[BUG] calling wp.printf() without arguments causes a KeyError for a missing 'args' key

[g1n0st]

Bug Description

import warp as wp

wp.init()

@wp.kernel
def test():
    wp.printf("ok")

wp.launch(test, dim=1)

wp.synchronize()

Error:

Warp 1.4.1 initialized:
   CUDA Toolkit 12.6, Driver 12.2
   Devices:
     "cpu"      : "x86_64"
     "cuda:0"   : "NVIDIA H100 NVL" (93 GiB, sm_90, mempool enabled)
   Kernel cache:
     /home/chang/.cache/warp/1.4.1
Module __main__ 964fa97 load on device 'cuda:0' took 0.29 ms
Traceback (most recent call last):
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 960, in build
    adj.eval(adj.tree.body[0])
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 2628, in eval
    return emit_node(adj, node)
           ^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 1548, in emit_FunctionDef
    adj.eval(f)
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 2628, in eval
    return emit_node(adj, node)
           ^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 2074, in emit_Expr
    return adj.eval(node.value)
           ^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 2628, in eval
    return emit_node(adj, node)
           ^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 2192, in emit_Call
    out = adj.add_call(func, args, kwargs, type_args, min_outputs=min_outputs)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 1288, in add_call
    func_args, template_args = func.dispatch_func(func.input_types, return_type, bound_args)
                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/builtins.py", line 2982, in printf_dispatch_func
    func_args = (args["fmt"], *args["args"])
                               ~~~~^^^^^^^^
KeyError: 'args'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/chang/bug.py", line 9, in <module>
    wp.launch(test, dim=1)
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/context.py", line 5003, in launch
    module_exec = kernel.module.load(device)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/context.py", line 1949, in load
    builder = ModuleBuilder(self, self.options, hasher=self.hasher)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/context.py", line 1549, in __init__
    self.build_kernel(kernel)
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/context.py", line 1578, in build_kernel
    kernel.adj.build(self)
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 970, in build
    raise e
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 960, in build
    adj.eval(adj.tree.body[0])
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 2628, in eval
    return emit_node(adj, node)
           ^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 1548, in emit_FunctionDef
    adj.eval(f)
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 2628, in eval
    return emit_node(adj, node)
           ^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 2074, in emit_Expr
    return adj.eval(node.value)
           ^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 2628, in eval
    return emit_node(adj, node)
           ^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 2192, in emit_Call
    out = adj.add_call(func, args, kwargs, type_args, min_outputs=min_outputs)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/codegen.py", line 1288, in add_call
    func_args, template_args = func.dispatch_func(func.input_types, return_type, bound_args)
                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/chang/miniconda3/lib/python3.12/site-packages/warp/builtins.py", line 2982, in printf_dispatch_func
    func_args = (args["fmt"], *args["args"])
                               ~~~~^^^^^^^^
KeyError: 'Error while parsing function "test" at /home/chang/bug.py:7:\n    wp.printf("ok")\n;args'

System Information

Warp 1.4.1 initialized:
CUDA Toolkit 12.6, Driver 12.2