Merge #3116

3116: vscode: added error handling to download file streams r=matklad a=Veetaha

As a followup for #3092 
`ts-nested-error` is mine, it is just [one file worth nothing](https://github.com/Veetaha/ts-nested-error/blob/master/src/nested-error.ts), but let's us inspect original errors


Co-authored-by: Veetaha <[email protected]>

Author: bors[bot]

editors/code/src/installation/download_file.ts

@@ -1,7 +1,11 @@
 import fetch from "node-fetch";
 import * as fs from "fs";
+import * as stream from "stream";
+import * as util from "util";
 import { strict as assert } from "assert";
 
+const pipeline = util.promisify(stream.pipeline);
+
 /**
  * Downloads file from `url` and stores it at `destFilePath` with `destFilePermissions`.
  * `onProgress` callback is called on recieveing each chunk of bytes
@@ -20,25 +24,28 @@ export async function downloadFile(
         console.log("Error", res.status, "while downloading file from", url);
         console.dir({ body: await res.text(), headers: res.headers }, { depth: 3 });
 
-        throw new Error(`Got response ${res.status} when trying to download a file`);
+        throw new Error(`Got response ${res.status} when trying to download a file.`);
     }
 
     const totalBytes = Number(res.headers.get('content-length'));
     assert(!Number.isNaN(totalBytes), "Sanity check of content-length protocol");
 
+    console.log("Downloading file of", totalBytes, "bytes size from", url, "to", destFilePath);
+
     let readBytes = 0;
+    res.body.on("data", (chunk: Buffer) => {
+        readBytes += chunk.length;
+        onProgress(readBytes, totalBytes);
+    });
 
-    console.log("Downloading file of", totalBytes, "bytes size from", url, "to", destFilePath);
+    const destFileStream = fs.createWriteStream(destFilePath, { mode: destFilePermissions });
+
+    await pipeline(res.body, destFileStream);
+    return new Promise<void>(resolve => {
+        destFileStream.on("close", resolve);
+        destFileStream.destroy();
 
-    return new Promise<void>((resolve, reject) => res.body
-        .on("data", (chunk: Buffer) => {
-            readBytes += chunk.length;
-            onProgress(readBytes, totalBytes);
-        })
-        .on("error", reject)
-        .pipe(fs
-            .createWriteStream(destFilePath, { mode: destFilePermissions })
-            .on("close", resolve)
-        )
-    );
+        // Details on workaround: https://github.com/rust-analyzer/rust-analyzer/pull/3092#discussion_r378191131
+        // Issue at nodejs repo: https://github.com/nodejs/node/issues/31776
+    });
 }

editors/code/src/installation/language_server.ts

@@ -104,6 +104,8 @@ export async function ensureLanguageServerBinary(
                     `GitHub repository: ${err.message}`
                 );
 
+                console.error(err);
+
                 dns.resolve('example.com').then(
                     addrs => console.log("DNS resolution for example.com was successful", addrs),
                     err => {