Log suspicious stdout

Author: alexheretic

.eslintrc.js

@@ -11,7 +11,7 @@ module.exports = {
   rules: {
     semi: ["warn", "never"],
     "no-unused-vars": "warn",
-    "no-console": ["warn", { allow: ["info", "warn", "error"] }],
+    "no-console": ["warn", { allow: ["debug", "info", "warn", "error"] }],
     "valid-jsdoc": ["warn", {
       requireParamDescription: false,
       requireReturn: false,

lib/index.js

@@ -173,6 +173,22 @@ async function installRlsComponents(toolchain) {
   }
 }
 
+/**
+ * Adds a listener on stdout to warn of non-LSP looking lines (potentially from wayward
+ * server-side printing). Non-LSP stdout usage will break vscode-jsonrpc.
+ * @param {ChildProcess} process Rls
+ * @return {ChildProcess}
+ */
+function logSuspiciousStdout(process) {
+  process.stdout.on('data', chunk => {
+    chunk.toString('utf8')
+      .split('\n')
+      .filter(l => l.trim() && !l.startsWith("Content-Length:") && !l.includes('"jsonrpc":"2.0"'))
+      .forEach(line => console.error("Rust (RLS) suspicious stdout:", line))
+  })
+  return process
+}
+
 // ongoing promise
 let _checkingRls
 
@@ -555,21 +571,21 @@ class RustLanguageClient extends AutoLanguageClient {
         atom.notifications.addInfo(`Using rls command \`${cmdOverride}\``)
         this._warnedAboutRlsCommandOverride = true
       }
-      return cp.spawn(cmdOverride, {
+      return logSuspiciousStdout(cp.spawn(cmdOverride, {
         env: await serverEnv(configToolchain()),
         shell: true,
         cwd: projectPath
-      })
+      }))
     }
 
     try {
       await this._checkToolchain()
       await checkRls(this.busySignalService)
       let toolchain = configToolchain()
-      return cp.spawn("rustup", ["run", toolchain, "rls"], {
+      return logSuspiciousStdout(cp.spawn("rustup", ["run", toolchain, "rls"], {
         env: await serverEnv(toolchain),
         cwd: projectPath
-      })
+      }))
     }
     catch (e) {
       throw new Error("failed to start server: " + e)