cli: print warning about git clean -fdx when creating colocated repo

We hear every now and then from users who have run `git clean -fdx`
and accidentally delete their repo. Let's at least warn users about it
when the create a colocated repo.

We could perhaps allow the `.jj/` directory to be inside a `.git/`
directory like Sapling does, but that seems a little ugly and it's a
larger change.

Author: martinvonz

cli/src/commands/git/clone.rs

@@ -162,6 +162,14 @@ pub fn cmd_git_clone(
             tx.finish(ui, "check out git remote's default branch")?;
         }
     }
+
+    if args.colocate {
+        writeln!(
+            ui.hint_default(),
+            r"Running `git clean -xdf` will remove `.jj/`!",
+        )?;
+    }
+
     Ok(())
 }
 

cli/src/commands/git/init.rs

@@ -112,6 +112,12 @@ pub fn cmd_git_init(
         r#"Initialized repo in "{}""#,
         relative_wc_path.display()
     )?;
+    if args.colocate {
+        writeln!(
+            ui.hint_default(),
+            r"Running `git clean -xdf` will remove `.jj/`!",
+        )?;
+    }
 
     Ok(())
 }

cli/tests/test_git_clone.rs

@@ -197,6 +197,7 @@ fn test_git_clone_colocate() {
     ------- stderr -------
     Fetching into new repo in "$TEST_ENV/empty"
     Nothing changed.
+    Hint: Running `git clean -xdf` will remove `.jj/`!
     [EOF]
     "#);
 
@@ -220,6 +221,7 @@ fn test_git_clone_colocate() {
     Working copy  (@) now at: uuqppmxq 3711b3b5 (empty) (no description set)
     Parent commit (@-)      : qomsplrm ebeb70d8 main | message
     Added 1 files, modified 0 files, removed 0 files
+    Hint: Running `git clean -xdf` will remove `.jj/`!
     [EOF]
     "#);
     let clone_dir = test_env.work_dir("clone");
@@ -365,6 +367,7 @@ fn test_git_clone_colocate() {
     Working copy  (@) now at: vzqnnsmr fea36bca (empty) (no description set)
     Parent commit (@-)      : qomsplrm ebeb70d8 main | message
     Added 1 files, modified 0 files, removed 0 files
+    Hint: Running `git clean -xdf` will remove `.jj/`!
     [EOF]
     "#);
 }

cli/tests/test_git_colocated.rs

@@ -1539,6 +1539,7 @@ fn test_git_colocated_operation_cleanup() {
     insta::assert_snapshot!(output, @r#"
     ------- stderr -------
     Initialized repo in "repo"
+    Hint: Running `git clean -xdf` will remove `.jj/`!
     [EOF]
     "#);
 

cli/tests/test_git_init.rs

@@ -776,6 +776,7 @@ fn test_git_init_colocated_via_flag_git_dir_exists() {
     ------- stderr -------
     Done importing changes from the underlying Git repo.
     Initialized repo in "repo"
+    Hint: Running `git clean -xdf` will remove `.jj/`!
     [EOF]
     "#);
 
@@ -806,6 +807,7 @@ fn test_git_init_colocated_via_flag_git_dir_not_exists() {
     insta::assert_snapshot!(output, @r#"
     ------- stderr -------
     Initialized repo in "repo"
+    Hint: Running `git clean -xdf` will remove `.jj/`!
     [EOF]
     "#);
     // No HEAD ref is available yet