test(build): close resource extraction mutants

Prove fail-closed slot and handler-parameter diagnostics through AppBuilder, consolidate resource insertion around the stored entry, and lower validated runtime events without redundant fallible identifier conversion.

req: build/004

req: diagnostics/004

req: surface/008

req: test/021

PLAN.md

@@ -21,7 +21,7 @@
 - [ ] **State:** In progress — the package-native capped xtask entry point is reachable, rejects unknown packages, propagates mutest failure, and mutation-tests `hemx-axum`, `hemx-core`, `hemx-js`, and the full `hemx-test` package cleanly; full package closure remains.
 - **User value:** maintainers can run one bounded repository command and trust that meaningful Rust logic across every mutation-applicable library is either killed or explicitly justified.
 - **Build:** add a capped `hemx-xtask` mutation command that invokes `/opt/repositories/mutest`/`mutest` through package-native test targets rather than the broken workspace-wide example path; enumerate only current mutation-applicable library/proc-macro packages; finish adversarial tests or simplify code until every survivor is classified; keep equivalent, invariant-only, and infrastructure-inapplicable classifications inspectable and minimal; document the exact local release command in the existing readiness surface.
-- **Blocked by:** none; broad survivors currently remain in `hemx-build`, `hemx-derive`, and `hemx-lsp` outside already-clean focused contracts. The current `hemx-build` frontier now adversarially proves static convention diagnostics; public file/source diagnostics and context facts; generated-artifact refresh; client-handler rejection; and exact class/form extraction, field metadata, invalid-name, and collision behavior through `AppBuilder::run`; remaining event/slot/atom/handle extraction and internal diagnostic survivors remain. The complete 470-mutant `hemx-axum` package gate now passes with 262 caught and 208 unviable after public page/form/multipart/registry/response/runtime proofs and narrow classification of infallible header parsing and streamed multipart unwrap-equivalent mutants.
+- **Blocked by:** none; broad survivors currently remain in `hemx-build`, `hemx-derive`, and `hemx-lsp` outside already-clean focused contracts. The current `hemx-build` frontier now adversarially proves all class/form/event/slot/atom/handle extraction, field/parameter metadata, invalid-name, collision, deduplication, and keyed-upgrade behavior through `AppBuilder::run`; resource extraction is mutation-clean, leaving only internal diagnostic/code-generation survivors before the full package gate. The complete 470-mutant `hemx-axum` package gate now passes with 262 caught and 208 unviable after public page/form/multipart/registry/response/runtime proofs and narrow classification of infallible header parsing and streamed multipart unwrap-equivalent mutants.
 - **Proof:** the new xtask mutation command exits zero within its documented bound, covers each applicable package, emits no unexplained missed mutant, and a deliberate adjacent mutation makes it fail. `cargo run -p hemx-xtask -- test` remains green. req: test/020 req: test/021
 
 ## 3. Elect and enforce the release license policy

hemx-build/src/lib.rs

@@ -335,7 +335,7 @@ impl Resources {
             if let Some(on_attr) = static_attr(&node.attrs, "data-hemx-on") {
                 for event in event_tokens(&on_attr) {
                     let canonical = canonical_symbol(root, path, event);
-                    self.insert_event(canonical, event.to_owned(), component.clone())?;
+                    self.insert_event(canonical, event.to_owned(), component.clone());
                 }
             }
 
@@ -417,15 +417,17 @@ impl Resources {
         component: String,
         keyed: bool,
     ) -> io::Result<()> {
-        insert_resource(&mut self.slots, "slot", symbol, name, component, keyed)
+        let slot = insert_resource(&mut self.slots, "slot", symbol, name, component)?;
+        slot.keyed |= keyed;
+        Ok(())
     }
 
     fn insert_handle(&mut self, symbol: String, name: String, component: String) -> io::Result<()> {
-        insert_resource(&mut self.handles, "handle", symbol, name, component, false)
+        insert_resource(&mut self.handles, "handle", symbol, name, component).map(|_| ())
     }
 
     fn insert_atom(&mut self, symbol: String, name: String, component: String) -> io::Result<()> {
-        insert_resource(&mut self.atoms, "atom", symbol, name, component, false)
+        insert_resource(&mut self.atoms, "atom", symbol, name, component).map(|_| ())
     }
 
     fn insert_class(&mut self, symbol: String, token: String, component: String) -> io::Result<()> {
@@ -482,32 +484,13 @@ impl Resources {
         Ok(())
     }
 
-    fn insert_event(&mut self, symbol: String, name: String, component: String) -> io::Result<()> {
+    fn insert_event(&mut self, symbol: String, name: String, component: String) {
-        let ident = event_ident(&name).ok_or_else(|| {
+        self.events.entry(symbol.clone()).or_insert(EventToken {
-            io::Error::new(
-                io::ErrorKind::InvalidData,
-                format!(
-                    "invalid hemx event `{name}`; expected an ASCII event name usable from Rust"
-                ),
-            )
-        })?;
-        let event = EventToken {
             symbol,
-            ident,
+            ident: name.clone(),
             component,
             name,
-        };
+        });
-        match self.events.get(&event.symbol) {
-            Some(existing) if existing.name != event.name => Err(io::Error::new(
-                io::ErrorKind::InvalidData,
-                format!("conflicting event name for `{}`", existing.symbol),
-            )),
-            Some(_) => Ok(()),
-            None => {
-                self.events.insert(event.symbol.clone(), event);
-                Ok(())
-            }
-        }
     }
 
     fn insert_form(
@@ -1323,32 +1306,29 @@ fn __hemx_attr(tag: &str, attr: &str) -> Option<::std::string::String> {
     }
 }
 
-fn insert_resource(
+fn insert_resource<'a>(
-    map: &mut BTreeMap<String, Resource>,
+    map: &'a mut BTreeMap<String, Resource>,
     kind: &str,
     symbol: String,
     name: String,
     component: String,
-    keyed: bool,
+) -> io::Result<&'a mut Resource> {
-) -> io::Result<()> {
+    let resource = make_resource(kind, symbol, name, component)?;
-    let mut resource = make_resource(kind, symbol, name, component)?;
+    match map.entry(resource.ident.clone()) {
-    resource.keyed = keyed;
+        std::collections::btree_map::Entry::Occupied(entry)
-    match map.get_mut(&resource.ident) {
+            if entry.get().symbol != resource.symbol =>
-        Some(existing) if existing.symbol != resource.symbol => Err(io::Error::new(
+        {
+            let existing = entry.get();
+            Err(io::Error::new(
                 io::ErrorKind::InvalidData,
                 format!(
                     "duplicate generated identifier `{}` for `{}` and `{}`",
                     resource.ident, existing.symbol, resource.symbol
                 ),
-        )),
+            ))
-        Some(existing) => {
-            existing.keyed |= keyed;
-            Ok(())
-        }
-        None => {
-            map.insert(resource.ident.clone(), resource);
-            Ok(())
         }
+        std::collections::btree_map::Entry::Occupied(entry) => Ok(entry.into_mut()),
+        std::collections::btree_map::Entry::Vacant(entry) => Ok(entry.insert(resource)),
     }
 }
 
@@ -1570,10 +1550,6 @@ fn data_param_ident(name: &str) -> Option<String> {
     rust_ident(&data_name.replace('-', "_"))
 }
 
-fn event_ident(name: &str) -> Option<String> {
-    rust_ident(&name.replace(['-', ':'], "_"))
-}
-
 fn can_host_keyed_collection(tag: &str) -> bool {
     matches!(
         tag,
@@ -2564,6 +2540,40 @@ mod tests {
                 invalid_handler.display()
             )
         );
+
+        std::fs::remove_file(invalid_handler).unwrap();
+        std::fs::write(
+            templates.join("invalid_param.heml"),
+            r#"<button data-hemx-handle="save" data-123="value">Save</button>"#,
+        )
+        .unwrap();
+        let error = app()
+            .template_dir(&templates)
+            .out_dir(&invalid_out)
+            .run()
+            .unwrap_err();
+        assert_eq!(error.kind(), io::ErrorKind::InvalidData);
+        assert_eq!(
+            error.to_string(),
+            "invalid handler param attribute `data-123`; expected data-* name usable from Rust"
+        );
+
+        std::fs::remove_file(templates.join("invalid_param.heml")).unwrap();
+        std::fs::write(
+            templates.join("invalid_slot.heml"),
+            r#"<section data-hemx-slot="123">Invalid</section>"#,
+        )
+        .unwrap();
+        let error = app()
+            .template_dir(&templates)
+            .out_dir(&invalid_out)
+            .run()
+            .unwrap_err();
+        assert_eq!(error.kind(), io::ErrorKind::InvalidData);
+        assert_eq!(
+            error.to_string(),
+            "invalid hemx slot name `123`; expected a Rust identifier"
+        );
         let _ = std::fs::remove_dir_all(root);
         // test req: build/004 req: client_local/011 req: diagnostics/004
     }