templates: Expose conflicted files in the template language

CHANGELOG.md

@@ -104,6 +104,13 @@ should not be broken.
 * `jj log` now supports a `--count` flag to print the number of commits instead
   of displaying them.
 
+* `Commit` type now has a `conflicted_files()` method that returns a list of
+  files with merge conflicts.
+
+* `TreeEntry` type now has a `num_conflict_sides()` method that returns the number
+  of sides in a merge conflict (1 for non-conflicted files, 2 or more for
+  conflicts).
+
 ### Fixed bugs
 
 * `jj fix` now prints a warning if a tool failed to run on a file.

cli/src/commit_templater.rs

@@ -1253,6 +1253,22 @@ fn builtin_commit_methods<'repo>() -> CommitTemplateBuildMethodFnMap<'repo, Comm
             Ok(out_property.into_dyn_wrapped())
         },
     );
+    map.insert(
+        "conflicted_files",
+        |_language, _diagnostics, _build_ctx, self_property, function| {
+            function.expect_no_arguments()?;
+            let out_property = self_property.and_then(|commit| {
+                let tree = commit.tree();
+                let entries: Vec<_> = tree
+                    .conflicts()
+                    .map(|(path, value)| value.map(|value| (path, value)))
+                    .map_ok(|(path, value)| TreeEntry { path, value })
+                    .try_collect()?;
+                Ok(entries)
+            });
+            Ok(out_property.into_dyn_wrapped())
+        },
+    );
     map.insert(
         "root",
         |language, _diagnostics, _build_ctx, self_property, function| {
@@ -2446,6 +2462,15 @@ fn builtin_tree_entry_methods<'repo>() -> CommitTemplateBuildMethodFnMap<'repo,
             Ok(out_property.into_dyn_wrapped())
         },
     );
+    map.insert(
+        "num_conflict_sides",
+        |_language, _diagnostics, _build_ctx, self_property, function| {
+            function.expect_no_arguments()?;
+            let out_property = self_property
+                .and_then(|entry| Ok(i64::try_from(entry.value.simplify().num_sides())?));
+            Ok(out_property.into_dyn_wrapped())
+        },
+    );
     map.insert(
         "file_type",
         |_language, _diagnostics, _build_ctx, self_property, function| {

cli/tests/test_commit_template.rs

@@ -1506,6 +1506,90 @@ fn test_file_list_entries() {
     ");
 }
 
+#[test]
+fn test_conflicted_files() {
+    let test_env = TestEnvironment::default();
+    test_env.run_jj_in(".", ["git", "init", "repo"]).success();
+    let work_dir = test_env.work_dir("repo");
+
+    // Base commit with files.
+    work_dir.write_file("normal-file", "base content");
+    work_dir.write_file("conflict-file1", "base content");
+    work_dir.write_file("conflict-file2", "base content");
+    work_dir.run_jj(["commit", "-m", "base"]).success();
+
+    // Sibling branches with conflicting changes.
+    work_dir.write_file("conflict-file1", "left content");
+    work_dir.write_file("conflict-file2", "left content");
+    work_dir.run_jj(["commit", "-m", "left"]).success();
+
+    work_dir.run_jj(["new", "description(base)"]).success();
+    work_dir.write_file("conflict-file1", "right content");
+    work_dir.write_file("conflict-file2", "right content");
+    work_dir.run_jj(["commit", "-m", "right"]).success();
+
+    // Merge with conflicts.
+    work_dir
+        .run_jj(["new", "description(left)", "description(right)"])
+        .success();
+
+    // Test basic conflicted_files() listing.
+    let template = r#"self.conflicted_files().map(|e| e.path()) ++ "\n""#;
+    let output = work_dir.run_jj(["log", "-r", "@", "-T", template, "--no-graph"]);
+    insta::assert_snapshot!(output, @r"
+    conflict-file1 conflict-file2
+    [EOF]
+    ");
+
+    // Test that non-conflicted commit returns empty list.
+    let template = r#"self.conflicted_files().len() ++ "\n""#;
+    let output = work_dir.run_jj([
+        "log",
+        "-r",
+        "description(substring:\"left\")",
+        "-T",
+        template,
+        "--no-graph",
+    ]);
+    insta::assert_snapshot!(output, @r"
+    0
+    [EOF]
+    ");
+
+    // Metadata for conflicted_files.
+    let template = indoc! {r#"
+        self.conflicted_files().map(|e| separate(" ",
+          e.path(),
+          "conflict=" ++ e.conflict(),
+          "type=" ++ e.file_type(),
+          "sides=" ++ e.num_conflict_sides(),
+        )).join("\n") ++ "\n"
+    "#};
+    let output = work_dir.run_jj(["log", "-r", "@", "-T", template, "--no-graph"]);
+    insta::assert_snapshot!(output, @r"
+    conflict-file1 conflict=true type=conflict sides=2
+    conflict-file2 conflict=true type=conflict sides=2
+    [EOF]
+    ");
+
+    // Metadata for all files.
+    let template = indoc! {r#"
+        self.files().map(|e| separate(" ",
+          e.path(),
+          "conflict=" ++ e.conflict(),
+          "type=" ++ e.file_type(),
+          "sides=" ++ e.num_conflict_sides(),
+        )).join("\n") ++ "\n"
+    "#};
+    let output = work_dir.run_jj(["log", "-r", "@", "-T", template, "--no-graph"]);
+    insta::assert_snapshot!(output, @r"
+    conflict-file1 conflict=true type=conflict sides=2
+    conflict-file2 conflict=true type=conflict sides=2
+    normal-file conflict=false type=file sides=1
+    [EOF]
+    ");
+}
+
 #[cfg(unix)]
 #[test]
 fn test_file_list_symlink() {

cli/tests/test_templater.rs

@@ -42,7 +42,7 @@ fn test_templater_parse_error() {
       | ^-------^
       |
       = Keyword `conflicts` doesn't exist
-    Hint: Did you mean `conflict`, `conflicting`?
+    Hint: Did you mean `conflict`, `conflicted_files`, `conflicting`?
     [EOF]
     [exit status: 1]
     ");

docs/templates.md

@@ -178,6 +178,7 @@ This type cannot be printed. The following methods are defined.
 * `.files([files: String]) -> List<TreeEntry>`: Files that exist in this commit,
   matching [the `files` expression](filesets.md). Use `.diff().files()` to list
   changed files.
+* `.conflicted_files() -> List<TreeEntry>`: Conflicted files in this commit.
 * `.root() -> Boolean`: True if the commit is the root commit.
 
 ### `CommitEvolutionEntry` type
@@ -614,6 +615,8 @@ This type cannot be printed. The following methods are defined.
 
 * `.path() -> RepoPath`: Path to the entry.
 * `.conflict() -> Boolean`: True if the entry is a merge conflict.
+* `.num_conflict_sides() -> Integer`: Number of sides in the merge conflict (1 if not
+  conflicted, 2 or more for multi-way merges).
 * `.file_type() -> String`: One of `"file"`, `"symlink"`, `"tree"`,
   `"git-submodule"`, or `"conflict"`.
 * `.executable() -> Boolean`: True if the entry is an executable file.