Debugging C# scripts

Useful functions

See Cookbook recipe Script testing and debugging.

Debugger

Debugger in LibreAutomate is similar to that of Visual Studio, VSCode, Rider etc.

Two panels are dedicated to debugging: Debug and Breakpoints. If the Debug panel was hidden when debugging starts, it becomes visible temporarily while debugging. Both panels initially are hidden; to show always, right-click any panel caption.

To run current script with the debugger, click the Debug run button or menu item, or use the toolbar in the Debug panel. Usually at first you add one or more breakpoints in code (click the white margin). The script stops at a breakpoint line, or on exception, or in Debugger.Break, Debug.Assert, or when clicked Pause. Then you can use the Debug toolbar or hotkeys to execute the script in steps. Also you can click the white margin and select Run to here.

To attach the debugger to an already running script, use the Tasks panel or script.debug. Or Debug.Assert, if the script starts with code like script.setup(debug: true);.

Features

• Standard stepping features.
• Breakpoints, logpoints.
• Break on exception.
• Call stack.
• List of variables. Click a variable to print it.
• Hover the mouse on a variable in code to display its value.
• Supports Debugger.Break, Debug.Assert, Debug.Print etc.
• Run to here.
• Jump to here.

Some missing features

• "Hot reload" or "Edit and continue".
• Evaluate any C# expression.
• Set variable's value.
• Open and debug source files that don't exist in the workspace.
• Attach the debugger to unknown processes.

Notes

Thanks to Samsung/netcoredbg.

Antivirus software may quarantine netcoredbg.exe (debugger). Add it to the exclusions list of the antivirus.

To debug optimized code (/*/ optimize true; /*/), temporarily check Debug optimized code in the options menu. Normally you don't debug optimized code, it may not work well.

Cannot debug 32-bit processes.

Other debuggers

You may have Visual Studio or other IDE with a better .NET debugger. You can attach that debugger to a running script. Let the script call one of these functions:

• Debugger.Launch. Example: Debugger.Launch(); Debugger.Break();. Note: it shows several dialogs before you can start debugging.
• script.debug. Example: script.debug(true); Debugger.Break();. It shows a dialog with the script process id and waits for a debugger attached. Then you can attach a debugger. To automate it, create a window-triggered script.

Triggers.Window[TWEvent.ActiveNew, "Attach debugger", "#32770"] = o => script.run("Attach debugger.cs", o.Window.ProcessId.ToS());

Script Attach debugger.cs:

// Attaches the Visual Studio debugger to the process id = args[0].
// If run from editor (args empty), attaches to this process for testing this script.

bool test = script.testing; //test this script
if (test) print.clear();
int id = test ? process.thisProcessId : args[0].ToInt();

bool canAttach = false;
var w = wnd.find("*Visual Studio*", "HwndWrapper[DefaultDomain;*");
if (w.Is0) {
	dialog.showInfo("Debugger window not found", "Supported debuggers: Visual Studio, VSCode, dnSpy.");
} else if (uacInfo.ofProcess(id).Elevation == UacElevation.Full && uacInfo.ofProcess(w.ProcessId).Elevation != UacElevation.Full) {
	dialog.showInfo("Debugger isn't admin", "The debugger process must be running as administrator.");
} else canAttach = true;
if (!canAttach) {
	if (!test) process.terminate(id); //because it's waiting in script.debug
	return;
}

w.Activate();
600.ms();
keys.send("Ctrl+Alt+P");
var w2 = wnd.find(5, "Attach to Process", "**m HwndWrapper[DefaultDomain;*||#32770");
300.ms();
if (w2.ClassNameIs("H*")) { //new VS
	w2.Elm["STATICTEXT", id.ToS()].Find(5).Parent.Focus(true);
} else { //old VS
	w2.Elm["LISTITEM", null, ["id=4102", $"desc=ID: {id}? *"]].Find(5).Focus(true); //note: use '?' because can be ',' or ';' etc depending on regional settings
}
w2.Elm["BUTTON", "Attach", "state=!DISABLED"].Find(3).Invoke();

if (test) {
	wait.until(0, () => Debugger.IsAttached);
	Debugger.Break();
	print.it("Debugger script.");
}