From f1acbc93efd8f834469b7f00c9e412d281a5a7a6 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Mon, 21 May 2018 12:19:48 -0700
Subject: [PATCH] Add noGetErrOnBackgroundUpdate session option to not queue
 diagnostics check for open files This will ensure that the getErr will be
 queued in by host and hence would make sure that it is cancellable. Handles
 one of the scenario delaying completions in #19458

---
 src/harness/unittests/tsserverProjectSystem.ts  | 17 ++++++++++++++---
 src/server/server.ts                            |  2 ++
 src/server/session.ts                           |  5 ++++-
 .../reference/api/tsserverlibrary.d.ts          |  2 ++
 4 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/src/harness/unittests/tsserverProjectSystem.ts b/src/harness/unittests/tsserverProjectSystem.ts
index 7a5f97b06d5ec..bda8f1d09a5f5 100644
--- a/src/harness/unittests/tsserverProjectSystem.ts
+++ b/src/harness/unittests/tsserverProjectSystem.ts
@@ -7445,10 +7445,17 @@ namespace ts.projectSystem {
         });
 
         describe("when event handler is not set but session is created with canUseEvents = true", () => {
-            verifyProjectsUpdatedInBackgroundEvent(createSessionThatUsesEvents);
+            describe("without noGetErrOnBackgroundUpdate, diagnostics for open files are queued", () => {
+                verifyProjectsUpdatedInBackgroundEvent(createSessionThatUsesEvents);
+            });
+
+            describe("with noGetErrOnBackgroundUpdate, diagnostics for open file are not queued", () => {
+                verifyProjectsUpdatedInBackgroundEvent(host => createSessionThatUsesEvents(host, /*noGetErrOnBackgroundUpdate*/ true));
+            });
 
-            function createSessionThatUsesEvents(host: TestServerHost): ProjectsUpdatedInBackgroundEventVerifier {
-                const session = createSession(host, { canUseEvents: true });
+
+            function createSessionThatUsesEvents(host: TestServerHost, noGetErrOnBackgroundUpdate?: boolean): ProjectsUpdatedInBackgroundEventVerifier {
+                const session = createSession(host, { canUseEvents: true, noGetErrOnBackgroundUpdate });
 
                 return {
                     session,
@@ -7480,6 +7487,10 @@ namespace ts.projectSystem {
 
                     // Verified the events, reset them
                     session.clearMessages();
+
+                    if (events.length) {
+                        host.checkTimeoutQueueLength(noGetErrOnBackgroundUpdate ? 0 : 1); // Error checking queued only if not noGetErrOnBackgroundUpdate
+                    }
                 }
             }
         });
diff --git a/src/server/server.ts b/src/server/server.ts
index 6eff32563497a..706a47a0aa5c5 100644
--- a/src/server/server.ts
+++ b/src/server/server.ts
@@ -505,6 +505,7 @@ namespace ts.server {
                 canUseEvents: true,
                 suppressDiagnosticEvents,
                 syntaxOnly,
+                noGetErrOnBackgroundUpdate,
                 globalPlugins,
                 pluginProbeLocations,
                 allowLocalPluginLoads,
@@ -939,6 +940,7 @@ namespace ts.server {
     const suppressDiagnosticEvents = hasArgument("--suppressDiagnosticEvents");
     const syntaxOnly = hasArgument("--syntaxOnly");
     const telemetryEnabled = hasArgument(Arguments.EnableTelemetry);
+    const noGetErrOnBackgroundUpdate = hasArgument("--noGetErrOnBackgroundUpdate");
 
     logger.info(`Starting TS Server`);
     logger.info(`Version: ${version}`);
diff --git a/src/server/session.ts b/src/server/session.ts
index 40f26785113cf..ccedad18aac89 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -295,6 +295,7 @@ namespace ts.server {
         suppressDiagnosticEvents?: boolean;
         syntaxOnly?: boolean;
         throttleWaitMilliseconds?: number;
+        noGetErrOnBackgroundUpdate?: boolean;
 
         globalPlugins?: ReadonlyArray<string>;
         pluginProbeLocations?: ReadonlyArray<string>;
@@ -319,6 +320,7 @@ namespace ts.server {
         protected canUseEvents: boolean;
         private suppressDiagnosticEvents?: boolean;
         private eventHandler: ProjectServiceEventHandler;
+        private readonly noGetErrOnBackgroundUpdate?: boolean;
 
         constructor(opts: SessionOptions) {
             this.host = opts.host;
@@ -329,6 +331,7 @@ namespace ts.server {
             this.logger = opts.logger;
             this.canUseEvents = opts.canUseEvents;
             this.suppressDiagnosticEvents = opts.suppressDiagnosticEvents;
+            this.noGetErrOnBackgroundUpdate = opts.noGetErrOnBackgroundUpdate;
 
             const { throttleWaitMilliseconds } = opts;
 
@@ -404,7 +407,7 @@ namespace ts.server {
         private projectsUpdatedInBackgroundEvent(openFiles: string[]): void {
             this.projectService.logger.info(`got projects updated in background, updating diagnostics for ${openFiles}`);
             if (openFiles.length) {
-                if (!this.suppressDiagnosticEvents) {
+                if (!this.suppressDiagnosticEvents && !this.noGetErrOnBackgroundUpdate) {
                     const checkList = this.createCheckList(openFiles);
 
                     // For now only queue error checking for open files. We can change this to include non open files as well
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index cbf39a2a48f5c..52568993f3e66 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -8391,6 +8391,7 @@ declare namespace ts.server {
         suppressDiagnosticEvents?: boolean;
         syntaxOnly?: boolean;
         throttleWaitMilliseconds?: number;
+        noGetErrOnBackgroundUpdate?: boolean;
         globalPlugins?: ReadonlyArray<string>;
         pluginProbeLocations?: ReadonlyArray<string>;
         allowLocalPluginLoads?: boolean;
@@ -8410,6 +8411,7 @@ declare namespace ts.server {
         protected canUseEvents: boolean;
         private suppressDiagnosticEvents?;
         private eventHandler;
+        private readonly noGetErrOnBackgroundUpdate?;
         constructor(opts: SessionOptions);
         private sendRequestCompletedEvent;
         private defaultEventHandler;