cli: add commands for working with sparse patterns (#52)

This adds a `jj sparse` command with options to list and manage the
set of paths to include in the working copy. It only supports includes
(postive matches) for now.

I'm not sure "sparse" is the best name for the feature. Perhaps it
would make sense as a subcommand under `jj workspace` - maybe `jj
workspace track`? However, there's also `jj untrack` for removing a
file from the working copy and leaving it in the working copy. I'm
happy to hear suggestions, or we can get back to the naming later.

CHANGELOG.md

@@ -30,6 +30,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * `jj split` now lets you specify on the CLI which paths to include in the first
   commit. The interactive diff-editing is not started when you do that.
 
+* Sparse checkouts are now supported. In fact, all working copies are now
+  "sparse", only to different degrees. Use the `jj sparse` command to manage
+  the paths included in the sparse checkout.  
+
 * The `$JJ_CONFIG` environment variable can now point to a directory. If it
   does, all files in the directory will be read, in alphabetical order.
 

docs/git-compatibility.md

@@ -57,9 +57,8 @@ a comparison with Git, including how workflows are different, see the
   which doesn't have support for partial clones.
 * **git-worktree: No.** However, there's native support for multiple working
   copies backed by a single repo. See the `jj workspace` family of commands.
-* **Sparse checkouts: No.** There is
-  [#52](https://github.com/martinvonz/jj/issues/52) about native support for
-  sparse checkouts.
+* **Sparse checkouts: No.** However, there's native support for sparse
+  checkouts. See the `jj sparse` command.
 * **Signed commits: No.** ([#58](https://github.com/martinvonz/jj/issues/58))
 * **Git LFS: No.** ([#80](https://github.com/martinvonz/jj/issues/80))
 

src/commands.rs

@@ -780,13 +780,7 @@ impl WorkspaceCommandHelper {
                 maybe_old_commit.as_ref(),
             )?;
             if let Some(stats) = stats {
-                if stats.added_files > 0 || stats.updated_files > 0 || stats.removed_files > 0 {
-                    writeln!(
-                        ui,
-                        "Added {} files, modified {} files, removed {} files",
-                        stats.added_files, stats.updated_files, stats.removed_files
-                    )?;
-                }
+                print_checkout_stats(ui, stats)?;
             }
         }
         if self.working_copy_shared_with_git {
@@ -797,6 +791,17 @@ impl WorkspaceCommandHelper {
     }
 }
 
+fn print_checkout_stats(ui: &mut Ui, stats: CheckoutStats) -> Result<(), std::io::Error> {
+    if stats.added_files > 0 || stats.updated_files > 0 || stats.removed_files > 0 {
+        writeln!(
+            ui,
+            "Added {} files, modified {} files, removed {} files",
+            stats.added_files, stats.updated_files, stats.removed_files
+        )?;
+    }
+    Ok(())
+}
+
 /// Expands "~/" to "$HOME/" as Git seems to do for e.g. core.excludesFile.
 fn expand_git_path(path_str: String) -> PathBuf {
     if let Some(remainder) = path_str.strip_prefix("~/") {
@@ -919,11 +924,11 @@ fn resolve_single_op_from_store(
     }
 }
 
-fn matcher_from_values(
+fn repo_paths_from_values(
     ui: &Ui,
     wc_path: &Path,
     values: &[String],
-) -> Result<Box<dyn Matcher>, CommandError> {
+) -> Result<Vec<RepoPath>, CommandError> {
     if !values.is_empty() {
         // TODO: Add support for globs and other formats
         let mut paths = vec![];
@@ -931,9 +936,22 @@ fn matcher_from_values(
             let repo_path = ui.parse_file_path(wc_path, value)?;
             paths.push(repo_path);
         }
-        Ok(Box::new(PrefixMatcher::new(&paths)))
+        Ok(paths)
     } else {
+        Ok(vec![])
+    }
+}
+
+fn matcher_from_values(
+    ui: &Ui,
+    wc_path: &Path,
+    values: &[String],
+) -> Result<Box<dyn Matcher>, CommandError> {
+    let paths = repo_paths_from_values(ui, wc_path, values)?;
+    if paths.is_empty() {
         Ok(Box::new(EverythingMatcher))
+    } else {
+        Ok(Box::new(PrefixMatcher::new(&paths)))
     }
 }
 
@@ -1072,6 +1090,7 @@ enum Commands {
     Undo(OperationUndoArgs),
     Operation(OperationArgs),
     Workspace(WorkspaceArgs),
+    Sparse(SparseArgs),
     Git(GitArgs),
     Bench(BenchArgs),
     Debug(DebugArgs),
@@ -1649,6 +1668,26 @@ struct WorkspaceForgetArgs {
 #[derive(clap::Args, Clone, Debug)]
 struct WorkspaceListArgs {}
 
+/// Manage which paths from the current checkout are present in the working copy
+#[derive(clap::Args, Clone, Debug)]
+struct SparseArgs {
+    /// Patterns to add to the working copy
+    #[clap(long)]
+    add: Vec<String>,
+    /// Patterns to remove from the working copy
+    #[clap(long, conflicts_with = "clear")]
+    remove: Vec<String>,
+    /// Include no files in the working copy (combine with --add)
+    #[clap(long)]
+    clear: bool,
+    /// Include all files in the working copy
+    #[clap(long, conflicts_with_all = &["add", "remove", "clear"])]
+    reset: bool,
+    /// List patterns
+    #[clap(long, conflicts_with_all = &["add", "remove", "clear", "reset"])]
+    list: bool,
+}
+
 /// Commands for working with the underlying Git repo
 ///
 /// For a comparison with Git, including a table of commands, see
@@ -4465,6 +4504,45 @@ fn cmd_workspace_list(
     Ok(())
 }
 
+fn cmd_sparse(ui: &mut Ui, command: &CommandHelper, args: &SparseArgs) -> Result<(), CommandError> {
+    if args.list {
+        let workspace_command = command.workspace_helper(ui)?;
+        for path in workspace_command.working_copy().sparse_patterns() {
+            let ui_path = workspace_command.format_file_path(&path);
+            writeln!(ui, "{}", ui_path)?;
+        }
+    } else {
+        let mut workspace_command = command.workspace_helper(ui)?;
+        workspace_command.commit_working_copy(ui)?;
+        let workspace_root = workspace_command.workspace_root().clone();
+        let paths_to_add = repo_paths_from_values(ui, &workspace_root, &args.add)?;
+        let (mut locked_wc, _current_checkout) = workspace_command.start_working_copy_mutation()?;
+        let mut new_patterns = HashSet::new();
+        if args.reset {
+            new_patterns.insert(RepoPath::root());
+        } else {
+            if !args.clear {
+                new_patterns.extend(locked_wc.sparse_patterns());
+                let paths_to_remove = repo_paths_from_values(ui, &workspace_root, &args.remove)?;
+                for path in paths_to_remove {
+                    new_patterns.remove(&path);
+                }
+            }
+            for path in paths_to_add {
+                new_patterns.insert(path);
+            }
+        }
+        let new_patterns = new_patterns.into_iter().sorted().collect();
+        let stats = locked_wc.set_sparse_patterns(new_patterns).map_err(|err| {
+            CommandError::InternalError(format!("Failed to update working copy paths: {}", err))
+        })?;
+        let operation_id = locked_wc.old_operation_id().clone();
+        locked_wc.finish(operation_id);
+        print_checkout_stats(ui, stats)?;
+    }
+    Ok(())
+}
+
 fn get_git_repo(store: &Store) -> Result<git2::Repository, CommandError> {
     match store.git_repo() {
         None => Err(CommandError::UserError(
@@ -4871,6 +4949,7 @@ where
         Commands::Undo(sub_args) => cmd_op_undo(&mut ui, &command_helper, sub_args),
         Commands::Operation(sub_args) => cmd_operation(&mut ui, &command_helper, sub_args),
         Commands::Workspace(sub_args) => cmd_workspace(&mut ui, &command_helper, sub_args),
+        Commands::Sparse(sub_args) => cmd_sparse(&mut ui, &command_helper, sub_args),
         Commands::Git(sub_args) => cmd_git(&mut ui, &command_helper, sub_args),
         Commands::Bench(sub_args) => cmd_bench(&mut ui, &command_helper, sub_args),
         Commands::Debug(sub_args) => cmd_debug(&mut ui, &command_helper, sub_args),

tests/test_sparse_command.rs

@@ -0,0 +1,105 @@
+// 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 crate::common::TestEnvironment;
+
+pub mod common;
+
+#[test]
+fn test_sparse_manage_patterns() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_success(test_env.env_root(), &["init", "repo", "--git"]);
+    let repo_path = test_env.env_root().join("repo");
+
+    // Write some files to the working copy
+    std::fs::write(repo_path.join("file1"), "contents").unwrap();
+    std::fs::write(repo_path.join("file2"), "contents").unwrap();
+    std::fs::write(repo_path.join("file3"), "contents").unwrap();
+
+    // By default, all files are tracked
+    let stdout = test_env.jj_cmd_success(&repo_path, &["sparse", "--list"]);
+    insta::assert_snapshot!(stdout, @".
+");
+
+    // Can stop tracking all files
+    let stdout = test_env.jj_cmd_success(&repo_path, &["sparse", "--remove", "."]);
+    insta::assert_snapshot!(stdout, @"Added 0 files, modified 0 files, removed 3 files
+");
+    // The list is now empty
+    let stdout = test_env.jj_cmd_success(&repo_path, &["sparse", "--list"]);
+    insta::assert_snapshot!(stdout, @"");
+    // They're removed from the working copy
+    assert!(!repo_path.join("file1").exists());
+    assert!(!repo_path.join("file2").exists());
+    assert!(!repo_path.join("file3").exists());
+    // But they're still in the commit
+    let stdout = test_env.jj_cmd_success(&repo_path, &["files"]);
+    insta::assert_snapshot!(stdout, @r###"
+    file1
+    file2
+    file3
+    "###);
+
+    // Can `--add` a few files
+    let stdout =
+        test_env.jj_cmd_success(&repo_path, &["sparse", "--add", "file2", "--add", "file3"]);
+    insta::assert_snapshot!(stdout, @"Added 2 files, modified 0 files, removed 0 files
+");
+    let stdout = test_env.jj_cmd_success(&repo_path, &["sparse", "--list"]);
+    insta::assert_snapshot!(stdout, @r###"
+    file2
+    file3
+    "###);
+    assert!(!repo_path.join("file1").exists());
+    assert!(repo_path.join("file2").exists());
+    assert!(repo_path.join("file3").exists());
+
+    // Can combine `--add` and `--remove`
+    let stdout = test_env.jj_cmd_success(
+        &repo_path,
+        &[
+            "sparse", "--add", "file1", "--remove", "file2", "--remove", "file3",
+        ],
+    );
+    insta::assert_snapshot!(stdout, @"Added 1 files, modified 0 files, removed 2 files
+");
+    let stdout = test_env.jj_cmd_success(&repo_path, &["sparse", "--list"]);
+    insta::assert_snapshot!(stdout, @"file1
+");
+    assert!(repo_path.join("file1").exists());
+    assert!(!repo_path.join("file2").exists());
+    assert!(!repo_path.join("file3").exists());
+
+    // Can use `--clear` and `--add`
+    let stdout = test_env.jj_cmd_success(&repo_path, &["sparse", "--clear", "--add", "file2"]);
+    insta::assert_snapshot!(stdout, @"Added 1 files, modified 0 files, removed 1 files
+");
+    let stdout = test_env.jj_cmd_success(&repo_path, &["sparse", "--list"]);
+    insta::assert_snapshot!(stdout, @"file2
+");
+    assert!(!repo_path.join("file1").exists());
+    assert!(repo_path.join("file2").exists());
+    assert!(!repo_path.join("file3").exists());
+
+    // Can reset back to all files
+    let stdout = test_env.jj_cmd_success(&repo_path, &["sparse", "--reset"]);
+    insta::assert_snapshot!(stdout, @"Added 2 files, modified 0 files, removed 0 files
+");
+    let stdout = test_env.jj_cmd_success(&repo_path, &["sparse", "--list"]);
+    insta::assert_snapshot!(stdout, @".
+");
+    assert!(repo_path.join("file1").exists());
+    assert!(repo_path.join("file2").exists());
+    assert!(repo_path.join("file3").exists());
+}

tests/test_untrack_command.rs

@@ -92,3 +92,28 @@ fn test_untrack() {
     let files_after = test_env.jj_cmd_success(&repo_path, &["files"]);
     assert!(!files_after.contains("target"));
 }
+
+#[test]
+fn test_untrack_sparse() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_success(test_env.env_root(), &["init", "repo"]);
+    let repo_path = test_env.env_root().join("repo");
+
+    std::fs::write(repo_path.join("file1"), "contents").unwrap();
+    std::fs::write(repo_path.join("file2"), "contents").unwrap();
+
+    // When untracking a file that's not included in the sparse working copy, it
+    // doesn't need to be ignored (because it won't be automatically added
+    // back).
+    let stdout = test_env.jj_cmd_success(&repo_path, &["files"]);
+    insta::assert_snapshot!(stdout, @r###"
+    file1
+    file2
+    "###);
+    test_env.jj_cmd_success(&repo_path, &["sparse", "--clear", "--add", "file1"]);
+    let stdout = test_env.jj_cmd_success(&repo_path, &["untrack", "file2"]);
+    insta::assert_snapshot!(stdout, @"");
+    let stdout = test_env.jj_cmd_success(&repo_path, &["files"]);
+    insta::assert_snapshot!(stdout, @"file1
+");
+}