reference::name::Error;
 
@@ -165,6 +164,8 @@ impl FullNameRef {
 impl Category<'_> {
     /// As the inverse of [`FullNameRef::category_and_short_name()`], use the prefix of this category alongside
     /// the `short_name` to create a valid fully qualified [reference name](FullName).
+    ///
+    /// If `short_name` already contains the prefix that it would receive (and is thus a full name), no duplication will occur.
     pub fn to_full_name<'a>(&self, short_name: impl Into<&'a BStr>) -> Result<FullName, crate::name::Error> {
         let mut out: BString = self.prefix().into();
         let short_name = short_name.into();
@@ -185,8 +186,12 @@ impl Category<'_> {
             | Category::PseudoRef
             | Category::MainPseudoRef => short_name,
         };
-        out.extend_from_slice(partial_name);
-        FullName::try_from(out)
+        if out.is_empty() || !partial_name.starts_with(&out) {
+            out.extend_from_slice(partial_name);
+            FullName::try_from(out)
+        } else {
+            FullName::try_from(partial_name.as_bstr())
+        }
     }
 }
 

gix-ref/tests/refs/fullname.rs

@@ -117,6 +117,25 @@ fn shorten_and_category() {
     );
 }
 
+#[test]
+fn to_full_name() -> gix_testtools::Result {
+    assert_eq!(
+        Category::LocalBranch.to_full_name("refs/heads/full")?.as_bstr(),
+        "refs/heads/full",
+        "prefixes aren't duplicated"
+    );
+
+    assert_eq!(
+        Category::LocalBranch
+            .to_full_name("refs/remotes/origin/other")?
+            .as_bstr(),
+        "refs/heads/refs/remotes/origin/other",
+        "full names with a different category will be prefixed, to support 'main-worktree' special cases"
+    );
+
+    Ok(())
+}
+
 #[test]
 fn prefix_with_namespace_and_stripping() {
     let ns = gix_ref::namespace::expand("foo").unwrap();