From ac5d8eb7844dc849f38afbeaf70efdb218174f8a Mon Sep 17 00:00:00 2001
From: Preston Van Loon <preston@pvl.dev>
Date: Fri, 11 Aug 2023 15:31:47 -0500
Subject: [PATCH] Add UTC format for timestamp formats. Thanks to @rauljordan
 for these changes.

Add tests for new UTC timestamp format

Add documentation for timestamp utc

Update CHANGELOG.md
---
 CHANGELOG.md                      |  2 ++
 cli/src/template_builder.rs       |  7 +++++++
 cli/tests/test_commit_template.rs | 13 +++++++++++++
 docs/templates.md                 |  1 +
 4 files changed, 23 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 722a2abbc..2a5bcf0ca 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -90,6 +90,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * Revsets gained a new function `mine()` that aliases `author(exact:"your_email")`.
 
+* `jj log` timestamp format now accepts `.utc()` to convert a timestamp to UTC.
+
 ### Fixed bugs
 
 * `jj config set --user` and `jj config edit --user` can now be used outside of any repository.
diff --git a/cli/src/template_builder.rs b/cli/src/template_builder.rs
index cc40ae866..166827acf 100644
--- a/cli/src/template_builder.rs
+++ b/cli/src/template_builder.rs
@@ -448,6 +448,13 @@ fn build_timestamp_method<'a, L: TemplateLanguage<'a>>(
                 time_util::format_absolute_timestamp_with(&timestamp, &format)
             }))
         }
+        "utc" => {
+            template_parser::expect_no_arguments(function)?;
+            language.wrap_timestamp(TemplateFunction::new(self_property, |mut timestamp| {
+                timestamp.tz_offset = 0;
+                timestamp
+            }))
+        }
         _ => return Err(TemplateParseError::no_such_method("Timestamp", function)),
     };
     Ok(property)
diff --git a/cli/tests/test_commit_template.rs b/cli/tests/test_commit_template.rs
index d21f84ef2..495d733b4 100644
--- a/cli/tests/test_commit_template.rs
+++ b/cli/tests/test_commit_template.rs
@@ -110,6 +110,19 @@ fn test_log_author_timestamp_ago() {
     );
 }
 
+#[test]
+fn test_log_author_timestamp_utc() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_success(test_env.env_root(), &["init", "repo", "--git"]);
+    let repo_path = test_env.env_root().join("repo");
+
+    let stdout = test_env.jj_cmd_success(&repo_path, &["log", "-T", "author.timestamp().utc()"]);
+    insta::assert_snapshot!(stdout, @r###"
+    @  2001-02-02 21:05:07.000 +00:00
+    ◉  1970-01-01 00:00:00.000 +00:00
+    "###);
+}
+
 #[test]
 fn test_log_default() {
     let test_env = TestEnvironment::default();
diff --git a/docs/templates.md b/docs/templates.md
index 74f27b4d7..4601a5716 100644
--- a/docs/templates.md
+++ b/docs/templates.md
@@ -154,6 +154,7 @@ The following methods are defined.
 * `.ago() -> String`: Format as relative timestamp.
 * `.format(format: String) -> String`: Format with [the specified strftime-like
   format string](https://docs.rs/chrono/latest/chrono/format/strftime/).
+* `.utc() -> Timestamp`: Convert timestamp into UTC timezone.
 
 ### TimestampRange type