Enable eslint rule ensuring rejected promises throw an error

Author: dibarbet

.eslintrc.js

@@ -33,6 +33,7 @@ module.exports = {
         ],
         "@typescript-eslint/no-namespace": "off",
         "@typescript-eslint/promise-function-async": "error",
+        "prefer-promise-reject-errors": "error",
         "curly": "error",
         "prettier/prettier": [ "error", { "endOfLine": "auto" } ],
         "unicorn/filename-case": [

src/features/codeActionProvider.ts

@@ -78,7 +78,7 @@ export default class OmniSharpCodeActionProvider
                 };
             });
         } catch (error) {
-            return Promise.reject(`Problem invoking 'GetCodeActions' on OmniSharp server: ${error}`);
+            return Promise.reject(new Error(`Problem invoking 'GetCodeActions' on OmniSharp server: ${error}`));
         }
     }
 
@@ -107,7 +107,7 @@ export default class OmniSharpCodeActionProvider
                 return buildEditForResponse(response.Changes, this._languageMiddlewareFeature, token);
             }
         } catch (error) {
-            return Promise.reject(`Problem invoking 'RunCodeAction' on OmniSharp server: ${error}`);
+            return Promise.reject(new Error(`Problem invoking 'RunCodeAction' on OmniSharp server: ${error}`));
         }
 
         return undefined;

src/features/commands.ts

@@ -198,13 +198,13 @@ async function dotnetRestoreAllProjects(server: OmniSharpServer, eventStream: Ev
 
 async function getProjectDescriptors(server: OmniSharpServer): Promise<protocol.ProjectDescriptor[]> {
     if (!server.isRunning()) {
-        return Promise.reject('OmniSharp server is not running.');
+        return Promise.reject(new Error('OmniSharp server is not running.'));
     }
 
     const info = await serverUtils.requestWorkspaceInformation(server);
     const descriptors = protocol.getDotNetCoreProjectDescriptors(info);
     if (descriptors.length === 0) {
-        return Promise.reject('No .NET Core projects found');
+        return Promise.reject(new Error('No .NET Core projects found'));
     }
 
     return descriptors;

src/features/inlayHintProvider.ts

@@ -67,14 +67,14 @@ export default class OmniSharpInlayHintProvider extends AbstractProvider impleme
                 return mappedHint;
             });
         } catch (error) {
-            return Promise.reject(`Problem invoking 'GetInlayHints' on OmniSharpServer: ${error}`);
+            return Promise.reject(new Error(`Problem invoking 'GetInlayHints' on OmniSharpServer: ${error}`));
         }
     }
 
     async resolveInlayHint?(hint: vscode.InlayHint, token: vscode.CancellationToken): Promise<vscode.InlayHint> {
         const inlayHint = this._hintsMap.get(hint);
         if (inlayHint === undefined) {
-            return Promise.reject(`Outdated inlay hint was requested to be resolved, aborting.`);
+            return Promise.reject(new Error(`Outdated inlay hint was requested to be resolved, aborting.`));
         }
 
         const request: InlayHintResolveRequest = { Hint: inlayHint };
@@ -83,7 +83,7 @@ export default class OmniSharpInlayHintProvider extends AbstractProvider impleme
             const result = await serverUtils.resolveInlayHints(this._server, request, token);
             return this.toVSCodeHint(result);
         } catch (error) {
-            return Promise.reject(`Problem invoking 'ResolveInlayHints' on OmniSharpServer: ${error}`);
+            return Promise.reject(new Error(`Problem invoking 'ResolveInlayHints' on OmniSharpServer: ${error}`));
         }
     }
 

src/lsptoolshost/roslynLanguageServer.ts

@@ -572,8 +572,9 @@ export class RoslynLanguageServer {
             // Error information will be captured from the stdout/stderr streams above.
             childProcess.on('exit', (code) => {
                 if (code && code !== 0) {
-                    _channel.appendLine(`Language server process exited with ${code}`);
-                    reject();
+                    const message = `Language server process exited with ${code}`;
+                    _channel.appendLine(message);
+                    reject(new Error(message));
                 }
             });
         });

src/omnisharp/server.ts

@@ -741,7 +741,7 @@ export class OmniSharpServer {
 
     public async makeRequest<TResponse>(command: string, data?: any, token?: CancellationToken): Promise<TResponse> {
         if (this._state.status !== ServerState.Started) {
-            return Promise.reject<TResponse>('OmniSharp server is not running.');
+            return Promise.reject<TResponse>(new Error('OmniSharp server is not running.'));
         }
 
         const { engine } = this._state;