HS: hyperscript:before:init / :after:init events (+2 tests)

integration.sx hs-activate! now wraps the activation block in a cancelable
hyperscript:before:init event (dispatched on the el via dom-dispatch which
returns the dispatchEvent boolean — true unless preventDefault was called).
On success it dispatches hyperscript:after:init at the end. Both events
bubble so listeners on a containing wa work-area receive them. Generator
gets two hand-rolled deftests that exercise the new dispatch via
hs-boot-subtree!: one captures both events into a list, the other
preventDefaults before:init and asserts data-hyperscript-powered is absent.

hs-upstream-core/bootstrap: 20/26 → 22/26. Smoke 0-195: 170 → 172.

Remaining 4 cluster-29 tests need stricter parser error-rejection
(hs-upstream-core/parser, parse-error event); larger than a single
cluster budget — leave as untranslated for now.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lib/hyperscript/integration.sx

@@ -80,11 +80,14 @@
       ((src (dom-get-attr el "_")) (prev (dom-get-data el "hs-script")))
       (when
         (and src (not (= src prev)))
-        (hs-log-event! "hyperscript:init")
-        (dom-set-data el "hs-script" src)
-        (dom-set-data el "hs-active" true)
-        (dom-set-attr el "data-hyperscript-powered" "true")
-        (let ((handler (hs-handler src))) (handler el))))))
+        (when
+          (dom-dispatch el "hyperscript:before:init" nil)
+          (hs-log-event! "hyperscript:init")
+          (dom-set-data el "hs-script" src)
+          (dom-set-data el "hs-active" true)
+          (dom-set-attr el "data-hyperscript-powered" "true")
+          (let ((handler (hs-handler src))) (handler el))
+          (dom-dispatch el "hyperscript:after:init" nil))))))
 
 ;; ── Boot: scan entire document ──────────────────────────────────
 ;; Called once at page load. Finds all elements with _ attribute,

shared/static/wasm/sx/hs-integration.sx

@@ -80,11 +80,14 @@
       ((src (dom-get-attr el "_")) (prev (dom-get-data el "hs-script")))
       (when
         (and src (not (= src prev)))
-        (hs-log-event! "hyperscript:init")
-        (dom-set-data el "hs-script" src)
-        (dom-set-data el "hs-active" true)
-        (dom-set-attr el "data-hyperscript-powered" "true")
-        (let ((handler (hs-handler src))) (handler el))))))
+        (when
+          (dom-dispatch el "hyperscript:before:init" nil)
+          (hs-log-event! "hyperscript:init")
+          (dom-set-data el "hs-script" src)
+          (dom-set-data el "hs-active" true)
+          (dom-set-attr el "data-hyperscript-powered" "true")
+          (let ((handler (hs-handler src))) (handler el))
+          (dom-dispatch el "hyperscript:after:init" nil))))))
 
 ;; ── Boot: scan entire document ──────────────────────────────────
 ;; Called once at page load. Finds all elements with _ attribute,

spec/tests/test-hyperscript-behavioral.sx

@@ -1396,7 +1396,17 @@
       (hs-activate! _el-div)
     ))
   (deftest "fires hyperscript:before:init and hyperscript:after:init"
-    (error "SKIP (untranslated): fires hyperscript:before:init and hyperscript:after:init"))
+    (hs-cleanup!)
+    (let ((wa (dom-create-element "div"))
+          (events (list)))
+      (dom-listen wa "hyperscript:before:init"
+        (fn (e) (set! events (append events (list "before:init")))))
+      (dom-listen wa "hyperscript:after:init"
+        (fn (e) (set! events (append events (list "after:init")))))
+      (dom-set-inner-html wa "<div _=\"on click add .foo\"></div>")
+      (hs-boot-subtree! wa)
+      (assert= events (list "before:init" "after:init")))
+  )
   (deftest "hyperscript can have more than one action"
     (hs-cleanup!)
     (let ((_el-bar (dom-create-element "div")) (_el-div (dom-create-element "div")))
@@ -1412,7 +1422,15 @@
       (assert (dom-has-class? (dom-query "div:nth-of-type(2)") "blah"))
     ))
   (deftest "hyperscript:before:init can cancel initialization"
-    (error "SKIP (untranslated): hyperscript:before:init can cancel initialization"))
+    (hs-cleanup!)
+    (let ((wa (dom-create-element "div")))
+      (dom-listen wa "hyperscript:before:init"
+        (fn (e) (host-call e "preventDefault")))
+      (dom-set-inner-html wa "<div _=\"on click add .foo\"></div>")
+      (hs-boot-subtree! wa)
+      (let ((d (host-call wa "querySelector" "div")))
+        (assert= (host-call d "hasAttribute" "data-hyperscript-powered") false)))
+  )
   (deftest "logAll config logs events to console"
     (hs-cleanup!)
     (hs-clear-log-captured!)

tests/playwright/generate-sx-tests.py

@@ -1881,6 +1881,39 @@ def generate_eval_only_test(test, idx):
             f'    (assert= (eval-hs "cookies.length") 0))'
         )
 
+    # Special case: cluster-29 init events. The two tractable tests both attach
+    # listeners to a wa container, set its innerHTML to a hyperscript fragment,
+    # then call `_hyperscript.processNode(wa)`. Hand-roll deftests using
+    # hs-boot-subtree! which now dispatches hyperscript:before:init / :after:init.
+    if test.get('name') == 'fires hyperscript:before:init and hyperscript:after:init':
+        return (
+            f'  (deftest "{safe_name}"\n'
+            f'    (hs-cleanup!)\n'
+            f'    (let ((wa (dom-create-element "div"))\n'
+            f'          (events (list)))\n'
+            f'      (dom-listen wa "hyperscript:before:init"\n'
+            f'        (fn (e) (set! events (append events (list "before:init")))))\n'
+            f'      (dom-listen wa "hyperscript:after:init"\n'
+            f'        (fn (e) (set! events (append events (list "after:init")))))\n'
+            f'      (dom-set-inner-html wa "<div _=\\"on click add .foo\\"></div>")\n'
+            f'      (hs-boot-subtree! wa)\n'
+            f'      (assert= events (list "before:init" "after:init")))\n'
+            f'  )'
+        )
+    if test.get('name') == 'hyperscript:before:init can cancel initialization':
+        return (
+            f'  (deftest "{safe_name}"\n'
+            f'    (hs-cleanup!)\n'
+            f'    (let ((wa (dom-create-element "div")))\n'
+            f'      (dom-listen wa "hyperscript:before:init"\n'
+            f'        (fn (e) (host-call e "preventDefault")))\n'
+            f'      (dom-set-inner-html wa "<div _=\\"on click add .foo\\"></div>")\n'
+            f'      (hs-boot-subtree! wa)\n'
+            f'      (let ((d (host-call wa "querySelector" "div")))\n'
+            f'        (assert= (host-call d "hasAttribute" "data-hyperscript-powered") false)))\n'
+            f'  )'
+        )
+
     # Special case: logAll config test. Body sets `_hyperscript.config.logAll = true`,
     # then mutates an element's innerHTML and calls `_hyperscript.processNode`.
     # Our runtime exposes this via hs-set-log-all! + hs-log-captured; we reuse