fix(lsp): apply code actions whose follow-up command no server provides (#1343)

vtsls offers Organize Imports as an edit plus
`_typescript.didOrganizeImports`, a command VS Code's TypeScript
extension runs itself. Optimize Imports in a TypeScript file asked the
servers to resolve and run that command and failed with "no language
server provides command" before applying the edit.

A command that follows a code action's edit and that no server provides
is now skipped: the edit is applied, and resolving the command asks
nothing. An action that is only a command still reports it can't run.

crates/ide-host/src/ops/lsp.rs

@@ -438,12 +438,30 @@ pub async fn lsp_apply_code_action(host: &Host, window: &str, doc: DocId, action
         let edit = edit.clone();
         blocking(move || apply_edit(&documents, &edit)).await?;
     }
-    if let Some(command) = action.command {
+    if let Some(command) = action.command
+        && !(action.edit.is_some() && is_client_follow_up(&project, doc, None, &command).await)
+    {
         project.lsp.execute_command(doc, command).await?;
     }
     Ok(())
 }
 
+/// A command after a code action's edit that no server provides: what other editors'
+/// extensions do once the edit is applied (vtsls' `_typescript.didOrganizeImports`). The edit
+/// is the action; there is nothing to run.
+async fn is_client_follow_up(
+    project: &crate::project::Project,
+    doc: DocId,
+    server: Option<ide_core::ServerId>,
+    command: &Command,
+) -> bool {
+    let provided = project.lsp.provides_command(doc, server, &command.command).await;
+    if !provided {
+        tracing::debug!("skipping `{}` after the code action's edit: no server provides it", command.command);
+    }
+    !provided
+}
+
 pub async fn lsp_prepare_rename(host: &Host, window: &str, doc: DocId, pos: Pos) -> IdeResult<Option<Range>> {
     host.project(window)?.lsp.prepare_rename(doc, pos).await
 }
@@ -676,6 +694,7 @@ pub async fn lsp_execute_code_action(
         if cancel.is_cancelled() {
             return Err(ide_core::IdeError::cancelled());
         }
+        let edited = action.edit.is_some();
         if let Some(edit) = action.edit {
             let documents = project.documents.clone();
             tokio::task::spawn_blocking(move || apply_edit(&documents, &edit))
@@ -683,6 +702,9 @@ pub async fn lsp_execute_code_action(
                 .map_err(|e| ide_core::IdeError::internal(e.to_string()))??;
         }
         match action.command {
+            Some(command) if edited && is_client_follow_up(&project, doc, Some(action.server), &command).await => {
+                Ok(Vec::new())
+            }
             Some(command) => project
                 .lsp
                 .execute_action_command(doc, action.server, command, answers, cancel)

crates/ide-host/tests/workspace_edits.rs

@@ -175,3 +175,66 @@ async fn contended_version_reads_do_not_block_the_async_worker() {
         assert!(watchdog.join().unwrap(), "request {request_kind} blocked the only async worker");
     }
 }
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn code_actions_skip_a_command_no_server_provides_after_their_edit() {
+    use ide_lsp::types::{CodeAction, Command};
+    let tmp = tempfile::tempdir().unwrap();
+    let file = tmp.path().join("imports.txt");
+    std::fs::write(&file, "unused\nused\n").unwrap();
+    let host = Host::new(HostConfig {
+        config_dir: tmp.path().join("config"),
+        data_dir: tmp.path().join("data"),
+        local_data_dir: tmp.path().join("local-data"),
+        languages: Arc::new(ide_language::LanguageRegistry::load(None).unwrap()),
+        syntax: Arc::default(),
+        sink_for: Box::new(|_| Arc::new(|_| {})),
+        owner: |window| window,
+        runtime: tokio::runtime::Handle::current(),
+        project_environment: false,
+    });
+    host.open_light("main", &file).unwrap();
+    let info = ops::doc::open(&host, "main", file.clone()).await.unwrap();
+    // Optimize Imports as vtsls offers it: the edit, then a command its client runs itself.
+    let action = |edit: bool| CodeAction {
+        title: "Organize Imports".into(),
+        kind: Some("source.organizeImports".into()),
+        is_preferred: false,
+        disabled_reason: None,
+        edit: edit.then(|| {
+            serde_json::from_value(json!({ "files": [{ "kind": "edit", "path": file, "edits": [
+                { "range": { "start": { "line": 0, "col": 0 }, "end": { "line": 1, "col": 0 } }, "new_text": "" }
+            ] }] }))
+            .unwrap()
+        }),
+        command: Some(Command {
+            title: String::new(),
+            command: "_typescript.didOrganizeImports".into(),
+            arguments: vec![],
+        }),
+        data: None,
+        server: ide_core::ServerId(1),
+    };
+    let follow_up = action(true).command.unwrap();
+    let asked = ops::lsp::lsp_resolve_command(
+        &host,
+        "main",
+        ide_core::RequestId(1),
+        info.id,
+        ide_core::ServerId(1),
+        follow_up,
+        vec![],
+    )
+    .await;
+    assert!(matches!(asked, Ok(None)), "{asked:?}");
+    ops::lsp::lsp_execute_code_action(&host, "main", ide_core::RequestId(2), info.id, action(true), vec![])
+        .await
+        .unwrap();
+    assert_eq!(ops::doc::snapshot(&host, "main", info.id).await.unwrap().text, "used\n");
+    ops::lsp::lsp_apply_code_action(&host, "main", info.id, action(true)).await.unwrap();
+    assert_eq!(ops::doc::snapshot(&host, "main", info.id).await.unwrap().text, "");
+    // Without an edit the command is the action: it still can't run.
+    let ran =
+        ops::lsp::lsp_execute_code_action(&host, "main", ide_core::RequestId(3), info.id, action(false), vec![]).await;
+    assert!(ran.is_err(), "{ran:?}");
+}

crates/ide-lsp/src/lib.rs

@@ -1692,6 +1692,20 @@ impl LspManager {
         Ok(())
     }
 
+    /// Whether a server of `doc` (`server`, when given) provides the command `name`. Code actions
+    /// can carry commands other editors' extensions run themselves after the edit (vtsls'
+    /// `_typescript.didOrganizeImports`): no server provides those.
+    pub async fn provides_command(&self, doc: DocId, server: Option<ide_core::ServerId>, name: &str) -> bool {
+        let servers = match self.snapshot(doc) {
+            Ok(snap) => snap.servers,
+            Err(_) => self.servers.lock().clone(),
+        };
+        self.ready_targets(&servers, |c| c.commands().iter().any(|c| c == name))
+            .await
+            .iter()
+            .any(|t| server.is_none_or(|s| t.server.id == s))
+    }
+
     async fn command_target(&self, doc: DocId, server: ide_core::ServerId, name: &str) -> IdeResult<Target> {
         let snap = self.snapshot(doc)?;
         self.ready_targets(&snap.servers, |c| c.commands().iter().any(|c| c == name))
@@ -1710,6 +1724,10 @@ impl LspManager {
         answers: Vec<FormAnswer>,
         cancel: CancellationToken,
     ) -> IdeResult<Option<CommandForm>> {
+        // Nothing to ask for a command its server doesn't provide (executing it decides).
+        if !self.provides_command(doc, Some(server), &command.command).await {
+            return Ok(None);
+        }
         let t = self.command_target(doc, server, &command.command).await?;
         let interactive = t.server.name == "gopls"
             && t.caps()