decide() DSL hardcodes value-param evaluator — JavaScript evaluator unreachable #24

Summary

The decide() DSL method hardcodes evaluator_type = 'value-param' for all SWITCH tasks. Users who need a JavaScript expression evaluator must construct WorkflowTask manually — there is no way to express this through the builder.

Tested against: Conductor OSS 3.32.0-rc.9

Root Cause

# lib/conductor/workflow/dsl/task_ref.rb:110-111
def apply_switch_fields(wf_task)
  wf_task.evaluator_type = 'value-param'  # hardcoded — cannot be 'javascript'
  ...
end

workflow_builder.rb#add_switch_task passes no evaluator_type in options; apply_switch_fields ignores any such option and hardcodes 'value-param'.

The server supports two evaluator types for SWITCH:

• "value-param" — compares inputParameters.switchCaseValue against case strings
• "javascript" — evaluates a full JavaScript expression and matches the result against cases

Impact

Users who want to branch on a computed value (not a simple reference comparison) cannot use the decide DSL. They must construct the task definition raw.

Fix

Thread evaluator_type through from decide():

# workflow_builder.rb
def decide(expression, evaluator_type: 'value-param', &block)
  builder = SwitchBuilder.new(resolve_value(expression), self)
  builder.instance_eval(&block)
  add_switch_task(builder, evaluator_type: evaluator_type)
end

def add_switch_task(builder, evaluator_type: 'value-param')
  task_ref = TaskRef.new(
    ...
    options: {
      expression: builder.expression,
      evaluator_type: evaluator_type,   # ← pass through
      decision_cases: builder.cases,
      default_case: builder.default
    }
  )
  ...
end

# task_ref.rb
def apply_switch_fields(wf_task)
  wf_task.evaluator_type = @options[:evaluator_type] || 'value-param'
  ...
end

Related: JavaScript SDK #139 — same gap.