[vcpkg edit] Now throws an error if it cannot launch an editor

toolsrc/src/commands_edit.cpp

@@ -11,12 +11,23 @@ namespace vcpkg
         const package_spec spec = Input::check_and_get_package_spec(args.command_arguments.at(0), default_target_triplet, example.c_str());
         Input::check_triplet(spec.target_triplet, paths);
 
+        const fs::path portpath = paths.ports / spec.name;
+
         // Find editor
         std::wstring env_EDITOR = System::wdupenv_str(L"EDITOR");
         if (env_EDITOR.empty())
-            env_EDITOR = LR"(C:\Program Files (x86)\Microsoft VS Code\Code.exe)";
+        {
+            static const std::wstring CODE_EXE_PATH = LR"(C:\Program Files (x86)\Microsoft VS Code\Code.exe)";
+            if (fs::exists(CODE_EXE_PATH))
+            {
+                env_EDITOR = CODE_EXE_PATH;
+            }
+            else
+            {
+                Checks::exit_with_message("Visual Studio Code was not found and the environmental variable EDITOR is not set");
+            }
+        }
 
-        const fs::path portpath = paths.ports / spec.name;
         std::wstring cmdLine = Strings::wformat(LR"("%s" "%s" "%s")", env_EDITOR, portpath.native(), (portpath / "portfile.cmake").native());
         exit(System::cmd_execute(cmdLine));
     }