Change GeneralScriptException to 400

[rjernst]

Errors in scripts are generally due to user errors in the script itself. ScriptException has a 400 status code reflecting that fact, but GeneralScriptException uses the default 500 status code. This commit fixes GeneralScriptException to match the 400 status code of other scripting errors.

[elasticsearchmachine]

Pinging @elastic/es-core-infra (Team:Core/Infra)

[elasticsearchmachine]

Hi @rjernst, I've created a changelog YAML for you.

[javanna]

LGTM

For posterity, we caught this in a scenario where the cause was a circuit breaking exception, whose status code was ignored.

org.elasticsearch.script.GeneralScriptException: Failed to compile inline script [if (doc.containsKey('live_start') && !doc['live_start'].empty && doc.containsKey('live_end') && !doc['live_end'].empty) { long now = 1751987618176L; boolean afterStart = now >= doc['live_start'].value.toInstant().toEpochMilli(); boolean beforeEnd = now < doc['live_end'].value.toInstant().toEpochMilli(); return afterStart && beforeEnd ? 1 : 0; } return 0;] using lang [painless]
	at [email protected]/org.elasticsearch.script.ScriptCache.compile(ScriptCache.java:120)
	at [email protected]/org.elasticsearch.script.ScriptService.compile(ScriptService.java:634)
	at [email protected]/org.elasticsearch.index.query.SearchExecutionContext.compile(SearchExecutionContext.java:581)
	at [email protected]/org.elasticsearch.search.sort.ScriptSortBuilder.fieldComparatorSource(ScriptSortBuilder.java:331)
	at [email protected]/org.elasticsearch.search.sort.ScriptSortBuilder.build(ScriptSortBuilder.java:251)
	at [email protected]/org.elasticsearch.search.sort.SortBuilder.buildSort(SortBuilder.java:161)
	at [email protected]/org.elasticsearch.search.sort.SortBuilder.buildSort(SortBuilder.java:153)
	at [email protected]/org.elasticsearch.search.SearchService.parseSource(SearchService.java:1574)
	at [email protected]/org.elasticsearch.search.SearchService.createContext(SearchService.java:1335)
	at [email protected]/org.elasticsearch.search.SearchService.executeQueryPhase(SearchService.java:869)
	at [email protected]/org.elasticsearch.search.SearchService.lambda$executeQueryPhase$7(SearchService.java:710)
	at [email protected]/org.elasticsearch.action.ActionRunnable$3.accept(ActionRunnable.java:79)
	at [email protected]/org.elasticsearch.action.ActionRunnable$3.accept(ActionRunnable.java:76)
	at [email protected]/org.elasticsearch.action.ActionRunnable$4.doRun(ActionRunnable.java:101)
	at [email protected]/org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:27)
	at [email protected]/org.elasticsearch.common.util.concurrent.TimedRunnable.doRun(TimedRunnable.java:35)
	at [email protected]/org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:1044)
	at [email protected]/org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:27)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1095)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:619)
	at java.base/java.lang.Thread.run(Thread.java:1447)
Caused by: org.elasticsearch.common.breaker.CircuitBreakingException: [script] Too many dynamic script compilations within, max: [150/5m]; please use indexed, or scripts with parameters instead; this limit can be changed by the [script.max_compilations_rate] setting
	at [email protected]/org.elasticsearch.script.ScriptCache.checkCompilationLimit(ScriptCache.java:178)
	at [email protected]/org.elasticsearch.script.ScriptCache.lambda$compile$0(ScriptCache.java:107)
	at [email protected]/org.elasticsearch.common.cache.Cache.computeIfAbsent(Cache.java:440)
	at [email protected]/org.elasticsearch.script.ScriptCache.compile(ScriptCache.java:91)
	... 20 more

Another path in that specific case may have been to surface the status code of the root cause perhaps (in that case 429 then), but I am not familiar enough with script exceptions to tell which way is better.