Fix candidate tier-1 transit detection to stop at failing candidates#12
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Fix candidate tier-1 transit detection to stop at failing candidates#12
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When a candidate tier-1 (HE/6939, Zayo/6461) is encountered and its next hop is not a true tier-1, stop the search entirely instead of continuing down the path. Previously, the algorithm would skip the failing candidate and find a true tier-1 further along, incorrectly marking all intermediate ASes (including the origin) as customers. Also removes the TIER1/TIER1_V4/TIER1_V6 combined constants and the separate global as2rel pass. Global results are now derived by combining v4 and v6 maps, ensuring consistent behavior across all outputs.
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Summary
TIER1/TIER1_V4/TIER1_V6combined constants and the separate global as2rel pass; global results are now derived by combining v4 and v6 mapsBug
For a path like
13335 → 6939 → 3741 → 3491(origin → collector), the old algorithm would skip 6939 (failing candidate) and continue to find 3491 (true tier-1), then mark13335→6939,6939→3741,3741→3491as customer→provider relationships. This incorrectly classified 13335 as a customer of 6939.The fix returns
Noneimmediately when a candidate is found without a true tier-1 next hop, preventing any relationships from being recorded for that path.Test plan
test_find_transit_point_candidate_blocks_further_search— directly covers the bug scenariotest_he_not_candidate_in_v4— confirms 6939 is not a candidate in IPv4 pathstest_candidate_blocks_when_next_is_candidate_not_true— candidate adjacent to another candidate (not true tier-1) stops search