Update refspec implementation

Author: zanieb

crates/uv-git/src/git.rs

@@ -907,10 +907,6 @@ pub(crate) fn fetch(
     // Translate the reference desired here into an actual list of refspecs
     // which need to get fetched. Additionally record if we're fetching tags.
     let mut refspecs = Vec::new();
-    // Track a secondary refspec list to include if the first fetch fails,
-    // this is important when using [`FetchStrategy::Cli`] as it will not
-    // succeed if _any_ given refspec cannot be found.
-    let mut secondary_refspecs = Vec::new();
     let mut tags = false;
     // The `+` symbol on the refspec means to allow a forced (fast-forward)
     // update which is needed if there is ever a force push that requires a
@@ -930,7 +926,7 @@ pub(crate) fn fetch(
             refspecs.push(format!(
                 "+refs/heads/{branch_or_tag}:refs/remotes/origin/{branch_or_tag}"
             ));
-            secondary_refspecs.push(format!(
+            refspecs.push(format!(
                 "+refs/tags/{branch_or_tag}:refs/remotes/origin/tags/{branch_or_tag}"
             ));
         }
@@ -974,16 +970,25 @@ pub(crate) fn fetch(
     debug!("Performing a Git fetch for: {remote_url}");
     match strategy {
         FetchStrategy::Cli => {
-            fetch_with_cli(repo, remote_url, &refspecs, tags).or_else(|err| {
-                // If secondary refspecs are populated i.e. from [`GitReference::BranchOrTag`],
-                // then ignore the first error and try again; ideally we'd only retry if the
-                // error was due to a missing ref but this is already not the fast path
-                if secondary_refspecs.is_empty() {
-                    Err(err)
-                } else {
-                    fetch_with_cli(repo, remote_url, &secondary_refspecs, tags)
+            // Try each refspec
+            let results = refspecs
+                .into_iter()
+                .map(|refspec| fetch_with_cli(repo, remote_url, &[refspec], tags))
+                .collect::<Vec<_>>();
+
+            // Only fail if _all_ refspecs cannot be found
+            // This matches the Libgit2 behavior
+            if results.iter().all(Result::is_err) {
+                let mut combined_err = anyhow!("failed to fetch all refspecs");
+                for err in results {
+                    if let Err(err) = err {
+                        combined_err = combined_err.context(err.to_string());
+                    }
                 }
-            })
+                Err(combined_err)
+            } else {
+                Ok(())
+            }
         }
         FetchStrategy::Libgit2 => {
             let git_config = git2::Config::open_default()?;
@@ -992,9 +997,6 @@ pub(crate) fn fetch(
                     opts.download_tags(git2::AutotagOption::All);
                 }
 
-                // When using libgit2, missing refspecs are okay
-                refspecs.append(&mut secondary_refspecs);
-
                 // The `fetch` operation here may fail spuriously due to a corrupt
                 // repository. It could also fail, however, for a whole slew of other
                 // reasons (aka network related reasons). We want Cargo to automatically