rework message styling (#2877)

https://github.com/user-attachments/assets/cf07f62b-1895-44bb-b9c3-7a12032eb371

Author: nornagon-openai

codex-rs/Cargo.lock

@@ -116,7 +116,9 @@ pub enum ApplyPatchFileChange {
     Add {
         content: String,
     },
-    Delete,
+    Delete {
+        content: String,
+    },
     Update {
         unified_diff: String,
         move_path: Option<PathBuf>,
@@ -210,7 +212,18 @@ pub fn maybe_parse_apply_patch_verified(argv: &[String], cwd: &Path) -> MaybeApp
                         changes.insert(path, ApplyPatchFileChange::Add { content: contents });
                     }
                     Hunk::DeleteFile { .. } => {
-                        changes.insert(path, ApplyPatchFileChange::Delete);
+                        let content = match std::fs::read_to_string(&path) {
+                            Ok(content) => content,
+                            Err(e) => {
+                                return MaybeApplyPatchVerified::CorrectnessError(
+                                    ApplyPatchError::IoError(IoError {
+                                        context: format!("Failed to read {}", path.display()),
+                                        source: e,
+                                    }),
+                                );
+                            }
+                        };
+                        changes.insert(path, ApplyPatchFileChange::Delete { content });
                     }
                     Hunk::UpdateFile {
                         move_path, chunks, ..

codex-rs/apply-patch/src/lib.rs

@@ -109,7 +109,9 @@ pub(crate) fn convert_apply_patch_to_protocol(
             ApplyPatchFileChange::Add { content } => FileChange::Add {
                 content: content.clone(),
             },
-            ApplyPatchFileChange::Delete => FileChange::Delete,
+            ApplyPatchFileChange::Delete { content } => FileChange::Delete {
+                content: content.clone(),
+            },
             ApplyPatchFileChange::Update {
                 unified_diff,
                 move_path,

codex-rs/core/src/apply_patch.rs

@@ -10,7 +10,35 @@ use tokio::process::Command;
 use tokio::time::Duration as TokioDuration;
 use tokio::time::timeout;
 
-use crate::util::is_inside_git_repo;
+/// Return `true` if the project folder specified by the `Config` is inside a
+/// Git repository.
+///
+/// The check walks up the directory hierarchy looking for a `.git` file or
+/// directory (note `.git` can be a file that contains a `gitdir` entry). This
+/// approach does **not** require the `git` binary or the `git2` crate and is
+/// therefore fairly lightweight.
+///
+/// Note that this does **not** detect *work‑trees* created with
+/// `git worktree add` where the checkout lives outside the main repository
+/// directory. If you need Codex to work from such a checkout simply pass the
+/// `--allow-no-git-exec` CLI flag that disables the repo requirement.
+pub fn get_git_repo_root(base_dir: &Path) -> Option<PathBuf> {
+    let mut dir = base_dir.to_path_buf();
+
+    loop {
+        if dir.join(".git").exists() {
+            return Some(dir);
+        }
+
+        // Pop one component (go up one directory).  `pop` returns false when
+        // we have reached the filesystem root.
+        if !dir.pop() {
+            break;
+        }
+    }
+
+    None
+}
 
 /// Timeout for git commands to prevent freezing on large repositories
 const GIT_COMMAND_TIMEOUT: TokioDuration = TokioDuration::from_secs(5);
@@ -94,9 +122,7 @@ pub async fn collect_git_info(cwd: &Path) -> Option<GitInfo> {
 
 /// Returns the closest git sha to HEAD that is on a remote as well as the diff to that sha.
 pub async fn git_diff_to_remote(cwd: &Path) -> Option<GitDiffToRemote> {
-    if !is_inside_git_repo(cwd) {
-        return None;
-    }
+    get_git_repo_root(cwd)?;
 
     let remotes = get_git_remotes(cwd).await?;
     let branches = branch_ancestry(cwd).await?;
@@ -440,7 +466,7 @@ async fn diff_against_sha(cwd: &Path, sha: &GitSha) -> Option<String> {
 }
 
 /// Resolve the path that should be used for trust checks. Similar to
-/// `[utils::is_inside_git_repo]`, but resolves to the root of the main
+/// `[get_git_repo_root]`, but resolves to the root of the main
 /// repository. Handles worktrees.
 pub fn resolve_root_git_project_for_trust(cwd: &Path) -> Option<PathBuf> {
     let base = if cwd.is_dir() { cwd } else { cwd.parent()? };