[FIX] In the ‘Method Constraints’ tab: Disable and explain methods that require resources not added in the ‘Resource input’ tab

tabs/tab2_constraints.py

@@ -51,6 +51,49 @@ def get_hidden_resources_for_method(m, method_to_primary_resources, cost_sliders
     return required, optional
 
 
+def get_uncovered_hidden_resources(m, cost_sliders_norm):
+    """Return (required, optional) hidden resources for method m that leave it unconstrained.
+
+    A hidden resource is "uncovered" only when the user has provided no resource
+    at all from the same group — neither a standard cap (> 0 in tab1) nor a
+    custom batch assigned to this method.  If at least one standard resource in
+    the group has a positive cap, the method is already constrained by it and the
+    missing hidden resource does not inflate results.
+
+    Returns:
+        tuple[list[str], list[str]]: (required, optional) uncovered hidden resource names.
+            required — must be added for the method to run (not in secondary_resources).
+            optional — in secondary_resources, shown as informational only.
+            Returns ([], []) when nothing is uncovered.
+    """
+    from config.config import resource_groups
+
+    custom_resources = st.session_state.get("custom_resources", [])
+    covered = {b["name"] for b in custom_resources if m in b.get("methods", {})}
+    resource_caps = st.session_state.get("resource_caps", {})
+    resource_to_group = {r: g for g, resources in resource_groups.items() for r in resources}
+
+    required, optional = [], []
+    for r, coeff_dict in cost_sliders_norm.get(m, {}).items():
+        if r not in hidden_resource_names:
+            continue
+        if coeff_dict.get("median", 0.0) <= 0:
+            continue
+        if r in covered:
+            continue
+        group = resource_to_group.get(r)
+        group_resources = resource_groups.get(group, []) if group else []
+        standard_in_group = [s for s in group_resources if s not in hidden_resource_names]
+        any_standard_provided = any(resource_caps.get(s, 0.0) > 0 for s in standard_in_group)
+        if any_standard_provided:
+            continue
+        if (m, r) in secondary_resources:
+            optional.append(r)
+        else:
+            required.append(r)
+    return required, optional
+
+
 def render_method(m, cols, i, method_to_primary_resources, cost_sliders_norm):
     """Render the constraint widget group (toggle + cap slider/input) for one method.
 
@@ -75,6 +118,22 @@ def render_method(m, cols, i, method_to_primary_resources, cost_sliders_norm):
         toggle_key = f"toggle_{m}"
         cap_type_key = f"cap_type_{m}"
 
+        # Check for missing hidden resources BEFORE the toggle widget is
+        # instantiated — Streamlit forbids modifying a widget's session-state
+        # key after the widget has been created.
+        uncovered_required, uncovered_optional = get_uncovered_hidden_resources(m, cost_sliders_norm)
+        if uncovered_required:
+            st.session_state.constraints[m]["active"] = False
+            st.session_state[toggle_key] = False
+            st.toggle(m, key=toggle_key, help=tooltip, disabled=True)
+            req_list = "\n".join(f"- **{r}** *(required)*" for r in uncovered_required)
+            opt_list = "\n".join(f"- **{r}** *(optional)*" for r in uncovered_optional) if uncovered_optional else ""
+            body = f"To use this method, add a new resource in the **Resource inputs** tab:\n\n{req_list}"
+            if opt_list:
+                body += f"\n{opt_list}"
+            st.info(body, icon=":material/info:")
+            return
+
         was_active = constraint["active"]
         st.session_state.setdefault(toggle_key, was_active)