chore: import upstream snapshot with attribution

packages/plugin-cli/tests/schema-drift.test.ts

@@ -0,0 +1,60 @@
+/**
+ * Guard against drift between the Zod source of truth and the committed
+ * JSON Schema at `schemas/emdash-plugin.schema.json`.
+ *
+ * The committed JSON Schema is shipped to users via
+ * `node_modules/@emdash-cms/plugin-cli/schemas/emdash-plugin.schema.json`
+ * so editors can offer completion and validation without running our CLI.
+ * If a contributor changes the Zod schema and forgets to regenerate, this
+ * test fails with a clear "run pnpm gen-schema" instruction.
+ *
+ * We assert byte-for-byte equality after re-running the same `toJSONSchema`
+ * call the generator script uses. The generator's wrapping fields (`$id`,
+ * `title`, `description`) are added on top so we replicate them here.
+ */
+
+import { readFile } from "node:fs/promises";
+import { resolve } from "node:path";
+import { fileURLToPath } from "node:url";
+
+import { describe, expect, it } from "vitest";
+import { z } from "zod";
+
+import { ManifestSchema } from "../src/manifest/schema.js";
+
+const HERE = fileURLToPath(new URL(".", import.meta.url));
+const COMMITTED_SCHEMA_PATH = resolve(HERE, "..", "schemas", "emdash-plugin.schema.json");
+
+describe("JSON Schema drift", () => {
+	it("matches the output of z.toJSONSchema(ManifestSchema)", async () => {
+		const committed = await readFile(COMMITTED_SCHEMA_PATH, "utf8");
+
+		// Reproduce the generator script's emit. If this diverges from
+		// `scripts/gen-schema.ts`, update both (the script is the
+		// canonical version users run; this is its mirror).
+		const jsonSchema = z.toJSONSchema(ManifestSchema, {
+			target: "draft-2020-12",
+			reused: "ref",
+		});
+		const document = {
+			$schema: "https://json-schema.org/draft/2020-12/schema",
+			$id: "https://emdashcms.com/schemas/emdash-plugin.schema.json",
+			title: "EmDash plugin manifest (emdash-plugin.jsonc)",
+			description:
+				"Authoring format for publishing plugins to the EmDash plugin registry. Translated to the on-wire atproto record format at publish time. See https://github.com/emdash-cms/emdash/issues/1028.",
+			...jsonSchema,
+		};
+		const regenerated = `${JSON.stringify(document, null, "\t")}\n`;
+
+		// On failure, the diff is enormous and unreadable. Surface a
+		// pointer to the fix command instead.
+		if (committed !== regenerated) {
+			throw new Error(
+				"schemas/emdash-plugin.schema.json is out of date with the Zod schema.\n" +
+					"Run: pnpm --filter @emdash-cms/plugin-cli gen-schema\n" +
+					"Then commit the result.",
+			);
+		}
+		expect(committed).toBe(regenerated);
+	});
+});