ES6 client crashes with NoClassDefFoundError: org/apache/logging/log4j/LogManager (log4j fully excluded from the es6 closure)

[fupelaqu]

Found live by the REPL.4 -all bundle E2E smoke against docker ES 6.8.23.

Symptom: the very first ES operations through softclient4es6-rest-client 0.20.1 fail — CREATE TABLE reports Execution failed: org/apache/logging/log4j/LogManager, and any search/scroll path kills the JVM:

java.lang.NoClassDefFoundError: org/apache/logging/log4j/LogManager
  at org.elasticsearch.search.fetch.subphase.highlight.PlainHighlighter.<clinit>(PlainHighlighter.java:57)
  at org.elasticsearch.search.SearchModule.setupHighlighters(SearchModule.java:627)
  at org.elasticsearch.search.SearchModule.<init>(SearchModule.java:307)
  at app.softnetwork.elastic.client.rest.RestHighLevelClientCompanion.namedXContentRegistry(RestHighLevelClientCompanion.scala:48)

Root cause: the published es6 client closure carries ZERO log4j jars — jacksonExclusions/elasticDependencies exclude org.apache.logging.log4j:* and log4j-api, and unlike ES7 (elastic4sDependencies(7) re-adds log4j-api % 2.17.1 for exactly this reason), the ES6 branch does not. The in-source comment "ES6 RHLC needs no log4j" (project/SoftClient4es.scala) is disproved by the live run — ES 6.8's SearchModule/PlainHighlighter.<clinit> hard-reference LogManager just like ES7's RHLC.

Impact: the published plain softclient4es6-cli 0.20.1 assembly and every consumer of softclient4es6-rest-client hit this on first use (pre-existing, independent of the -all bundles).

Fix: mirror the es7 line in elastic4sDependencies(6): add "org.apache.logging.log4j" % "log4j-api" % Versions.log4j — one line. The softclient4es-repl es6 bundle already carries the explicit dependency as a workaround until an engine release ships this.

Verification: after the fix, the softclient4es-repl e2e-smoke.sh 6 recipe (CREATE ×2, INSERT, JOIN, aggregation, SHOW LICENSE vs docker ES 6.8.23) passes — it failed on 0.20.1 and passed with log4j-api added.