cli: git: escape bookmark and remote names in trunk() config

Closes #5359.

CHANGELOG.md

@@ -163,6 +163,10 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
   now materialized in a way that can be parsed correctly.
   [#3968](https://github.com/jj-vcs/jj/issues/3968)
 
+* Bookmark and remote names written by `jj git clone` to
+  `revset-aliases.'trunk()'` are now escaped if necessary.
+  [#5359](https://github.com/jj-vcs/jj/issues/5359)
+
 ## [0.25.0] - 2025-01-01
 
 ### Release highlights

cli/src/commands/git/mod.rs

@@ -26,6 +26,7 @@ use std::path::Path;
 use clap::Subcommand;
 use jj_lib::config::ConfigFile;
 use jj_lib::config::ConfigSource;
+use jj_lib::revset;
 
 use self::clone::cmd_git_clone;
 use self::clone::GitCloneArgs;
@@ -120,6 +121,8 @@ fn write_repository_level_trunk_alias(
     branch: &str,
 ) -> Result<(), CommandError> {
     let mut file = ConfigFile::load_or_empty(ConfigSource::Repo, repo_path.join("config.toml"))?;
+    let branch = revset::format_symbol(branch);
+    let remote = revset::format_symbol(remote);
     file.set_value(["revset-aliases", "trunk()"], format!("{branch}@{remote}"))
         .expect("initial repo config shouldn't have invalid values");
     file.save()?;

cli/tests/test_git_clone.rs

@@ -599,6 +599,36 @@ fn test_git_clone_remote_default_bookmark(subprocess: bool) {
     revset-aliases.'trunk()' = "feature1@origin"
     "###);
     }
+
+    // A branch with a strange name gets escaped in the config. Windows doesn't like
+    // the strange name.
+    if cfg!(unix) {
+        git_repo.reference("refs/heads/\"", oid, false, "").unwrap();
+        git_repo.set_head("refs/heads/\"").unwrap();
+        let (_stdout, stderr) =
+            test_env.jj_cmd_ok(test_env.env_root(), &["git", "clone", "source", "clone4"]);
+        insta::allow_duplicates! {
+        insta::assert_snapshot!(stderr, @r#"
+    Fetching into new repo in "$TEST_ENV/clone4"
+    bookmark: "@origin        [new] untracked
+    bookmark: feature1@origin [new] untracked
+    bookmark: main@origin     [new] untracked
+    Setting the revset alias "trunk()" to ""\""@origin"
+    Working copy now at: wmwvqwsz abb7c50b (empty) (no description set)
+    Parent commit      : mzyxwzks 9f01a0e0 " feature1@origin main@origin | message
+    Added 1 files, modified 0 files, removed 0 files
+    "#);
+        }
+
+        // "trunk()" alias should be set to new default bookmark "\""
+        let stdout = test_env.jj_cmd_success(
+            &test_env.env_root().join("clone4"),
+            &["config", "list", "--repo", "revset-aliases.'trunk()'"],
+        );
+        insta::allow_duplicates! {
+        insta::assert_snapshot!(stdout, @r#"revset-aliases.'trunk()' = '"\""@origin'"#);
+        }
+    }
 }
 
 #[test_case(false; "use git2 for remote calls")]