templates: Expose status_char to the template language

Author: algmyr

CHANGELOG.md

@@ -104,8 +104,10 @@ should not be broken.
 * `jj log` now supports a `--count` flag to print the number of commits instead
   of displaying them.
 
-* `TreeDiffEntry` type now has a `formatted_path()` method that formats
-  renames/copies appropriately.
+* `TreeDiffEntry` type now has `formatted_path()` and `status_char()` methods.
+  `formatted_path()` shows renames/copies with common prefix extraction (e.g.,
+  `src/{old => new}/file.rs`). `status_char()` returns single-character status
+  codes (M/A/D/C/R).
 
 ### Fixed bugs
 

cli/src/commit_templater.rs

@@ -2414,7 +2414,18 @@ fn builtin_tree_diff_entry_methods<'repo>() -> CommitTemplateBuildMethodFnMap<'r
             Ok(out_property.into_dyn_wrapped())
         },
     );
-    // TODO: add status_code() or status_char()?
+    map.insert(
+        "status_char",
+        |_language, _diagnostics, _build_ctx, self_property, function| {
+            function.expect_no_arguments()?;
+            let out_property = self_property.map(|entry| {
+                let (_label, sigil) =
+                    diff_util::diff_status_label_and_char(&entry.path, &entry.values);
+                sigil.to_string()
+            });
+            Ok(out_property.into_dyn_wrapped())
+        },
+    );
     map.insert(
         "source",
         |_language, _diagnostics, _build_ctx, self_property, function| {

cli/tests/test_commit_template.rs

@@ -1492,6 +1492,57 @@ fn test_log_diff_formatted_path() {
     ");
 }
 
+#[test]
+fn test_log_diff_status_char() {
+    let test_env = TestEnvironment::default();
+    test_env.run_jj_in(".", ["git", "init", "repo"]).success();
+    let work_dir = test_env.work_dir("repo");
+
+    // Create a structure with nested directories.
+    work_dir.create_dir("src");
+    work_dir.create_dir("src/old");
+    work_dir.create_dir("src/new");
+    work_dir.write_file("src/old/file.rs", "content");
+    work_dir.write_file("src/common.rs", "content");
+    work_dir.write_file("top.txt", "content");
+    work_dir.run_jj(["commit", "-m", "initial"]).success();
+
+    // Rename within nested directory (common prefix/suffix).
+    work_dir
+        .run_jj(["file", "track", "src/new/file.rs"])
+        .success();
+    work_dir.write_file("src/new/file.rs", "content");
+    std::fs::remove_file(work_dir.root().join("src/old/file.rs")).unwrap();
+    work_dir.run_jj(["commit", "-m", "rename nested"]).success();
+
+    // Rename at top level.
+    work_dir.run_jj(["file", "track", "renamed.txt"]).success();
+    work_dir.write_file("renamed.txt", "content");
+    std::fs::remove_file(work_dir.root().join("top.txt")).unwrap();
+    work_dir.run_jj(["commit", "-m", "rename top"]).success();
+
+    let template = indoc! {r#"
+        concat(
+          description.first_line() ++ ":\n",
+          diff.files().map(|e| 
+            e.status_char() ++ " " ++ e.path() ++ "\n"
+          ).join(""),
+        )
+    "#};
+    let output = work_dir.run_jj(["log", "--no-graph", "-r", "::@- & ~root()", "-T", template]);
+    insta::assert_snapshot!(output, @r"
+    rename top:
+    R renamed.txt
+    rename nested:
+    R src/new/file.rs
+    initial:
+    A src/common.rs
+    A src/old/file.rs
+    A top.txt
+    [EOF]
+    ");
+}
+
 #[test]
 fn test_file_list_entries() {
     let test_env = TestEnvironment::default();

docs/templates.md

@@ -603,6 +603,8 @@ This type cannot be printed. The following methods are defined.
   points to the target (or right) entry.
 * `.status() -> String`: One of `"modified"`, `"added"`, `"removed"`,
   `"copied"`, or `"renamed"`.
+* `.status_char() -> String`: Single-character status indicator: `"M"` for modified,
+  `"A"` for added, `"D"` for removed, `"C"` for copied, or `"R"` for renamed.
 * `.formatted_path() -> String`: Formatted path with common prefix/suffix extraction
   for renames and copies. For example, `src/{old => new}/file.rs` instead of showing
   full paths. For non-copy/rename operations, equivalent to `.path()`.