HHH-12086 - Batch order_inserts: flush during transaction causes incorrect insert ordering and subsequent constraint violation

Add a maximum iteration threshold, to avoid a stack overflow error in case there will be circular dependency that's not properly detected

Author: vladmihalcea

hibernate-core/src/main/java/org/hibernate/engine/spi/ActionQueue.java

@@ -1166,12 +1166,17 @@ public void sort(List<AbstractEntityInsertAction> insertions) {
 }
 }
 
-boolean stored = false;
+boolean sorted = false;
+
+long maxIterations = latestBatches.size() * 2;
+long iterations = 0;
 
 sort:
 do {
 // Examine each entry in the batch list, sorting them based on parent/child association
 // as depicted by the dependency graph.
+iterations++;
+
 for ( int i = 0; i < latestBatches.size(); i++ ) {
 BatchIdentifier batchIdentifier = latestBatches.get( i );
 
@@ -1204,9 +1209,14 @@ public void sort(List<AbstractEntityInsertAction> insertions) {
 }
 }
 }
-stored = true;
+sorted = true;
+}
+while ( !sorted && iterations <= maxIterations);
+
+if ( iterations > maxIterations ) {
+LOG.warn( "The batch containing " + latestBatches.size() + " statements could not be sorted after " + maxIterations + " iterations. " +
+ "This might indicate a bug in Hibernate!" );
 }
-while ( !stored );
 
 // Now, rebuild the insertions list. There is a batch for each entry in the name list.
 for ( BatchIdentifier rootIdentifier : latestBatches ) {