cli: list new remote branches during git fetch

CHANGELOG.md

@@ -45,6 +45,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#1252](https://github.com/martinvonz/jj/issues/1252),
   [#2971](https://github.com/martinvonz/jj/issues/2971)). This may become the
   default depending on feedback.
+* `jj git fetch` now automatically prints new remote branches and tags by default.
 
 ### Fixed bugs
 

cli/src/cli_util.rs

@@ -948,7 +948,7 @@ impl WorkspaceCommandHelper {
             return Ok(());
         }
 
-        print_git_import_stats(ui, &stats)?;
+        print_git_import_stats(ui, &stats, false)?;
         let mut tx = tx.into_inner();
         // Rebase here to show slightly different status message.
         let num_rebased = tx.mut_repo().rebase_descendants(&self.settings)?;

cli/src/commands/git.rs

@@ -447,7 +447,7 @@ fn init_git_refs(
     if !tx.mut_repo().has_changes() {
         return Ok(repo);
     }
-    print_git_import_stats(ui, &stats)?;
+    print_git_import_stats(ui, &stats, false)?;
     if colocated {
         // If git.auto-local-branch = true, local branches could be created for
         // the imported remote branches.
@@ -537,7 +537,7 @@ fn cmd_git_fetch(
             GitFetchError::InternalGitError(err) => map_git_error(err),
             _ => user_error(err),
         })?;
-        print_git_import_stats(ui, &stats.import_stats)?;
+        print_git_import_stats(ui, &stats.import_stats, true)?;
     }
     tx.finish(
         ui,
@@ -751,7 +751,7 @@ fn do_git_clone(
             unreachable!("we didn't provide any globs")
         }
     })?;
-    print_git_import_stats(ui, &stats.import_stats)?;
+    print_git_import_stats(ui, &stats.import_stats, false)?;
     fetch_tx.finish(ui, "fetch from git remote into empty repo")?;
     Ok((workspace_command, stats))
 }
@@ -1190,7 +1190,7 @@ fn cmd_git_import(
     // That's why cmd_git_export() doesn't export the HEAD ref.
     git::import_head(tx.mut_repo())?;
     let stats = git::import_refs(tx.mut_repo(), &command.settings().git_settings())?;
-    print_git_import_stats(ui, &stats)?;
+    print_git_import_stats(ui, &stats, false)?;
     tx.finish(ui, "import git refs")?;
     Ok(())
 }

cli/src/git_util.rs

@@ -21,7 +21,7 @@ use std::sync::Mutex;
 use std::time::Instant;
 use std::{error, iter};
 
-use jj_lib::git::{self, FailedRefExport, FailedRefExportReason, GitImportStats};
+use jj_lib::git::{self, FailedRefExport, FailedRefExportReason, GitImportStats, RefName};
 use jj_lib::git_backend::GitBackend;
 use jj_lib::repo::{ReadonlyRepo, Repo as _};
 use jj_lib::store::Store;
@@ -172,7 +172,45 @@ pub fn with_remote_git_callbacks<T>(
     f(callbacks)
 }
 
-pub fn print_git_import_stats(ui: &mut Ui, stats: &GitImportStats) -> Result<(), CommandError> {
+pub fn print_git_import_stats(
+    ui: &mut Ui,
+    stats: &GitImportStats,
+    show_ref_stats: bool,
+) -> Result<(), CommandError> {
+    use std::collections::BTreeMap;
+
+    if show_ref_stats && !stats.new_remote_refs.is_empty() {
+        let mut new_remote_branches: BTreeMap<_, Vec<_>> = BTreeMap::new();
+        let mut tags = Vec::new();
+        let mut local_branches = Vec::new();
+        for refname in &stats.new_remote_refs {
+            match refname {
+                RefName::RemoteBranch { branch, remote } => {
+                    new_remote_branches.entry(remote).or_default().push(branch);
+                }
+                RefName::Tag(tag) => tags.push(tag),
+                RefName::LocalBranch(b) => local_branches.push(b),
+            }
+        }
+        local_branches.sort_unstable();
+        for branch in local_branches {
+            writeln!(ui.stderr(), "* [imported local branch]  {branch}")?;
+        }
+        for (remote, branches) in new_remote_branches.iter_mut() {
+            writeln!(ui.stderr(), "From {remote}")?;
+            branches.sort_unstable();
+            for branch in branches {
+                writeln!(ui.stderr(), "* [new untracked branch]  {branch}")?;
+            }
+        }
+        if !tags.is_empty() {
+            writeln!(ui.stderr(), "Tags:")?;
+            tags.sort_unstable();
+            for tag in tags {
+                writeln!(ui.stderr(), "* [new tag]  {tag}")?;
+            }
+        }
+    }
     if !stats.abandoned_commits.is_empty() {
         writeln!(
             ui.stderr(),

cli/tests/test_branch_command.rs

@@ -536,7 +536,10 @@ fn test_branch_forget_fetched_branch() {
     // We can fetch feature1 again.
     let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["git", "fetch", "--remote=origin"]);
     insta::assert_snapshot!(stdout, @"");
-    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    From origin
+    * [new untracked branch]  feature1
+    "###);
     insta::assert_snapshot!(get_branch_output(&test_env, &repo_path), @r###"
     feature1: mzyxwzks 9f01a0e0 message
       @origin: mzyxwzks 9f01a0e0 message
@@ -548,7 +551,10 @@ fn test_branch_forget_fetched_branch() {
     // Fetch works even without the export-import
     let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["git", "fetch", "--remote=origin"]);
     insta::assert_snapshot!(stdout, @"");
-    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    From origin
+    * [new untracked branch]  feature1
+    "###);
     insta::assert_snapshot!(get_branch_output(&test_env, &repo_path), @r###"
     feature1: mzyxwzks 9f01a0e0 message
       @origin: mzyxwzks 9f01a0e0 message
@@ -574,7 +580,10 @@ fn test_branch_forget_fetched_branch() {
     // Fetching a moved branch does not create a conflict
     let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["git", "fetch", "--remote=origin"]);
     insta::assert_snapshot!(stdout, @"");
-    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    From origin
+    * [new untracked branch]  feature1
+    "###);
     insta::assert_snapshot!(get_branch_output(&test_env, &repo_path), @r###"
     feature1: ooosovrs 38aefb17 (empty) another message
       @origin: ooosovrs 38aefb17 (empty) another message
@@ -687,7 +696,12 @@ fn test_branch_track_untrack() {
     );
     test_env.add_config("git.auto-local-branch = false");
     let (_stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["git", "fetch"]);
-    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    From origin
+    * [new untracked branch]  feature1
+    * [new untracked branch]  feature2
+    * [new untracked branch]  main
+    "###);
     insta::assert_snapshot!(get_branch_output(&test_env, &repo_path), @r###"
     feature1@origin: sptzoqmo 7b33f629 commit 1
     feature2@origin: sptzoqmo 7b33f629 commit 1
@@ -759,7 +773,12 @@ fn test_branch_track_untrack() {
         ],
     );
     let (_stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["git", "fetch"]);
-    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    From origin
+    * [new untracked branch]  feature1
+    * [new untracked branch]  feature2
+    * [new untracked branch]  main
+    "###);
     insta::assert_snapshot!(get_branch_output(&test_env, &repo_path), @r###"
     feature1: sptzoqmo 7b33f629 commit 1
     feature1@origin: mmqqkyyt 40dabdaf commit 2
@@ -791,6 +810,11 @@ fn test_branch_track_untrack() {
     test_env.add_config("git.auto-local-branch = true");
     let (_stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["git", "fetch"]);
     insta::assert_snapshot!(stderr, @r###"
+    From origin
+    * [new untracked branch]  feature1
+    * [new untracked branch]  feature2
+    * [new untracked branch]  feature3
+    * [new untracked branch]  main
     Abandoned 1 commits that are no longer reachable.
     "###);
     insta::assert_snapshot!(get_branch_output(&test_env, &repo_path), @r###"
@@ -847,7 +871,11 @@ fn test_branch_track_untrack_patterns() {
     // Fetch new commit without auto tracking
     test_env.add_config("git.auto-local-branch = false");
     let (_stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["git", "fetch"]);
-    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    From origin
+    * [new untracked branch]  feature1
+    * [new untracked branch]  feature2
+    "###);
 
     // Track local branch
     test_env.jj_cmd_ok(&repo_path, &["branch", "create", "main"]);

cli/tests/test_git_colocated.rs

@@ -507,6 +507,9 @@ fn test_git_colocated_fetch_deleted_or_moved_branch() {
     let (stdout, stderr) = test_env.jj_cmd_ok(&clone_path, &["git", "fetch"]);
     insta::assert_snapshot!(stdout, @"");
     insta::assert_snapshot!(stderr, @r###"
+    From origin
+    * [new untracked branch]  B_to_delete
+    * [new untracked branch]  C_to_move
     Abandoned 2 commits that are no longer reachable.
     "###);
     // "original C" and "B_to_delete" are abandoned, as the corresponding branches