(~/clojure)-(!2009)-> java -version
openjdk version "17.0.4" 2022-07-19
OpenJDK Runtime Environment (build 17.0.4+8-Ubuntu-120.04)
OpenJDK 64-Bit Server VM (build 17.0.4+8-Ubuntu-120.04, mixed mode, sharing)

Tue Nov 29 09:30:29
(~/clojure)-(!2010)-> echo $JAVA_CMD
/Developer/jdk-19+36/bin/java

Tue Nov 29 09:30:46
(~/clojure)-(!2011)-> clj -Sdeps '{:deps {io.github.clojure/tools.build {:git/tag "v0.8.5" :git/sha "9c738da"}}}'
Clojure 1.11.1
user=> (require '[clojure.tools.build.api :refer :all])
nil
user=> (System/getenv "JAVA_CMD")
"/Developer/jdk-19+36/bin/java"
user=> (System/getProperty "java.version")
"19"
user=> (java-command {:main 'clojure.main :basis (create-basis) :main-args ["-e" "[(System/getenv \"JAVA_CMD\") (System/getProperty \"java.version\")]"]})
{:command-args ["java" "-cp" "src:/home/sean/.m2/repository/org/clojure/clojure/1.11.1/clojure-1.11.1.jar:/home/sean/.m2/repository/org/clojure/core.specs.alpha/0.2.62/core.specs.alpha-0.2.62.jar:/home/sean/.m2/repository/org/clojure/spec.alpha/0.3.218/spec.alpha-0.3.218.jar" "clojure.main" "-e" "[(System/getenv \"JAVA_CMD\") (System/getProperty \"java.version\")]"]}
user=> (process *1)
["/Developer/jdk-19+36/bin/java" "17.0.4"]
{:exit 0}
user=>

I tripped over this writing an external test runner for Polylith (which runs in a subprocess instead of using classloader isolation) and realized it was picking up the system default java so I added "find java" logic based on those env vars to fix it. Then I noticed various subprocesses in our build.clj were also picking up the system default java even tho' they were using java-command and so they were running with JDK 17 instead of JDK 19 (which the top-level build stuff was using since JAVA_CMD was set).

I think there's a jira for this, haven't gotten to it yet

https://clojure.atlassian.net/browse/TBUILD-34 ?

That's just for compile-clj

well feel free to expand its scope in the jira

OK, wanted to check you were amenable to that.

yes, compile-clj relies on java-command so the more generic fix here would cover both

I left the title of TBUILD-34 as-is but added a comment suggesting a expansion of scope.

I had missed that my patch for TDEPS-184 needed additional work, sorry. I don't think I got an email about your comment (or it went into spam).

(I responded with some questions about approach)

I updated my build-clj wrapper to do this defaulting since we needed it at work. Once there's an official solution in tools.build, I can remove it from build-clj (and also update my Polylith external test runner and part of our build.clj file at work -- our exec-command -- to match). Thanks!

yeah, happy to take it on the next time I pass through tbuild