Make new workspace inherit sparse patterns

CHANGELOG.md

@@ -48,6 +48,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   [#2971](https://github.com/martinvonz/jj/issues/2971)). This may become the
   default depending on feedback.
 
+* When creating a new workspace, the sparse patterns are now copied over from
+  the current workspace.
+
 ### Fixed bugs
 
 * On Windows, symlinks in the repo are now materialized as regular files in the

cli/src/commands/workspace.rs

@@ -44,6 +44,8 @@ use crate::ui::Ui;
 /// Each workspace has its own working-copy commit. When you have more than one
 /// workspace attached to a repo, they are indicated by `@<workspace name>` in
 /// `jj log`.
+///
+/// Each workspace also has own sparse patterns.
 #[derive(Subcommand, Clone, Debug)]
 pub(crate) enum WorkspaceCommand {
     Add(WorkspaceAddArgs),
@@ -54,6 +56,8 @@ pub(crate) enum WorkspaceCommand {
 }
 
 /// Add a workspace
+///
+/// Sparse patterns will be copied over from the current workspace.
 #[derive(clap::Args, Clone, Debug)]
 pub(crate) struct WorkspaceAddArgs {
     /// Where to create the new workspace
@@ -167,7 +171,20 @@ fn cmd_workspace_add(
             .display()
     )?;
 
+    // Copy sparse patterns from workspace where the command was run
     let mut new_workspace_command = WorkspaceCommandHelper::new(ui, command, new_workspace, repo)?;
+    let (mut locked_ws, _wc_commit) = new_workspace_command.start_working_copy_mutation()?;
+    let sparse_patterns = old_workspace_command
+        .working_copy()
+        .sparse_patterns()?
+        .to_vec();
+    locked_ws
+        .locked_wc()
+        .set_sparse_patterns(sparse_patterns)
+        .map_err(|err| internal_error_with_message("Failed to set sparse patterns", err))?;
+    let operation_id = locked_ws.locked_wc().old_operation_id().clone();
+    locked_ws.finish(operation_id)?;
+
     let mut tx = new_workspace_command.start_transaction();
 
     // If no parent revisions are specified, create a working-copy commit based

cli/tests/cli-reference@.md.snap

@@ -1888,6 +1888,8 @@ Workspaces let you add additional working copies attached to the same repo. A co
 
 Each workspace has its own working-copy commit. When you have more than one workspace attached to a repo, they are indicated by `@<workspace name>` in `jj log`.
 
+Each workspace also has own sparse patterns.
+
 **Usage:** `jj workspace <COMMAND>`
 
 ###### **Subcommands:**
@@ -1904,6 +1906,8 @@ Each workspace has its own working-copy commit. When you have more than one work
 
 Add a workspace
 
+Sparse patterns will be copied over from the current workspace.
+
 **Usage:** `jj workspace add [OPTIONS] <DESTINATION>`
 
 ###### **Arguments:**

cli/tests/test_workspaces.rs

@@ -69,6 +69,30 @@ fn test_workspaces_add_second_workspace() {
     "###);
 }
 
+/// Test how sparse patterns are inherited
+#[test]
+fn test_workspaces_sparse_patterns() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_ok(test_env.env_root(), &["init", "--git", "ws1"]);
+    let ws1_path = test_env.env_root().join("ws1");
+    let ws2_path = test_env.env_root().join("ws2");
+    let ws3_path = test_env.env_root().join("ws3");
+
+    test_env.jj_cmd_ok(&ws1_path, &["sparse", "set", "--clear", "--add=foo"]);
+    test_env.jj_cmd_ok(&ws1_path, &["workspace", "add", "../ws2"]);
+    let stdout = test_env.jj_cmd_success(&ws2_path, &["sparse", "list"]);
+    insta::assert_snapshot!(stdout, @r###"
+    foo
+    "###);
+    test_env.jj_cmd_ok(&ws2_path, &["sparse", "set", "--add=bar"]);
+    test_env.jj_cmd_ok(&ws2_path, &["workspace", "add", "../ws3"]);
+    let stdout = test_env.jj_cmd_success(&ws3_path, &["sparse", "list"]);
+    insta::assert_snapshot!(stdout, @r###"
+    bar
+    foo
+    "###);
+}
+
 /// Test adding a second workspace while the current workspace is editing a
 /// merge
 #[test]