feat: warning large commits (#6838)

codex-rs/utils/git/src/ghost_commits.rs

@@ -1,3 +1,4 @@
+use std::collections::BTreeMap;
 use std::collections::HashSet;
 use std::ffi::OsString;
 use std::fs;
@@ -21,6 +22,8 @@ use crate::operations::run_git_for_stdout_all;
 
 /// Default commit message used for ghost commits when none is provided.
 const DEFAULT_COMMIT_MESSAGE: &str = "codex snapshot";
+/// Default threshold that triggers a warning about large untracked directories.
+const LARGE_UNTRACKED_WARNING_THRESHOLD: usize = 200;
 
 /// Options to control ghost commit creation.
 pub struct CreateGhostCommitOptions<'a> {
@@ -29,6 +32,19 @@ pub struct CreateGhostCommitOptions<'a> {
     pub force_include: Vec<PathBuf>,
 }
 
+/// Summary produced alongside a ghost snapshot.
+#[derive(Debug, Default, Clone, PartialEq, Eq)]
+pub struct GhostSnapshotReport {
+    pub large_untracked_dirs: Vec<LargeUntrackedDir>,
+}
+
+/// Directory containing a large amount of untracked content.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct LargeUntrackedDir {
+    pub path: PathBuf,
+    pub file_count: usize,
+}
+
 impl<'a> CreateGhostCommitOptions<'a> {
     /// Creates options scoped to the provided repository path.
     pub fn new(repo_path: &'a Path) -> Self {
@@ -64,10 +80,94 @@ impl<'a> CreateGhostCommitOptions<'a> {
     }
 }
 
+fn detect_large_untracked_dirs(files: &[PathBuf], dirs: &[PathBuf]) -> Vec<LargeUntrackedDir> {
+    let mut counts: BTreeMap<PathBuf, usize> = BTreeMap::new();
+
+    let mut sorted_dirs: Vec<&PathBuf> = dirs.iter().collect();
+    sorted_dirs.sort_by(|a, b| {
+        let a_components = a.components().count();
+        let b_components = b.components().count();
+        b_components.cmp(&a_components).then_with(|| a.cmp(b))
+    });
+
+    for file in files {
+        let mut key: Option<PathBuf> = None;
+        for dir in &sorted_dirs {
+            if file.starts_with(dir.as_path()) {
+                key = Some((*dir).clone());
+                break;
+            }
+        }
+        let key = key.unwrap_or_else(|| {
+            file.parent()
+                .map(PathBuf::from)
+                .unwrap_or_else(|| PathBuf::from("."))
+        });
+        let entry = counts.entry(key).or_insert(0);
+        *entry += 1;
+    }
+
+    let mut result: Vec<LargeUntrackedDir> = counts
+        .into_iter()
+        .filter(|(_, count)| *count >= LARGE_UNTRACKED_WARNING_THRESHOLD)
+        .map(|(path, file_count)| LargeUntrackedDir { path, file_count })
+        .collect();
+    result.sort_by(|a, b| {
+        b.file_count
+            .cmp(&a.file_count)
+            .then_with(|| a.path.cmp(&b.path))
+    });
+    result
+}
+
+fn to_session_relative_path(path: &Path, repo_prefix: Option<&Path>) -> PathBuf {
+    match repo_prefix {
+        Some(prefix) => path
+            .strip_prefix(prefix)
+            .map(PathBuf::from)
+            .unwrap_or_else(|_| path.to_path_buf()),
+        None => path.to_path_buf(),
+    }
+}
+
 /// Create a ghost commit capturing the current state of the repository's working tree.
 pub fn create_ghost_commit(
     options: &CreateGhostCommitOptions<'_>,
 ) -> Result<GhostCommit, GitToolingError> {
+    create_ghost_commit_with_report(options).map(|(commit, _)| commit)
+}
+
+/// Compute a report describing the working tree for a ghost snapshot without creating a commit.
+pub fn capture_ghost_snapshot_report(
+    options: &CreateGhostCommitOptions<'_>,
+) -> Result<GhostSnapshotReport, GitToolingError> {
+    ensure_git_repository(options.repo_path)?;
+
+    let repo_root = resolve_repository_root(options.repo_path)?;
+    let repo_prefix = repo_subdir(repo_root.as_path(), options.repo_path);
+    let existing_untracked =
+        capture_existing_untracked(repo_root.as_path(), repo_prefix.as_deref())?;
+
+    let warning_files = existing_untracked
+        .files
+        .iter()
+        .map(|path| to_session_relative_path(path, repo_prefix.as_deref()))
+        .collect::<Vec<_>>();
+    let warning_dirs = existing_untracked
+        .dirs
+        .iter()
+        .map(|path| to_session_relative_path(path, repo_prefix.as_deref()))
+        .collect::<Vec<_>>();
+
+    Ok(GhostSnapshotReport {
+        large_untracked_dirs: detect_large_untracked_dirs(&warning_files, &warning_dirs),
+    })
+}
+
+/// Create a ghost commit capturing the current state of the repository's working tree along with a report.
+pub fn create_ghost_commit_with_report(
+    options: &CreateGhostCommitOptions<'_>,
+) -> Result<(GhostCommit, GhostSnapshotReport), GitToolingError> {
     ensure_git_repository(options.repo_path)?;
 
     let repo_root = resolve_repository_root(options.repo_path)?;
@@ -76,6 +176,18 @@ pub fn create_ghost_commit(
     let existing_untracked =
         capture_existing_untracked(repo_root.as_path(), repo_prefix.as_deref())?;
 
+    let warning_files = existing_untracked
+        .files
+        .iter()
+        .map(|path| to_session_relative_path(path, repo_prefix.as_deref()))
+        .collect::<Vec<_>>();
+    let warning_dirs = existing_untracked
+        .dirs
+        .iter()
+        .map(|path| to_session_relative_path(path, repo_prefix.as_deref()))
+        .collect::<Vec<_>>();
+    let large_untracked_dirs = detect_large_untracked_dirs(&warning_files, &warning_dirs);
+
     let normalized_force = options
         .force_include
         .iter()
@@ -143,11 +255,18 @@ pub fn create_ghost_commit(
         Some(commit_env.as_slice()),
     )?;
 
-    Ok(GhostCommit::new(
+    let ghost_commit = GhostCommit::new(
         commit_id,
         parent,
         existing_untracked.files,
         existing_untracked.dirs,
+    );
+
+    Ok((
+        ghost_commit,
+        GhostSnapshotReport {
+            large_untracked_dirs,
+        },
     ))
 }
 
@@ -460,6 +579,95 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn create_snapshot_reports_large_untracked_dirs() -> Result<(), GitToolingError> {
+        let temp = tempfile::tempdir()?;
+        let repo = temp.path();
+        init_test_repo(repo);
+
+        std::fs::write(repo.join("tracked.txt"), "contents\n")?;
+        run_git_in(repo, &["add", "tracked.txt"]);
+        run_git_in(
+            repo,
+            &[
+                "-c",
+                "user.name=Tester",
+                "-c",
+                "user.email=test@example.com",
+                "commit",
+                "-m",
+                "initial",
+            ],
+        );
+
+        let models = repo.join("models");
+        std::fs::create_dir(&models)?;
+        for idx in 0..(LARGE_UNTRACKED_WARNING_THRESHOLD + 1) {
+            let file = models.join(format!("weights-{idx}.bin"));
+            std::fs::write(file, "data\n")?;
+        }
+
+        let (ghost, report) =
+            create_ghost_commit_with_report(&CreateGhostCommitOptions::new(repo))?;
+        assert!(ghost.parent().is_some());
+        assert_eq!(
+            report.large_untracked_dirs,
+            vec![LargeUntrackedDir {
+                path: PathBuf::from("models"),
+                file_count: LARGE_UNTRACKED_WARNING_THRESHOLD + 1,
+            }]
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn create_snapshot_reports_nested_large_untracked_dirs_under_tracked_parent()
+    -> Result<(), GitToolingError> {
+        let temp = tempfile::tempdir()?;
+        let repo = temp.path();
+        init_test_repo(repo);
+
+        // Create a tracked src directory.
+        let src = repo.join("src");
+        std::fs::create_dir(&src)?;
+        std::fs::write(src.join("main.rs"), "fn main() {}\n")?;
+        run_git_in(repo, &["add", "src/main.rs"]);
+        run_git_in(
+            repo,
+            &[
+                "-c",
+                "user.name=Tester",
+                "-c",
+                "user.email=test@example.com",
+                "commit",
+                "-m",
+                "initial",
+            ],
+        );
+
+        // Create a large untracked tree nested under the tracked src directory.
+        let generated = src.join("generated").join("cache");
+        std::fs::create_dir_all(&generated)?;
+        for idx in 0..(LARGE_UNTRACKED_WARNING_THRESHOLD + 1) {
+            let file = generated.join(format!("file-{idx}.bin"));
+            std::fs::write(file, "data\n")?;
+        }
+
+        let (_, report) = create_ghost_commit_with_report(&CreateGhostCommitOptions::new(repo))?;
+        assert_eq!(report.large_untracked_dirs.len(), 1);
+        let entry = &report.large_untracked_dirs[0];
+        assert_ne!(entry.path, PathBuf::from("src"));
+        assert!(
+            entry.path.starts_with(Path::new("src/generated")),
+            "unexpected path for large untracked directory: {}",
+            entry.path.display()
+        );
+        assert_eq!(entry.file_count, LARGE_UNTRACKED_WARNING_THRESHOLD + 1);
+
+        Ok(())
+    }
+
     #[test]
     /// Ensures ghost commits succeed in repositories without an existing HEAD.
     fn create_snapshot_without_existing_head() -> Result<(), GitToolingError> {