Chrysler: fuzzy fingerprint on part numbers, tolerate one unseen part - #3717
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Chrysler: fuzzy fingerprint on part numbers, tolerate one unseen part#3717ping-dev-ui wants to merge 1 commit into
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Add a brand fuzzy fingerprinting function for Chrysler that matches on Mopar part numbers instead of exact FW strings, so unseen software revisions still fingerprint. One platform code ECU (cluster, SRS, ABS, EPS) may carry an unseen part number, which is what a new model year typically changes; two never match. A test asserts every pair of platforms differs on at least two platform code ECUs so the tolerance cannot confuse sibling platforms.
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Car behavior reportReplays driving segments through this PR and compares the behavior to master. Testing 40 segments for: CHRYSLER_PACIFICA_2018_HYBRID, CHRYSLER_PACIFICA_2019_HYBRID, CHRYSLER_PACIFICA_2018, CHRYSLER_PACIFICA_2020 ✅ 0 changed, 40 passed, 0 errors |
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Title: Chrysler: fuzzy fingerprint on part numbers, tolerate one unseen part
Closes #1092
Problem
Chrysler FW responses are a Mopar part number plus a software revision (
68227902AF→ part68227902, revisionAF). Today only the generic fuzzy matcher runs for Chrysler, and it needs exact FW strings. A dealer flash that bumpsAF→AGon any ECU therefore makes the car unfingerprintable until someone submits a new route. Simulated on the current Chrysler database (10 platforms, 652 FW versions), a known car whose ECUs report an unseen revision letter fuzzy matches in 0 of 300 trials.Change
Add
match_fw_to_car_fuzzyfor Chrysler in the same shape as the Ford and Hyundai implementations:FW_PATTERNsplits each FW into part number and revision;get_platform_codesreturns the part numbers.Why this is safe
test_platforms_distinguishableasserts that every pair of platforms differs on at least two platform code ECUs, so tolerating one unseen ECU cannot turn one platform into its sibling. Today the closest pairs are Durango / Grand Cherokee 2019 (share ABS and EPS part numbers, differ on cluster and SRS) and Pacifica 2018 / 2020 (share EPS, differ on the other three). The test fails as soon as a future fingerprint submission breaks that margin, which is the signal to revisit the tolerance.Simulation on the full database (script and numbers in the PR discussion):
Tests
opendbc/car/chrysler/tests/test_chrysler.py, modeled on the Ford tests: every FW in the database parses; known FW and unseen revisions match exactly one platform; one unseen part number still matches and never another platform; two unseen part numbers or two missing ECUs never match; the Pacifica 2018/2020 and Durango/Grand Cherokee 2019 sibling cases with an unseen cluster; the distinguishability invariant above.print_platform_codes.pymirrors the Ford/Hyundai helper.Validation
opendbc/car/tests/test_fw_fingerprint.py, which checks the brand function never disagrees with the generic matcher on known FW.Related: #3520 takes the same part-number approach but requires all four ECUs; the numbers above are why this PR tolerates one.