ScriptTransformationService: Implement missing script dependency tracking

[florian-h05]

Fixes #5046.

[dilyanpalauzov]

In the use case described at #5046 with automation/js/node_modules/nmod1/index.js

var a = "G"
console.log("uuu")
module.exports = { a }

sitemap

sitemap cd label="B" {
  Text item=x label="Y [JS(|require('nmod1').a + ' E'):%s]"
}

and the current change applied, when I change index.js sometimes it works, and sometimes it logs

2025-10-07 17:21:38.913 [WARN ] [ui.internal.items.ItemUIRegistryImpl] - Failed transforming the value 'NULL' with pattern 'JS(|require('nmod1').a + ' E'):NULL': Transformation service of type 'JS' threw an exception: null

and shows in the sitemap "Y -".

I think I have to reload the sitemap twice. The first time the above waring is logged, the second time console.log("uuu") is executed (logged) and the transformation is applied correctly using OH 5.1.0 Build 4847.

[florian-h05]

I see the the root cause of the issue, close is called two times inside the ScriptTransformationService if ScriptEngine implements Compilable, else once, and after the engine is already closed, on the next invocation of transform the ScriptEngineManager::createScriptEngine call causes the ScriptEngineManager to internally clean up the old engine, calling scriptUnloaded on the closed engine.

[florian-h05]

See #5063 for that fix.

[dilyanpalauzov]

With both patches applied, it works. After changing the dependency, the dependency is reloaded when:

• the sitemap is reloaded (F5 key in the browser), that probably means when the transformation is executed again, or
• the item, involved in the transformation is changed with curl --header "Content-Type: text/plain" -H POST "http://192.168.0.11:8080/rest/items/x" --data "a"

After changing the dependency, the dependency does not reload when:

• nothing else happens, or
• the item is updated, e.g. with curl --header "Content-Type: text/plain" -H POST "http://192.168.0.11:8080/rest/items/x" --data "abcM" when the value is not changed.

[florian-h05]

Turn on debug logging and you will see the script is always reloaded when the dependency changes.
You can't close from Item state change to dependency reload, on dependency change the transformation is not invoked again for all Items it is used on. And architecture-wise this isn’t possible. So you make sure yourself the transformation is invoked again, e.g. by reloading the page.

[dilyanpalauzov]

Turn on debug logging and you will see the script is always reloaded when the dependency changes.

I mean above with reload, that if the dependency contains console.log("uuu") uuu is not logged. So it is maybe reloaded in memory as bytecode, but the dependency is not executed.

[florian-h05]

When the dependency changes, the bytecode of the script is thrown away.
The script and thus the dependency is loaded again when the transformation is invoked the next time. Not before.

I use a JS transformation with an Item, the transformation depends on the items namespace from openhab-js:

1. Open the Item in Main UI. The transformation gets invoked.
2. Edit node_modules/openhab/src/items/items.js, add a log statement.
3. ScriptTransformation service clears the cache for the transformation script
4. I reload the Main UI page, so the transformation gets invoked again.
5. Now the log statement is executed, as the dependency is now loaded when the script is loaded.

Proper behaviour.