working_copy: plumbing to propagate untracked paths to caller

cli/examples/custom-working-copy/main.rs

@@ -41,6 +41,7 @@ use jj_lib::working_copy::LockedWorkingCopy;
 use jj_lib::working_copy::ResetError;
 use jj_lib::working_copy::SnapshotError;
 use jj_lib::working_copy::SnapshotOptions;
+use jj_lib::working_copy::SnapshotStats;
 use jj_lib::working_copy::WorkingCopy;
 use jj_lib::working_copy::WorkingCopyFactory;
 use jj_lib::working_copy::WorkingCopyStateError;
@@ -233,7 +234,10 @@ impl LockedWorkingCopy for LockedConflictsWorkingCopy {
         self.inner.old_tree_id()
     }
 
-    fn snapshot(&mut self, options: &SnapshotOptions) -> Result<MergedTreeId, SnapshotError> {
+    fn snapshot(
+        &mut self,
+        options: &SnapshotOptions,
+    ) -> Result<(MergedTreeId, SnapshotStats), SnapshotError> {
         let options = SnapshotOptions {
             base_ignores: options.base_ignores.chain("", "/.conflicts".as_bytes())?,
             ..options.clone()

cli/src/cli_util.rs

@@ -1806,7 +1806,8 @@ See https://martinvonz.github.io/jj/latest/working-copy/#stale-working-copy \
             };
         self.user_repo = ReadonlyUserRepo::new(repo);
         let progress = crate::progress::snapshot_progress(ui);
-        let new_tree_id = locked_ws
+        // TODO: print stats
+        let (new_tree_id, _stats) = locked_ws
             .locked_wc()
             .snapshot(&SnapshotOptions {
                 base_ignores,

cli/src/commands/file/track.rs

@@ -52,7 +52,8 @@ pub(crate) fn cmd_file_track(
     let mut tx = workspace_command.start_transaction().into_inner();
     let base_ignores = workspace_command.base_ignores()?;
     let (mut locked_ws, _wc_commit) = workspace_command.start_working_copy_mutation()?;
-    locked_ws.locked_wc().snapshot(&SnapshotOptions {
+    // TODO: print stats
+    let (_tree_id, _stats) = locked_ws.locked_wc().snapshot(&SnapshotOptions {
         base_ignores,
         fsmonitor_settings: command.settings().fsmonitor_settings()?,
         progress: None,

cli/src/commands/file/untrack.rs

@@ -76,7 +76,8 @@ pub(crate) fn cmd_file_untrack(
     locked_ws.locked_wc().reset(&new_commit)?;
     // Commit the working copy again so we can inform the user if paths couldn't be
     // untracked because they're not ignored.
-    let wc_tree_id = locked_ws.locked_wc().snapshot(&SnapshotOptions {
+    // TODO: print stats
+    let (wc_tree_id, _stats) = locked_ws.locked_wc().snapshot(&SnapshotOptions {
         base_ignores,
         fsmonitor_settings: command.settings().fsmonitor_settings()?,
         progress: None,

lib/src/local_working_copy.rs

@@ -108,6 +108,8 @@ use crate::working_copy::ResetError;
 use crate::working_copy::SnapshotError;
 use crate::working_copy::SnapshotOptions;
 use crate::working_copy::SnapshotProgress;
+use crate::working_copy::SnapshotStats;
+use crate::working_copy::UntrackedReason;
 use crate::working_copy::WorkingCopy;
 use crate::working_copy::WorkingCopyFactory;
 use crate::working_copy::WorkingCopyStateError;
@@ -908,7 +910,10 @@ impl TreeState {
     /// Look for changes to the working copy. If there are any changes, create
     /// a new tree from it.
     #[instrument(skip_all)]
-    pub fn snapshot(&mut self, options: &SnapshotOptions) -> Result<bool, SnapshotError> {
+    pub fn snapshot(
+        &mut self,
+        options: &SnapshotOptions,
+    ) -> Result<(bool, SnapshotStats), SnapshotError> {
         let &SnapshotOptions {
             ref base_ignores,
             ref fsmonitor_settings,
@@ -935,11 +940,12 @@ impl TreeState {
         if matcher.visit(RepoPath::root()).is_nothing() {
             // No need to load the current tree, set up channels, etc.
             self.watchman_clock = watchman_clock;
-            return Ok(is_dirty);
+            return Ok((is_dirty, SnapshotStats::default()));
         }
 
         let (tree_entries_tx, tree_entries_rx) = channel();
         let (file_states_tx, file_states_rx) = channel();
+        let (untracked_paths_tx, untracked_paths_rx) = channel();
         let (deleted_files_tx, deleted_files_rx) = channel();
 
         trace_span!("traverse filesystem").in_scope(|| -> Result<(), SnapshotError> {
@@ -951,6 +957,7 @@ impl TreeState {
                 // Move tx sides so they'll be dropped at the end of the scope.
                 tree_entries_tx,
                 file_states_tx,
+                untracked_paths_tx,
                 deleted_files_tx,
                 error: OnceLock::new(),
                 progress,
@@ -972,6 +979,9 @@ impl TreeState {
             snapshotter.into_result()
         })?;
 
+        let stats = SnapshotStats {
+            untracked_paths: untracked_paths_rx.into_iter().collect(),
+        };
         let mut tree_builder = MergedTreeBuilder::new(self.tree_id.clone());
         trace_span!("process tree entries").in_scope(|| {
             for (path, tree_values) in &tree_entries_rx {
@@ -1011,7 +1021,7 @@ impl TreeState {
             assert_eq!(state_paths, tree_paths);
         }
         self.watchman_clock = watchman_clock;
-        Ok(is_dirty)
+        Ok((is_dirty, stats))
     }
 
     #[instrument(skip_all)]
@@ -1087,6 +1097,8 @@ struct FileSnapshotter<'a> {
     start_tracking_matcher: &'a dyn Matcher,
     tree_entries_tx: Sender<(RepoPathBuf, MergedTreeValue)>,
     file_states_tx: Sender<(RepoPathBuf, FileState)>,
+    #[allow(unused)] // TODO
+    untracked_paths_tx: Sender<(RepoPathBuf, UntrackedReason)>,
     deleted_files_tx: Sender<RepoPathBuf>,
     error: OnceLock<SnapshotError>,
     progress: Option<&'a SnapshotProgress<'a>>,
@@ -2150,7 +2162,10 @@ impl LockedWorkingCopy for LockedLocalWorkingCopy {
         &self.old_tree_id
     }
 
-    fn snapshot(&mut self, options: &SnapshotOptions) -> Result<MergedTreeId, SnapshotError> {
+    fn snapshot(
+        &mut self,
+        options: &SnapshotOptions,
+    ) -> Result<(MergedTreeId, SnapshotStats), SnapshotError> {
         let tree_state = self
             .wc
             .tree_state_mut()
@@ -2158,8 +2173,9 @@ impl LockedWorkingCopy for LockedLocalWorkingCopy {
                 message: "Failed to read the working copy state".to_string(),
                 err: err.into(),
             })?;
-        self.tree_state_dirty |= tree_state.snapshot(options)?;
+        let (is_dirty, stats) = tree_state.snapshot(options)?;
-        Ok(tree_state.current_tree_id().clone())
+        self.tree_state_dirty |= is_dirty;
+        Ok((tree_state.current_tree_id().clone(), stats))
     }
 
     fn check_out(

lib/src/working_copy.rs

@@ -16,6 +16,7 @@
 //! default local-disk implementation.
 
 use std::any::Any;
+use std::collections::BTreeMap;
 use std::ffi::OsString;
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -113,8 +114,11 @@ pub trait LockedWorkingCopy {
     /// The tree at the time the lock was taken
     fn old_tree_id(&self) -> &MergedTreeId;
 
-    /// Snapshot the working copy and return the tree id.
+    /// Snapshot the working copy. Returns the tree id and stats.
-    fn snapshot(&mut self, options: &SnapshotOptions) -> Result<MergedTreeId, SnapshotError>;
+    fn snapshot(
+        &mut self,
+        options: &SnapshotOptions,
+    ) -> Result<(MergedTreeId, SnapshotStats), SnapshotError>;
 
     /// Check out the specified commit in the working copy.
     fn check_out(
@@ -249,6 +253,25 @@ impl SnapshotOptions<'_> {
 /// A callback for getting progress updates.
 pub type SnapshotProgress<'a> = dyn Fn(&RepoPath) + 'a + Sync;
 
+/// Stats about a snapshot operation on a working copy.
+#[derive(Clone, Debug, Default)]
+pub struct SnapshotStats {
+    /// List of new (previously untracked) files which are still untracked.
+    pub untracked_paths: BTreeMap<RepoPathBuf, UntrackedReason>,
+}
+
+/// Reason why the new path isn't tracked.
+#[derive(Clone, Debug)]
+pub enum UntrackedReason {
+    /// File was larger than the specified maximum file size.
+    FileTooLarge {
+        /// Actual size of the large file.
+        size: u64,
+        /// Maximum allowed size.
+        max_size: u64,
+    },
+}
+
 /// Options used when checking out a tree in the working copy.
 #[derive(Clone)]
 pub struct CheckoutOptions {

lib/tests/test_local_working_copy.rs

@@ -939,7 +939,7 @@ fn test_snapshot_racy_timestamps() {
             .workspace
             .start_working_copy_mutation()
             .unwrap();
-        let new_tree_id = locked_ws
+        let (new_tree_id, _stats) = locked_ws
             .locked_wc()
             .snapshot(&SnapshotOptions::empty_for_test())
             .unwrap();
@@ -973,7 +973,7 @@ fn test_snapshot_special_file() {
 
     // Snapshot the working copy with the socket file
     let mut locked_ws = ws.start_working_copy_mutation().unwrap();
-    let tree_id = locked_ws
+    let (tree_id, _stats) = locked_ws
         .locked_wc()
         .snapshot(&SnapshotOptions::empty_for_test())
         .unwrap();
@@ -2052,7 +2052,7 @@ fn test_fsmonitor() {
             .iter()
             .map(|p| p.to_fs_path_unchecked(Path::new("")))
             .collect();
-        locked_ws
+        let (tree_id, _stats) = locked_ws
             .locked_wc()
             .snapshot(&SnapshotOptions {
                 fsmonitor_settings: FsmonitorSettings::Test {
@@ -2060,7 +2060,8 @@ fn test_fsmonitor() {
                 },
                 ..SnapshotOptions::empty_for_test()
             })
-            .unwrap()
+            .unwrap();
+        tree_id
     };
 
     {

lib/tests/test_local_working_copy_concurrent.rs

@@ -169,7 +169,7 @@ fn test_checkout_parallel() {
                 // &CheckoutOptions::empty_for_test()) should never produce a
                 // different tree.
                 let mut locked_ws = workspace.start_working_copy_mutation().unwrap();
-                let new_tree_id = locked_ws
+                let (new_tree_id, _stats) = locked_ws
                     .locked_wc()
                     .snapshot(&SnapshotOptions::empty_for_test())
                     .unwrap();

lib/testutils/src/lib.rs

@@ -60,6 +60,7 @@ use jj_lib::tree::Tree;
 use jj_lib::tree_builder::TreeBuilder;
 use jj_lib::working_copy::SnapshotError;
 use jj_lib::working_copy::SnapshotOptions;
+use jj_lib::working_copy::SnapshotStats;
 use jj_lib::workspace::Workspace;
 use pollster::FutureExt;
 use tempfile::TempDir;
@@ -302,17 +303,18 @@ impl TestWorkspace {
     pub fn snapshot_with_options(
         &mut self,
         options: &SnapshotOptions,
-    ) -> Result<MergedTree, SnapshotError> {
+    ) -> Result<(MergedTree, SnapshotStats), SnapshotError> {
         let mut locked_ws = self.workspace.start_working_copy_mutation().unwrap();
-        let tree_id = locked_ws.locked_wc().snapshot(options)?;
+        let (tree_id, stats) = locked_ws.locked_wc().snapshot(options)?;
         // arbitrary operation id
         locked_ws.finish(self.repo.op_id().clone()).unwrap();
-        Ok(self.repo.store().get_root_tree(&tree_id).unwrap())
+        Ok((self.repo.store().get_root_tree(&tree_id).unwrap(), stats))
     }
 
     /// Like `snapshot_with_option()` but with default options
     pub fn snapshot(&mut self) -> Result<MergedTree, SnapshotError> {
-        self.snapshot_with_options(&SnapshotOptions::empty_for_test())
+        let (tree_id, _stats) = self.snapshot_with_options(&SnapshotOptions::empty_for_test())?;
+        Ok(tree_id)
     }
 }