`LOAD_SMALL_INT` has empty `argrepr` via `Bytecode`
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Description
Bug report
Bug description:
When using Bytecode to disassemble some Python code I've noticed that the argrepr attribute of the Instruction holding a LOAD_SMALL_INT isn't populated. For example:
Python 3.14.0 (main, Oct 16 2025, 09:17:39) [Clang 17.0.0 (clang-1700.3.19.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from dis import Bytecode
>>> list(Bytecode("1"))
[
Instruction(
opname='RESUME',
opcode=128,
arg=0,
argval=0,
argrepr='',
offset=0,
start_offset=0,
starts_line=True,
line_number=0,
label=None,
positions=Positions(lineno=0, end_lineno=1, col_offset=0, end_col_offset=0),
cache_info=None
),
Instruction(
opname='LOAD_SMALL_INT',
opcode=94,
arg=1,
argval=1,
argrepr='', # <--- Empty string
offset=2,
start_offset=2,
starts_line=True,
line_number=1,
label=None,
positions=Positions(lineno=1, end_lineno=1, col_offset=0, end_col_offset=1),
cache_info=None
),
Instruction(
opname='RETURN_VALUE',
opcode=35,
arg=None,
argval=None,
argrepr='',
offset=4,
start_offset=4,
starts_line=False,
line_number=1,
label=None,
positions=Positions(lineno=1, end_lineno=1, col_offset=0, end_col_offset=1),
cache_info=None
)
]
I would have expected this to have the repr of the argument in there.
A quick and ignorant reading of dis.py suggests to me that there should be a change akin to this:
--- ../cpython/Lib/dis.py 2025-10-17 14:31:35.495151419 +0100
+++ my/dis.py 2025-10-17 14:43:26.650409153 +0100
@@ -586,7 +586,7 @@
# _disassemble_bytes needs the string repr of the
# raw name index for LOAD_GLOBAL, LOAD_CONST, etc.
argval = arg
- if deop in hasconst:
+ if deop in hasconst or deop == LOAD_SMALL_INT:
argval, argrepr = _get_const_info(deop, arg, self.co_consts)
elif deop in hasname:
if deop == LOAD_GLOBAL:
CPython versions tested on:
3.14
Operating systems tested on:
macOS
Linked PRs
- gh-140258
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- Open a pull request that references the issue number.
Research direction
Start in Lib/dis.py at the Bytecode argument-handling logic and reproduce the example with list(Bytecode("1")). Check the LOAD_SMALL_INT path and _get_const_info behavior; done means its Instruction has the expected non-empty argrepr, with behavior checked against the linked gh-140258 work.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 25/100