REPL hot-reload for workers#88
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Without this exclusion, this is the error that is shown every time temporal.workflow is loaded: WARNING: await already refers to: #'clojure.core/await in namespace: temporal.workflow, being replaced by: #'temporal.workflow/await Signed-off-by: Александар Симић <a@repl.ist>
Workers used to capture activity and workflow function values when they started, which meant re-evaluating a definition at the REPL had no effect until the worker was restarted. Also requested here: manetu#72 Add opt-in hot reload flags that keep dispatch entries linked to vars and resolve them when work is executed. This lets activity changes, and optionally workflow changes, be picked up by a running worker during development. Workflow hot reload remains explicit because workflow code changes can affect replay determinism. Signed-off-by: Александар Симић <a@repl.ist>
thenonameguy
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May 13, 2026
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Great, this will make my life much better. Thanks Alex :)
ghaskins
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Jun 18, 2026
| (let [d (u/find-dispatch dispatch workflow-type) | ||
| f (:fn d) | ||
| (let [d (u/resolve-dispatch ::def (u/find-dispatch dispatch workflow-type)) | ||
| f (u/resolve-dispatch-fn d) |
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IIUC, both resolve-dispatch and resolve-dispatch-fn do a (:var entry) decode. This seems like it could be a TOCTOU race, albeit I think a race with only mild implications. Would we be better off caching (:var) result and using it in both places?
| (defn- -execute | ||
| [ctx dispatch args] | ||
| (let [{:keys [activity-type activity-id] :as _info} (get-info) | ||
| f (u/find-dispatch-fn dispatch activity-type) |
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I think this s-exp is now unused, but it is left defined in the code. If there are no more users, please clean it up.
| (format "%.3fx" (double x)) | ||
| x)) | ||
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| (defn- report-criterium-comparison |
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Two things that make REPLing a bit nicer
1. Silences the clojure.core/await warning
The SDK only ever uses its own
temporal.workflow/await.2. Hot reload, this is the real change in this PR
Adds two opt-in flags that store dispatch entries as Vars and deref them at execution time instead:
Re-evaluate a defactivity and the running worker picks it up immediately. Workflow hot reload is available too but marked as dev-only since workflow changes can mess with replay determinism.
Also closes #72