From 5cb5d9e2cb2b45c7e14b87f17a44488eea97433b Mon Sep 17 00:00:00 2001
From: Niklas Higi <niklas@shroudedcode.com>
Date: Sat, 26 Jun 2021 18:40:05 +0200
Subject: [PATCH] Implement `UserError` class for errors that don't require a
 stack trace

---
 src/cli.ts                       |  6 ++++++
 src/tasks/check-prerequisites.ts |  5 +++--
 src/utils/get-java-version.ts    |  5 +++--
 src/utils/user-error.ts          | 10 ++++++++++
 4 files changed, 22 insertions(+), 4 deletions(-)
 create mode 100644 src/utils/user-error.ts

diff --git a/src/cli.ts b/src/cli.ts
index 13e7be5..4bd30ba 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -10,6 +10,7 @@ import { patchXapkBundle, patchApksBundle } from './patch-app-bundle'
 import Apktool from './tools/apktool'
 import UberApkSigner from './tools/uber-apk-signer'
 import Tool from './tools/tool'
+import UserError from './utils/user-error'
 
 export type TaskOptions = {
   inputPath: string
@@ -131,7 +132,12 @@ async function main() {
 }
 
 function getErrorMessage(error: PatchingError, { tmpDir }: { tmpDir: string }) {
+  // User errors can be shown without a stack trace
+  if (error instanceof UserError) return error.message
+
+  // Errors from commands can also be shown without a stack trace
   if (error.all) return formatCommandError(error.all, { tmpDir })
+
   return error.stack
 }
 
diff --git a/src/tasks/check-prerequisites.ts b/src/tasks/check-prerequisites.ts
index 69f4331..f8c9398 100644
--- a/src/tasks/check-prerequisites.ts
+++ b/src/tasks/check-prerequisites.ts
@@ -3,6 +3,7 @@ import Listr = require('listr')
 
 import { TaskOptions } from '../cli'
 import getJavaVersion from '../utils/get-java-version'
+import UserError from '../utils/user-error'
 import downloadTools from './download-tools'
 
 const MIN_NODE_VERSION = 14
@@ -49,14 +50,14 @@ async function ensureZipUlitiesAvailable() {
     await execa('unzip', ['-v'])
     await execa('zip', ['-v'])
   } catch {
-    throw new Error(
+    throw new UserError(
       'apk-mitm requires the commands "unzip" and "zip" to be installed when patching App Bundles.' +
         " Make sure they're both installed and try again!",
     )
   }
 }
 
-class VersionError extends Error {
+class VersionError extends UserError {
   constructor(tool: string, minVersion: number, currentVersion: number) {
     super(
       `apk-mitm requires at least ${tool} ${minVersion} to work and you seem to be using ${tool} ${currentVersion}.` +
diff --git a/src/utils/get-java-version.ts b/src/utils/get-java-version.ts
index 7d3f23e..515a8c6 100644
--- a/src/utils/get-java-version.ts
+++ b/src/utils/get-java-version.ts
@@ -1,4 +1,5 @@
 import execa = require('execa')
+import UserError from './user-error'
 
 /** Returns the major version of the system's default Java installation. */
 export default async function getJavaVersion() {
@@ -7,13 +8,13 @@ export default async function getJavaVersion() {
     const majorVersionString = stderr.match(JAVA_VERSION_PATTERN)?.groups?.major
     if (!majorVersionString) {
       const message = `Could not extract Java major version from "java -version" output!\n${stderr}`
-      throw new Error(message)
+      throw new UserError(message)
     }
 
     return parseInt(majorVersionString)
   } catch (error) {
     if (error.code === 'ENOENT')
-      throw new Error(
+      throw new UserError(
         'No "java" executable could be found!' +
           ' Make sure that Java is installed and available in your PATH.',
       )
diff --git a/src/utils/user-error.ts b/src/utils/user-error.ts
new file mode 100644
index 0000000..e40367f
--- /dev/null
+++ b/src/utils/user-error.ts
@@ -0,0 +1,10 @@
+/**
+ * Class for custom errors that can be shown directly to users of the CLI
+ * without displaying the entire stack trace.
+ */
+export default class UserError extends Error {
+  constructor(message: string) {
+    super(message)
+    this.name = UserError.name
+  }
+}