The per-language "resolve calls in AST node" walkers recurse once per nesting
level. Four of them — Python (py_resolve_calls_in), Go (resolve_calls_in_node),
PHP (php_resolve_calls_in_node), Kotlin (kt_resolve_calls_in_node) — had no depth
guard, so a deeply-nested or cyclic file could drive them into a native stack
overflow (SIGSEGV) that takes down the whole index run. C and Java already guard
this (C_LSP_MAX_WALK_DEPTH / JAVA_LSP_MAX_WALK_DEPTH).
Add the same wrapper/inner depth guard to all four, backed by a shared,
env-configurable cap: CBM_LSP_MAX_WALK_DEPTH (default 512) in scope.h. Past the
cap the wrapper skips the subtree — those calls stay unresolved (graceful
degradation, not a crash). The walk_depth-- runs after the inner body returns, so
early returns can't leak the counter.
Reproduce-first: lsp_{python,go,php,kotlin}_deep_nesting_no_crash (30000-deep
nested calls, run under a forked child + WIFSIGNALED). RED without the cap (the
child SIGSEGVs — verified by raising CBM_LSP_MAX_WALK_DEPTH to 100M), GREEN with
it. Full suite 5752/0, no ASan/leak.
Part of the resilient-indexing effort (Track B prevention layer). Refs #668.
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>
Martin Vogel
f47e8b5bf5