probe symbols/query silently drops entire files on #ifdef-heavy C (0 functions for acls.c, checksum.c, etc.) #577

Bug

probe symbols and probe query silently return zero functions for C files with heavy #ifdef preprocessor directives — despite those files containing 12-39 function definitions each. No error or warning is emitted.

Reproduction

# These 5 production files all return 0 functions:
for f in checksum.c acls.c compat.c hlink.c xattrs.c; do
    count=$(probe symbols --format json "$f" | python3 -c "
import sys,json
print(sum(1 for x in json.load(sys.stdin) if x.get('kind')=='function'))
" 2>/dev/null)
    echo "$f: probe=$count functions"
done

Expected

Each file should return its actual function definitions (verified by ground-truth regex):

Actual

All 5 files return 0 functions — silently. No error, no warning.

Root cause (preliminary)

The tree-sitter C parser appears to bail after the leading extern/declaration block when it hits heavy #ifdef directives inside struct initializers or tables (e.g. checksum.c:52 has valid_checksums_items[] with #ifdef guards inside the array initializer). After the parse failure, probe symbols emits only the pre-failure declarations and silently stops.

probe query shares the same tree-sitter parser, so it has the same failure — it's not a fallback.

Impact

Critical for proof's function-enumeration use cases (e.g. property-based-test coverage checks). 111 function definitions silently missed across 5 production files. A "0 functions" result must be treated as a hard error, not "empty file" — otherwise coverage gaps are masked.

Environment

• probe-code 0.6.0
• macOS darwin (arm64)
• Tested on rsync 3.5.0 C codebase