Fix interactive use of "command script add". (#83350)

There was a think-o in a previous commit that made us only able to
define 1 line commands when using command script add interactively.

There was also no test for this feature, so I fixed the think-o and
added a test.

Author: jimingham

lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp

@@ -1417,7 +1417,7 @@ bool ScriptInterpreterPythonImpl::GenerateScriptAliasFunction(
   sstr.Printf("def %s (debugger, args, exe_ctx, result, internal_dict):",
               auto_generated_function_name.c_str());
 
-  if (!GenerateFunction(sstr.GetData(), user_input, /*is_callback=*/true)
+  if (!GenerateFunction(sstr.GetData(), user_input, /*is_callback=*/false)
            .Success())
     return false;
 

lldb/test/API/commands/command/script/TestCommandScript.py

@@ -216,3 +216,17 @@ def test_persistence(self):
         # The result object will be replaced by an empty result object (in the
         # "Started" state).
         self.expect("script str(persistence.result_copy)", substrs=["Started"])
+
+    def test_interactive(self):
+        """
+        Test that we can add multiple lines interactively.
+        """
+        interp = self.dbg.GetCommandInterpreter()
+        cmd_file = self.getSourcePath("cmd_file.lldb")
+        result = lldb.SBCommandReturnObject()
+        interp.HandleCommand(f"command source {cmd_file}", result)
+        self.assertCommandReturn(result, "Sourcing the command should cause no errors.")
+        self.assertTrue(interp.UserCommandExists("my_cmd"), "Command defined.")
+        interp.HandleCommand("my_cmd", result)
+        self.assertCommandReturn(result, "Running the command succeeds")
+        self.assertIn("My Command Result", result.GetOutput(), "Command was correct")

lldb/test/API/commands/command/script/cmd_file.lldb

@@ -0,0 +1,4 @@
+command script add my_cmd
+result.PutCString("My Command Result")
+result.SetStatus(lldb.eReturnStatusSuccessFinishResult)
+DONE