feat: REPL import specifier auto-completions (#13078)

cli/file_fetcher.rs

@@ -26,7 +26,6 @@ use deno_runtime::deno_tls::rustls::RootCertStore;
 use deno_runtime::deno_web::BlobStore;
 use deno_runtime::permissions::Permissions;
 use log::debug;
-use log::info;
 use std::borrow::Borrow;
 use std::collections::HashMap;
 use std::env;
@@ -254,6 +253,7 @@ pub struct FileFetcher {
   pub(crate) http_cache: HttpCache,
   http_client: reqwest::Client,
   blob_store: BlobStore,
+  download_log_level: log::Level,
 }
 
 impl FileFetcher {
@@ -280,9 +280,15 @@ impl FileFetcher {
         None,
       )?,
       blob_store,
+      download_log_level: log::Level::Info,
     })
   }
 
+  /// Sets the log level to use when outputting the download message.
+  pub fn set_download_log_level(&mut self, level: log::Level) {
+    self.download_log_level = level;
+  }
+
   /// Creates a `File` structure for a remote file.
   fn build_remote_file(
     &self,
@@ -512,7 +518,12 @@ impl FileFetcher {
       .boxed();
     }
 
-    info!("{} {}", colors::green("Download"), specifier);
+    log::log!(
+      self.download_log_level,
+      "{} {}",
+      colors::green("Download"),
+      specifier
+    );
 
     let maybe_etag = match self.http_cache.get(specifier) {
       Ok((_, headers, _)) => headers.get("etag").cloned(),

cli/logger.rs

@@ -1,13 +1,6 @@
 // Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
 
 use std::io::Write;
-use std::sync::atomic::AtomicBool;
-use std::sync::atomic::Ordering;
-use std::sync::Arc;
-
-lazy_static::lazy_static! {
-  pub static ref LSP_DEBUG_FLAG: Arc<AtomicBool> = Arc::new(AtomicBool::new(false));
-}
 
 struct CliLogger(env_logger::Logger);
 
@@ -23,14 +16,8 @@ impl CliLogger {
 
 impl log::Log for CliLogger {
   fn enabled(&self, metadata: &log::Metadata) -> bool {
-    if metadata.target() == "deno::lsp::performance"
-      && metadata.level() == log::Level::Debug
-    {
-      LSP_DEBUG_FLAG.load(Ordering::Relaxed)
-    } else {
     self.0.enabled(metadata)
   }
-  }
 
   fn log(&self, record: &log::Record) {
     if self.enabled(record.metadata()) {

cli/lsp/client.rs

@@ -0,0 +1,228 @@
+use std::future::Future;
+use std::pin::Pin;
+use std::sync::Arc;
+
+use deno_core::anyhow::anyhow;
+use deno_core::error::AnyError;
+use deno_core::futures::future;
+use deno_core::serde_json;
+use deno_core::serde_json::json;
+use lspower::lsp;
+
+use crate::lsp::config::SETTINGS_SECTION;
+use crate::lsp::repl::get_repl_workspace_settings;
+
+use super::lsp_custom;
+
+#[derive(Clone)]
+pub struct Client(Arc<dyn ClientTrait>);
+
+impl std::fmt::Debug for Client {
+  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    f.debug_tuple("Client").finish()
+  }
+}
+
+impl Client {
+  pub fn from_lspower(client: lspower::Client) -> Self {
+    Self(Arc::new(LspowerClient(client)))
+  }
+
+  pub fn new_for_repl() -> Self {
+    Self(Arc::new(ReplClient))
+  }
+
+  pub async fn publish_diagnostics(
+    &self,
+    uri: lsp::Url,
+    diags: Vec<lsp::Diagnostic>,
+    version: Option<i32>,
+  ) {
+    self.0.publish_diagnostics(uri, diags, version).await;
+  }
+
+  pub async fn send_registry_state_notification(
+    &self,
+    params: lsp_custom::RegistryStateNotificationParams,
+  ) {
+    self.0.send_registry_state_notification(params).await;
+  }
+
+  pub async fn configuration(
+    &self,
+    items: Vec<lsp::ConfigurationItem>,
+  ) -> Result<Vec<serde_json::Value>, AnyError> {
+    self.0.configuration(items).await
+  }
+
+  pub async fn show_message(
+    &self,
+    message_type: lsp::MessageType,
+    message: impl std::fmt::Display,
+  ) {
+    self
+      .0
+      .show_message(message_type, format!("{}", message))
+      .await
+  }
+
+  pub async fn register_capability(
+    &self,
+    registrations: Vec<lsp::Registration>,
+  ) -> Result<(), AnyError> {
+    self.0.register_capability(registrations).await
+  }
+}
+
+type AsyncReturn<T> = Pin<Box<dyn Future<Output = T> + 'static + Send>>;
+
+trait ClientTrait: Send + Sync {
+  fn publish_diagnostics(
+    &self,
+    uri: lsp::Url,
+    diagnostics: Vec<lsp::Diagnostic>,
+    version: Option<i32>,
+  ) -> AsyncReturn<()>;
+  fn send_registry_state_notification(
+    &self,
+    params: lsp_custom::RegistryStateNotificationParams,
+  ) -> AsyncReturn<()>;
+  fn configuration(
+    &self,
+    items: Vec<lsp::ConfigurationItem>,
+  ) -> AsyncReturn<Result<Vec<serde_json::Value>, AnyError>>;
+  fn show_message(
+    &self,
+    message_type: lsp::MessageType,
+    text: String,
+  ) -> AsyncReturn<()>;
+  fn register_capability(
+    &self,
+    registrations: Vec<lsp::Registration>,
+  ) -> AsyncReturn<Result<(), AnyError>>;
+}
+
+#[derive(Clone)]
+struct LspowerClient(lspower::Client);
+
+impl ClientTrait for LspowerClient {
+  fn publish_diagnostics(
+    &self,
+    uri: lsp::Url,
+    diagnostics: Vec<lsp::Diagnostic>,
+    version: Option<i32>,
+  ) -> AsyncReturn<()> {
+    let client = self.0.clone();
+    Box::pin(async move {
+      client.publish_diagnostics(uri, diagnostics, version).await
+    })
+  }
+
+  fn send_registry_state_notification(
+    &self,
+    params: lsp_custom::RegistryStateNotificationParams,
+  ) -> AsyncReturn<()> {
+    let client = self.0.clone();
+    Box::pin(async move {
+      client
+        .send_custom_notification::<lsp_custom::RegistryStateNotification>(
+          params,
+        )
+        .await
+    })
+  }
+
+  fn configuration(
+    &self,
+    items: Vec<lsp::ConfigurationItem>,
+  ) -> AsyncReturn<Result<Vec<serde_json::Value>, AnyError>> {
+    let client = self.0.clone();
+    Box::pin(async move {
+      client
+        .configuration(items)
+        .await
+        .map_err(|err| anyhow!("{}", err))
+    })
+  }
+
+  fn show_message(
+    &self,
+    message_type: lsp::MessageType,
+    message: String,
+  ) -> AsyncReturn<()> {
+    let client = self.0.clone();
+    Box::pin(async move { client.show_message(message_type, message).await })
+  }
+
+  fn register_capability(
+    &self,
+    registrations: Vec<lsp::Registration>,
+  ) -> AsyncReturn<Result<(), AnyError>> {
+    let client = self.0.clone();
+    Box::pin(async move {
+      client
+        .register_capability(registrations)
+        .await
+        .map_err(|err| anyhow!("{}", err))
+    })
+  }
+}
+
+#[derive(Clone)]
+struct ReplClient;
+
+impl ClientTrait for ReplClient {
+  fn publish_diagnostics(
+    &self,
+    _uri: lsp::Url,
+    _diagnostics: Vec<lsp::Diagnostic>,
+    _version: Option<i32>,
+  ) -> AsyncReturn<()> {
+    Box::pin(future::ready(()))
+  }
+
+  fn send_registry_state_notification(
+    &self,
+    _params: lsp_custom::RegistryStateNotificationParams,
+  ) -> AsyncReturn<()> {
+    Box::pin(future::ready(()))
+  }
+
+  fn configuration(
+    &self,
+    items: Vec<lsp::ConfigurationItem>,
+  ) -> AsyncReturn<Result<Vec<serde_json::Value>, AnyError>> {
+    let is_global_config_request = items.len() == 1
+      && items[0].scope_uri.is_none()
+      && items[0].section.as_deref() == Some(SETTINGS_SECTION);
+    let response = if is_global_config_request {
+      vec![serde_json::to_value(get_repl_workspace_settings()).unwrap()]
+    } else {
+      // all specifiers are enabled for the REPL
+      items
+        .into_iter()
+        .map(|_| {
+          json!({
+            "enable": true,
+          })
+        })
+        .collect()
+    };
+    Box::pin(future::ready(Ok(response)))
+  }
+
+  fn show_message(
+    &self,
+    _message_type: lsp::MessageType,
+    _message: String,
+  ) -> AsyncReturn<()> {
+    Box::pin(future::ready(()))
+  }
+
+  fn register_capability(
+    &self,
+    _registrations: Vec<lsp::Registration>,
+  ) -> AsyncReturn<Result<(), AnyError>> {
+    Box::pin(future::ready(Ok(())))
+  }
+}

cli/lsp/completions.rs

@@ -1,5 +1,6 @@
 // Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
 
+use super::client::Client;
 use super::language_server;
 use super::lsp_custom;
 use super::tsc;
@@ -37,7 +38,7 @@ pub struct CompletionItemData {
 async fn check_auto_config_registry(
   url_str: &str,
   snapshot: &language_server::StateSnapshot,
-  client: lspower::Client,
+  client: Client,
 ) {
   // check to see if auto discovery is enabled
   if snapshot
@@ -82,7 +83,7 @@ async fn check_auto_config_registry(
           // TODO(@kitsonk) clean up protocol when doing v2 of suggestions
           if suggestions {
             client
-              .send_custom_notification::<lsp_custom::RegistryStateNotification>(
+              .send_registry_state_notification(
                 lsp_custom::RegistryStateNotificationParams {
                   origin,
                   suggestions,
@@ -133,7 +134,7 @@ pub(crate) async fn get_import_completions(
   specifier: &ModuleSpecifier,
   position: &lsp::Position,
   state_snapshot: &language_server::StateSnapshot,
-  client: lspower::Client,
+  client: Client,
 ) -> Option<lsp::CompletionResponse> {
   let document = state_snapshot.documents.get(specifier)?;
   let (text, _, range) = document.get_maybe_dependency(position)?;

cli/lsp/config.rs

@@ -19,6 +19,8 @@ use std::sync::Arc;
 use std::thread;
 use tokio::sync::mpsc;
 
+use super::client::Client;
+
 pub const SETTINGS_SECTION: &str = "deno";
 
 #[derive(Debug, Clone, Default)]
@@ -229,7 +231,7 @@ pub struct Config {
 }
 
 impl Config {
-  pub fn new(client: lspower::Client) -> Self {
+  pub fn new(client: Client) -> Self {
     let (tx, mut rx) = mpsc::channel::<ConfigRequest>(100);
     let settings = Arc::new(RwLock::new(Settings::default()));
     let settings_ref = settings.clone();
@@ -284,16 +286,16 @@ impl Config {
               if settings_ref.read().specifiers.contains_key(&specifier) {
                 continue;
               }
-              if let Ok(value) = client
+              match client
                 .configuration(vec![lsp::ConfigurationItem {
                   scope_uri: Some(uri.clone()),
                   section: Some(SETTINGS_SECTION.to_string()),
                 }])
                 .await
               {
-                match serde_json::from_value::<SpecifierSettings>(
+                Ok(values) => {
-                  value[0].clone(),
+                  if let Some(value) = values.first() {
-                ) {
+                    match serde_json::from_value::<SpecifierSettings>(value.clone()) {
                       Ok(specifier_settings) => {
                         settings_ref
                           .write()
@@ -301,18 +303,24 @@ impl Config {
                           .insert(specifier, (uri, specifier_settings));
                       }
                       Err(err) => {
-                    error!("Error converting specifier settings: {}", err);
+                        error!("Error converting specifier settings ({}): {}", specifier, err);
                       }
                     }
                   } else {
+                    error!("Expected the client to return a configuration item for specifier: {}", specifier);
+                  }
+                },
+                Err(err) => {
                   error!(
-                  "Error retrieving settings for specifier: {}",
+                    "Error retrieving settings for specifier ({}): {}",
-                  specifier
+                    specifier,
+                    err,
                   );
                 }
               }
             }
           }
+        }
       })
     });
 
@@ -453,9 +461,9 @@ mod tests {
   }
 
   fn setup() -> Config {
-    let mut maybe_client: Option<lspower::Client> = None;
+    let mut maybe_client: Option<Client> = None;
     let (_service, _) = lspower::LspService::new(|client| {
-      maybe_client = Some(client);
+      maybe_client = Some(Client::from_lspower(client));
       MockLanguageServer::default()
     });
     Config::new(maybe_client.unwrap())

cli/lsp/diagnostics.rs

@@ -1,6 +1,7 @@
 // Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
 
 use super::analysis;
+use super::client::Client;
 use super::documents;
 use super::documents::Documents;
 use super::language_server;
@@ -125,7 +126,7 @@ impl DiagnosticsServer {
   pub(crate) fn start(
     &mut self,
     language_server: Arc<Mutex<language_server::Inner>>,
-    client: lspower::Client,
+    client: Client,
     ts_server: Arc<tsc::TsServer>,
   ) {
     let (tx, mut rx) = mpsc::unbounded_channel::<()>();
@@ -530,7 +531,7 @@ async fn generate_deps_diagnostics(
 
 /// Publishes diagnostics to the client.
 async fn publish_diagnostics(
-  client: &lspower::Client,
+  client: &Client,
   collection: &mut DiagnosticCollection,
   snapshot: &language_server::StateSnapshot,
 ) {
@@ -569,7 +570,7 @@ async fn publish_diagnostics(
 /// Updates diagnostics for any specifiers that don't have the correct version
 /// generated and publishes the diagnostics to the client.
 async fn update_diagnostics(
-  client: &lspower::Client,
+  client: &Client,
   collection: Arc<Mutex<DiagnosticCollection>>,
   snapshot: Arc<language_server::StateSnapshot>,
   ts_server: &tsc::TsServer,

cli/lsp/language_server.rs

@@ -16,7 +16,6 @@ use lspower::jsonrpc::Error as LspError;
 use lspower::jsonrpc::Result as LspResult;
 use lspower::lsp::request::*;
 use lspower::lsp::*;
-use lspower::Client;
 use serde_json::from_value;
 use std::env;
 use std::path::PathBuf;
@@ -30,6 +29,7 @@ use super::analysis::CodeActionCollection;
 use super::analysis::CodeActionData;
 use super::cache::CacheServer;
 use super::capabilities;
+use super::client::Client;
 use super::code_lens;
 use super::completions;
 use super::config::Config;
@@ -61,6 +61,7 @@ use crate::deno_dir;
 use crate::file_fetcher::get_source_from_data_url;
 use crate::fs_util;
 use crate::logger;
+use crate::lsp::logging::lsp_log;
 use crate::tools::fmt::format_file;
 use crate::tools::fmt::format_parsed_source;
 
@@ -299,7 +300,7 @@ impl Inner {
     let maybe_config = workspace_settings.config;
     if let Some(config_str) = &maybe_config {
       if !config_str.is_empty() {
-        info!("Setting TypeScript configuration from: \"{}\"", config_str);
+        lsp_log!("Setting TypeScript configuration from: \"{}\"", config_str);
         let config_url = if let Ok(url) = Url::from_file_path(config_str) {
           Ok(url)
         } else if let Some(root_uri) = maybe_root_uri {
@@ -312,7 +313,7 @@ impl Inner {
             config_str
           ))
         }?;
-        info!("  Resolved configuration file: \"{}\"", config_url);
+        lsp_log!("  Resolved configuration file: \"{}\"", config_url);
 
         let config_file = ConfigFile::from_specifier(&config_url)?;
         return Ok(Some((config_file, config_url)));
@@ -393,7 +394,7 @@ impl Inner {
       )
     };
     let maybe_cache_path = if let Some(cache_str) = &maybe_cache {
-      info!("Setting cache path from: \"{}\"", cache_str);
+      lsp_log!("Setting cache path from: \"{}\"", cache_str);
       let cache_url = if let Ok(url) = Url::from_file_path(cache_str) {
         Ok(url)
       } else if let Some(root_uri) = &maybe_root_uri {
@@ -409,7 +410,7 @@ impl Inner {
         ))
       }?;
       let cache_path = fs_util::specifier_to_file_path(&cache_url)?;
-      info!(
+      lsp_log!(
         "  Resolved cache path: \"{}\"",
         cache_path.to_string_lossy()
       );
@@ -444,7 +445,7 @@ impl Inner {
       )
     };
     if let Some(import_map_str) = &maybe_import_map {
-      info!("Setting import map from: \"{}\"", import_map_str);
+      lsp_log!("Setting import map from: \"{}\"", import_map_str);
       let import_map_url = if let Ok(url) = Url::from_file_path(import_map_str)
       {
         Ok(url)
@@ -469,7 +470,7 @@ impl Inner {
         get_source_from_data_url(&import_map_url)?.0
       } else {
         let import_map_path = fs_util::specifier_to_file_path(&import_map_url)?;
-        info!(
+        lsp_log!(
           "  Resolved import map: \"{}\"",
           import_map_path.to_string_lossy()
         );
@@ -494,16 +495,9 @@ impl Inner {
     Ok(())
   }
 
-  pub fn update_debug_flag(&self) -> bool {
+  pub fn update_debug_flag(&self) {
     let internal_debug = self.config.get_workspace_settings().internal_debug;
-    logger::LSP_DEBUG_FLAG
+    super::logging::set_lsp_debug_flag(internal_debug)
-      .compare_exchange(
-        !internal_debug,
-        internal_debug,
-        Ordering::Acquire,
-        Ordering::Relaxed,
-      )
-      .is_ok()
   }
 
   async fn update_registries(&mut self) -> Result<(), AnyError> {
@@ -517,7 +511,7 @@ impl Inner {
       .iter()
     {
       if *enabled {
-        info!("Enabling import suggestions for: {}", registry);
+        lsp_log!("Enabling import suggestions for: {}", registry);
         self.module_registries.enable(registry).await?;
       } else {
         self.module_registries.disable(registry).await?;
@@ -621,7 +615,7 @@ impl Inner {
     &mut self,
     params: InitializeParams,
   ) -> LspResult<InitializeResult> {
-    info!("Starting Deno language server...");
+    lsp_log!("Starting Deno language server...");
     let mark = self.performance.mark("initialize", Some(&params));
 
     // exit this process when the parent is lost
@@ -637,9 +631,9 @@ impl Inner {
       env!("PROFILE"),
       env!("TARGET")
     );
-    info!("  version: {}", version);
+    lsp_log!("  version: {}", version);
     if let Ok(path) = std::env::current_exe() {
-      info!("  executable: {}", path.to_string_lossy());
+      lsp_log!("  executable: {}", path.to_string_lossy());
     }
 
     let server_info = ServerInfo {
@@ -648,7 +642,7 @@ impl Inner {
     };
 
     if let Some(client_info) = params.client_info {
-      info!(
+      lsp_log!(
         "Connected to \"{}\" {}",
         client_info.name,
         client_info.version.unwrap_or_default(),
@@ -746,7 +740,7 @@ impl Inner {
       }
     }
 
-    info!("Server ready.");
+    lsp_log!("Server ready.");
   }
 
   async fn shutdown(&self) -> LspResult<()> {

cli/lsp/logging.rs

@@ -0,0 +1,49 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+use std::sync::atomic::AtomicBool;
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering;
+
+static LSP_DEBUG_FLAG: AtomicBool = AtomicBool::new(false);
+static LSP_LOG_LEVEL: AtomicUsize = AtomicUsize::new(log::Level::Info as usize);
+
+pub fn set_lsp_debug_flag(value: bool) {
+  LSP_DEBUG_FLAG.store(value, Ordering::SeqCst)
+}
+
+pub fn lsp_debug_enabled() -> bool {
+  LSP_DEBUG_FLAG.load(Ordering::SeqCst)
+}
+
+pub fn set_lsp_log_level(level: log::Level) {
+  LSP_LOG_LEVEL.store(level as usize, Ordering::SeqCst)
+}
+
+pub fn lsp_log_level() -> log::Level {
+  let level = LSP_LOG_LEVEL.load(Ordering::SeqCst);
+  unsafe { std::mem::transmute(level) }
+}
+
+/// Use this macro to do "info" logs in the lsp code. This allows
+/// for downgrading these logs to another log level in the REPL.
+macro_rules! lsp_log {
+  ($($arg:tt)+) => (
+    let lsp_log_level = crate::lsp::logging::lsp_log_level();
+    if lsp_log_level == log::Level::Debug {
+      crate::lsp::logging::lsp_debug!($($arg)+)
+    } else {
+      log::log!(lsp_log_level, $($arg)+)
+    }
+  )
+}
+
+macro_rules! lsp_debug {
+  ($($arg:tt)+) => (
+    if crate::lsp::logging::lsp_debug_enabled() {
+      log::debug!($($arg)+)
+    }
+  )
+}
+
+pub(super) use lsp_debug;
+pub(super) use lsp_log;

cli/lsp/mod.rs

@@ -7,21 +7,27 @@ use deno_core::error::AnyError;
 use lspower::LspService;
 use lspower::Server;
 
+pub use repl::ReplCompletionItem;
+pub use repl::ReplLanguageServer;
+
 mod analysis;
 mod cache;
 mod capabilities;
+mod client;
 mod code_lens;
 mod completions;
 mod config;
 mod diagnostics;
 mod documents;
 pub(crate) mod language_server;
+mod logging;
 mod lsp_custom;
 mod parent_process_checker;
 mod path_to_regex;
 mod performance;
 mod refactor;
 mod registries;
+mod repl;
 mod semantic_tokens;
 mod text;
 mod tsc;
@@ -31,8 +37,9 @@ pub async fn start() -> Result<(), AnyError> {
   let stdin = tokio::io::stdin();
   let stdout = tokio::io::stdout();
 
-  let (service, messages) =
+  let (service, messages) = LspService::new(|client| {
-    LspService::new(language_server::LanguageServer::new);
+    language_server::LanguageServer::new(client::Client::from_lspower(client))
+  });
   Server::new(stdin, stdout)
     .interleave(messages)
     .serve(service)

cli/lsp/performance.rs

@@ -4,7 +4,6 @@ use deno_core::parking_lot::Mutex;
 use deno_core::serde::Deserialize;
 use deno_core::serde::Serialize;
 use deno_core::serde_json::json;
-use log::debug;
 use std::cmp;
 use std::collections::HashMap;
 use std::collections::VecDeque;
@@ -13,6 +12,8 @@ use std::sync::Arc;
 use std::time::Duration;
 use std::time::Instant;
 
+use super::logging::lsp_debug;
+
 #[derive(Debug, Deserialize, Serialize, PartialEq, Eq)]
 #[serde(rename_all = "camelCase")]
 pub struct PerformanceAverage {
@@ -156,7 +157,7 @@ impl Performance {
         "name": name,
       })
     };
-    debug!("{},", msg);
+    lsp_debug!("{},", msg);
     PerformanceMark {
       name: name.to_string(),
       count: *count,
@@ -169,7 +170,7 @@ impl Performance {
   /// measurement to the internal buffer.
   pub fn measure(&self, mark: PerformanceMark) -> Duration {
     let measure = PerformanceMeasure::from(mark);
-    debug!(
+    lsp_debug!(
       "{},",
       json!({
         "type": "measure",

cli/lsp/registries.rs

@@ -395,29 +395,14 @@ impl Default for ModuleRegistry {
     // custom root.
     let dir = deno_dir::DenoDir::new(None).unwrap();
     let location = dir.root.join("registries");
-    let http_cache = HttpCache::new(&location);
+    Self::new(&location)
-    let cache_setting = CacheSetting::RespectHeaders;
-    let file_fetcher = FileFetcher::new(
-      http_cache,
-      cache_setting,
-      true,
-      None,
-      BlobStore::default(),
-      None,
-    )
-    .unwrap();
-
-    Self {
-      origins: HashMap::new(),
-      file_fetcher,
-    }
   }
 }
 
 impl ModuleRegistry {
   pub fn new(location: &Path) -> Self {
     let http_cache = HttpCache::new(location);
-    let file_fetcher = FileFetcher::new(
+    let mut file_fetcher = FileFetcher::new(
       http_cache,
       CacheSetting::RespectHeaders,
       true,
@@ -427,6 +412,7 @@ impl ModuleRegistry {
     )
     .context("Error creating file fetcher in module registry.")
     .unwrap();
+    file_fetcher.set_download_log_level(super::logging::lsp_log_level());
 
     Self {
       origins: HashMap::new(),

cli/lsp/repl.rs

@@ -0,0 +1,297 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+use std::collections::HashMap;
+use std::future::Future;
+
+use deno_ast::swc::common::BytePos;
+use deno_ast::swc::common::Span;
+use deno_ast::LineAndColumnIndex;
+use deno_ast::ModuleSpecifier;
+use deno_ast::SourceTextInfo;
+use deno_core::anyhow::anyhow;
+use deno_core::error::AnyError;
+use deno_core::serde_json;
+use lspower::lsp::ClientCapabilities;
+use lspower::lsp::ClientInfo;
+use lspower::lsp::CompletionContext;
+use lspower::lsp::CompletionParams;
+use lspower::lsp::CompletionResponse;
+use lspower::lsp::CompletionTextEdit;
+use lspower::lsp::CompletionTriggerKind;
+use lspower::lsp::DidChangeTextDocumentParams;
+use lspower::lsp::DidCloseTextDocumentParams;
+use lspower::lsp::DidOpenTextDocumentParams;
+use lspower::lsp::InitializeParams;
+use lspower::lsp::InitializedParams;
+use lspower::lsp::PartialResultParams;
+use lspower::lsp::Position;
+use lspower::lsp::Range;
+use lspower::lsp::TextDocumentContentChangeEvent;
+use lspower::lsp::TextDocumentIdentifier;
+use lspower::lsp::TextDocumentItem;
+use lspower::lsp::TextDocumentPositionParams;
+use lspower::lsp::VersionedTextDocumentIdentifier;
+use lspower::lsp::WorkDoneProgressParams;
+use lspower::LanguageServer;
+
+use crate::logger;
+
+use super::client::Client;
+use super::config::CompletionSettings;
+use super::config::ImportCompletionSettings;
+use super::config::WorkspaceSettings;
+
+#[derive(Debug)]
+pub struct ReplCompletionItem {
+  pub new_text: String,
+  pub span: Span,
+}
+
+pub struct ReplLanguageServer {
+  language_server: super::language_server::LanguageServer,
+  document_version: i32,
+  document_text: String,
+  pending_text: String,
+  cwd_uri: ModuleSpecifier,
+}
+
+impl ReplLanguageServer {
+  pub async fn new_initialized() -> Result<ReplLanguageServer, AnyError> {
+    super::logging::set_lsp_log_level(log::Level::Debug);
+    let language_server =
+      super::language_server::LanguageServer::new(Client::new_for_repl());
+
+    let cwd_uri = get_cwd_uri()?;
+
+    #[allow(deprecated)]
+    language_server
+      .initialize(InitializeParams {
+        process_id: None,
+        root_path: None,
+        root_uri: Some(cwd_uri.clone()),
+        initialization_options: Some(
+          serde_json::to_value(get_repl_workspace_settings()).unwrap(),
+        ),
+        capabilities: ClientCapabilities {
+          workspace: None,
+          text_document: None,
+          window: None,
+          general: None,
+          experimental: None,
+        },
+        trace: None,
+        workspace_folders: None,
+        client_info: Some(ClientInfo {
+          name: "Deno REPL".to_string(),
+          version: None,
+        }),
+        locale: None,
+      })
+      .await?;
+
+    language_server.initialized(InitializedParams {}).await;
+
+    let server = ReplLanguageServer {
+      language_server,
+      document_version: 0,
+      document_text: String::new(),
+      pending_text: String::new(),
+      cwd_uri,
+    };
+    server.open_current_document().await;
+
+    Ok(server)
+  }
+
+  pub async fn commit_text(&mut self, line_text: &str) {
+    self.did_change(line_text).await;
+    self.document_text.push_str(&self.pending_text);
+    self.pending_text = String::new();
+  }
+
+  pub async fn completions(
+    &mut self,
+    line_text: &str,
+    position: usize,
+  ) -> Vec<ReplCompletionItem> {
+    self.did_change(line_text).await;
+    let before_line_len = BytePos(self.document_text.len() as u32);
+    let position = before_line_len + BytePos(position as u32);
+    let text_info = deno_ast::SourceTextInfo::from_string(format!(
+      "{}{}",
+      self.document_text, self.pending_text
+    ));
+    let line_and_column = text_info.line_and_column_index(position);
+    let response = self
+      .language_server
+      .completion(CompletionParams {
+        text_document_position: TextDocumentPositionParams {
+          text_document: TextDocumentIdentifier {
+            uri: self.get_document_specifier(),
+          },
+          position: Position {
+            line: line_and_column.line_index as u32,
+            character: line_and_column.column_index as u32,
+          },
+        },
+        work_done_progress_params: WorkDoneProgressParams {
+          work_done_token: None,
+        },
+        partial_result_params: PartialResultParams {
+          partial_result_token: None,
+        },
+        context: Some(CompletionContext {
+          trigger_kind: CompletionTriggerKind::INVOKED,
+          trigger_character: None,
+        }),
+      })
+      .await
+      .ok()
+      .unwrap_or_default();
+
+    let items = match response {
+      Some(CompletionResponse::Array(items)) => items,
+      Some(CompletionResponse::List(list)) => list.items,
+      None => Vec::new(),
+    };
+    items
+      .into_iter()
+      .filter_map(|item| {
+        item.text_edit.and_then(|edit| match edit {
+          CompletionTextEdit::Edit(edit) => Some(ReplCompletionItem {
+            new_text: edit.new_text,
+            span: lsp_range_to_span(&text_info, &edit.range),
+          }),
+          CompletionTextEdit::InsertAndReplace(_) => None,
+        })
+      })
+      .filter(|item| {
+        // filter the results to only exact matches
+        let text = &text_info.text_str()
+          [item.span.lo.0 as usize..item.span.hi.0 as usize];
+        item.new_text.starts_with(text)
+      })
+      .map(|mut item| {
+        // convert back to a line position
+        item.span = Span::new(
+          item.span.lo - before_line_len,
+          item.span.hi - before_line_len,
+          Default::default(),
+        );
+        item
+      })
+      .collect()
+  }
+
+  async fn did_change(&mut self, new_text: &str) {
+    self.check_cwd_change().await;
+    let new_text = if new_text.ends_with('\n') {
+      new_text.to_string()
+    } else {
+      format!("{}\n", new_text)
+    };
+    self.document_version += 1;
+    let current_line_count =
+      self.document_text.chars().filter(|c| *c == '\n').count() as u32;
+    let pending_line_count =
+      self.pending_text.chars().filter(|c| *c == '\n').count() as u32;
+    self
+      .language_server
+      .did_change(DidChangeTextDocumentParams {
+        text_document: VersionedTextDocumentIdentifier {
+          uri: self.get_document_specifier(),
+          version: self.document_version,
+        },
+        content_changes: vec![TextDocumentContentChangeEvent {
+          range: Some(Range {
+            start: Position::new(current_line_count, 0),
+            end: Position::new(current_line_count + pending_line_count, 0),
+          }),
+          range_length: None,
+          text: new_text.to_string(),
+        }],
+      })
+      .await;
+    self.pending_text = new_text;
+  }
+
+  async fn check_cwd_change(&mut self) {
+    // handle if the cwd changes, if the cwd is deleted in the case of
+    // get_cwd_uri() erroring, then keep using it as the base
+    let cwd_uri = get_cwd_uri().unwrap_or_else(|_| self.cwd_uri.clone());
+    if self.cwd_uri != cwd_uri {
+      self
+        .language_server
+        .did_close(DidCloseTextDocumentParams {
+          text_document: TextDocumentIdentifier {
+            uri: self.get_document_specifier(),
+          },
+        })
+        .await;
+      self.cwd_uri = cwd_uri;
+      self.document_version = 0;
+      self.open_current_document().await;
+    }
+  }
+
+  async fn open_current_document(&self) {
+    self
+      .language_server
+      .did_open(DidOpenTextDocumentParams {
+        text_document: TextDocumentItem {
+          uri: self.get_document_specifier(),
+          language_id: "typescript".to_string(),
+          version: self.document_version,
+          text: format!("{}{}", self.document_text, self.pending_text),
+        },
+      })
+      .await;
+  }
+
+  fn get_document_specifier(&self) -> ModuleSpecifier {
+    self.cwd_uri.join("$deno$repl.ts").unwrap()
+  }
+}
+
+fn lsp_range_to_span(text_info: &SourceTextInfo, range: &Range) -> Span {
+  Span::new(
+    text_info.byte_index(LineAndColumnIndex {
+      line_index: range.start.line as usize,
+      column_index: range.start.character as usize,
+    }),
+    text_info.byte_index(LineAndColumnIndex {
+      line_index: range.end.line as usize,
+      column_index: range.end.character as usize,
+    }),
+    Default::default(),
+  )
+}
+
+fn get_cwd_uri() -> Result<ModuleSpecifier, AnyError> {
+  let cwd = std::env::current_dir()?;
+  ModuleSpecifier::from_directory_path(&cwd)
+    .map_err(|_| anyhow!("Could not get URI from {}", cwd.display()))
+}
+
+pub fn get_repl_workspace_settings() -> WorkspaceSettings {
+  WorkspaceSettings {
+    enable: true,
+    config: None,
+    cache: None,
+    import_map: None,
+    code_lens: Default::default(),
+    internal_debug: false,
+    lint: false,
+    unstable: false,
+    suggest: CompletionSettings {
+      complete_function_calls: false,
+      names: false,
+      paths: false,
+      auto_imports: false,
+      imports: ImportCompletionSettings {
+        auto_discover: false,
+        hosts: HashMap::from([("https://deno.land".to_string(), true)]),
+      },
+    },
+  }
+}

cli/tests/integration/repl_tests.rs

@@ -122,6 +122,44 @@ fn pty_complete_primitives() {
   });
 }
 
+#[test]
+fn pty_complete_imports() {
+  util::with_pty(&["repl"], |mut console| {
+    // single quotes
+    console.write_line("import './001_hel\t'");
+    // double quotes
+    console.write_line("import { output } from \"./045_out\t\"");
+    console.write_line("output('testing output');");
+    console.write_line("close();");
+
+    let output = console.read_all_output();
+    assert!(output.contains("Hello World"));
+    assert!(output.contains("\ntesting output"));
+  });
+
+  // ensure when the directory changes that the suggestions come from the cwd
+  util::with_pty(&["repl"], |mut console| {
+    console.write_line("Deno.chdir('./subdir');");
+    console.write_line("import '../001_hel\t'");
+    console.write_line("close();");
+
+    let output = console.read_all_output();
+    assert!(output.contains("Hello World"));
+  });
+
+  // ensure nothing too bad happens when deleting the cwd
+  util::with_pty(&["repl"], |mut console| {
+    console.write_line("Deno.mkdirSync('./temp-repl-lsp-dir');");
+    console.write_line("Deno.chdir('./temp-repl-lsp-dir');");
+    console.write_line("Deno.removeSync('../temp-repl-lsp-dir');");
+    console.write_line("import '../001_hello\t'");
+    console.write_line("close();");
+
+    let output = console.read_all_output();
+    assert!(output.contains("Hello World"));
+  });
+}
+
 #[test]
 fn pty_ignore_symbols() {
   util::with_pty(&["repl"], |mut console| {

cli/tools/repl/channel.rs

@@ -11,6 +11,8 @@ use tokio::sync::mpsc::Sender;
 use tokio::sync::mpsc::UnboundedReceiver;
 use tokio::sync::mpsc::UnboundedSender;
 
+use crate::lsp::ReplCompletionItem;
+
 /// Rustyline uses synchronous methods in its interfaces, but we need to call
 /// async methods. To get around this, we communicate with async code by using
 /// a channel and blocking on the result.
@@ -31,8 +33,21 @@ pub fn rustyline_channel(
   )
 }
 
-pub type RustylineSyncMessage = (String, Option<Value>);
+pub enum RustylineSyncMessage {
-pub type RustylineSyncResponse = Result<Value, AnyError>;
+  PostMessage {
+    method: String,
+    params: Option<Value>,
+  },
+  LspCompletions {
+    line_text: String,
+    position: usize,
+  },
+}
+
+pub enum RustylineSyncResponse {
+  PostMessage(Result<Value, AnyError>),
+  LspCompletions(Vec<ReplCompletionItem>),
+}
 
 pub struct RustylineSyncMessageSender {
   message_tx: Sender<RustylineSyncMessage>,
@@ -46,11 +61,41 @@ impl RustylineSyncMessageSender {
     params: Option<Value>,
   ) -> Result<Value, AnyError> {
     if let Err(err) =
-      self.message_tx.blocking_send((method.to_string(), params))
+      self
+        .message_tx
+        .blocking_send(RustylineSyncMessage::PostMessage {
+          method: method.to_string(),
+          params,
+        })
     {
       Err(anyhow!("{}", err))
     } else {
-      self.response_rx.borrow_mut().blocking_recv().unwrap()
+      match self.response_rx.borrow_mut().blocking_recv().unwrap() {
+        RustylineSyncResponse::PostMessage(result) => result,
+        RustylineSyncResponse::LspCompletions(_) => unreachable!(),
+      }
+    }
+  }
+
+  pub fn lsp_completions(
+    &self,
+    line_text: &str,
+    position: usize,
+  ) -> Vec<ReplCompletionItem> {
+    if self
+      .message_tx
+      .blocking_send(RustylineSyncMessage::LspCompletions {
+        line_text: line_text.to_string(),
+        position,
+      })
+      .is_err()
+    {
+      Vec::new()
+    } else {
+      match self.response_rx.borrow_mut().blocking_recv().unwrap() {
+        RustylineSyncResponse::LspCompletions(result) => result,
+        RustylineSyncResponse::PostMessage(_) => unreachable!(),
+      }
     }
   }
 }

cli/tools/repl/mod.rs

@@ -4,7 +4,10 @@ use crate::ast::transpile;
 use crate::ast::Diagnostics;
 use crate::ast::ImportsNotUsedAsValues;
 use crate::colors;
+use crate::lsp::ReplLanguageServer;
 use crate::proc_state::ProcState;
+use crate::tools::repl::channel::RustylineSyncMessage;
+use crate::tools::repl::channel::RustylineSyncResponse;
 use deno_ast::swc::parser::error::SyntaxError;
 use deno_ast::swc::parser::token::Token;
 use deno_ast::swc::parser::token::Word;
@@ -181,6 +184,15 @@ impl Completer for EditorHelper {
     pos: usize,
     _ctx: &Context<'_>,
   ) -> Result<(usize, Vec<String>), ReadlineError> {
+    let lsp_completions = self.sync_sender.lsp_completions(line, pos);
+    if !lsp_completions.is_empty() {
+      // assumes all lsp completions have the same start position
+      return Ok((
+        lsp_completions[0].span.lo.0 as usize,
+        lsp_completions.into_iter().map(|c| c.new_text).collect(),
+      ));
+    }
+
     let expr = get_expr_from_line_at_pos(line, pos);
 
     // check if the expression is in the form `obj.prop`
@@ -428,14 +440,21 @@ impl std::fmt::Display for EvaluationOutput {
   }
 }
 
+struct TsEvaluateResponse {
+  ts_code: String,
+  value: Value,
+}
+
 struct ReplSession {
   worker: MainWorker,
   session: LocalInspectorSession,
   pub context_id: u64,
+  language_server: ReplLanguageServer,
 }
 
 impl ReplSession {
   pub async fn initialize(mut worker: MainWorker) -> Result<Self, AnyError> {
+    let language_server = ReplLanguageServer::new_initialized().await?;
     let mut session = worker.create_inspector_session().await;
 
     worker
@@ -467,6 +486,7 @@ impl ReplSession {
       worker,
       session,
       context_id,
+      language_server,
     };
 
     // inject prelude
@@ -520,13 +540,18 @@ impl ReplSession {
 
     match self.evaluate_line_with_object_wrapping(line).await {
       Ok(evaluate_response) => {
-        let evaluate_result = evaluate_response.get("result").unwrap();
+        let evaluate_result = evaluate_response.value.get("result").unwrap();
         let evaluate_exception_details =
-          evaluate_response.get("exceptionDetails");
+          evaluate_response.value.get("exceptionDetails");
 
         if evaluate_exception_details.is_some() {
           self.set_last_thrown_error(evaluate_result).await?;
         } else {
+          self
+            .language_server
+            .commit_text(&evaluate_response.ts_code)
+            .await;
+
           self.set_last_eval_result(evaluate_result).await?;
         }
 
@@ -561,7 +586,7 @@ impl ReplSession {
   async fn evaluate_line_with_object_wrapping(
     &mut self,
     line: &str,
-  ) -> Result<Value, AnyError> {
+  ) -> Result<TsEvaluateResponse, AnyError> {
     // Expressions like { "foo": "bar" } are interpreted as block expressions at the
     // statement level rather than an object literal so we interpret it as an expression statement
     // to match the behavior found in a typical prompt including browser developer tools.
@@ -582,6 +607,7 @@ impl ReplSession {
         || evaluate_response
           .as_ref()
           .unwrap()
+          .value
           .get("exceptionDetails")
           .is_some())
     {
@@ -658,7 +684,7 @@ impl ReplSession {
   async fn evaluate_ts_expression(
     &mut self,
     expression: &str,
-  ) -> Result<Value, AnyError> {
+  ) -> Result<TsEvaluateResponse, AnyError> {
     let parsed_module = deno_ast::parse_module(deno_ast::ParseParams {
       specifier: "repl.ts".to_string(),
       source: deno_ast::SourceTextInfo::from_string(expression.to_string()),
@@ -688,12 +714,17 @@ impl ReplSession {
     )?
     .0;
 
-    self
+    let value = self
       .evaluate_expression(&format!(
         "'use strict'; void 0;\n{}",
         transpiled_src
       ))
-      .await
+      .await?;
+
+    Ok(TsEvaluateResponse {
+      ts_code: expression.to_string(),
+      value,
+    })
   }
 
   async fn evaluate_expression(
@@ -727,11 +758,24 @@ async fn read_line_and_poll(
         return result.unwrap();
       }
       result = message_handler.recv() => {
-        if let Some((method, params)) = result {
+        match result {
+          Some(RustylineSyncMessage::PostMessage {
+            method,
+            params
+          }) => {
             let result = repl_session
               .post_message_with_event_loop(&method, params)
               .await;
-          message_handler.send(result).unwrap();
+            message_handler.send(RustylineSyncResponse::PostMessage(result)).unwrap();
+          },
+          Some(RustylineSyncMessage::LspCompletions {
+            line_text,
+            position,
+          }) => {
+            let result = repl_session.language_server.completions(&line_text, position).await;
+            message_handler.send(RustylineSyncResponse::LspCompletions(result)).unwrap();
+          }
+          None => {}, // channel closed
         }
 
         poll_worker = true;