templater: make "git_head" return boolean, render it as "git_head()"

For the same reason as the root revision is indicated by "root()".

CHANGELOG.md

@@ -16,7 +16,8 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 * Evaluation error of `revsets.short-prefixes` configuration is now reported.
 
 * The `HEAD@git` symbol no longer resolves to the Git HEAD revision. Use
-  `git_head()` or `@-` revset expression instead.
+  `git_head()` or `@-` revset expression instead. The `git_head` template
+  keyword now returns a boolean.
 
 * Help command doesn't work recursively anymore, i.e. `jj workspace help root`
   doesn't work anymore.

cli/src/commit_templater.rs

@@ -30,7 +30,6 @@ use jj_lib::extensions_map::ExtensionsMap;
 use jj_lib::fileset;
 use jj_lib::fileset::FilesetDiagnostics;
 use jj_lib::fileset::FilesetExpression;
-use jj_lib::git;
 use jj_lib::id_prefix::IdPrefixContext;
 use jj_lib::id_prefix::IdPrefixIndex;
 use jj_lib::matchers::Matcher;
@@ -703,8 +702,11 @@ fn builtin_commit_methods<'repo>() -> CommitTemplateBuildMethodFnMap<'repo, Comm
         |language, _diagnostics, _build_ctx, self_property, function| {
             function.expect_no_arguments()?;
             let repo = language.repo;
-            let out_property = self_property.map(|commit| extract_git_head(repo, &commit));
-            Ok(L::wrap_ref_name_opt(out_property))
+            let out_property = self_property.map(|commit| {
+                let target = repo.view().git_head();
+                target.added_ids().contains(commit.id())
+            });
+            Ok(L::wrap_boolean(out_property))
         },
     );
     map.insert(
@@ -1230,14 +1232,6 @@ fn build_ref_names_index<'a>(
     index
 }
 
-fn extract_git_head(repo: &dyn Repo, commit: &Commit) -> Option<Rc<RefName>> {
-    let target = repo.view().git_head();
-    target
-        .added_ids()
-        .contains(commit.id())
-        .then(|| RefName::remote_only("HEAD", git::REMOTE_NAME_FOR_LOCAL_GIT_REPO, target.clone()))
-}
-
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub enum CommitOrChangeId {
     Commit(CommitId),

cli/src/config/templates.toml

@@ -78,7 +78,7 @@ if(root,
         bookmarks,
         tags,
         working_copies,
-        git_head,
+        if(git_head, label("git_head", "git_head()")),
         format_short_commit_id(commit_id),
         if(conflict, label("conflict", "conflict")),
         if(empty, label("empty", "(empty)")),
@@ -103,7 +103,7 @@ if(root,
         bookmarks,
         tags,
         working_copies,
-        git_head,
+        if(git_head, label("git_head", "git_head()")),
         format_short_commit_id(commit_id),
         if(conflict, label("conflict", "conflict")),
       ) ++ "\n",

cli/tests/test_commit_template.rs

@@ -671,27 +671,21 @@ fn test_log_git_head() {
     test_env.jj_cmd_ok(&repo_path, &["new", "-m=initial"]);
     std::fs::write(repo_path.join("file"), "foo\n").unwrap();
 
-    let template = r#"
-    separate(", ",
-      if(git_head, "name: " ++ git_head.name()),
-      "remote: " ++ git_head.remote(),
-    ) ++ "\n"
-    "#;
-    let stdout = test_env.jj_cmd_success(&repo_path, &["log", "-T", template]);
-    insta::assert_snapshot!(stdout, @r###"
-    @  remote: <Error: No RefName available>
-    ○  name: HEAD, remote: git
-    ◆  remote: <Error: No RefName available>
-    "###);
+    let stdout = test_env.jj_cmd_success(&repo_path, &["log", "-T", "git_head"]);
+    insta::assert_snapshot!(stdout, @r#"
+    @  false
+    ○  true
+    ◆  false
+    "#);
 
     let stdout = test_env.jj_cmd_success(&repo_path, &["log", "--color=always"]);
-    insta::assert_snapshot!(stdout, @r###"
+    insta::assert_snapshot!(stdout, @r#"
     @  rlvkpnrz test.user@example.com 2001-02-03 08:05:09 50aaf475
     │  initial
-    ○  qpvuntsm test.user@example.com 2001-02-03 08:05:07 HEAD@git 230dd059
+    ○  qpvuntsm test.user@example.com 2001-02-03 08:05:07 git_head() 230dd059
     │  (empty) (no description set)
     ◆  zzzzzzzz root() 00000000
-    "###);
+    "#);
 }
 
 #[test]

cli/tests/test_git_colocated.rs

@@ -56,11 +56,11 @@ fn test_git_colocated() {
 
     // Import the repo
     test_env.jj_cmd_ok(&workspace_root, &["git", "init", "--git-repo", "."]);
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  3e9369cd54227eb88455e1834dbc08aad6a16ac4
-    ○  e61b6729ff4292870702f2f72b2a60165679ef37 master HEAD@git initial
+    ○  e61b6729ff4292870702f2f72b2a60165679ef37 master git_head() initial
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
     insta::assert_snapshot!(
         git_repo.head().unwrap().peel_to_commit().unwrap().id().to_string(),
         @"e61b6729ff4292870702f2f72b2a60165679ef37"
@@ -69,11 +69,11 @@ fn test_git_colocated() {
     // Modify the working copy. The working-copy commit should changed, but the Git
     // HEAD commit should not
     std::fs::write(workspace_root.join("file"), "modified").unwrap();
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  4f546c80f30abc0803fb83e5032a4d49fede4d68
-    ○  e61b6729ff4292870702f2f72b2a60165679ef37 master HEAD@git initial
+    ○  e61b6729ff4292870702f2f72b2a60165679ef37 master git_head() initial
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
     insta::assert_snapshot!(
         git_repo.head().unwrap().peel_to_commit().unwrap().id().to_string(),
         @"e61b6729ff4292870702f2f72b2a60165679ef37"
@@ -81,12 +81,12 @@ fn test_git_colocated() {
 
     // Create a new change from jj and check that it's reflected in Git
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  0e2301a42b288b9568344e32cfdd8c76d1e56a83
-    ○  4f546c80f30abc0803fb83e5032a4d49fede4d68 HEAD@git
+    ○  4f546c80f30abc0803fb83e5032a4d49fede4d68 git_head()
     ○  e61b6729ff4292870702f2f72b2a60165679ef37 master initial
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
     insta::assert_snapshot!(
         git_repo.head().unwrap().target().unwrap().to_string(),
         @"4f546c80f30abc0803fb83e5032a4d49fede4d68"
@@ -165,13 +165,13 @@ fn test_git_colocated_unborn_bookmark() {
         git_repo.head().unwrap().peel_to_commit().unwrap().id().to_string(),
         @"e3e01407bd3539722ae4ffff077700d97c60cb11"
     );
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  0e14610343ef50775f5c44db5aeef19aee45d9ad
-    ○  e3e01407bd3539722ae4ffff077700d97c60cb11 HEAD@git
+    ○  e3e01407bd3539722ae4ffff077700d97c60cb11 git_head()
     │ ○  993600f1189571af5bbeb492cf657dc7d0fde48a
     ├─╯
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
     // Staged change shouldn't persist.
     checkout_index();
     insta::assert_snapshot!(test_env.jj_cmd_success(&workspace_root, &["status"]), @r###"
@@ -219,16 +219,16 @@ fn test_git_colocated_unborn_bookmark() {
     Working copy now at: wqnwkozp 101e2723 (empty) (no description set)
     Parent commit      : znkkpsqq fc8af934 (no description set)
     "###);
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  101e272377a9daff75358f10dbd078df922fe68c
-    ○  fc8af9345b0830dcb14716e04cd2af26e2d19f63 HEAD@git
+    ○  fc8af9345b0830dcb14716e04cd2af26e2d19f63 git_head()
     │ ○  ef75c0b0dcc9b080e00226908c21316acaa84dc6
     │ ○  e3e01407bd3539722ae4ffff077700d97c60cb11 master
     ├─╯
     │ ○  993600f1189571af5bbeb492cf657dc7d0fde48a
     ├─╯
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
 }
 
 #[test]
@@ -293,11 +293,11 @@ fn test_git_colocated_rebase_on_import() {
     let commit1 = commit2.parents().next().unwrap();
     git_repo.branch("master", &commit1, true).unwrap();
     let (stdout, stderr) = get_log_output_with_stderr(&test_env, &workspace_root);
-    insta::assert_snapshot!(stdout, @r###"
+    insta::assert_snapshot!(stdout, @r#"
     @  15b1d70c5e33b5d2b18383292b85324d5153ffed
-    ○  47fe984daf66f7bf3ebf31b9cb3513c995afb857 master HEAD@git add a file
+    ○  47fe984daf66f7bf3ebf31b9cb3513c995afb857 master git_head() add a file
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
     insta::assert_snapshot!(stderr, @r###"
     Abandoned 1 commits that are no longer reachable.
     Rebased 1 descendant commits off of commits rewritten from git
@@ -316,13 +316,13 @@ fn test_git_colocated_bookmarks() {
     test_env.jj_cmd_ok(&workspace_root, &["git", "init", "--git-repo", "."]);
     test_env.jj_cmd_ok(&workspace_root, &["new", "-m", "foo"]);
     test_env.jj_cmd_ok(&workspace_root, &["new", "@-", "-m", "bar"]);
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  3560559274ab431feea00b7b7e0b9250ecce951f bar
     │ ○  1e6f0b403ed2ff9713b5d6b1dc601e4804250cda foo
     ├─╯
-    ○  230dd059e1b059aefc0da06a2e5a7dbf22362f22 HEAD@git
+    ○  230dd059e1b059aefc0da06a2e5a7dbf22362f22 git_head()
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
 
     // Create a bookmark in jj. It should be exported to Git even though it points
     // to the working- copy commit.
@@ -350,13 +350,13 @@ fn test_git_colocated_bookmarks() {
         )
         .unwrap();
     let (stdout, stderr) = get_log_output_with_stderr(&test_env, &workspace_root);
-    insta::assert_snapshot!(stdout, @r###"
+    insta::assert_snapshot!(stdout, @r#"
     @  096dc80da67094fbaa6683e2a205dddffa31f9a8
     │ ○  1e6f0b403ed2ff9713b5d6b1dc601e4804250cda master foo
     ├─╯
-    ○  230dd059e1b059aefc0da06a2e5a7dbf22362f22 HEAD@git
+    ○  230dd059e1b059aefc0da06a2e5a7dbf22362f22 git_head()
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
     insta::assert_snapshot!(stderr, @r###"
     Abandoned 1 commits that are no longer reachable.
     Working copy now at: yqosqzyt 096dc80d (empty) (no description set)
@@ -373,11 +373,11 @@ fn test_git_colocated_bookmark_forget() {
     test_env.jj_cmd_ok(&workspace_root, &["git", "init", "--git-repo", "."]);
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
     test_env.jj_cmd_ok(&workspace_root, &["bookmark", "create", "foo"]);
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  65b6b74e08973b88d38404430f119c8c79465250 foo
-    ○  230dd059e1b059aefc0da06a2e5a7dbf22362f22 HEAD@git
+    ○  230dd059e1b059aefc0da06a2e5a7dbf22362f22 git_head()
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
     insta::assert_snapshot!(get_bookmark_output(&test_env, &workspace_root), @r###"
     foo: rlvkpnrz 65b6b74e (empty) (no description set)
       @git: rlvkpnrz 65b6b74e (empty) (no description set)
@@ -504,13 +504,13 @@ fn test_git_colocated_checkout_non_empty_working_copy() {
 
     assert_eq!(git_head_target, "refs/heads/master");
 
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  149cc31cb08a1589e6c5ee2cb2061559dc758ecb new
     │ ○  4ec6f6506bd1903410f15b80058a7f0d8f62deea two
     ├─╯
-    ○  e61b6729ff4292870702f2f72b2a60165679ef37 master HEAD@git initial
+    ○  e61b6729ff4292870702f2f72b2a60165679ef37 master git_head() initial
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
 }
 
 #[test]
@@ -531,15 +531,15 @@ fn test_git_colocated_fetch_deleted_or_moved_bookmark() {
     git2::Repository::clone(origin_path.to_str().unwrap(), &clone_path).unwrap();
     test_env.jj_cmd_ok(&clone_path, &["git", "init", "--git-repo=."]);
     test_env.jj_cmd_ok(&clone_path, &["new", "A"]);
-    insta::assert_snapshot!(get_log_output(&test_env, &clone_path), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &clone_path), @r#"
     @  9c2de797c3c299a40173c5af724329012b77cbdd
     │ ○  4a191a9013d3f3398ccf5e172792a61439dbcf3a C_to_move original C
     ├─╯
     │ ○  c49ec4fb50844d0e693f1609da970b11878772ee B_to_delete B_to_delete
     ├─╯
-    ◆  a7e4cec4256b7995129b9d1e1bda7e1df6e60678 A HEAD@git A
+    ◆  a7e4cec4256b7995129b9d1e1bda7e1df6e60678 A git_head() A
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
 
     test_env.jj_cmd_ok(&origin_path, &["bookmark", "delete", "B_to_delete"]);
     // Move bookmark C sideways
@@ -553,13 +553,13 @@ fn test_git_colocated_fetch_deleted_or_moved_bookmark() {
     "###);
     // "original C" and "B_to_delete" are abandoned, as the corresponding bookmarks
     // were deleted or moved on the remote (#864)
-    insta::assert_snapshot!(get_log_output(&test_env, &clone_path), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &clone_path), @r#"
     ○  4f3d13296f978cbc351c46a43b4619c91b888475 C_to_move moved C
     │ @  9c2de797c3c299a40173c5af724329012b77cbdd
     ├─╯
-    ◆  a7e4cec4256b7995129b9d1e1bda7e1df6e60678 A HEAD@git A
+    ◆  a7e4cec4256b7995129b9d1e1bda7e1df6e60678 A git_head() A
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
 }
 
 #[test]
@@ -599,11 +599,11 @@ fn test_git_colocated_rebase_dirty_working_copy() {
       feature: Modified ref had been deleted in Git
     Done importing changes from the underlying Git repo.
     "###);
-    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r#"
     @  6bad94b10401f5fafc8a91064661224650d10d1b feature??
-    ○  3230d52258f6de7e9afbd10da8d64503cc7cdca5 HEAD@git
+    ○  3230d52258f6de7e9afbd10da8d64503cc7cdca5 git_head()
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
 
     // The working-copy content shouldn't be lost.
     insta::assert_snapshot!(
@@ -628,13 +628,13 @@ fn test_git_colocated_external_checkout() {
     test_env.jj_cmd_ok(&repo_path, &["new"]);
 
     // Checked out anonymous bookmark
-    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r#"
     @  f8a23336e41840ed1757ef323402a770427dc89a
-    ○  eccedddfa5152d99fc8ddd1081b375387a8a382a HEAD@git B
+    ○  eccedddfa5152d99fc8ddd1081b375387a8a382a git_head() B
     │ ○  a7e4cec4256b7995129b9d1e1bda7e1df6e60678 master A
     ├─╯
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
 
     // Check out another bookmark by external command
     git_check_out_ref("refs/heads/master");
@@ -642,13 +642,13 @@ fn test_git_colocated_external_checkout() {
     // The old working-copy commit gets abandoned, but the whole bookmark should not
     // be abandoned. (#1042)
     let (stdout, stderr) = get_log_output_with_stderr(&test_env, &repo_path);
-    insta::assert_snapshot!(stdout, @r###"
+    insta::assert_snapshot!(stdout, @r#"
     @  8bb9e8d42a37c2a4e8dcfad97fce0b8f49bc7afa
-    ○  a7e4cec4256b7995129b9d1e1bda7e1df6e60678 master HEAD@git A
+    ○  a7e4cec4256b7995129b9d1e1bda7e1df6e60678 master git_head() A
     │ ○  eccedddfa5152d99fc8ddd1081b375387a8a382a B
     ├─╯
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
     insta::assert_snapshot!(stderr, @r###"
     Reset the working copy parent to the new Git HEAD.
     "###);
@@ -656,29 +656,29 @@ fn test_git_colocated_external_checkout() {
     // Edit non-head commit
     test_env.jj_cmd_ok(&repo_path, &["new", "description(B)"]);
     test_env.jj_cmd_ok(&repo_path, &["new", "-m=C", "--no-edit"]);
-    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r#"
     ○  99a813753d6db988d8fc436b0d6b30a54d6b2707 C
     @  81e086b7f9b1dd7fde252e28bdcf4ba4abd86ce5
-    ○  eccedddfa5152d99fc8ddd1081b375387a8a382a HEAD@git B
+    ○  eccedddfa5152d99fc8ddd1081b375387a8a382a git_head() B
     │ ○  a7e4cec4256b7995129b9d1e1bda7e1df6e60678 master A
     ├─╯
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
 
     // Check out another bookmark by external command
     git_check_out_ref("refs/heads/master");
 
     // The old working-copy commit shouldn't be abandoned. (#3747)
     let (stdout, stderr) = get_log_output_with_stderr(&test_env, &repo_path);
-    insta::assert_snapshot!(stdout, @r###"
+    insta::assert_snapshot!(stdout, @r#"
     @  ca2a4e32f08688c6fb795c4c034a0a7e09c0d804
-    ○  a7e4cec4256b7995129b9d1e1bda7e1df6e60678 master HEAD@git A
+    ○  a7e4cec4256b7995129b9d1e1bda7e1df6e60678 master git_head() A
     │ ○  99a813753d6db988d8fc436b0d6b30a54d6b2707 C
     │ ○  81e086b7f9b1dd7fde252e28bdcf4ba4abd86ce5
     │ ○  eccedddfa5152d99fc8ddd1081b375387a8a382a B
     ├─╯
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
     insta::assert_snapshot!(stderr, @r###"
     Reset the working copy parent to the new Git HEAD.
     "###);
@@ -692,26 +692,26 @@ fn test_git_colocated_squash_undo() {
     test_env.jj_cmd_ok(&repo_path, &["git", "init", "--git-repo=."]);
     test_env.jj_cmd_ok(&repo_path, &["ci", "-m=A"]);
     // Test the setup
-    insta::assert_snapshot!(get_log_output_divergence(&test_env, &repo_path), @r###"
+    insta::assert_snapshot!(get_log_output_divergence(&test_env, &repo_path), @r#"
     @  rlvkpnrzqnoo 9670380ac379
-    ○  qpvuntsmwlqt a7e4cec4256b A HEAD@git
+    ○  qpvuntsmwlqt a7e4cec4256b A git_head()
     ◆  zzzzzzzzzzzz 000000000000
-    "###);
+    "#);
 
     test_env.jj_cmd_ok(&repo_path, &["squash"]);
-    insta::assert_snapshot!(get_log_output_divergence(&test_env, &repo_path), @r###"
+    insta::assert_snapshot!(get_log_output_divergence(&test_env, &repo_path), @r#"
     @  zsuskulnrvyr 6ee662324e5a
-    ○  qpvuntsmwlqt 13ab6b96d82e A HEAD@git
+    ○  qpvuntsmwlqt 13ab6b96d82e A git_head()
     ◆  zzzzzzzzzzzz 000000000000
-    "###);
+    "#);
     test_env.jj_cmd_ok(&repo_path, &["undo"]);
     // TODO: There should be no divergence here; 2f376ea1478c should be hidden
     // (#922)
-    insta::assert_snapshot!(get_log_output_divergence(&test_env, &repo_path), @r###"
+    insta::assert_snapshot!(get_log_output_divergence(&test_env, &repo_path), @r#"
     @  rlvkpnrzqnoo 9670380ac379
-    ○  qpvuntsmwlqt a7e4cec4256b A HEAD@git
+    ○  qpvuntsmwlqt a7e4cec4256b A git_head()
     ◆  zzzzzzzzzzzz 000000000000
-    "###);
+    "#);
 }
 
 #[test]
@@ -726,11 +726,11 @@ fn test_git_colocated_undo_head_move() {
     insta::assert_snapshot!(
         git_repo.head().unwrap().target().unwrap().to_string(),
         @"230dd059e1b059aefc0da06a2e5a7dbf22362f22");
-    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r#"
     @  65b6b74e08973b88d38404430f119c8c79465250
-    ○  230dd059e1b059aefc0da06a2e5a7dbf22362f22 HEAD@git
+    ○  230dd059e1b059aefc0da06a2e5a7dbf22362f22 git_head()
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
 
     // HEAD should be unset
     test_env.jj_cmd_ok(&repo_path, &["undo"]);
@@ -743,12 +743,12 @@ fn test_git_colocated_undo_head_move() {
     // Create commit on non-root commit
     test_env.jj_cmd_ok(&repo_path, &["new"]);
     test_env.jj_cmd_ok(&repo_path, &["new"]);
-    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r#"
     @  69b19f73cf584f162f078fb0d91c55ca39d10bc7
-    ○  eb08b363bb5ef8ee549314260488980d7bbe8f63 HEAD@git
+    ○  eb08b363bb5ef8ee549314260488980d7bbe8f63 git_head()
     ○  230dd059e1b059aefc0da06a2e5a7dbf22362f22
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
     insta::assert_snapshot!(
         git_repo.head().unwrap().target().unwrap().to_string(),
         @"eb08b363bb5ef8ee549314260488980d7bbe8f63");
@@ -764,11 +764,11 @@ fn test_git_colocated_undo_head_move() {
     insta::assert_snapshot!(
         git_repo.head().unwrap().target().unwrap().to_string(),
         @"230dd059e1b059aefc0da06a2e5a7dbf22362f22");
-    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r#"
     @  eb08b363bb5ef8ee549314260488980d7bbe8f63
-    ○  230dd059e1b059aefc0da06a2e5a7dbf22362f22 HEAD@git
+    ○  230dd059e1b059aefc0da06a2e5a7dbf22362f22 git_head()
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
 }
 
 fn get_log_output_divergence(test_env: &TestEnvironment, repo_path: &Path) -> String {
@@ -778,7 +778,7 @@ fn get_log_output_divergence(test_env: &TestEnvironment, repo_path: &Path) -> St
       commit_id.short(),
       description.first_line(),
       bookmarks,
-      git_head,
+      if(git_head, "git_head()"),
       if(divergent, "!divergence!"),
     )
     "#;
@@ -786,7 +786,14 @@ fn get_log_output_divergence(test_env: &TestEnvironment, repo_path: &Path) -> St
 }
 
 fn get_log_output(test_env: &TestEnvironment, workspace_root: &Path) -> String {
-    let template = r#"separate(" ", commit_id, bookmarks, git_head, description)"#;
+    let template = r#"
+    separate(" ",
+      commit_id,
+      bookmarks,
+      if(git_head, "git_head()"),
+      description,
+    )
+    "#;
     test_env.jj_cmd_success(workspace_root, &["log", "-T", template, "-r=all()"])
 }
 
@@ -794,7 +801,14 @@ fn get_log_output_with_stderr(
     test_env: &TestEnvironment,
     workspace_root: &Path,
 ) -> (String, String) {
-    let template = r#"separate(" ", commit_id, bookmarks, git_head, description)"#;
+    let template = r#"
+    separate(" ",
+      commit_id,
+      bookmarks,
+      if(git_head, "git_head()"),
+      description,
+    )
+    "#;
     test_env.jj_cmd_ok(workspace_root, &["log", "-T", template, "-r=all()"])
 }
 
@@ -853,11 +867,11 @@ fn test_git_colocated_unreachable_commits() {
 
     // Import the repo while there is no path to the second commit
     test_env.jj_cmd_ok(&workspace_root, &["git", "init", "--git-repo", "."]);
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  66ae47cee4f8c28ee8d7e4f5d9401b03c07e22f2
-    ○  2ee37513d2b5e549f7478c671a780053614bff19 master HEAD@git initial
+    ○  2ee37513d2b5e549f7478c671a780053614bff19 master git_head() initial
     ◆  0000000000000000000000000000000000000000
-    "###);
+    "#);
     insta::assert_snapshot!(
         git_repo.head().unwrap().peel_to_commit().unwrap().id().to_string(),
         @"2ee37513d2b5e549f7478c671a780053614bff19"

cli/tests/test_git_init.rs

@@ -64,7 +64,13 @@ fn get_bookmark_output(test_env: &TestEnvironment, repo_path: &Path) -> String {
 }
 
 fn get_log_output(test_env: &TestEnvironment, workspace_root: &Path) -> String {
-    let template = r#"separate(" ", commit_id.short(), bookmarks, git_head, description)"#;
+    let template = r#"
+    separate(" ",
+      commit_id.short(),
+      bookmarks,
+      if(git_head, "git_head()"),
+      description,
+    )"#;
     test_env.jj_cmd_success(workspace_root, &["log", "-T", template, "-r=all()"])
 }
 
@@ -168,11 +174,11 @@ fn test_git_init_external(bare: bool) {
 
     // Check that the Git repo's HEAD got checked out
     insta::allow_duplicates! {
-        insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+        insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r#"
         @  f6950fc115ae
-        ○  8d698d4a8ee1 my-bookmark HEAD@git My commit message
+        ○  8d698d4a8ee1 my-bookmark git_head() My commit message
         ◆  000000000000
-        "###);
+        "#);
     }
 }
 
@@ -342,20 +348,20 @@ fn test_git_init_colocated_via_git_repo_path() {
         .ends_with("../../../.git"));
 
     // Check that the Git repo's HEAD got checked out
-    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r#"
     @  f61b77cd4bb5
-    ○  8d698d4a8ee1 my-bookmark HEAD@git My commit message
+    ○  8d698d4a8ee1 my-bookmark git_head() My commit message
     ◆  000000000000
-    "###);
+    "#);
 
     // Check that the Git repo's HEAD moves
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  f1c7aa7c62d8
-    ○  f61b77cd4bb5 HEAD@git
+    ○  f61b77cd4bb5 git_head()
     ○  8d698d4a8ee1 my-bookmark My commit message
     ◆  000000000000
-    "###);
+    "#);
 }
 
 #[test]
@@ -378,20 +384,20 @@ fn test_git_init_colocated_via_git_repo_path_gitlink() {
     insta::assert_snapshot!(read_git_target(&workspace_root), @"../../../.git");
 
     // Check that the Git repo's HEAD got checked out
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  f61b77cd4bb5
-    ○  8d698d4a8ee1 my-bookmark HEAD@git My commit message
+    ○  8d698d4a8ee1 my-bookmark git_head() My commit message
     ◆  000000000000
-    "###);
+    "#);
 
     // Check that the Git repo's HEAD moves
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  f1c7aa7c62d8
-    ○  f61b77cd4bb5 HEAD@git
+    ○  f61b77cd4bb5 git_head()
     ○  8d698d4a8ee1 my-bookmark My commit message
     ◆  000000000000
-    "###);
+    "#);
 }
 
 #[cfg(unix)]
@@ -413,20 +419,20 @@ fn test_git_init_colocated_via_git_repo_path_symlink_directory() {
     insta::assert_snapshot!(read_git_target(&workspace_root), @"../../../.git");
 
     // Check that the Git repo's HEAD got checked out
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  f61b77cd4bb5
-    ○  8d698d4a8ee1 my-bookmark HEAD@git My commit message
+    ○  8d698d4a8ee1 my-bookmark git_head() My commit message
     ◆  000000000000
-    "###);
+    "#);
 
     // Check that the Git repo's HEAD moves
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  f1c7aa7c62d8
-    ○  f61b77cd4bb5 HEAD@git
+    ○  f61b77cd4bb5 git_head()
     ○  8d698d4a8ee1 my-bookmark My commit message
     ◆  000000000000
-    "###);
+    "#);
 }
 
 #[cfg(unix)]
@@ -451,20 +457,20 @@ fn test_git_init_colocated_via_git_repo_path_symlink_directory_without_bare_conf
     insta::assert_snapshot!(read_git_target(&workspace_root), @"../../../.git");
 
     // Check that the Git repo's HEAD got checked out
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  f61b77cd4bb5
-    ○  8d698d4a8ee1 my-bookmark HEAD@git My commit message
+    ○  8d698d4a8ee1 my-bookmark git_head() My commit message
     ◆  000000000000
-    "###);
+    "#);
 
     // Check that the Git repo's HEAD moves
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  f1c7aa7c62d8
-    ○  f61b77cd4bb5 HEAD@git
+    ○  f61b77cd4bb5 git_head()
     ○  8d698d4a8ee1 my-bookmark My commit message
     ◆  000000000000
-    "###);
+    "#);
 }
 
 #[cfg(unix)]
@@ -491,20 +497,20 @@ fn test_git_init_colocated_via_git_repo_path_symlink_gitlink() {
     insta::assert_snapshot!(read_git_target(&workspace_root), @"../../../.git");
 
     // Check that the Git repo's HEAD got checked out
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  f61b77cd4bb5
-    ○  8d698d4a8ee1 my-bookmark HEAD@git My commit message
+    ○  8d698d4a8ee1 my-bookmark git_head() My commit message
     ◆  000000000000
-    "###);
+    "#);
 
     // Check that the Git repo's HEAD moves
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  f1c7aa7c62d8
-    ○  f61b77cd4bb5 HEAD@git
+    ○  f61b77cd4bb5 git_head()
     ○  8d698d4a8ee1 my-bookmark My commit message
     ◆  000000000000
-    "###);
+    "#);
 }
 
 #[test]
@@ -614,17 +620,17 @@ fn test_git_init_colocated_dirty_working_copy() {
 
     // Working-copy changes should have been snapshotted.
     let stdout = test_env.jj_cmd_success(&workspace_root, &["log", "-s", "--ignore-working-copy"]);
-    insta::assert_snapshot!(stdout, @r###"
+    insta::assert_snapshot!(stdout, @r#"
     @  sqpuoqvx test.user@example.com 2001-02-03 08:05:07 cd1e144d
     │  (no description set)
     │  C {some-file => new-staged-file}
     │  M some-file
     │  C {some-file => unstaged-file}
-    ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark HEAD@git 8d698d4a
+    ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark git_head() 8d698d4a
     │  My commit message
     │  A some-file
     ◆  zzzzzzzz root() 00000000
-    "###);
+    "#);
 
     // Git index should be consistent with the working copy parent. With the
     // current implementation, the index is unchanged. Since jj created new
@@ -717,20 +723,20 @@ fn test_git_init_colocated_via_flag_git_dir_exists() {
     "###);
 
     // Check that the Git repo's HEAD got checked out
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  f61b77cd4bb5
-    ○  8d698d4a8ee1 my-bookmark HEAD@git My commit message
+    ○  8d698d4a8ee1 my-bookmark git_head() My commit message
     ◆  000000000000
-    "###);
+    "#);
 
     // Check that the Git repo's HEAD moves
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
-    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r###"
+    insta::assert_snapshot!(get_log_output(&test_env, &workspace_root), @r#"
     @  f1c7aa7c62d8
-    ○  f61b77cd4bb5 HEAD@git
+    ○  f61b77cd4bb5 git_head()
     ○  8d698d4a8ee1 my-bookmark My commit message
     ◆  000000000000
-    "###);
+    "#);
 }
 
 #[test]

cli/tests/test_init_command.rs

@@ -140,11 +140,11 @@ fn test_init_git_external(bare: bool) {
     // Check that the Git repo's HEAD got checked out
     let stdout = test_env.jj_cmd_success(&repo_path, &["log", "-r", "@-"]);
     insta::allow_duplicates! {
-        insta::assert_snapshot!(stdout, @r###"
-        ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark HEAD@git 8d698d4a
+        insta::assert_snapshot!(stdout, @r#"
+        ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark git_head() 8d698d4a
         │  My commit message
         ~
-        "###);
+        "#);
     }
 }
 
@@ -208,20 +208,20 @@ fn test_init_git_colocated() {
 
     // Check that the Git repo's HEAD got checked out
     let stdout = test_env.jj_cmd_success(&repo_path, &["log", "-r", "@-"]);
-    insta::assert_snapshot!(stdout, @r###"
-    ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark HEAD@git 8d698d4a
+    insta::assert_snapshot!(stdout, @r#"
+    ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark git_head() 8d698d4a
     │  My commit message
     ~
-    "###);
+    "#);
 
     // Check that the Git repo's HEAD moves
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
     let stdout = test_env.jj_cmd_success(&workspace_root, &["log", "-r", "@-"]);
-    insta::assert_snapshot!(stdout, @r###"
-    ○  sqpuoqvx test.user@example.com 2001-02-03 08:05:07 HEAD@git f61b77cd
+    insta::assert_snapshot!(stdout, @r#"
+    ○  sqpuoqvx test.user@example.com 2001-02-03 08:05:07 git_head() f61b77cd
     │  (no description set)
     ~
-    "###);
+    "#);
 }
 
 #[test]
@@ -247,20 +247,20 @@ fn test_init_git_colocated_gitlink() {
 
     // Check that the Git repo's HEAD got checked out
     let stdout = test_env.jj_cmd_success(&workspace_root, &["log", "-r", "@-"]);
-    insta::assert_snapshot!(stdout, @r###"
-    ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark HEAD@git 8d698d4a
+    insta::assert_snapshot!(stdout, @r#"
+    ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark git_head() 8d698d4a
     │  My commit message
     ~
-    "###);
+    "#);
 
     // Check that the Git repo's HEAD moves
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
     let stdout = test_env.jj_cmd_success(&workspace_root, &["log", "-r", "@-"]);
-    insta::assert_snapshot!(stdout, @r###"
-    ○  sqpuoqvx test.user@example.com 2001-02-03 08:05:07 HEAD@git f61b77cd
+    insta::assert_snapshot!(stdout, @r#"
+    ○  sqpuoqvx test.user@example.com 2001-02-03 08:05:07 git_head() f61b77cd
     │  (no description set)
     ~
-    "###);
+    "#);
 }
 
 #[cfg(unix)]
@@ -285,20 +285,20 @@ fn test_init_git_colocated_symlink_directory() {
 
     // Check that the Git repo's HEAD got checked out
     let stdout = test_env.jj_cmd_success(&workspace_root, &["log", "-r", "@-"]);
-    insta::assert_snapshot!(stdout, @r###"
-    ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark HEAD@git 8d698d4a
+    insta::assert_snapshot!(stdout, @r#"
+    ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark git_head() 8d698d4a
     │  My commit message
     ~
-    "###);
+    "#);
 
     // Check that the Git repo's HEAD moves
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
     let stdout = test_env.jj_cmd_success(&workspace_root, &["log", "-r", "@-"]);
-    insta::assert_snapshot!(stdout, @r###"
-    ○  sqpuoqvx test.user@example.com 2001-02-03 08:05:07 HEAD@git f61b77cd
+    insta::assert_snapshot!(stdout, @r#"
+    ○  sqpuoqvx test.user@example.com 2001-02-03 08:05:07 git_head() f61b77cd
     │  (no description set)
     ~
-    "###);
+    "#);
 }
 
 #[cfg(unix)]
@@ -326,20 +326,20 @@ fn test_init_git_colocated_symlink_directory_without_bare_config() {
 
     // Check that the Git repo's HEAD got checked out
     let stdout = test_env.jj_cmd_success(&workspace_root, &["log", "-r", "@-"]);
-    insta::assert_snapshot!(stdout, @r###"
-    ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark HEAD@git 8d698d4a
+    insta::assert_snapshot!(stdout, @r#"
+    ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark git_head() 8d698d4a
     │  My commit message
     ~
-    "###);
+    "#);
 
     // Check that the Git repo's HEAD moves
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
     let stdout = test_env.jj_cmd_success(&workspace_root, &["log", "-r", "@-"]);
-    insta::assert_snapshot!(stdout, @r###"
-    ○  sqpuoqvx test.user@example.com 2001-02-03 08:05:07 HEAD@git f61b77cd
+    insta::assert_snapshot!(stdout, @r#"
+    ○  sqpuoqvx test.user@example.com 2001-02-03 08:05:07 git_head() f61b77cd
     │  (no description set)
     ~
-    "###);
+    "#);
 }
 
 #[cfg(unix)]
@@ -369,20 +369,20 @@ fn test_init_git_colocated_symlink_gitlink() {
 
     // Check that the Git repo's HEAD got checked out
     let stdout = test_env.jj_cmd_success(&workspace_root, &["log", "-r", "@-"]);
-    insta::assert_snapshot!(stdout, @r###"
-    ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark HEAD@git 8d698d4a
+    insta::assert_snapshot!(stdout, @r#"
+    ○  mwrttmos git.user@example.com 1970-01-01 11:02:03 my-bookmark git_head() 8d698d4a
     │  My commit message
     ~
-    "###);
+    "#);
 
     // Check that the Git repo's HEAD moves
     test_env.jj_cmd_ok(&workspace_root, &["new"]);
     let stdout = test_env.jj_cmd_success(&workspace_root, &["log", "-r", "@-"]);
-    insta::assert_snapshot!(stdout, @r###"
-    ○  sqpuoqvx test.user@example.com 2001-02-03 08:05:07 HEAD@git f61b77cd
+    insta::assert_snapshot!(stdout, @r#"
+    ○  sqpuoqvx test.user@example.com 2001-02-03 08:05:07 git_head() f61b77cd
     │  (no description set)
     ~
-    "###);
+    "#);
 }
 
 #[test]

cli/tests/test_operations.rs

@@ -767,15 +767,15 @@ fn test_op_recover_from_bad_gc() {
 
     // The repo should no longer be corrupt.
     let (stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["log"]);
-    insta::assert_snapshot!(stdout, @r###"
+    insta::assert_snapshot!(stdout, @r#"
     ○  mzvwutvl?? test.user@example.com 2001-02-03 08:05:15 dc2c6d52
     │  (empty) 4.1
     │ @  mzvwutvl?? test.user@example.com 2001-02-03 08:05:12 6d868f04
     ├─╯  (empty) 4
-    ○  zsuskuln test.user@example.com 2001-02-03 08:05:10 HEAD@git f652c321
+    ○  zsuskuln test.user@example.com 2001-02-03 08:05:10 git_head() f652c321
     │  (empty) (no description set)
     ◆  zzzzzzzz root() 00000000
-    "###);
+    "#);
     insta::assert_snapshot!(stderr, @r###"
     Concurrent modification detected, resolving automatically.
     "###);

docs/templates.md

@@ -102,7 +102,7 @@ This type cannot be printed. The following methods are defined.
 * `remote_bookmarks() -> List<RefName>`: All remote bookmarks pointing to the commit.
 * `tags() -> List<RefName>`
 * `git_refs() -> List<RefName>`
-* `git_head() -> Option<RefName>`
+* `git_head() -> Boolean`: True for the Git `HEAD` commit.
 * `divergent() -> Boolean`: True if the commit's change id corresponds to multiple
   visible commits.
 * `hidden() -> Boolean`: True if the commit is not visible (a.k.a. abandoned).