no_redundant_jumps: Assertion `0' failed

[15r10nk]

Bug report

Bug description:

The following code causes a crash on cpython 3.13 branch (f5289c4) and the current main.

import ast

code="""
try:
    if name_4:
        pass
    else:
        pass
except* name_0:
    pass
else:
    name_4
"""

tree = ast.parse(code)
for node in ast.walk(tree):
    if hasattr(node,"lineno"):
         del   node.lineno
         del   node.end_lineno
         del   node.col_offset
         del   node.end_col_offset

compile(ast.fix_missing_locations(tree), "<file>", "exec")

output (Python 3.13.0a3+):

python: Python/flowgraph.c:511: no_redundant_jumps: Assertion `0' failed.

I bisected the problem down to 2091fb2.
@iritkatriel can you take a look at it?

CPython versions tested on:

3.13, CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-120367: fix removal of redundant NOPs and jumps after reordering hot-cold blocks #120425
• [3.13] gh-120367: fix removal of redundant NOPs and jumps after reordering hot-cold blocks (GH-120425) #120621
• gh-120367: fix bug where compiler detects redundant jump after pseudo op replacement #120714
• [3.13] gh-120367: fix bug where compiler detects redundant jump after pseudo op replacement (GH-120714) #120716

[15r10nk]

I have also several other code samples which trigger the same assertion like:

try:
    pass
except:
    pass
else:
    match name_2:
        case b'':
            pass
finally:
    something

let me know if you need more of them to fix the issue. (The good news is that I have only samples for this issue 😄)

[aisk]

I can re-produce the same crash with f5289c4 or current main branch(7dd8c37).

[picnixz]

On main (e16aed6), I can reproduce the first crash but not the one given in #120367 (comment). The second one only gives me NameError on name_2 (which is fine).

[15r10nk]

@picnixz sorry I that I did not post the complete example.

import ast

code="""
try:
    pass
except:
    pass
else:
    match name_2:
        case b'':
            pass
finally:
    something
"""

tree = ast.parse(code)
for node in ast.walk(tree):
    if hasattr(node,"lineno"):
         del   node.lineno
         del   node.end_lineno
         del   node.col_offset
         del   node.end_col_offset

compile(ast.fix_missing_locations(tree), "<file>", "exec")

This fails for me also on main

[picnixz]

Oh yes, now it works (I mean, it works in its failure).