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  1. camunda BPM
  2. CAM-11090

Cannot resolve S function with enabled Javascript compilation

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    Details

    • Type: Bug Report
    • Status: Closed
    • Priority: L3 - Default
    • Resolution: Fixed
    • Affects Version/s: 7.12.0-alpha6
    • Fix Version/s: 7.12.0
    • Component/s: engine
    • Labels:
      None

      Description

      Scenario:

      • I deploy a process with two Javascript script tasks and run the process. Both tasks use the S function from Spin.

      Current behavior:

      • First task succeeds
      • Second fails, because it cannot find S

      Expected behavior:

      • Both tasks are successful

      Root cause:

      • Script compilation is currently enabled by default (see CAM-10506)
      • A compiled Nashorn script references its script engine; A variable defined by such a script can only be referenced by another script that was compiled with the same script engine
      • We do not cache Nashorn script engines
      • The first script succeeds, because both the environment script defining S, as well as the actual script are compiled with the same scripting engine
      • The second script fails, because the actual script is compiled with a different engine than the (previously compiled) environment script

      Solution approaches:

      • Short-term: Revert changes of CAM-10506 and have a test for this case
      • Long term ideas: Evaluate if script engine caching for Nashorn is possible (not clear, we check this via scriptEngine.getFactory().getParameter("THREADING");, see org.camunda.bpm.engine.impl.scripting.engine.ScriptEngineResolver.isCachable(ScriptEngine). Nashorn returns null indicating a scripting engine is not thread-safe). Even if we cache the scripting engine, we must still be aware that we cache scripting engines at different levels (engine-global and process-application-local), so that may require that we keep up to one compiled script per source script on each of these levels. Before we go in this direction, we must have a very good understanding how script compilation and evaluation in Nashorn works (e.g. where the S function ends up when its environment script is evaluated)

      We will go with the short-term solution to avoid regressions.

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              Assignee:
              Unassigned
              Reporter:
              thorben.lindhauer Thorben Lindhauer
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                Updated:
                Resolved: