Replaces the cursor ascent from 0b0d143c. That commit fixed a real hang --
ts_node_parent() is O(depth), so a parent chain is O(depth^2) per call and
O(depth^3) across a file where every level of f(f(f(...))) is itself a bare
call, which hung stack_overflow_b's 30,000-deep fixture at 900s. But it fixed
it by making each hop cheap rather than by removing the per-call walk, so the
cost stayed O(depth) per call and needed a 64-ancestor cap to stay bounded.
That cap FAILS OPEN. Past 64 ancestors the guard stopped suppressing, so
deep-but-ordinary code silently kept the fabricated edges the guard exists to
remove -- and nothing failed when it did.
Carry the answer instead. The unified walk binds a def's or lambda's parameters
when it opens that scope and unwinds them when it closes, so the guard is an
O(1) map lookup. This is the lesson CBMWalkScope already records one struct
away: carry walk state, never recompute it per node.
- CBMParamSlot is a name -> active-count map, not a set. `def outer(run):
def inner(run):` binds one name twice and leaving the inner scope must not
unbind the outer.
- Bindings are pushed at the end of push_boundary_scopes, after every scope
push for that node, so they land in the frame just pushed -- covering
function_definition (push_function_scope) and lambda (push_lexical_boundary)
alike -- and pop_expired_scopes unwinds to the frame's entry height.
- Allocation failure sets py_param_tracking_failed and the lookup answers
false forever after: a lost suppression, never a lost edge.
The repo's other binding table cannot serve this. CBMLexicalBinding is qsort-ed
in cbm_finalize_lexical_usages AFTER the walk and its active_end stays 0 until
then, so its binary search is invalid from handle_calls, which runs mid-walk
and before handle_usages.
extract_python_bare_call_scope_walk_is_bounded pinned the cap's fail-open
contract, which no longer exists, and is replaced by
extract_python_bare_call_flag_is_depth_independent. It keeps the shallow and
200-ancestor cases -- the deep one now asserts the call IS flagged, so
reintroducing a cap fails it -- and adds an unwind case: `handler` as both a
parameter and a module-level def, asserting the two shadowed calls are flagged
and the sibling call after that scope closed is NOT. A binding outliving its
frame would destroy that true edge, the one direction this guard must never
fail in. It passed on the first run.
extraction 327 passed; pipeline registry parallel complexity 407 passed;
stack_overflow_b 6 passed in 38s (46s with the cursor ascent, 900s rc=124
before it), lsp_python_deep_nesting_no_crash PASS.
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>
Martin Vogel
97517a4652