config: migrate log/show timestamp format away from config knob

Since oplog still relies on ui.relative-timestamps, this config key
isn't removed.

CHANGELOG.md

@@ -42,6 +42,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   `label(if(current_working_copy, "working_copy"), ...)` to label the
   working-copy entry.
 
+* `jj log` and `jj show` no longer respect `ui.relative-timestamps = true`.
+  Use the `format_timestamp()` template alias instead. For details, see
+  [the documentation](docs/config.md).
+
 * The global `--no-commit-working-copy` is now called `--ignore-working-copy`.
 
 * The `diff.format` config option is now called `ui.diff.format`. The old name
@@ -81,7 +85,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * Per-repository configuration is now read from `.jj/repo/config.toml`.
 
-* The `ui.relative-timestamps` option now also affects `jj op log`.
+* The `ui.relative-timestamps` option now affects `jj op log`.
 
 * Background colors, bold text, and underlining are now supported. You can set
   e.g. `color.error = { bg = "red", bold = true, underline = true }` in your

src/cli_util.rs

@@ -1548,15 +1548,6 @@ fn load_template_aliases(
     // TODO: Reorganize default template aliases and config knobs:
     // - remove these configs and let user override aliases?
     // - separate namespace or config section for these "default" aliases? but how?
-    let timestamp_template = if settings.relative_timestamps() {
-        "timestamp.ago()"
-    } else {
-        "timestamp"
-    };
-    aliases_map
-        .insert("format_timestamp(timestamp)", timestamp_template)
-        .unwrap();
-
     let signature_template = match settings.log_author_format().as_str() {
         "none" => r#""""#,
         "full" => "signature",

src/config/templates.toml

@@ -34,6 +34,7 @@ show = 'show'
 
 # Hook points for users to customize the default templates:
 'format_short_id(id)' = 'id.shortest(12)'
+'format_timestamp(timestamp)' = 'timestamp'
 
 # TODO: Add branches, tags, etc
 # TODO: Indent the description like Git does

tests/test_show_command.rs

@@ -41,7 +41,12 @@ fn test_show_relative_timestamps() {
     test_env.jj_cmd_success(test_env.env_root(), &["init", "repo", "--git"]);
     let repo_path = test_env.env_root().join("repo");
 
-    test_env.add_config(r#"ui.relative-timestamps = true"#);
+    test_env.add_config(
+        r#"
+        [template-aliases]
+        'format_timestamp(timestamp)' = 'timestamp.ago()'
+        "#,
+    );
 
     let stdout = test_env.jj_cmd_success(&repo_path, &["show"]);
     let timestamp_re = Regex::new(r"\([0-9]+ years ago\)").unwrap();