feat: add layered render recovery boundaries

tests/component/render-boundary.test.jsx

@@ -0,0 +1,87 @@
+// @vitest-environment jsdom
+
+import { render, screen } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { describe, expect, it, vi } from "vitest";
+
+import { createFailure } from "../../src/contracts/errors.js";
+import { deriveAsyncState } from "../../src/application/view-models/async-state.js";
+import { AsyncSurface } from "../../src/presentation/components/async-surface.jsx";
+import { BootErrorShell } from "../../src/presentation/boundaries/boot-error-shell.jsx";
+import { FeatureBoundary } from "../../src/presentation/boundaries/render-error-boundary.jsx";
+
+function Defect() {
+  throw new Error("raw render stack");
+}
+
+describe("render recovery boundaries", () => {
+  it("catches programmer defects and emits best-effort safe telemetry", () => {
+    const telemetry = { emit: vi.fn() };
+    render(
+      <FeatureBoundary
+        routeId="APP_HOME"
+        buildId="build-a"
+        telemetry={telemetry}
+      >
+        <Defect />
+      </FeatureBoundary>,
+    );
+
+    expect(screen.getByRole("alert")).toHaveTextContent("error.render_failure");
+    expect(telemetry.emit).toHaveBeenCalledWith("ui.render.failed", {
+      route_id: "APP_HOME",
+      build_id: "build-a",
+      component_boundary: "feature",
+    });
+  });
+
+  it("keeps normalized operational failures in normal async state", () => {
+    const state = deriveAsyncState({
+      failure: createFailure("SERVER_FAILURE", "LIST", 0),
+    });
+    render(
+      <FeatureBoundary routeId="APP_HOME" buildId="build-a">
+        <AsyncSurface state={state} />
+      </FeatureBoundary>,
+    );
+    expect(screen.getByRole("alert")).toHaveTextContent("error.server_failure");
+  });
+
+  it("renders a safe boot shell with no endpoint or stack", () => {
+    render(
+      <BootErrorShell
+        kind="BOOT_CONFIG_FAILURE"
+        code="CONFIG_SCHEMA_INVALID"
+        buildId="build-a"
+        configSchemaVersion="1"
+        supportReference="build-a:CONFIG_SCHEMA_INVALID"
+      />,
+    );
+    const shell = screen.getByRole("alert");
+    expect(shell).toHaveTextContent("build-a:CONFIG_SCHEMA_INVALID");
+    expect(shell).not.toHaveTextContent("https://");
+    expect(shell).not.toHaveTextContent("stack");
+  });
+
+  it("allows a boundary reset action without reloading the page", async () => {
+    let shouldThrow = true;
+    function Recoverable() {
+      if (shouldThrow) throw new Error("defect");
+      return <p>recovered</p>;
+    }
+    const user = userEvent.setup();
+    const view = render(
+      <FeatureBoundary routeId="APP_HOME" buildId="build-a">
+        <Recoverable />
+      </FeatureBoundary>,
+    );
+    shouldThrow = false;
+    await user.click(screen.getByRole("button", { name: "retry" }));
+    view.rerender(
+      <FeatureBoundary routeId="APP_HOME" buildId="build-a">
+        <Recoverable />
+      </FeatureBoundary>,
+    );
+    expect(screen.getByText("recovered")).toBeVisible();
+  });
+});

tests/unit/chunk-recovery.test.js

@@ -0,0 +1,52 @@
+import { describe, expect, it } from "vitest";
+
+import { decideChunkRecovery } from "../../src/application/use-cases/decide-chunk-recovery.js";
+
+function memoryStorage() {
+  let value;
+  return {
+    read: () => ({ ok: true, value }),
+    write: (_key, next) => {
+      value = next;
+      return { ok: true };
+    },
+    remove: () => ({ ok: true }),
+  };
+}
+
+describe("controlled chunk recovery", () => {
+  it("records the release pair before allowing one reload", () => {
+    const storage = memoryStorage();
+    const input = {
+      failureKind: "CHUNK_LOAD_FAILURE",
+      manifestLoaded: true,
+      currentBuildId: "build-a",
+      activeReleaseId: "release-b",
+      storage,
+    };
+    expect(decideChunkRecovery(input)).toEqual({
+      action: "reload-once",
+      releasePair: "build-a->release-b",
+    });
+    expect(decideChunkRecovery(input)).toEqual({
+      action: "support",
+      reason: "reload-already-attempted",
+    });
+  });
+
+  it.each([
+    [{ failureKind: "SERVER_FAILURE" }, "not-recoverable"],
+    [{ manifestLoaded: false }, "manifest-unavailable"],
+    [{ activeReleaseId: "build-a" }, "same-release"],
+  ])("stops when a recovery invariant fails: %#", (override, reason) => {
+    const result = decideChunkRecovery({
+      failureKind: "DEPLOY_MISMATCH",
+      manifestLoaded: true,
+      currentBuildId: "build-a",
+      activeReleaseId: "release-b",
+      storage: memoryStorage(),
+      ...override,
+    });
+    expect(result).toEqual({ action: "support", reason });
+  });
+});