StringSchema.hashCode inconsistent across executions

[elrodro83]

This seems to happen because formatValidator is a lambda (https://github.com/everit-org/json-schema/blob/master/core/src/main/java/org/everit/json/schema/FormatValidator.java#L2), and lambdas d not have a fixed hashCode.

This is causing different runs to sort subschemas of a CombinedSchema differently, after this change: 81f0b2f#diff-66627cee53cd6d5d44872a44ab6dac6906bdf991afa3433ada63cbdea1466f63R177

[erosb]

Hello @elrodro83 I pushed a fix in this commit: 5436bb7

Does it work for you? Do you need a release urgently?

[elrodro83]

Hi!

I retested and am still having failures even with this fix. The change seems to fix the equals method, but the problem i am having is getting inconsitent sorting of elements, because the lib is using a HashSet, which sots its elements according to its hashCode.

[brianmaresca]

possibly related. SchemaLoader.load() is giving inconsistent behavior. the issue seems to be isolated to 1.14.4, i wasn't able to reproduce in 1.14.3.

to reproduce, i just ran this simple test:

while (true) {
  SchemaLoader.load(json);
}

which will eventually cause this:

java.lang.IllegalArgumentException: Comparison method violates its general contract!
	at java.base/java.util.TimSort.mergeHi(Unknown Source)
	at java.base/java.util.TimSort.mergeAt(Unknown Source)
	at java.base/java.util.TimSort.mergeForceCollapse(Unknown Source)
	at java.base/java.util.TimSort.sort(Unknown Source)
	at java.base/java.util.Arrays.sort(Unknown Source)
	at java.base/java.util.stream.SortedOps$SizedRefSortingSink.end(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.copyInto(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.evaluate(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline.collect(Unknown Source)
	at org.everit.json.schema.CombinedSchema.sortByCombinedFirst(CombinedSchema.java:187)
	at org.everit.json.schema.CombinedSchema.<init>(CombinedSchema.java:171)
	at org.everit.json.schema.CombinedSchema$Builder.build(CombinedSchema.java:30)
	at org.everit.json.schema.CombinedSchema$Builder.build(CombinedSchema.java:20)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(Unknown Source)
	at java.base/java.util.HashMap$KeySpliterator.forEachRemaining(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.copyInto(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.evaluate(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline.collect(Unknown Source)
	at org.everit.json.schema.loader.SchemaLoader.loadSchemaObject(SchemaLoader.java:399)
	at org.everit.json.schema.loader.JsonValue$Multiplexer.requireAny(JsonValue.java:47)
	at org.everit.json.schema.loader.SchemaLoader.load(SchemaLoader.java:462)
	at org.everit.json.schema.loader.SchemaLoader.loadChild(SchemaLoader.java:466)
	at org.everit.json.schema.loader.ArraySchemaLoader.lambda$load$2(ArraySchemaLoader.java:49)
	at org.everit.json.schema.loader.JsonValue$VoidMultiplexer.lambda$new$0(JsonValue.java:60)
	at org.everit.json.schema.loader.JsonValue$Multiplexer.requireAny(JsonValue.java:47)
	at org.everit.json.schema.loader.JsonValue$VoidMultiplexerWithSchemaPredicate.requireAny(JsonValue.java:89)
	at org.everit.json.schema.loader.JsonValue$VoidMultiplexerWithSchemaPredicate.requireAny(JsonValue.java:75)
	at org.everit.json.schema.loader.ArraySchemaLoader.lambda$load$4(ArraySchemaLoader.java:51)
	at java.base/java.util.Optional.ifPresent(Unknown Source)
	at org.everit.json.schema.loader.ArraySchemaLoader.load(ArraySchemaLoader.java:48)
	at org.everit.json.schema.loader.AbstractSchemaExtractor.buildArraySchema(SchemaExtractor.java:144)
	at org.everit.json.schema.loader.TypeBasedSchemaExtractor.loadForExplicitType(SchemaExtractor.java:281)
	at org.everit.json.schema.loader.JsonValue$Multiplexer.requireAny(JsonValue.java:47)
	at org.everit.json.schema.loader.TypeBasedSchemaExtractor.extract(SchemaExtractor.java:253)
	at org.everit.json.schema.loader.AbstractSchemaExtractor.extract(SchemaExtractor.java:114)
	at org.everit.json.schema.loader.SchemaLoader.runSchemaExtractors(SchemaLoader.java:424)
	at org.everit.json.schema.loader.SchemaLoader.loadSchemaObject(SchemaLoader.java:388)
	at org.everit.json.schema.loader.JsonValue$Multiplexer.requireAny(JsonValue.java:47)
	at org.everit.json.schema.loader.SchemaLoader.load(SchemaLoader.java:462)
	at org.everit.json.schema.loader.SchemaLoader.loadChild(SchemaLoader.java:466)
	at org.everit.json.schema.loader.ObjectSchemaLoader.addPropertySchemaDefinition(ObjectSchemaLoader.java:70)
	at org.everit.json.schema.loader.ObjectSchemaLoader.lambda$populatePropertySchemas$9(ObjectSchemaLoader.java:64)
	at org.everit.json.schema.loader.JsonObject.iterateOnEntry(JsonObject.java:84)
	at org.everit.json.schema.loader.JsonObject.lambda$forEach$1(JsonObject.java:79)
	at java.base/java.util.HashMap$EntrySet.forEach(Unknown Source)
	at org.everit.json.schema.loader.JsonObject.forEach(JsonObject.java:79)
	at org.everit.json.schema.loader.ObjectSchemaLoader.populatePropertySchemas(ObjectSchemaLoader.java:61)
	at org.everit.json.schema.loader.ObjectSchemaLoader.lambda$load$0(ObjectSchemaLoader.java:32)
	at java.base/java.util.Optional.ifPresent(Unknown Source)
	at org.everit.json.schema.loader.ObjectSchemaLoader.load(ObjectSchemaLoader.java:32)
	at org.everit.json.schema.loader.AbstractSchemaExtractor.buildObjectSchema(SchemaExtractor.java:139)
	at org.everit.json.schema.loader.TypeBasedSchemaExtractor.loadForExplicitType(SchemaExtractor.java:283)
	at org.everit.json.schema.loader.JsonValue$Multiplexer.requireAny(JsonValue.java:47)
	at org.everit.json.schema.loader.TypeBasedSchemaExtractor.extract(SchemaExtractor.java:253)
	at org.everit.json.schema.loader.AbstractSchemaExtractor.extract(SchemaExtractor.java:114)
	at org.everit.json.schema.loader.SchemaLoader.runSchemaExtractors(SchemaLoader.java:424)
	at org.everit.json.schema.loader.SchemaLoader.loadSchemaObject(SchemaLoader.java:388)
	at org.everit.json.schema.loader.JsonValue$Multiplexer.requireAny(JsonValue.java:47)
	at org.everit.json.schema.loader.SchemaLoader.load(SchemaLoader.java:462)
	at org.everit.json.schema.loader.SchemaLoader.loadChild(SchemaLoader.java:466)
	at org.everit.json.schema.loader.ArraySchemaLoader.lambda$load$2(ArraySchemaLoader.java:49)
	at org.everit.json.schema.loader.JsonValue$VoidMultiplexer.lambda$new$0(JsonValue.java:60)
	at org.everit.json.schema.loader.JsonValue$Multiplexer.requireAny(JsonValue.java:47)
	at org.everit.json.schema.loader.JsonValue$VoidMultiplexerWithSchemaPredicate.requireAny(JsonValue.java:89)
	at org.everit.json.schema.loader.JsonValue$VoidMultiplexerWithSchemaPredicate.requireAny(JsonValue.java:75)
	at org.everit.json.schema.loader.ArraySchemaLoader.lambda$load$4(ArraySchemaLoader.java:51)
	at java.base/java.util.Optional.ifPresent(Unknown Source)
	at org.everit.json.schema.loader.ArraySchemaLoader.load(ArraySchemaLoader.java:48)
	at org.everit.json.schema.loader.AbstractSchemaExtractor.buildArraySchema(SchemaExtractor.java:144)
	at org.everit.json.schema.loader.TypeBasedSchemaExtractor.loadForExplicitType(SchemaExtractor.java:281)
	at org.everit.json.schema.loader.JsonValue$Multiplexer.requireAny(JsonValue.java:47)
	at org.everit.json.schema.loader.TypeBasedSchemaExtractor.extract(SchemaExtractor.java:253)
	at org.everit.json.schema.loader.AbstractSchemaExtractor.extract(SchemaExtractor.java:114)
	at org.everit.json.schema.loader.SchemaLoader.runSchemaExtractors(SchemaLoader.java:424)
	at org.everit.json.schema.loader.SchemaLoader.loadSchemaObject(SchemaLoader.java:388)
	at org.everit.json.schema.loader.JsonValue$Multiplexer.requireAny(JsonValue.java:47)
	at org.everit.json.schema.loader.SchemaLoader.load(SchemaLoader.java:462)
	at org.everit.json.schema.loader.SchemaLoader.loadChild(SchemaLoader.java:466)
	at org.everit.json.schema.loader.ObjectSchemaLoader.addPropertySchemaDefinition(ObjectSchemaLoader.java:70)
	at org.everit.json.schema.loader.ObjectSchemaLoader.lambda$populatePropertySchemas$9(ObjectSchemaLoader.java:64)
	at org.everit.json.schema.loader.JsonObject.iterateOnEntry(JsonObject.java:84)
	at org.everit.json.schema.loader.JsonObject.lambda$forEach$1(JsonObject.java:79)
	at java.base/java.util.HashMap$EntrySet.forEach(Unknown Source)
	at org.everit.json.schema.loader.JsonObject.forEach(JsonObject.java:79)
	at org.everit.json.schema.loader.ObjectSchemaLoader.populatePropertySchemas(ObjectSchemaLoader.java:61)
	at org.everit.json.schema.loader.ObjectSchemaLoader.lambda$load$0(ObjectSchemaLoader.java:32)
	at java.base/java.util.Optional.ifPresent(Unknown Source)
	at org.everit.json.schema.loader.ObjectSchemaLoader.load(ObjectSchemaLoader.java:32)
	at org.everit.json.schema.loader.AbstractSchemaExtractor.buildObjectSchema(SchemaExtractor.java:139)
	at org.everit.json.schema.loader.TypeBasedSchemaExtractor.loadForExplicitType(SchemaExtractor.java:283)
	at org.everit.json.schema.loader.JsonValue$Multiplexer.requireAny(JsonValue.java:47)
	at org.everit.json.schema.loader.TypeBasedSchemaExtractor.extract(SchemaExtractor.java:253)
	at org.everit.json.schema.loader.AbstractSchemaExtractor.extract(SchemaExtractor.java:114)
	at org.everit.json.schema.loader.SchemaLoader.runSchemaExtractors(SchemaLoader.java:424)
	at org.everit.json.schema.loader.SchemaLoader.loadSchemaObject(SchemaLoader.java:388)
	at org.everit.json.schema.loader.JsonValue$Multiplexer.requireAny(JsonValue.java:47)
	at org.everit.json.schema.loader.SchemaLoader.load(SchemaLoader.java:462)
	at org.everit.json.schema.loader.SchemaLoader.load(SchemaLoader.java:308)
	at org.everit.json.schema.loader.SchemaLoader.load(SchemaLoader.java:291)

my json object is quite large and complex, which might be exacerbating the issue. but with the same exact json, i am certain i'm only seeing this in 1.14.4. i also tried 5436bb7 - same thing