working_copy: allow updating sparse patterns (#52)

With this patch, we add support for setting the sparse patterns, and
we respect it when updating the working copy.

lib/src/working_copy.rs

@@ -37,7 +37,7 @@ use crate::backend::{
 use crate::conflicts::{materialize_conflict, update_conflict_from_content};
 use crate::gitignore::GitIgnoreFile;
 use crate::lock::FileLock;
-use crate::matchers::{EverythingMatcher, Matcher};
+use crate::matchers::{DifferenceMatcher, Matcher, PrefixMatcher};
 use crate::op_store::{OperationId, WorkspaceId};
 use crate::repo_path::{RepoPath, RepoPathComponent, RepoPathJoin};
 use crate::store::Store;
@@ -226,6 +226,10 @@ impl TreeState {
         &self.sparse_patterns
     }
 
+    fn sparse_matcher(&self) -> Box<dyn Matcher> {
+        Box::new(PrefixMatcher::new(&self.sparse_patterns))
+    }
+
     pub fn init(store: Arc<Store>, working_copy_path: PathBuf, state_path: PathBuf) -> TreeState {
         let mut wc = TreeState::empty(store, working_copy_path, state_path);
         wc.save();
@@ -579,13 +583,39 @@ impl TreeState {
                 BackendError::NotFound => CheckoutError::SourceNotFound,
                 other => CheckoutError::InternalBackendError(other),
             })?;
-        let stats = self.update(&old_tree, new_tree, &EverythingMatcher)?;
+        let stats = self.update(&old_tree, new_tree, self.sparse_matcher().as_ref())?;
         self.tree_id = new_tree.id().clone();
         Ok(stats)
     }
 
-    pub fn set_sparse_patterns(&mut self, sparse_patterns: Vec<RepoPath>) {
+    pub fn set_sparse_patterns(
+        &mut self,
+        sparse_patterns: Vec<RepoPath>,
+    ) -> Result<CheckoutStats, CheckoutError> {
+        let tree = self
+            .store
+            .get_tree(&RepoPath::root(), &self.tree_id)
+            .map_err(|err| match err {
+                BackendError::NotFound => CheckoutError::SourceNotFound,
+                other => CheckoutError::InternalBackendError(other),
+            })?;
+        let old_matcher = PrefixMatcher::new(&self.sparse_patterns);
+        let new_matcher = PrefixMatcher::new(&sparse_patterns);
+        let added_matcher = DifferenceMatcher::new(&new_matcher, &old_matcher);
+        let removed_matcher = DifferenceMatcher::new(&old_matcher, &new_matcher);
+        let empty_tree = Tree::null(self.store.clone(), RepoPath::root());
+        let added_stats = self.update(&empty_tree, &tree, &added_matcher)?;
+        let removed_stats = self.update(&tree, &empty_tree, &removed_matcher)?;
         self.sparse_patterns = sparse_patterns;
+        assert_eq!(added_stats.updated_files, 0);
+        assert_eq!(added_stats.removed_files, 0);
+        assert_eq!(removed_stats.updated_files, 0);
+        assert_eq!(removed_stats.added_files, 0);
+        Ok(CheckoutStats {
+            updated_files: 0,
+            added_files: added_stats.added_files,
+            removed_files: removed_stats.removed_files,
+        })
     }
 
     fn update(
@@ -684,7 +714,7 @@ impl TreeState {
                 other => ResetError::InternalBackendError(other),
             })?;
 
-        for (path, diff) in old_tree.diff(new_tree, &EverythingMatcher) {
+        for (path, diff) in old_tree.diff(new_tree, self.sparse_matcher().as_ref()) {
             match diff {
                 Diff::Removed(_before) => {
                     self.file_states.remove(&path);
@@ -766,6 +796,10 @@ impl WorkingCopy {
         }
     }
 
+    pub fn working_copy_path(&self) -> &Path {
+        &self.working_copy_path
+    }
+
     pub fn state_path(&self) -> &Path {
         &self.state_path
     }
@@ -925,8 +959,8 @@ impl LockedWorkingCopy<'_> {
     }
 
     pub fn check_out(&mut self, new_tree: &Tree) -> Result<CheckoutStats, CheckoutError> {
-        // TODO: Write a "pending_checkout" file with the old and new TreeIds so we can
-        // continue an interrupted checkout if we find such a file.
+        // TODO: Write a "pending_checkout" file with the new TreeId so we can
+        // continue an interrupted update if we find such a file.
         let stats = self.wc.tree_state().as_mut().unwrap().check_out(new_tree)?;
         Ok(stats)
     }
@@ -939,7 +973,12 @@ impl LockedWorkingCopy<'_> {
         self.wc.sparse_patterns()
     }
 
-    pub fn set_sparse_patterns(&mut self, new_sparse_patterns: Vec<RepoPath>) {
+    pub fn set_sparse_patterns(
+        &mut self,
+        new_sparse_patterns: Vec<RepoPath>,
+    ) -> Result<CheckoutStats, CheckoutError> {
+        // TODO: Write a "pending_checkout" file with new sparse patterns so we can
+        // continue an interrupted update if we find such a file.
         self.wc
             .tree_state()
             .as_mut()

lib/tests/test_working_copy_sparse.rs

@@ -0,0 +1,124 @@
+// Copyright 2022 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use itertools::Itertools;
+use jujutsu_lib::repo_path::RepoPath;
+use jujutsu_lib::testutils;
+use jujutsu_lib::working_copy::{CheckoutStats, WorkingCopy};
+
+#[test]
+fn test_sparse_checkout() {
+    let settings = testutils::user_settings();
+    let mut test_workspace = testutils::init_workspace(&settings, false);
+    let repo = &test_workspace.repo;
+    let working_copy_path = test_workspace.workspace.workspace_root().clone();
+
+    let root_file1_path = RepoPath::from_internal_string("file1");
+    let root_file2_path = RepoPath::from_internal_string("file2");
+    let dir1_path = RepoPath::from_internal_string("dir1");
+    let dir1_file1_path = RepoPath::from_internal_string("dir1/file1");
+    let dir1_file2_path = RepoPath::from_internal_string("dir1/file2");
+    let dir1_subdir1_path = RepoPath::from_internal_string("dir1/subdir1");
+    let dir1_subdir1_file1_path = RepoPath::from_internal_string("dir1/subdir1/file1");
+    let dir2_path = RepoPath::from_internal_string("dir2");
+    let dir2_file1_path = RepoPath::from_internal_string("dir2/file1");
+
+    let tree = testutils::create_tree(
+        repo,
+        &[
+            (&root_file1_path, "contents"),
+            (&root_file2_path, "contents"),
+            (&dir1_file1_path, "contents"),
+            (&dir1_file2_path, "contents"),
+            (&dir1_subdir1_file1_path, "contents"),
+            (&dir2_file1_path, "contents"),
+        ],
+    );
+
+    let wc = test_workspace.workspace.working_copy_mut();
+    wc.check_out(repo.op_id().clone(), None, &tree).unwrap();
+
+    // Set sparse patterns to only dir1/
+    let mut locked_wc = wc.start_mutation();
+    let sparse_patterns = vec![dir1_path];
+    let stats = locked_wc
+        .set_sparse_patterns(sparse_patterns.clone())
+        .unwrap();
+    assert_eq!(
+        stats,
+        CheckoutStats {
+            updated_files: 0,
+            added_files: 0,
+            removed_files: 3
+        }
+    );
+    assert_eq!(locked_wc.sparse_patterns(), sparse_patterns);
+    assert!(!root_file1_path.to_fs_path(&working_copy_path).exists());
+    assert!(!root_file2_path.to_fs_path(&working_copy_path).exists());
+    assert!(dir1_file1_path.to_fs_path(&working_copy_path).exists());
+    assert!(dir1_file2_path.to_fs_path(&working_copy_path).exists());
+    assert!(dir1_subdir1_file1_path
+        .to_fs_path(&working_copy_path)
+        .exists());
+    assert!(!dir2_file1_path.to_fs_path(&working_copy_path).exists());
+
+    // Write the new state to disk
+    locked_wc.finish(repo.op_id().clone());
+    assert_eq!(
+        wc.file_states().keys().collect_vec(),
+        vec![&dir1_file1_path, &dir1_file2_path, &dir1_subdir1_file1_path]
+    );
+    assert_eq!(wc.sparse_patterns(), sparse_patterns);
+
+    // Reload the state to check that it was persisted
+    let mut wc = WorkingCopy::load(
+        repo.store().clone(),
+        wc.working_copy_path().to_path_buf(),
+        wc.state_path().to_path_buf(),
+    );
+    assert_eq!(
+        wc.file_states().keys().collect_vec(),
+        vec![&dir1_file1_path, &dir1_file2_path, &dir1_subdir1_file1_path]
+    );
+    assert_eq!(wc.sparse_patterns(), sparse_patterns);
+
+    // Set sparse patterns to file2, dir1/subdir1/ and dir2/
+    let mut locked_wc = wc.start_mutation();
+    let sparse_patterns = vec![root_file1_path.clone(), dir1_subdir1_path, dir2_path];
+    let stats = locked_wc
+        .set_sparse_patterns(sparse_patterns.clone())
+        .unwrap();
+    assert_eq!(
+        stats,
+        CheckoutStats {
+            updated_files: 0,
+            added_files: 2,
+            removed_files: 2
+        }
+    );
+    assert_eq!(locked_wc.sparse_patterns(), sparse_patterns);
+    assert!(root_file1_path.to_fs_path(&working_copy_path).exists());
+    assert!(!root_file2_path.to_fs_path(&working_copy_path).exists());
+    assert!(!dir1_file1_path.to_fs_path(&working_copy_path).exists());
+    assert!(!dir1_file2_path.to_fs_path(&working_copy_path).exists());
+    assert!(dir1_subdir1_file1_path
+        .to_fs_path(&working_copy_path)
+        .exists());
+    assert!(dir2_file1_path.to_fs_path(&working_copy_path).exists());
+    locked_wc.finish(repo.op_id().clone());
+    assert_eq!(
+        wc.file_states().keys().collect_vec(),
+        vec![&dir1_subdir1_file1_path, &dir2_file1_path, &root_file1_path]
+    );
+}