Add error hierarchy and print stacktraces

Author: fendor

src/errors.ts

@@ -0,0 +1,57 @@
+import { Uri } from 'vscode';
+
+// tslint:disable max-classes-per-file
+export class HlsError extends Error {}
+
+export class MissingToolError extends HlsError {
+  public readonly tool: string;
+  constructor(tool: string) {
+    let prettyTool: string;
+    switch (tool.toLowerCase()) {
+      case 'stack':
+        prettyTool = 'Stack';
+        break;
+      case 'cabal':
+        prettyTool = 'Cabal';
+        break;
+      case 'ghc':
+        prettyTool = 'GHC';
+        break;
+      case 'ghcup':
+        prettyTool = 'GHCup';
+        break;
+      case 'haskell-language-server':
+        prettyTool = 'HLS';
+        break;
+      case 'hls':
+        prettyTool = 'HLS';
+        break;
+      default:
+        prettyTool = tool;
+        break;
+    }
+    super(`Project requires ${prettyTool} but it isn't installed`);
+    this.tool = prettyTool;
+  }
+
+  public installLink(): Uri | null {
+    switch (this.tool) {
+      case 'Stack':
+        return Uri.parse('https://docs.haskellstack.org/en/stable/install_and_upgrade/');
+      case 'GHCup':
+      case 'Cabal':
+      case 'HLS':
+      case 'GHC':
+        return Uri.parse('https://www.haskell.org/ghcup/');
+      default:
+        return null;
+    }
+  }
+}
+
+export class NoMatchingHls extends Error {
+  constructor(readonly ghcProjVersion: string) {
+    const noMatchingHLS = `No HLS version was found for supporting GHC ${ghcProjVersion}.`;
+    super(noMatchingHLS);
+  }
+}

src/extension.ts

@@ -23,7 +23,8 @@ import {
 import { CommandNames } from './commands/constants';
 import { ImportIdentifier } from './commands/importIdentifier';
 import { DocsBrowser } from './docsBrowser';
-import { findHaskellLanguageServer, IEnvVars, MissingToolError } from './hlsBinaries';
+import { HlsError, MissingToolError } from './errors';
+import { findHaskellLanguageServer, IEnvVars } from './hlsBinaries';
 import { addPathToProcessPath, expandHomeDir, ExtensionLogger } from './utils';
 
 // The current map of documents & folders to language servers.
@@ -172,8 +173,17 @@ async function activateServerForFolder(context: ExtensionContext, uri: Uri, fold
       } else {
         await window.showErrorMessage(e.message);
       }
+    } else if (e instanceof HlsError) {
+      logger.error(`General HlsError: ${e.message}`);
+      if (e.stack) {
+        logger.error(`${e.stack}`);
+      }
+      window.showErrorMessage(e.message);
     } else if (e instanceof Error) {
-      logger.error(`Error getting the server executable: ${e.message}`);
+      logger.error(`Internal Error: ${e.message}`);
+      if (e.stack) {
+        logger.error(`${e.stack}`);
+      }
       window.showErrorMessage(e.message);
     }
     return;

src/hlsBinaries.ts

@@ -7,16 +7,9 @@ import * as path from 'path';
 import { match } from 'ts-pattern';
 import * as url from 'url';
 import { promisify } from 'util';
-import {
-  ConfigurationTarget,
-  ExtensionContext,
-  ProgressLocation,
-  Uri,
-  window,
-  workspace,
-  WorkspaceFolder,
-} from 'vscode';
+import { ConfigurationTarget, ExtensionContext, ProgressLocation, window, workspace, WorkspaceFolder } from 'vscode';
 import { Logger } from 'vscode-languageclient';
+import { HlsError, MissingToolError, NoMatchingHls } from './errors';
 import {
   addPathToProcessPath,
   executableExists,
@@ -39,52 +32,6 @@ let manageHLS = workspace.getConfiguration('haskell').get('manageHLS') as Manage
 // On Windows the executable needs to be stored somewhere with an .exe extension
 const exeExt = process.platform === 'win32' ? '.exe' : '';
 
-export class MissingToolError extends Error {
-  public readonly tool: string;
-  constructor(tool: string) {
-    let prettyTool: string;
-    switch (tool.toLowerCase()) {
-      case 'stack':
-        prettyTool = 'Stack';
-        break;
-      case 'cabal':
-        prettyTool = 'Cabal';
-        break;
-      case 'ghc':
-        prettyTool = 'GHC';
-        break;
-      case 'ghcup':
-        prettyTool = 'GHCup';
-        break;
-      case 'haskell-language-server':
-        prettyTool = 'HLS';
-        break;
-      case 'hls':
-        prettyTool = 'HLS';
-        break;
-      default:
-        prettyTool = tool;
-        break;
-    }
-    super(`Project requires ${prettyTool} but it isn't installed`);
-    this.tool = prettyTool;
-  }
-
-  public installLink(): Uri | null {
-    switch (this.tool) {
-      case 'Stack':
-        return Uri.parse('https://docs.haskellstack.org/en/stable/install_and_upgrade/');
-      case 'GHCup':
-      case 'Cabal':
-      case 'HLS':
-      case 'GHC':
-        return Uri.parse('https://www.haskell.org/ghcup/');
-      default:
-        return null;
-    }
-  }
-}
-
 /**
  * Call a process asynchronously.
  * While doing so, update the windows with progress information.
@@ -489,7 +436,7 @@ async function callGHCup(
       callback
     );
   } else {
-    throw new Error(`Internal error: tried to call ghcup while haskell.manageHLS is set to ${manageHLS}. Aborting!`);
+    throw new HlsError(`Internal error: tried to call ghcup while haskell.manageHLS is set to ${manageHLS}. Aborting!`);
   }
 }
 
@@ -498,7 +445,7 @@ async function getLatestProjectHLS(
   logger: Logger,
   workingDir: string,
   toolchainBindir: string
-): Promise<[string, string | null]> {
+): Promise<[string, string]> {
   // get project GHC version, but fallback to system ghc if necessary.
   const projectGhc = toolchainBindir
     ? await getProjectGHCVersion(toolchainBindir, workingDir, logger).catch(async (e) => {
@@ -509,7 +456,6 @@ async function getLatestProjectHLS(
         return await callAsync(`ghc${exeExt}`, ['--numeric-version'], logger, undefined, undefined, false);
       })
     : await callAsync(`ghc${exeExt}`, ['--numeric-version'], logger, undefined, undefined, false);
-  const noMatchingHLS = `No HLS version was found for supporting GHC ${projectGhc}.`;
 
   // first we get supported GHC versions from available HLS bindists (whether installed or not)
   const metadataMap = (await getHLSesfromMetadata(context, logger)) || new Map<string, string[]>();
@@ -526,7 +472,7 @@ async function getLatestProjectHLS(
     .pop();
 
   if (!latest) {
-    throw new Error(noMatchingHLS);
+    throw new NoMatchingHls(projectGhc);
   } else {
     return [latest[0], projectGhc];
   }