Recently, with the Developer Preview – February 2019, a new feature was added to the AL extension for Visual Studio Code: Debug without publishing. This new feature brings more than you would expect. It is not just another option in the list of Publish and Publish without debugging.
What’s the difference? With the option Publish and Publish without debugging you are going to publish the extension that you currently have open in the VS Code workspace. With the option Debug without publishing, you don’t publish anything. In fact, you don’t even have to have any code open. This option allows you to debug the actual code on the server instead of debugging the code inside the VS Code workspace you have open. A quote from the blog post about Developer preview – February 2019:
Please be aware that if you start debugging without publishing you will be debugging the last published code of your app.
What you basically need is a workspace in VS Code with a server configuration in the launch.json. This server will be the server that you are going to debug. You don’t even need to download the symbols files. And the app.json can also be ignored. Just follow these steps:
and a debugging session will be started. If the code runs into an error, the corresponding .dal file will be downloaded. From there you can view variables, set breakpoints (in the .dal file) and step through the code.
The launch.json has a breakOnError setting. By default this setting is true. Since there is no way to set breakpoints manually, you wil need this setting. Optionally you can use the setting breakOnRecordWrite.
Again, basically the only thing you need to debug the actual code is a workspace with a launch.json file.
I believe this feature helps to support scenario’s like ‘an error occurred but I don’t know where the error comes from’. The debugger will allow you to debug any code, including all installed extensions.
One final comment: according to this documentation, you can’t debug an extension that has set ShowMyCode = false in the app.json.