The `fieldFlow` predicate contained a fragile join that has become
ordered wrong recently, either as result of an unrelated change in the
data-flow library or as part of the stats change for the last dbscheme
change.
The minimal fix is to use `getEnclosingCallable` instead of
`getFunction` since the former uses `unique` to ensure good join
ordering in its callers. A longer-term fix should be applied to the AST
base libraries, but this will be invasive and require independent
testing.
Tuple counts on Wireshark before (cancelled after a few minutes):
(747s) Starting to evaluate predicate DataFlowUtil::localFlowStep#ff/2@bdba82
(848s) Tuple counts for DataFlowUtil::localFlowStep#ff:
1766640980 ~1% {2} r1 = JOIN DataFlowUtil::Node::getFunction_dispred#ff_10#join_rhs AS L WITH DataFlowUtil::Node::getFunction_dispred#ff_10#join_rhs AS R ON FIRST 1 OUTPUT L.<1>, R.<1>
1327 ~0% {2} r2 = JOIN r1 WITH project#DataFlowImplLocal::Configuration::hasFlow#fbb AS R ON FIRST 2 OUTPUT r1.<0>, r1.<1>
9691232 ~0% {2} r3 = DataFlowUtil::simpleLocalFlowStep#ff@staged_ext \/ r2
return r3
After:
(0s) Starting to evaluate predicate DataFlowUtil::localFlowStep#ff/2@a852a0
(0s) Tuple counts for DataFlowUtil::localFlowStep#ff:
49017 ~4% {3} r1 = JOIN project#DataFlowImplLocal::Configuration::hasFlow#fff AS L WITH DataFlowUtil::Node::getEnclosingCallable_dispred#ff AS R ON FIRST 1 OUTPUT L.<1>, R.<1>, R.<0>
42359 ~0% {2} r2 = JOIN r1 WITH DataFlowUtil::Node::getEnclosingCallable_dispred#ff AS R ON FIRST 2 OUTPUT r1.<2>, r1.<0>
9732264 ~0% {2} r3 = DataFlowUtil::simpleLocalFlowStep#ff@staged_ext \/ r2
return r3
CodeQL
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