[Lldb-commits] [lldb] [lldb] Fix crash when adding a python ParsedCommand (PR #215807)

[Ebuka Ezike via lldb-commits]

https://github.com/da-viper created https://github.com/llvm/llvm-project/pull/215807

The expected result of `ParsedCommand.get_args_definition` is a List of Lists and should not crash when it is not the case.

>From 6e5c63700f2d2372da21cf11687393bd2188bf7b Mon Sep 17 00:00:00 2001
From: Ebuka Ezike <yerimyah1 at gmail.com>
Date: Tue, 11 Aug 2026 16:21:08 +0100
Subject: [PATCH] [lldb] Fix crash when adding a python ParsedCommand

The expected result of ParsedCommand.get_args_definition is a
List of lists and should not crash when it is not the case.
---
 lldb/source/Commands/CommandObjectCommands.cpp      |  1 +
 .../command/script/add/TestAddParsedCommand.py      |  5 +++++
 .../commands/command/script/add/test_commands.py    | 13 +++++++++++++
 3 files changed, 19 insertions(+)

diff --git a/lldb/source/Commands/CommandObjectCommands.cpp b/lldb/source/Commands/CommandObjectCommands.cpp
index 2acbbda4e8553..f069b7e27df9a 100644
--- a/lldb/source/Commands/CommandObjectCommands.cpp
+++ b/lldb/source/Commands/CommandObjectCommands.cpp
@@ -1949,6 +1949,7 @@ class CommandObjectScriptingObjectParsed : public CommandObjectParsed {
               Status::FromErrorStringWithFormatv("Argument definition element "
                                                  "{0} is not an array",
                                                  counter);
+          return false;
         }
         
         args_array->ForEach(args_adder);
diff --git a/lldb/test/API/commands/command/script/add/TestAddParsedCommand.py b/lldb/test/API/commands/command/script/add/TestAddParsedCommand.py
index da150499a53a2..d5553dce189f7 100644
--- a/lldb/test/API/commands/command/script/add/TestAddParsedCommand.py
+++ b/lldb/test/API/commands/command/script/add/TestAddParsedCommand.py
@@ -331,3 +331,8 @@ def cleanup():
             results.count("SECOND_ARG"), 2, "Passed second arg to both commands"
         )
         self.assertEqual(results.count("THIRD_ARG"), 1, "Passed third arg in repeat")
+
+        # Verify lldb did not register the 'fail_cmd'.
+        self.expect(
+            "fail_cmd", substrs=["'fail_cmd' is not a valid command"], error=True
+        )
diff --git a/lldb/test/API/commands/command/script/add/test_commands.py b/lldb/test/API/commands/command/script/add/test_commands.py
index db302796819ad..0d8acaed9e611 100644
--- a/lldb/test/API/commands/command/script/add/test_commands.py
+++ b/lldb/test/API/commands/command/script/add/test_commands.py
@@ -254,6 +254,19 @@ def get_long_help(self):
         return self.help_string
 
 
+class FailCommand(ParsedCommand):
+    program: str = "fail_cmd"
+
+    def __call__(self, debugger, args_list, exe_ctx, result):
+        result.AppendMessage("hello world")
+
+    def setup_command_definition(self):
+        parser = self.get_parser()
+        # add_argument_set is expecting a list not dict.
+        parser.add_argument_set(
+            parser.make_argument_element(lldb.eArgTypeSymbol, "plain")
+        )
+
 def __lldb_init_module(debugger, dict):
     # Register all classes that have a register_lldb_command method
     for _name, cls in inspect.getmembers(sys.modules[__name__]):