ui: Show messages for ref updates (#31)

Co-authored-by: Brandon W Maister <[email protected]>

CHANGELOG.md

@@ -2,7 +2,8 @@
 
 # Version 0.2.4
 
-* Retarget multiple branches pointing at the same commit
+* Retarget multiple branches pointing at the same commit, eg:
+  > updated branch my-cool-branch: deadbeef -> c0ffee
 
 # Version 0.2.3
 

src/lib.rs

@@ -134,7 +134,11 @@ fn apply_diff_in_rebase(
             let rewrit_id = target_commit.amend(None, None, None, None, None, Some(&tree))?;
             let rewrit_object = repo.find_object(rewrit_id, None)?;
             let rewrit_commit_id = repo.find_commit(rewrit_object.id())?.id();
-            branches.retarget_branches(target_commit.id(), rewrit_commit_id, rebase)?;
+            let retargeted =
+                branches.retarget_branches(target_commit.id(), rewrit_commit_id, rebase)?;
+            for b in retargeted {
+                println!("{}", b);
+            }
 
             repo.reset(&rewrit_object, git2::ResetType::Soft, None)?;
         }
@@ -162,7 +166,10 @@ fn do_rebase_inner(
                 let message = commit.message();
                 if message.is_some() && message != fixup_message {
                     let new_id = rebase.commit(None, &sig, None)?;
-                    branches.retarget_branches(commit.id(), new_id, rebase)?;
+                    let retargeted = branches.retarget_branches(commit.id(), new_id, rebase)?;
+                    for b in retargeted {
+                        println!("{}", b);
+                    }
                 }
             }
             Some(Fixup) | Some(Squash) | Some(Exec) | Some(Edit) | Some(Reword) => {
@@ -178,6 +185,21 @@ fn do_rebase_inner(
 
 struct RepoBranches<'a>(HashMap<Oid, Vec<Branch<'a>>>);
 
+struct RetargetedBranch {
+    name: String,
+    from: Oid,
+    to: Oid,
+}
+
+impl std::fmt::Display for RetargetedBranch {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let from = &self.from.to_string()[..15];
+        let to = &self.to.to_string()[..15];
+        let name = &self.name;
+        f.write_fmt(format_args!("updated branch {name}: {from} -> {to}"))
+    }
+}
+
 impl<'a> RepoBranches<'a> {
     fn for_repo(repo: &'a Repository) -> Result<RepoBranches<'a>, anyhow::Error> {
         let mut branches: HashMap<Oid, Vec<Branch>> = HashMap::new();
@@ -194,18 +216,28 @@ impl<'a> RepoBranches<'a> {
         original_commit: Oid,
         target_commit: Oid,
         rebase: &mut Rebase<'_>,
-    ) -> Result<(), anyhow::Error> {
+    ) -> Result<Vec<RetargetedBranch>, anyhow::Error> {
+        let mut retargeted = vec![];
         if let Some(branches) = self.0.get_mut(&original_commit) {
             // Don't retarget the last branch, rebase.finish does that for us
             if rebase.operation_current() != Some(rebase.len() - 1) {
                 for branch in branches.iter_mut() {
+                    retargeted.push(RetargetedBranch {
+                        name: branch
+                            .name()
+                            .context("getting a branch name")?
+                            .ok_or(anyhow!("branch should have a name"))?
+                            .to_owned(),
+                        from: original_commit,
+                        to: target_commit,
+                    });
                     branch
                         .get_mut()
                         .set_target(target_commit, "git-instafix retarget historical branch")?;
                 }
             }
         }
-        Ok(())
+        Ok(retargeted)
     }
 }