fix(setup/pico): verify source of arm-gcc before removing

src/toolbox/setup/homebrew.ts

@@ -42,3 +42,16 @@ export async function ensureHomebrew(): Promise<void> {
     throw new Error(`Visit https://brew.sh/ to learn more about installing Homebrew. If you don't want to use Homebrew, please install the following packages manually before trying this command again: `)
   }
 }
+
+type SpawnResult = {
+  stdout: null | string;
+  status: number;
+  error: null | Error;
+}
+
+export async function formulaeExists(formulae: string): Promise<boolean> {
+  if (system.which('brew') === null) return false
+
+  const result: SpawnResult = await system.spawn(`brew list ${formulae}`, { shell: process.env.SHELL })
+  return result.status === 0;
+}

src/toolbox/setup/pico/mac.ts

@@ -1,5 +1,5 @@
 import { GluegunPrint, print, system } from 'gluegun'
-import { ensureHomebrew } from '../homebrew';
+import { ensureHomebrew, formulaeExists } from '../homebrew';
 
 export async function installDeps(
   spinner: ReturnType<GluegunPrint['spin']>
@@ -13,7 +13,7 @@ export async function installDeps(
     }
   }
 
-  if (system.which('arm-none-eabi-gcc') !== null) {
+  if (system.which('arm-none-eabi-gcc') !== null && (await formulaeExists('arm-none-eabi-gcc'))) {
     spinner.start('Removing outdated arm gcc dependency')
     await system.exec('brew untap ArmMbed/homebrew-formulae')
     await system.exec('brew uninstall arm-none-eabi-gcc')