fix(compiler): type-check the emitted ssr binding array and share error handling across call sites

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

packages/compiler/test/api-block-ssr.test.ts

@@ -1,7 +1,58 @@
-import { expect, test } from "bun:test";
+import { afterEach, expect, test } from "bun:test";
+import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
 import { parse } from "@wrnexus/syntax";
 import { generate } from "../src/codegen.ts";
 
+const ROOT_TSCONFIG = join(import.meta.dir, "../../../tsconfig.json").replace(/\\/g, "/");
+// The repo's own tsc, not a `bunx`-fetched one — `bunx tsc` can resolve an
+// unrelated TypeScript version that doesn't understand this repo's tsconfig
+// options (observed: it rejected `ignoreDeprecations: "6.0"` and couldn't
+// find the `bun` type-definition entry point), unlike `bun run typecheck`,
+// which uses this same local binary.
+const LOCAL_TSC = join(import.meta.dir, "../../../node_modules/.bin/tsc").replace(/\\/g, "/");
+// `types`/`typeRoots` in an extended tsconfig resolve relative to the config
+// file that's actually invoked (our temp one), not the base file — so the
+// ambient `bun` types need an explicit path back to the repo's node_modules.
+const TYPE_ROOTS = join(import.meta.dir, "../../../node_modules/@types").replace(/\\/g, "/");
+
+const roots: string[] = [];
+afterEach(() => {
+  for (const root of roots.splice(0)) rmSync(root, { recursive: true, force: true });
+});
+
+/**
+ * Runs the real TypeScript compiler over a generated server module. Proves
+ * the emitted `__wrnexusSsrBindings` annotation (and everything else in the
+ * module) actually type-checks — string-containment assertions alone can't
+ * catch a declared type that omits a field every emitted object literal has.
+ */
+function typecheckGenerated(source: string): { ok: boolean; output: string } {
+  const root = mkdtempSync(join(tmpdir(), "wrnexus-ssr-tsc-"));
+  roots.push(root);
+  const file = join(root, "page.ts");
+  writeFileSync(file, source);
+  // Reuse the repo's own tsconfig (paths, lib, types, jsx, ...) so this only
+  // checks the one file we care about instead of hand-duplicating the whole
+  // compiler configuration (and drifting from it over time).
+  writeFileSync(
+    join(root, "tsconfig.json"),
+    JSON.stringify({
+      extends: ROOT_TSCONFIG,
+      compilerOptions: { noEmit: true, typeRoots: [TYPE_ROOTS] },
+      include: ["page.ts"],
+    }),
+  );
+  const result = Bun.spawnSync([LOCAL_TSC, "--project", join(root, "tsconfig.json")], {
+    cwd: root,
+    stdout: "pipe",
+    stderr: "pipe",
+  });
+  const output = `${result.stdout?.toString() ?? ""}${result.stderr?.toString() ?? ""}`;
+  return { ok: result.exitCode === 0, output };
+}
+
 function serverModule(inner: string): string {
   return generate(
     parse(`page Repro {
@@ -60,3 +111,95 @@ test("an ssr block without an error section emits no catch entry for that bindin
 
   expect(generated).not.toContain('"errorBody"');
 });
+
+test("tsc: a sectioned ssr block's generated module has no diagnostics", () => {
+  const generated = serverModule(`    api ssrUsers GET /api/users {
+      response {
+        return data.users.length
+      }
+      error {
+        return message + status + data
+      }
+    }`);
+
+  const { ok, output } = typecheckGenerated(generated);
+
+  expect(output.trim()).toBe("");
+  expect(ok).toBe(true);
+});
+
+test("an ssr block used in {#each} with an error section runs the error body on failure", async () => {
+  const generated = generate(
+    parse(`page Repro {
+  ssr {
+    api ssrUsers GET /api/users {
+      response {
+        return data.users
+      }
+      error {
+        return ["fallback"]
+      }
+    }
+  }
+
+  view { <main>{#each ssrUsers as u}<p>{u}</p>{/each}</main> }
+}
+`),
+  );
+
+  const root = mkdtempSync(join(tmpdir(), "wrnexus-ssr-each-"));
+  roots.push(root);
+  mkdirSync(root, { recursive: true });
+  const file = join(root, "page.ts");
+  writeFileSync(file, generated);
+
+  const mod = await import(`${file.replace(/\\/g, "/")}?t=${Date.now()}`);
+  const html = await mod.default({
+    req: { url: "http://localhost/", headers: new Headers() },
+    cookies: {},
+    session: {},
+    localStorage: {},
+    __wrnexusCallApi: async () => {
+      throw new Error("boom");
+    },
+  });
+
+  expect(html).toContain("fallback");
+});
+
+test("an ssr block used in {#each} without an error section still propagates a failure", async () => {
+  const generated = generate(
+    parse(`page Repro {
+  ssr {
+    api ssrUsers GET /api/users {
+      response {
+        return data.users
+      }
+    }
+  }
+
+  view { <main>{#each ssrUsers as u}<p>{u}</p>{/each}</main> }
+}
+`),
+  );
+
+  const root = mkdtempSync(join(tmpdir(), "wrnexus-ssr-each-propagate-"));
+  roots.push(root);
+  mkdirSync(root, { recursive: true });
+  const file = join(root, "page.ts");
+  writeFileSync(file, generated);
+
+  const mod = await import(`${file.replace(/\\/g, "/")}?t=${Date.now()}`);
+
+  await expect(
+    mod.default({
+      req: { url: "http://localhost/", headers: new Headers() },
+      cookies: {},
+      session: {},
+      localStorage: {},
+      __wrnexusCallApi: async () => {
+        throw new Error("boom");
+      },
+    }),
+  ).rejects.toThrow("boom");
+});