fix: add React 19 / SSR compatibility guards (#1363)

- Schema: return null for empty oneOf/anyOf arrays instead of
  passing zero TabItems to SchemaTabs (which would throw)
- SchemaTabs: filter null/undefined children and wrap
  sanitizeTabsChildren in try-catch; return null if no valid
  children survive sanitization
- MethodEndpoint: early-return a static render during SSR to
  avoid useSelector running outside a Redux Provider

Closes #1130. Partial credit to @stuartbuckell (PR #1257).

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: sserrata

packages/docusaurus-theme-openapi-docs/src/theme/ApiExplorer/MethodEndpoint/index.tsx

@@ -8,6 +8,7 @@
 import React from "react";
 
 import BrowserOnly from "@docusaurus/BrowserOnly";
+import ExecutionEnvironment from "@docusaurus/ExecutionEnvironment";
 import { useTypedSelector } from "@theme/ApiItem/hooks";
 
 function colorForMethod(method: string) {
@@ -38,6 +39,26 @@ export interface Props {
 }
 
 function MethodEndpoint({ method, path, context }: Props) {
+  // During SSR, render without Redux store access to avoid "Cannot read properties
+  // of null (reading 'store')" errors caused by useSelector running outside a Provider.
+  if (!ExecutionEnvironment.canUseDOM) {
+    return (
+      <>
+        <pre className="openapi__method-endpoint">
+          <span className={"badge badge--" + colorForMethod(method)}>
+            {method === "event" ? "Webhook" : method.toUpperCase()}
+          </span>{" "}
+          {method !== "event" && (
+            <h2 className="openapi__method-endpoint-path">
+              {`${path.replace(/{([a-z0-9-_]+)}/gi, ":$1")}`}
+            </h2>
+          )}
+        </pre>
+        <div className="openapi__divider" />
+      </>
+    );
+  }
+
   let serverValue = useTypedSelector((state: any) => state.server.value);
   let serverUrlWithVariables = "";
 

packages/docusaurus-theme-openapi-docs/src/theme/Schema/index.tsx

@@ -214,6 +214,14 @@ const AnyOneOf: React.FC<SchemaProps> = ({
   schemaPath,
 }) => {
   const key = schema.oneOf ? "oneOf" : "anyOf";
+  const schemaArray = schema[key];
+
+  // Empty oneOf/anyOf arrays are valid in OpenAPI specs but would cause the
+  // Tabs component to throw "requires at least one TabItem". Return null instead.
+  if (!schemaArray || !Array.isArray(schemaArray) || schemaArray.length === 0) {
+    return null;
+  }
+
   const type = schema.oneOf
     ? translate({ id: OPENAPI_SCHEMA_ITEM.ONE_OF, message: "oneOf" })
     : translate({ id: OPENAPI_SCHEMA_ITEM.ANY_OF, message: "anyOf" });

packages/docusaurus-theme-openapi-docs/src/theme/SchemaTabs/index.tsx

@@ -223,16 +223,43 @@ function TabsComponent(props: SchemaTabsProps): React.JSX.Element {
     </div>
   );
 }
-export default function SchemaTabs(props: SchemaTabsProps): React.JSX.Element {
+export default function SchemaTabs(
+  props: SchemaTabsProps
+): React.JSX.Element | null {
   const isBrowser = useIsBrowser();
+
+  const children = Array.isArray(props.children)
+    ? props.children.filter(Boolean)
+    : props.children
+      ? [props.children]
+      : [];
+
+  if (children.length === 0) {
+    return null;
+  }
+
+  let sanitizedChildren;
+  try {
+    sanitizedChildren = sanitizeTabsChildren(children);
+  } catch {
+    return null;
+  }
+
+  if (
+    !sanitizedChildren ||
+    (Array.isArray(sanitizedChildren) && sanitizedChildren.length === 0)
+  ) {
+    return null;
+  }
+
   return (
     <TabsComponent
       // Remount tabs after hydration
       // Temporary fix for https://github.com/facebook/docusaurus/issues/5653
       key={String(isBrowser)}
       {...props}
     >
-      {sanitizeTabsChildren(props.children)}
+      {sanitizedChildren}
     </TabsComponent>
   );
 }