From 3711979a8f4daed42fd9a5ef8af9be2022be7403 Mon Sep 17 00:00:00 2001
From: Yuya Nishihara <yuya@tcha.org>
Date: Wed, 15 Jan 2025 14:17:51 +0900
Subject: [PATCH] absorb: show warning if source commit contains file deletion

---
 cli/tests/test_absorb_command.rs | 19 +++++++++++++++++++
 lib/src/absorb.rs                | 11 ++++++++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/cli/tests/test_absorb_command.rs b/cli/tests/test_absorb_command.rs
index 01fa10e64..eb6ec390b 100644
--- a/cli/tests/test_absorb_command.rs
+++ b/cli/tests/test_absorb_command.rs
@@ -438,6 +438,25 @@ fn test_absorb_conflict() {
     ");
 }
 
+#[test]
+fn test_absorb_deleted_file() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_ok(test_env.env_root(), &["git", "init", "repo"]);
+    let repo_path = test_env.env_root().join("repo");
+
+    test_env.jj_cmd_ok(&repo_path, &["describe", "-m1"]);
+    std::fs::write(repo_path.join("file1"), "1a\n").unwrap();
+
+    test_env.jj_cmd_ok(&repo_path, &["new"]);
+    std::fs::remove_file(repo_path.join("file1")).unwrap();
+
+    let (_stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["absorb"]);
+    insta::assert_snapshot!(stderr, @r"
+    Warning: Skipping file1: Deleted file
+    Nothing changed.
+    ");
+}
+
 #[test]
 fn test_absorb_file_mode() {
     let test_env = TestEnvironment::default();
diff --git a/lib/src/absorb.rs b/lib/src/absorb.rs
index d28dc0a8f..37d14ef5b 100644
--- a/lib/src/absorb.rs
+++ b/lib/src/absorb.rs
@@ -110,6 +110,7 @@ pub async fn split_hunks_to_trees(
         let (left_value, right_value) = entry.values?;
         let (left_text, executable) = match to_file_value(left_value) {
             Ok(Some(mut value)) => (value.read(left_path)?, value.executable),
+            // New file should have no destinations
             Ok(None) => continue,
             Err(reason) => {
                 selected_trees
@@ -120,7 +121,15 @@ pub async fn split_hunks_to_trees(
         };
         let right_text = match to_file_value(right_value) {
             Ok(Some(mut value)) => value.read(right_path)?,
-            Ok(None) => continue,
+            // Deleted file could be absorbed, but that would require special
+            // handling to propagate deletion of the tree entry
+            Ok(None) => {
+                let reason = "Deleted file".to_owned();
+                selected_trees
+                    .skipped_paths
+                    .push((right_path.to_owned(), reason));
+                continue;
+            }
             Err(reason) => {
                 selected_trees
                     .skipped_paths