Fix cannot set property of undefined when no busySignalService

Author: alexheretic

lib/rls-project.js

@@ -23,14 +23,17 @@ class RlsProject {
     // ie a `didChangeConfiguration` during a build, so we consider Rls
     // to be building as long as we're waiting for _any_ build.
     server.connection.onCustom('rustDocument/beginBuild', () => {
-      if (!this._busyMessage) {
+      if (this._busyMessage) {
+        this._busyMessage.count += 1
+      }
+      else {
         let busySignal = this.getBusySignalService()
-        this._busyMessage = busySignal &&
-          busySignal.reportBusy(`RLS building ${path.basename(this.server.projectPath)}`)
-        this._busyMessage.count = 0
+        if (busySignal) {
+          this._busyMessage = busySignal
+            .reportBusy(`RLS building ${path.basename(this.server.projectPath)}`)
+          this._busyMessage.count = 1
+        }
       }
-
-      this._busyMessage.count += 1
     })
     server.connection.onCustom('rustDocument/diagnosticsEnd', () => {
       if (this._busyMessage && this._busyMessage.count > 0) {