Add git fetch to universe dependency handling (#78)

Summary:
Identical to how http archive rules are done.

Pull Request resolved: #78

Reviewed By: JakobDegen

Differential Revision: D75387030

Pulled By: dtolnay

fbshipit-source-id: 20d67f668566854ee16462471325d23f3f8cbe1a

Author: benbrittain

src/buck.rs

@@ -509,7 +509,7 @@ impl Serialize for ExtractArchive {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, PartialEq)]
 pub struct GitFetch {
     pub name: Name,
     pub repo: String,

src/universe.rs

@@ -222,6 +222,14 @@ pub fn merge_universes(
                             panic!("expected http_archive rules to be identical in every universe")
                         }
                     }
+                    Rule::GitFetch(old) => {
+                        let Rule::GitFetch(new) = rule else {
+                            panic!("expected git_fetch")
+                        };
+                        if *old != new {
+                            panic!("expected git_fetch rules to be identical in every universe")
+                        }
+                    }
                     _ => {
                         log::warn!(
                             "Skipping unhandled rule while merging universes: {:?}",