fix(lsp): properly handle disabled configuration requests (#20358)

Fixes #19802.

Properly respect when clients do not have the `workspace/configuration`
capability, a.k.a. when an editor cannot provide scoped settings on
request from the LSP.

- Fix one spot where we weren't checking for the capability before
sending this request.
- For `enablePaths`, fall back to the settings passed in the
initialization options in more cases.
- Respect the `workspace/configuration` capability in the test harness
client.

See:
https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#workspace_configuration.

4 files changed, 111 insertions, 16 deletions

diff --git a/cli/lsp/config.rs b/cli/lsp/config.rs
index b70af6519..2d77abaee 100644
--- a/cli/lsp/config.rs
+++ b/cli/lsp/config.rs
@@ -718,13 +718,12 @@ impl Config {
     if let Some(workspace_folders) = self.workspace_folders.clone() {
       let mut touched = false;
       for (workspace, _) in workspace_folders {
-        if let Some(settings) = self.settings.specifiers.get(&workspace) {
-          if self.update_enabled_paths_entry(
-            workspace,
-            settings.enable_paths.clone(),
-          ) {
-            touched = true;
-          }
+        let enabled_paths = match self.settings.specifiers.get(&workspace) {
+          Some(settings) => settings.enable_paths.clone(),
+          None => self.settings.workspace.enable_paths.clone(),
+        };
+        if self.update_enabled_paths_entry(workspace, enabled_paths) {
+          touched = true;
         }
       }
       touched
diff --git a/cli/lsp/language_server.rs b/cli/lsp/language_server.rs
index dc85eb1cc..d4e5b3da9 100644
--- a/cli/lsp/language_server.rs
+++ b/cli/lsp/language_server.rs
@@ -1275,6 +1275,7 @@ impl Inner {
           error!("Cannot set workspace settings: {}", err);
           LspError::internal_error()
         })?;
+        self.config.update_enabled_paths();
       }
       self.config.workspace_folders = params.workspace_folders.map(|folders| {
         folders
@@ -1471,6 +1472,7 @@ impl Inner {
       if let Err(err) = self.config.set_workspace_settings(value) {
         error!("failed to update settings: {}", err);
       }
+      self.config.update_enabled_paths();
     }
 
     self.update_debug_flag();
@@ -3125,7 +3127,7 @@ impl tower_lsp::LanguageServer for LanguageServer {
       return;
     }
 
-    let (client, client_uri, specifier, had_specifier_settings) = {
+    let (client, client_uri, specifier, should_get_specifier_settings) = {
       let mut inner = self.0.write().await;
       let client = inner.client.clone();
       let client_uri = LspClientUrl::new(params.text_document.uri.clone());
@@ -3133,24 +3135,25 @@ impl tower_lsp::LanguageServer for LanguageServer {
         .url_map
         .normalize_url(client_uri.as_url(), LspUrlKind::File);
       let document = inner.did_open(&specifier, params).await;
-      let has_specifier_settings =
-        inner.config.has_specifier_settings(&specifier);
+      let should_get_specifier_settings =
+        !inner.config.has_specifier_settings(&specifier)
+          && inner.config.client_capabilities.workspace_configuration;
       if document.is_diagnosable() {
         inner.refresh_npm_specifiers().await;
         let specifiers = inner.documents.dependents(&specifier);
         inner.diagnostics_server.invalidate(&specifiers);
         // don't send diagnostics yet if we don't have the specifier settings
-        if has_specifier_settings {
+        if !should_get_specifier_settings {
           inner.send_diagnostics_update();
           inner.send_testing_update();
         }
       }
-      (client, client_uri, specifier, has_specifier_settings)
+      (client, client_uri, specifier, should_get_specifier_settings)
     };
 
     // retrieve the specifier settings outside the lock if
     // they haven't been asked for yet
-    if !had_specifier_settings {
+    if should_get_specifier_settings {
       let response = client
         .when_outside_lsp_lock()
         .specifier_configuration(&client_uri)
diff --git a/cli/tests/integration/lsp_tests.rs b/cli/tests/integration/lsp_tests.rs
index 218b1db40..19b968602 100644
--- a/cli/tests/integration/lsp_tests.rs
+++ b/cli/tests/integration/lsp_tests.rs
@@ -643,6 +643,87 @@ fn lsp_import_map_node_specifiers() {
   client.shutdown();
 }
 
+// Regression test for https://github.com/denoland/deno/issues/19802.
+// Disable the `workspace/configuration` capability. Ensure the LSP falls back
+// to using `enablePaths` from the `InitializationOptions`.
+#[test]
+fn lsp_workspace_enable_paths_no_workspace_configuration() {
+  let context = TestContextBuilder::new().use_temp_cwd().build();
+  let temp_dir = context.temp_dir();
+  temp_dir.write("main_disabled.ts", "Date.now()");
+  temp_dir.write("main_enabled.ts", "Date.now()");
+
+  let mut client = context.new_lsp_command().build();
+  client.initialize(|builder| {
+    builder.with_capabilities(|capabilities| {
+      capabilities.workspace.as_mut().unwrap().configuration = Some(false);
+    });
+    builder.set_workspace_folders(vec![lsp::WorkspaceFolder {
+      uri: temp_dir.uri(),
+      name: "project".to_string(),
+    }]);
+    builder.set_root_uri(temp_dir.uri());
+    builder.set_enable_paths(vec!["./main_enabled.ts".to_string()]);
+  });
+
+  client.did_open(json!({
+    "textDocument": {
+      "uri": temp_dir.uri().join("main_disabled.ts").unwrap(),
+      "languageId": "typescript",
+      "version": 1,
+      "text": temp_dir.read_to_string("main_disabled.ts"),
+    }
+  }));
+
+  client.did_open(json!({
+    "textDocument": {
+      "uri": temp_dir.uri().join("main_enabled.ts").unwrap(),
+      "languageId": "typescript",
+      "version": 1,
+      "text": temp_dir.read_to_string("main_enabled.ts"),
+    }
+  }));
+
+  let res = client.write_request(
+    "textDocument/hover",
+    json!({
+      "textDocument": {
+        "uri": temp_dir.uri().join("main_disabled.ts").unwrap(),
+      },
+      "position": { "line": 0, "character": 5 }
+    }),
+  );
+  assert_eq!(res, json!(null));
+
+  let res = client.write_request(
+    "textDocument/hover",
+    json!({
+      "textDocument": {
+        "uri": temp_dir.uri().join("main_enabled.ts").unwrap(),
+      },
+      "position": { "line": 0, "character": 5 }
+    }),
+  );
+  assert_eq!(
+    res,
+    json!({
+      "contents": [
+        {
+          "language": "typescript",
+          "value": "(method) DateConstructor.now(): number",
+        },
+        "Returns the number of milliseconds elapsed since midnight, January 1, 1970 Universal Coordinated Time (UTC)."
+      ],
+      "range": {
+        "start": { "line": 0, "character": 5, },
+        "end": { "line": 0, "character": 8, }
+      }
+    })
+  );
+
+  client.shutdown();
+}
+
 #[test]
 fn lsp_deno_task() {
   let context = TestContextBuilder::new().use_temp_cwd().build();
diff --git a/test_util/src/lsp.rs b/test_util/src/lsp.rs
index 8a1f24b32..5369d6361 100644
--- a/test_util/src/lsp.rs
+++ b/test_util/src/lsp.rs
@@ -591,6 +591,7 @@ impl LspClientBuilder {
       writer,
       deno_dir,
       stderr_lines_rx,
+      supports_workspace_configuration: false,
     })
   }
 }
@@ -604,6 +605,7 @@ pub struct LspClient {
   deno_dir: TempDir,
   context: TestContext,
   stderr_lines_rx: Option<mpsc::Receiver<String>>,
+  supports_workspace_configuration: bool,
 }
 
 impl Drop for LspClient {
@@ -689,9 +691,17 @@ impl LspClient {
     let mut builder = InitializeParamsBuilder::new();
     builder.set_root_uri(self.context.temp_dir().uri());
     do_build(&mut builder);
-    self.write_request("initialize", builder.build());
+    let params: InitializeParams = builder.build();
+    self.supports_workspace_configuration = match &params.capabilities.workspace
+    {
+      Some(workspace) => workspace.configuration == Some(true),
+      _ => false,
+    };
+    self.write_request("initialize", params);
     self.write_notification("initialized", json!({}));
-    self.handle_configuration_request(config);
+    if self.supports_workspace_configuration {
+      self.handle_configuration_request(config);
+    }
   }
 
   pub fn did_open(&mut self, params: Value) -> CollectedDiagnostics {
@@ -712,7 +722,9 @@ impl LspClient {
     config: Value,
   ) -> CollectedDiagnostics {
     self.did_open_raw(params);
-    self.handle_configuration_request(config);
+    if self.supports_workspace_configuration {
+      self.handle_configuration_request(config);
+    }
     self.read_diagnostics()
   }