cli: add context to checkout/abandon messages triggered by automated git import

Otherwise, it's unclear why "jj status" abandoned commits for example.

cli/src/cli_util.rs

@@ -838,6 +838,7 @@ impl WorkspaceCommandHelper {
                 self.finish_transaction(ui, tx)?;
             }
         }
+        writeln!(ui, "Done importing changes from the underlying Git repo.")?;
         Ok(())
     }
 

cli/tests/test_commit_template.rs

@@ -371,6 +371,7 @@ fn test_log_git_head() {
     std::fs::write(repo_path.join("file"), "foo\n").unwrap();
     let stdout = test_env.jj_cmd_success(&repo_path, &["log", "--color=always"]);
     insta::assert_snapshot!(stdout, @r###"
+    Done importing changes from the underlying Git repo.
     @  rlvkpnrz test.user@example.com 2001-02-03 04:05:09.000 +07:00 50aaf475
     │  initial
     ◉  qpvuntsm test.user@example.com 2001-02-03 04:05:07.000 +07:00 master HEAD@git 230dd059

cli/tests/test_git_colocated.rs

@@ -160,6 +160,7 @@ fn test_git_colocated_rebase_on_import() {
     insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
     Abandoned the following commits:
       rlvkpnrz 45fbe1af master | modify a file
+    Done importing changes from the underlying Git repo.
     @  7f96185cfbe36341d0f9a86ebfaeab67a5922c7e
     ◉  4bcbeaba9a4b309c5f45a8807fbf5499b9714315 master HEAD@git add a file
     ◉  0000000000000000000000000000000000000000
@@ -212,6 +213,7 @@ fn test_git_colocated_branches() {
       kkmpptxz 35605592 master | (empty) bar
     Working copy now at: yqosqzyt 096dc80d (empty) (no description set)
     Parent commit      : qpvuntsm 230dd059 (empty) (no description set)
+    Done importing changes from the underlying Git repo.
     @  096dc80da67094fbaa6683e2a205dddffa31f9a8
     │ ◉  1e6f0b403ed2ff9713b5d6b1dc601e4804250cda master foo
     ├─╯
@@ -347,6 +349,7 @@ fn test_git_colocated_external_checkout() {
     // The old working-copy commit gets abandoned, but the whole branch should not
     // be abandoned. (#1042)
     insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    Done importing changes from the underlying Git repo.
     @  0521ce3b8c4e29aab79f3c750e2845dcbc4c3874
     ◉  a86754f975f953fa25da4265764adc0c62e9ce6b master HEAD@git A
     │ ◉  66f4d1806ae41bd604f69155dece64062a0056cf B
@@ -364,6 +367,7 @@ fn test_git_colocated_squash_undo() {
     test_env.jj_cmd_success(&repo_path, &["ci", "-m=A"]);
     // Test the setup
     insta::assert_snapshot!(get_log_output_divergence(&test_env, &repo_path), @r###"
+    Done importing changes from the underlying Git repo.
     @  rlvkpnrzqnoo 8f71e3b6a3be
     ◉  qpvuntsmwlqt a86754f975f9 A master HEAD@git
     ◉  zzzzzzzzzzzz 000000000000

cli/tests/test_git_fetch.rs

@@ -262,6 +262,7 @@ fn test_git_fetch_from_remote_named_git() {
     test_env.jj_cmd_success(&repo_path, &["git", "remote", "rename", "git", "bar"]);
     let stdout = test_env.jj_cmd_success(&repo_path, &["branch", "list"]);
     insta::assert_snapshot!(stdout, @r###"
+    Done importing changes from the underlying Git repo.
     git: mrylzrtu 76fc7466 message
     "###);
 }

cli/tests/test_git_submodule.rs

@@ -50,9 +50,12 @@ fn test_gitsubmodule_print_gitmodules() {
         &["git", "submodule", "print-gitmodules", "-r", "@-"],
     );
     insta::assert_snapshot!(stdout, @r###"
-	name:old
-	url:https://github.com/old/old.git
-	path:old
+    Done importing changes from the underlying Git repo.
+    name:old
+    url:https://github.com/old/old.git
+    path:old
+
+
     "###);
 
     let stdout =

cli/tests/test_init_command.rs

@@ -164,6 +164,7 @@ fn test_init_git_colocated() {
     init_git_repo(&workspace_root, false);
     let stdout = test_env.jj_cmd_success(&workspace_root, &["init", "--git-repo", "."]);
     insta::assert_snapshot!(stdout, @r###"
+    Done importing changes from the underlying Git repo.
     Initialized repo in "."
     "###);
 
@@ -211,6 +212,7 @@ fn test_init_git_colocated_gitlink() {
     assert!(workspace_root.join(".git").is_file());
     let stdout = test_env.jj_cmd_success(&workspace_root, &["init", "--git-repo", "."]);
     insta::assert_snapshot!(stdout, @r###"
+    Done importing changes from the underlying Git repo.
     Initialized repo in "."
     "###);
 
@@ -244,6 +246,7 @@ fn test_init_git_colocated_symlink_directory() {
     std::os::unix::fs::symlink(git_repo_path.join(".git"), workspace_root.join(".git")).unwrap();
     let stdout = test_env.jj_cmd_success(&workspace_root, &["init", "--git-repo", "."]);
     insta::assert_snapshot!(stdout, @r###"
+    Done importing changes from the underlying Git repo.
     Initialized repo in "."
     "###);
 
@@ -282,6 +285,7 @@ fn test_init_git_colocated_symlink_gitlink() {
     std::os::unix::fs::symlink(git_workdir_path.join(".git"), workspace_root.join(".git")).unwrap();
     let stdout = test_env.jj_cmd_success(&workspace_root, &["init", "--git-repo", "."]);
     insta::assert_snapshot!(stdout, @r###"
+    Done importing changes from the underlying Git repo.
     Initialized repo in "."
     "###);