refactor(ssr): wizard2 engine absorbs the per-consumer boilerplate (review follow-up)

Adversarial review of Phase 6 found the engine's coupling had relocated rather than
dissolved: every wizard consumer had to hand-build a decode allowlist, re-implement the
open-handler modal wrap, mint temp ids for added rows, and hand-roll the nav buttons +
Enter guard. The engine had the information to prevent all four. Now it does:

- handle-step-submit strips its own nav fields (wizard-id/current-step/direction) from
  form-params before calling a step's :decode -- no per-consumer allowlist, and they can
  no longer leak into the saved entity (the Phase-6 "500 on save" class of bug is
  structurally impossible).
- open-wizard takes an :open-response config fn and owns the create!/render/wrap/thread
  flow, so modal wizards route through (partial wizard2/open-wizard config) directly.
- wizard2/blank-row supplies a temp :db/id (+ :new?) so an added row passes schema
  validation and the step actually advances.
- wizard2/nav-footer emits the direction buttons (Back/advance/Save), marks the primary,
  and wizard-form guards Enter to trigger the primary button.

Consumer (transaction_rules.clj) gets correspondingly leaner: deleted rule-form-keys +
the decode allowlist, rule-nav, and the hand-rolled open-rule-wizard; new/edit routes are
now (partial wizard2/open-wizard config). A new wizard is now just a config map + the step
:render fns. LOC 964 -> 932, and the deleted code was exactly the cross-consumer
boilerplate, not modal-specific logic.

Verification: rule spec 4/4; full suite 55/55; cljfmt clean. Skill gotchas updated from
"three traps" to "use the engine's primitives" (the engine now absorbs them).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.claude/skills/ssr-form-migration/reference/gotchas.md

@@ -265,23 +265,31 @@ carve-out. Verify with `load-file` (compile) + `lein cljfmt check`, not by eyeba
 diff is contained with `git diff -U0 <file> | grep '^@@'` — the hunks should cluster only where you
 edited (requires + the modal region), nothing else.
 
-## Wiring a modal onto the wizard2 engine — three traps that cost a debug cycle each
+## Wiring a modal onto the wizard2 engine — use the engine's primitives, don't re-roll them
 
-1. **Strip the engine's nav fields in the step `:decode`.** The posted form carries
+Phase 6's first migration (Transaction Rule) hit three traps; an adversarial review pointed
-   `wizard-id` / `current-step` / `direction` alongside the real fields. If the step schema is
+out the engine had the information to prevent all three, so **the engine now absorbs them**.
-   an open `:map` (most are), `mc/decode` keeps them, they ride into `get-all`, and the save's
+A consumer is just a config map + the step `:render` fns — reach for these instead of
-   `:upsert-entity` dies with `:db.error/not-an-entity ... :current-step`. Fix: `select-keys`
+re-implementing them (and re-hitting the bug):
-   the decode to the schema's known top-level keys (the same allowlist trick as the flat-form
+
-   migrations). Symptom is a **500 on save**, not a validation message.
+- **Nav fields are stripped for you.** `handle-step-submit` `dissoc`s its own
-2. **New repeated-row needs a temp `:db/id` or the step can't advance.** If the row schema
+  `wizard-id`/`current-step`/`direction` from `:form-params` before calling a step's
-   requires `[:db/id [:or entity-id temp-id]]`, an added row with no id fails per-step
+  `:decode` (`wizard2.clj`), so your decode sees only real fields and they can't ride into
-   validation, so the engine re-renders the *same* step instead of advancing — looks like "the
+  the saved entity. (The old failure was a **500 on save** — `:db.error/not-an-entity
-   Next/Test button does nothing." Give new rows `(str (java.util.UUID/randomUUID))`.
+  :current-step` — because an open `:map` decode kept them. No allowlist needed anymore.)
-3. **Nav is a `direction` field, and Back/Save are both submit buttons.** The footer buttons
+- **`wizard2/open-wizard` owns the modal wrap.** Give the config an `:open-response` fn
-   are plain `<button type="submit" name="direction" value="next|back|submit">`; the clicked
+  (e.g. `(fn [form] (modal-response [:div#transitioner.flex-1 form]))`); then the
-   one's value rides in the POST and the engine branches on it. In tests, a selector like
+  new/edit routes are literally `(partial wizard2/open-wizard config)`. Don't hand-roll
-   `button:has-text("Save"), button[type=submit]` also matches **Back** (also a submit) and
+  `create!/render/wrap/thread` — that boilerplate was duplicating engine internals.
-   `.first()` clicks Back — target the button by its text/value precisely.
+- **Add rows with `wizard2/blank-row`.** It supplies a temp `:db/id` (so a row schema
+  requiring `[:db/id [:or entity-id temp-id]]` validates and the step actually advances —
+  the old symptom was "the Next/Test button does nothing") plus `:new?` for the appear
+  animation: `(wizard2/blank-row :foo/location "Shared")`.
+- **Footer with `wizard2/nav-footer`.** It emits the `direction` submit buttons (Back /
+  primary advance / Save), marks the advance/save button `data-primary`, and the form's
+  Enter guard (`wizard2/wizard-form`) triggers `data-primary` — so Enter and Back/Save
+  aren't left to per-consumer convention. (Testing note that survives: Back and Save are
+  *both* `type=submit`, so target a save button by its text, not `button[type=submit]`.)
 
 ## Scorecard exceptions (ratchet violations with a reason)
 

src/clj/auto_ap/ssr/admin/transaction_rules.clj

@@ -16,7 +16,6 @@
    [auto-ap.ssr-routes :as ssr-routes]
    [auto-ap.ssr.company :refer [bank-account-typeahead*]]
    [auto-ap.ssr.components :as com]
-   [auto-ap.ssr.components.wizard-state :as ws]
    [auto-ap.ssr.components.wizard2 :as wizard2]
    [auto-ap.ssr.grid-page-helper :as helper :refer [wrap-apply-sort]]
    [auto-ap.ssr.hx :as hx]
@@ -664,19 +663,6 @@
    (com/modal-body {} body)
    (com/modal-footer {} footer)))
 
-(defn- rule-nav
-  "Footer step controls. Buttons post a `direction` field the engine reads:
-   next = validate + advance, back = no validate, submit = finish."
-  [{:keys [next back? save?]}]
-  [:div.flex.justify-end.gap-x-4
-   [:div#form-errors]
-   (when back?
-     (com/button {:type "submit" :name "direction" :value "back" :class "w-24"} "Back"))
-   (when next
-     (com/button {:type "submit" :name "direction" :value "next" :color :primary :class "w-24"} next))
-   (when save?
-     (com/button {:type "submit" :name "direction" :value "submit" :color :primary :class "w-24" :x-ref "next"} "Save"))])
-
 (defn render-edit-step
   "Edit step: the rule form, de-cursored (explicit data + path->name2 + *errors*)."
   [{:keys [step-data errors]}]
@@ -783,7 +769,7 @@
                                                       :name (fname :transaction-rule/transaction-approval-status)
                                                       :size :small
                                                       :orientation :horizontal}))]]]
-       :footer (rule-nav {:next "Test"})))))
+       :footer (wizard2/nav-footer {:next "Test"})))))
 
 (defn render-test-step
   "Test step: a read-only preview of the transactions the rule (the combined session
@@ -793,24 +779,15 @@
    :head [:div.p-2.flex.space-x-4 [:div "Transaction Rule"] [:div ">"] [:div "Results"]]
    :body [:div.space-y-1 {:class "w-[850px] h-[600px]"}
           (transaction-rule-test-table* {:entity all-data :clients (:clients request)})]
-   :footer (rule-nav {:back? true :save? true})))
+   :footer (wizard2/nav-footer {:back? true :save? true})))
-
-(def ^:private rule-form-keys
-  "Top-level keys form-schema recognises. The posted form also carries the engine's nav
-   fields (wizard-id / current-step / direction); without this allowlist they'd ride into
-   the decoded rule (form-schema is an open :map) and break the upsert."
-  [:db/id :transaction-rule/client :transaction-rule/client-group :transaction-rule/description
-   :transaction-rule/bank-account :transaction-rule/amount-gte :transaction-rule/amount-lte
-   :transaction-rule/dom-gte :transaction-rule/dom-lte :transaction-rule/vendor
-   :transaction-rule/transaction-approval-status :transaction-rule/accounts])
 
 (defn- decode-rule-form
-  "Parse the posted edit-step fields straight into the rule map (no step-params prefix);
+  "Parse the posted edit-step fields straight into the rule map (no step-params prefix).
-   strip the stray engine nav fields."
+   The engine has already stripped its own nav fields (wizard-id / current-step /
+   direction), so they can't leak into the decoded rule."
   [request]
-  (let [nested (:form-params (nfp/nested-params-request request {}))
+  (let [nested (:form-params (nfp/nested-params-request request {}))]
-        decoded (mc/decode form-schema nested main-transformer)]
+    (mc/decode form-schema nested main-transformer)))
-    (if (map? decoded) (select-keys decoded rule-form-keys) {})))
 
 (defn- rule-form-errors
   "Per-step validation: schema-validate so an invalid form can't advance to the test step
@@ -846,6 +823,11 @@
    :init-fn (fn [request]
               {:context {}
                :init-data (when-let [e (:entity request)] {:edit e})})
+   ;; The engine owns the modal wrap: open-wizard applies this to the rendered form, so the
+   ;; new/edit routes are just (partial wizard2/open-wizard config) -- no hand-rolled
+   ;; create!/render/wrap/thread boilerplate.
+   :open-response (fn [form]
+                    (modal-response [:div#transitioner.flex-1 form]))
    :steps [{:key :edit
             :decode decode-rule-form
             :validate rule-form-errors
@@ -857,18 +839,6 @@
             :next (fn [_] :done)}]
    :done-fn save-rule!})
 
-(defn open-rule-wizard
-  "Open handler (new or edit): create the wizard instance, render its first step, and
-   wrap it in the modal shell the stack expects."
-  [request]
-  (let [cfg transaction-rule-wizard-config
-        {:keys [context init-data]} ((:init-fn cfg) request)
-        [id session'] (ws/create-wizard! (:session request) (:name cfg)
-                                         {:first-step :edit :context context :init-data init-data})
-        form (wizard2/render-wizard {:config cfg :wizard-id id :session session' :request request})]
-    (-> (modal-response [:div#transitioner.flex-1 form])
-        (assoc :session session'))))
-
 (defn save-step
   "POST handler for every step transition (next / back / save) -- the engine reads the
    `direction` field and either advances, goes back, or finishes via done-fn."
@@ -884,9 +854,7 @@
         client-id (-> request :query-params :client-id)
         client-locations (some->> client-id (pull-attr (dc/db conn) :client/locations))]
     (html-response
-     (transaction-rule-account-row* {:db/id (str (java.util.UUID/randomUUID))
+     (transaction-rule-account-row* (wizard2/blank-row :transaction-rule-account/location "Shared")
-                                     :new? true
-                                     :transaction-rule-account/location "Shared"}
                                     idx client-id client-locations))))
 
 (def key->handler
@@ -948,11 +916,11 @@
                                 (wrap-entity [:route-params :db/id] default-read)
                                 (wrap-schema-enforce :route-schema [:map [:db/id entity-id]]))
 
-     ::route/edit-dialog (-> open-rule-wizard
+     ::route/edit-dialog (-> (partial wizard2/open-wizard transaction-rule-wizard-config)
                              (wrap-entity [:route-params :db/id] default-read)
                              (wrap-schema-enforce :route-schema [:map [:db/id entity-id]]))
 
-     ::route/new-dialog  open-rule-wizard})
+     ::route/new-dialog  (partial wizard2/open-wizard transaction-rule-wizard-config)})
    (fn [h]
      (-> h
          (wrap-copy-qp-pqp)

src/clj/auto_ap/ssr/components/wizard2.clj

@@ -47,17 +47,46 @@
 
 (defn wizard-form
   "Wrap a step body in the wizard <form>: the form posts to the submit route, and only the
-   wizard-id + current-step ride along (no accumulated data — that lives in the session)."
+   wizard-id + current-step ride along (no accumulated data — that lives in the session).
+   Enter is guarded so it triggers the step's primary nav button (the one marked
+   `data-primary`) rather than whichever submit button the browser picks first."
   [config wizard-id current-step body]
   [:form (merge {:id (:form-id config "wizard-form")
                  :hx-post (:submit-route config)
                  :hx-target "this"
-                 :hx-swap "outerHTML"}
+                 :hx-swap "outerHTML"
+                 "@keydown.enter.prevent.stop" "$el.querySelector('[data-primary]')?.click()"}
                 (:form-attrs config))
    (com/hidden {:name "wizard-id" :value wizard-id})
    (com/hidden {:name "current-step" :value (name current-step)})
    body])
 
+(defn nav-footer
+  "Standard wizard footer controls — so consumers don't hand-roll the `direction` buttons
+   (and mis-target Back vs Save, or forget the Enter guard). Buttons post a `direction`
+   field the engine branches on; the advance/save button is marked `data-primary` so the
+   form's Enter guard triggers it. Also renders the `#form-errors` slot.
+
+     (nav-footer {:next \"Test\"})            ; an intermediate step: Next
+     (nav-footer {:back? true :save? true})  ; the last step: Back + Save"
+  [{:keys [next back? save?]}]
+  [:div.flex.justify-end.items-baseline.gap-x-4
+   [:div#form-errors]
+   (when back?
+     (com/button {:type "submit" :name "direction" :value "back" :class "w-24"} "Back"))
+   (when next
+     (com/button {:type "submit" :name "direction" :value "next" :data-primary "" :color :primary :class "w-24"} next))
+   (when save?
+     (com/button {:type "submit" :name "direction" :value "submit" :data-primary "" :color :primary :class "w-24"} "Save"))])
+
+(defn blank-row
+  "A fresh repeated-row map for an 'add row' interaction, with a temp `:db/id` (so a row
+   schema requiring `[:db/id [:or entity-id temp-id]]` validates and the step can advance,
+   instead of the add button silently doing nothing) plus `:new?` for the appear
+   animation. Merge in any field defaults: `(blank-row :foo/location \"Shared\")`."
+  [& {:as defaults}]
+  (merge {:db/id (str (java.util.UUID/randomUUID)) :new? true} defaults))
+
 (defn render-wizard
   "Render the current step's body inside the wizard form. `step-data`/`errors` let a
    validation re-render show the just-posted values + messages."
@@ -86,16 +115,23 @@
       (assoc :session session)))
 
 (defn open-wizard
-  "Create a wizard instance in the session and render its first step. `:init-fn` returns
+  "Create a wizard instance in the session, render its first step, and return a Ring
-   {:context ..., :init-data ...} (both optional)."
+   response with the updated session threaded. `:init-fn` returns {:context ..., :init-data
+   ...} (both optional). If the config supplies an `:open-response` fn it is applied to the
+   rendered form hiccup to build the response (e.g. wrap it in a modal shell via
+   modal-response); otherwise a bare html-response is returned. This makes open-wizard
+   directly usable as a route handler — `(partial open-wizard config)` — for modal
+   wizards, instead of every consumer re-implementing create!/render/wrap/thread."
   [config request]
   (let [{:keys [context init-data]} ((:init-fn config) request)
         first-step (-> config :steps first :key)
         [id session'] (ws/create-wizard! (:session request) (:name config)
                                          {:first-step first-step
                                           :context context
-                                          :init-data init-data})]
+                                          :init-data init-data})
-    (render-response config id session' request)))
+        form (render-wizard {:config config :wizard-id id :session session' :request request})
+        resp ((or (:open-response config) html-response) form)]
+    (assoc resp :session session')))
 
 (defn- expired-response
   "The wizard instance is gone from the session (server restart / session expiry / a stale
@@ -127,7 +163,11 @@
 
       :else
       (let [step (step-by-key config current-step)
-            posted ((:decode step) request)
+            ;; The engine owns wizard-id / current-step / direction. Strip them so the
+            ;; step's :decode never sees them and can decode straight into its schema --
+            ;; no per-consumer allowlist, and they can't leak into the saved entity.
+            clean (update request :form-params dissoc "wizard-id" "current-step" "direction")
+            posted ((:decode step) clean)
             errors (when-let [v (:validate step)] (v posted request))]
         (if (seq errors)
           (render-response config wizard-id session request