cli: redefine default log revset using immutable_heads()

I think most users who change the set of immutable heads away from
`trunk() | tags()` are going to also want to change the default log
revset to include the newly mutable commit and to exclude the newly
immutable commits. So let's update the default log revset to use
`immutable_heads()` instead.

`test_templater` changed because we have overridden the set of
immutable commits there so `jj log` now includes the remote branch.

cli/src/commands/mod.rs

@@ -355,7 +355,8 @@ struct StatusArgs {}
 #[derive(clap::Args, Clone, Debug)]
 struct LogArgs {
     /// Which revisions to show. Defaults to the `revsets.log` setting, or
-    /// `@ | ancestors((remote_branches() | tags()).., 2)` if it is not set.
+    /// `@ | ancestors(immutable_heads().., 2) | heads(immutable_heads())` if
+    /// it is not set.
     #[arg(long, short)]
     revisions: Vec<RevisionArg>,
     /// Show commits modifying the given paths

cli/src/config-schema.json

@@ -294,7 +294,7 @@
                 "log": {
                     "type": "string",
                     "description": "Default set of revisions to show when no explicit revset is given for jj log and similar commands",
-                    "default": "@ | ancestors((remote_branches() | tags()).., 2)"
+                    "default": "@ | ancestors(immutable_heads().., 2) | heads(immutable_heads())"
                 },
                 "short-prefixes": {
                     "type": "string",

cli/tests/test_branch_command.rs

@@ -165,17 +165,15 @@ fn test_branch_delete_glob() {
 
     insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
     @  bar-2 foo-1 foo-3 foo-4 6fbf398c2d59
-    │
-    ~
+    ◉   000000000000
     "###);
     let stdout = test_env.jj_cmd_success(&repo_path, &["branch", "delete", "--glob", "foo-[1-3]"]);
     insta::assert_snapshot!(stdout, @r###"
     Deleted 2 branches.
     "###);
     insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
     @  bar-2 foo-1@origin foo-3@origin foo-4 6fbf398c2d59
-    │
-    ~
+    ◉   000000000000
     "###);
 
     // We get an error if none of the globs match live branches. Unlike `jj branch
@@ -196,8 +194,7 @@ fn test_branch_delete_glob() {
     insta::assert_snapshot!(stdout, @"");
     insta::assert_snapshot!(get_log_output(&test_env, &repo_path), @r###"
     @  bar-2 foo-1@origin foo-3@origin foo-4@origin 6fbf398c2d59
-    │
-    ~
+    ◉   000000000000
     "###);
 
     // The deleted branches are still there

cli/tests/test_immutable_commits.rs

@@ -60,9 +60,23 @@ fn test_rewrite_immutable_generic() {
     Hint: Configure the set of immutable commits via `revset-aliases.immutable_heads()`.
     "###);
     // Error if we redefine immutable_heads() with an argument
+    // TODO: This error comes from the built-in definition of
+    // `revsets.short-prefixes`. That's not clear to the user.
     test_env.add_config(r#"revset-aliases."immutable_heads(foo)" = "none()""#);
     let stderr = test_env.jj_cmd_failure(&repo_path, &["edit", "root()"]);
     insta::assert_snapshot!(stderr, @r###"
+    Config error: Invalid `revsets.short-prefixes`:  --> 1:31
+      |
+    1 | @ | ancestors(immutable_heads().., 2) | heads(immutable_heads())
+      |                               ^
+      |
+      = Invalid arguments to revset function "immutable_heads": Expected 1 arguments
+    For help, see https://github.com/martinvonz/jj/blob/main/docs/config.md.
+    "###);
+    // ... even if we also update the built-in call sites
+    test_env.add_config(r#"revsets.short-prefixes = "immutable_heads(root())""#);
+    let stderr = test_env.jj_cmd_failure(&repo_path, &["edit", "root()"]);
+    insta::assert_snapshot!(stderr, @r###"
     Error: The `revset-aliases.immutable_heads()` function must be declared without arguments.
     "###);
 }
@@ -82,19 +96,20 @@ fn test_rewrite_immutable_commands() {
     test_env.jj_cmd_success(&repo_path, &["branch", "create", "main"]);
     test_env.jj_cmd_success(&repo_path, &["new", "description(b)"]);
     test_env.add_config(r#"revset-aliases."immutable_heads()" = "main""#);
+
+    // Log shows mutable commits and immutable heads by default
     let stdout = test_env.jj_cmd_success(&repo_path, &["log"]);
     insta::assert_snapshot!(stdout, @r###"
     @  yqosqzyt [email protected] 2001-02-03 04:05:13.000 +07:00 3f89addf
     │  (empty) (no description set)
     │ ◉  mzvwutvl [email protected] 2001-02-03 04:05:11.000 +07:00 main d809c5d9 conflict
     ╭─┤  (empty) merge
-    ◉ │  kkmpptxz [email protected] 2001-02-03 04:05:10.000 +07:00 c8d4c7ca
-    │ │  b
-    │ ◉  zsuskuln [email protected] 2001-02-03 04:05:11.000 +07:00 6e11f430
-    ├─╯  c
-    ◉  qpvuntsm [email protected] 2001-02-03 04:05:08.000 +07:00 46a8dc51
-    │  a
-    ◉  zzzzzzzz root() 00000000
+    │ │
+    │ ~
+    │
+    ◉  kkmpptxz [email protected] 2001-02-03 04:05:10.000 +07:00 c8d4c7ca
+    │  b
+    ~
     "###);
 
     // abandon

cli/tests/test_templater.rs

@@ -67,7 +67,9 @@ fn test_templater_branches() {
     let template = r#"commit_id.short() ++ " " ++ branches"#;
     let output = test_env.jj_cmd_success(&workspace_root, &["log", "-T", template]);
     insta::assert_snapshot!(output, @r###"
-    ◉  b1bb3766d584 branch3??
+    ◉  fed794e2ba44 branch3?? branch3@origin
+    │ ◉  b1bb3766d584 branch3??
+    ├─╯
     │ ◉  21c33875443e branch1*
     ├─╯
     │ @  a5b4d15489cc branch2* new-branch

lib/src/settings.rs

@@ -159,7 +159,9 @@ impl UserSettings {
             // For compatibility with old config files (<0.8.0)
             self.config
                 .get_string("ui.default-revset")
-                .unwrap_or_else(|_| "@ | ancestors((remote_branches() | tags()).., 2)".to_string())
+                .unwrap_or_else(|_| {
+                    "@ | ancestors(immutable_heads().., 2) | heads(immutable_heads())".to_string()
+                })
         })
     }