cli: branch: print stats even if just one branch is updated

We usually print stats at the end of mutable operation, and I think these
messages are useful even if N = 1. I understand that "Deleted N" (N > 1) is
unusual and the original intent of these messages was to signal possible
mistakes. However, I don't think printing N=1 stats would nullify the original
purpose.

No emptiness check is needed for delete/forget, but names can be empty in
track/untrack because of noop changes.

cli/src/commands/branch/delete.rs

@@ -54,8 +54,6 @@ pub fn cmd_branch_delete(
             matched_branches.iter().map(|(name, _)| name).join(", ")
         ),
     )?;
-    if matched_branches.len() > 1 {
-        writeln!(ui.status(), "Deleted {} branches.", matched_branches.len())?;
-    }
+    writeln!(ui.status(), "Deleted {} branches.", matched_branches.len())?;
     Ok(())
 }

cli/src/commands/branch/forget.rs

@@ -62,9 +62,7 @@ pub fn cmd_branch_forget(
             matched_branches.iter().map(|(name, _)| name).join(", ")
         ),
     )?;
-    if matched_branches.len() > 1 {
-        writeln!(ui.status(), "Forgot {} branches.", matched_branches.len())?;
-    }
+    writeln!(ui.status(), "Forgot {} branches.", matched_branches.len())?;
     Ok(())
 }
 

cli/src/commands/branch/track.rs

@@ -67,7 +67,7 @@ pub fn cmd_branch_track(
         ui,
         format!("track remote branch {}", names.iter().join(", ")),
     )?;
-    if names.len() > 1 {
+    if !names.is_empty() {
         writeln!(
             ui.status(),
             "Started tracking {} remote branches.",

cli/src/commands/branch/untrack.rs

@@ -70,7 +70,7 @@ pub fn cmd_branch_untrack(
         ui,
         format!("untrack remote branch {}", names.iter().join(", ")),
     )?;
-    if names.len() > 1 {
+    if !names.is_empty() {
         writeln!(
             ui.status(),
             "Stopped tracking {} remote branches.",

cli/tests/test_branch_command.rs

@@ -445,7 +445,9 @@ fn test_branch_forget_glob() {
         &["branch", "forget", "foo-4", "glob:foo-*", "glob:foo-*"],
     );
     insta::assert_snapshot!(stdout, @"");
-    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    Forgot 1 branches.
+    "###);
     insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
     @  bar-2 230dd059e1b0
     ◉   000000000000
@@ -529,7 +531,9 @@ fn test_branch_delete_glob() {
         &["branch", "delete", "foo-4", "glob:foo-*", "glob:foo-*"],
     );
     insta::assert_snapshot!(stdout, @"");
-    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    Deleted 1 branches.
+    "###);
     insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
     @  bar-2 foo-1@origin foo-3@origin foo-4@origin 312a98d6f27b
     ◉   000000000000
@@ -608,7 +612,9 @@ fn test_branch_forget_export() {
     insta::assert_snapshot!(stderr, @"");
     let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["branch", "forget", "foo"]);
     insta::assert_snapshot!(stdout, @"");
-    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    Forgot 1 branches.
+    "###);
     // Forgetting a branch deletes local and remote-tracking branches including
     // the corresponding git-tracking branch.
     insta::assert_snapshot!(get_branch_output(&test_env, &repo_path), @"");
@@ -734,7 +740,9 @@ fn test_branch_forget_fetched_branch() {
         .unwrap();
     let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["branch", "forget", "feature1"]);
     insta::assert_snapshot!(stdout, @"");
-    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    Forgot 1 branches.
+    "###);
 
     // Fetching a moved branch does not create a conflict
     let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["git", "fetch", "--remote=origin"]);
@@ -1014,6 +1022,7 @@ fn test_branch_track_conflict() {
     );
     let (_, stderr) = test_env.jj_cmd_ok(&repo_path, &["branch", "track", "main@origin"]);
     insta::assert_snapshot!(stderr, @r###"
+    Started tracking 1 remote branches.
     main (conflicted):
       + qpvuntsm e802c4f8 (empty) b
       + qpvuntsm hidden 427890ea (empty) a
@@ -1129,6 +1138,7 @@ fn test_branch_track_untrack_patterns() {
     Warning: Git-tracking branch cannot be untracked: feature1@git
     Warning: Remote branch not tracked yet: feature2@origin
     Warning: Git-tracking branch cannot be untracked: main@git
+    Stopped tracking 1 remote branches.
     "###);
     insta::assert_snapshot!(get_branch_output(&test_env, &repo_path), @r###"
     feature1: omvolwpu 1336caed commit

cli/tests/test_git_colocated.rs

@@ -383,7 +383,9 @@ fn test_git_colocated_branch_forget() {
 
     let (stdout, stderr) = test_env.jj_cmd_ok(&workspace_root, &["branch", "forget", "foo"]);
     insta::assert_snapshot!(stdout, @"");
-    insta::assert_snapshot!(stderr, @"");
+    insta::assert_snapshot!(stderr, @r###"
+    Forgot 1 branches.
+    "###);
     // A forgotten branch is deleted in the git repo. For a detailed demo explaining
     // this, see `test_branch_forget_export` in `test_branch_command.rs`.
     insta::assert_snapshot!(get_branch_output(&test_env, &workspace_root), @"");