ResourcePatternHints should not be merged in a single json entry

[snicoll]

As reported by #28977

The ResourcePatternHints is a container for includes and excludes and multiple ResourcePatternHints can be registered. It's possible that callers may expect that these includes and excludes are related, however, when the JSON is written all excludes and all includes are included together. See ResourceHintsPredicates.AggregatedResourcePatternHints for an example of the flattening that needs to occur when using the pattern hints.

[bdshadow]

I want to help with this, but please advise on what is expected.
For example, let's say that we have the following resource hints:

ResourceHints hints = new ResourceHints();
hints.registerPattern(hint -> hint.includes("com/*").excludes("com/example/*"));
hints.registerPattern(hint -> hint.includes("com/example/*/all.properties").excludes("com/example/ignore/all.properties"));

Currently, it produces:

{
	"resources": {
		"includes": [
			{ "pattern": "\\Q/\\E"},
			{ "pattern": "\\Qcom/\\E.*"},
			{ "pattern": "\\Qcom\\E"},
			{ "pattern": "\\Qcom/example/\\E.*\\Q/all.properties\\E"},
			{ "pattern": "\\Qcom/example\\E"}
		],
		"excludes": [
			{ "pattern": "\\Qcom/example/\\E.*"},
			{ "pattern": "\\Qcom/example/ignore/all.properties\\E"}
		]
	}
}

Am I right that it's supposed to be the following way:

{
	"resources": {
		"includes": [
			{ "pattern": "\\Q/\\E"},
			{ "pattern": "\\Qcom/\\E.*"},
			{ "pattern": "\\Qcom\\E"},
		],
		"excludes": [
			{ "pattern": "\\Qcom/example/\\E.*"},
			{ "pattern": "\\Qcom/example/ignore/all.properties\\E"}
		]
	}
}

I think it can be quite complicated in some cases to filter it out properly. However, a simple filter is possible - for example, if it's the same or if a particular "include" is of a particular pattern of some "exclude" - then remove this "include".

Alsoб just for a note, here is the corresponding implementation in the graalvm: https://github.com/oracle/graal/pull/2912/files#diff-4b973ff5fd08418824ad1f4c7ce54a757b0641094f899f02a1c54fdc112739f2R263. It goes the same way as ResourceHintsPredicates.AggregatedResourcePatternHints, so making such filtering is better but not necessary. I meanб this ticket doesn't look like a bug to me (but probably, I'm missing smth).

[snicoll]

@bdshadow you are correct. I think the assumption made in #28977 was wrong. I think @philwebb thought that you could register an array of includes/excludes pair but, looking at the documentation it really is an array of includes and an array of excludes.

As such, I believe the current behavior is correct based on that constraints. Thanks for bringing this up!

[philwebb]

I think @philwebb thought that you could register an array of includes/excludes pair

No, I didn't think that, but I was worried that users might as include and exclude are on ResourcePatternHints. I think I was thinking a ResourceHints.registerInclude and ResourceHints.registerExclude method might be better to show that includes/excludes are completely independent.

Given that the API is out there and nobody seems to have hit the issue it looks like my fears were unfounded.

[bclozel]

Excludes will go away in #31340 as GraalVM will simplify support on the resource-config format.