Don't add bailout adjustment for non-strict deserialize calls.

RhodiumToad · RhodiumToad · commit f7f2a28d4350 · 2021-01-28T11:09:57.000Z
When building aggregate expression steps, strict checks need a bailout jump for when a null value is encountered, so there is a list of steps that require later adjustment. Adding entries to that list for steps that aren't actually strict would be harmless, except that there is an Assert which catches them. This leads to spurious errors on asserts builds, for data sets that trigger parallel aggregation of an aggregate with a non-strict deserialization function (no such aggregates exist in the core system). Repair by not adding the adjustment entry when it's not needed. Backpatch back to 11 where the code was introduced. Per a report from Darafei (Komzpa) of the PostGIS project; analysis and patch by me. Discussion: https://postgr.es/m/87mty7peb3.fsf@news-spur.riddles.org.uk
diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c
@@ -2950,8 +2950,10 @@ ExecBuildAggTrans(AggState *aggstate, AggStatePerPhase phase,
 				scratch.resnull = &trans_fcinfo->argnull[argno + 1];
 
 				ExprEvalPushStep(state, &scratch);
-				adjust_bailout = lappend_int(adjust_bailout,
-											 state->steps_len - 1);
+				/* don't add an adjustment unless the function is strict */
+				if (pertrans->deserialfn.fn_strict)
+					adjust_bailout = lappend_int(adjust_bailout,
+												 state->steps_len - 1);
 
 				/* restore normal settings of scratch fields */
 				scratch.resvalue = &state->resvalue;
