fix(better-auth): keep package subpaths in sync with build entries (#11822)

.changeset/plugin-subpath-exports.md

@@ -0,0 +1,7 @@
+---
+"better-auth": patch
+---
+
+You can now import the Captcha and OpenAPI plugins from `better-auth/plugins/captcha` and `better-auth/plugins/open-api`, as you can for other plugins. Previously these imports failed with a "not exported" error. Imports from `better-auth/plugins` are unchanged.
+
+If your TypeScript config uses `"moduleResolution": "node"` (or `node10`), `better-auth/plugins/multi-session` and `better-auth/test` now resolve their types. Previously TypeScript reported that it could not find their declarations. Projects using `bundler`, `node16`, or `nodenext` resolution are unaffected.

packages/better-auth/package.json

@@ -231,6 +231,11 @@
       "types": "./dist/plugins/bearer/index.d.mts",
       "default": "./dist/plugins/bearer/index.mjs"
     },
+    "./plugins/captcha": {
+      "dev-source": "./src/plugins/captcha/index.ts",
+      "types": "./dist/plugins/captcha/index.d.mts",
+      "default": "./dist/plugins/captcha/index.mjs"
+    },
     "./plugins/custom-session": {
       "dev-source": "./src/plugins/custom-session/index.ts",
       "types": "./dist/plugins/custom-session/index.d.mts",
@@ -291,6 +296,11 @@
       "types": "./dist/plugins/one-tap/index.d.mts",
       "default": "./dist/plugins/one-tap/index.mjs"
     },
+    "./plugins/open-api": {
+      "dev-source": "./src/plugins/open-api/index.ts",
+      "types": "./dist/plugins/open-api/index.d.mts",
+      "default": "./dist/plugins/open-api/index.mjs"
+    },
     "./plugins/phone-number": {
       "dev-source": "./src/plugins/phone-number/index.ts",
       "types": "./dist/plugins/phone-number/index.d.mts",
@@ -370,6 +380,9 @@
       "api": [
         "./dist/api/index.d.mts"
       ],
+      "test": [
+        "./dist/test-utils/index.d.mts"
+      ],
       "db": [
         "./dist/db/index.d.mts"
       ],
@@ -430,6 +443,9 @@
       "plugins/bearer": [
         "./dist/plugins/bearer/index.d.mts"
       ],
+      "plugins/captcha": [
+        "./dist/plugins/captcha/index.d.mts"
+      ],
       "plugins/custom-session": [
         "./dist/plugins/custom-session/index.d.mts"
       ],
@@ -451,12 +467,18 @@
       "plugins/one-tap": [
         "./dist/plugins/one-tap/index.d.mts"
       ],
+      "plugins/open-api": [
+        "./dist/plugins/open-api/index.d.mts"
+      ],
       "plugins/jwt": [
         "./dist/plugins/jwt/index.d.mts"
       ],
       "plugins/magic-link": [
         "./dist/plugins/magic-link/index.d.mts"
       ],
+      "plugins/multi-session": [
+        "./dist/plugins/multi-session/index.d.mts"
+      ],
       "plugins/organization": [
         "./dist/plugins/organization/index.d.mts"
       ],

packages/better-auth/src/package-exports.test.ts

@@ -0,0 +1,56 @@
+import { readFileSync } from "node:fs";
+import path from "node:path";
+import { describe, expect, it } from "vitest";
+
+const pkgDir = path.resolve(import.meta.dirname, "..");
+const pkg: {
+	exports: Record<string, { "dev-source": string; types: string }>;
+	typesVersions: { "*": Record<string, string[]> };
+} = JSON.parse(readFileSync(path.join(pkgDir, "package.json"), "utf8"));
+const entries = [
+	...readFileSync(path.join(pkgDir, "tsdown.config.ts"), "utf8").matchAll(
+		/"(\.\/src\/[^"]+\.ts)"/g,
+	),
+].map((match) => match[1]!);
+
+/**
+ * Build entries that intentionally have no subpath export.
+ */
+const internalEntries = new Set([
+	// Lazy-loaded by the built-in Kysely adapter; users import `@better-auth/kysely-adapter`.
+	"./src/adapters/kysely-adapter/index.ts",
+]);
+
+const toTypes = (entry: string) =>
+	entry.replace("./src/", "./dist/").replace(/\.ts$/, ".d.mts");
+
+/**
+ * @see https://github.com/better-auth/better-auth/issues/10172
+ */
+describe("package.json subpaths", () => {
+	it("reads the build entries from tsdown.config.ts", () => {
+		expect(entries).toContain("./src/index.ts");
+	});
+
+	it.each(entries.filter((entry) => !internalEntries.has(entry)))(
+		"exposes %s through exports and typesVersions",
+		(entry) => {
+			const subpath = Object.keys(pkg.exports).find(
+				(key) => pkg.exports[key]!["dev-source"] === entry,
+			);
+			expect(subpath, `no exports entry for ${entry}`).toBeDefined();
+			expect(pkg.exports[subpath!]!.types).toBe(toTypes(entry));
+			expect(
+				pkg.typesVersions["*"][subpath === "." ? "*" : subpath!.slice(2)],
+			).toEqual([toTypes(entry)]);
+		},
+	);
+
+	it("builds every exported subpath", () => {
+		for (const [subpath, target] of Object.entries(pkg.exports)) {
+			expect(entries, `${subpath} is not a build entry`).toContain(
+				target["dev-source"],
+			);
+		}
+	});
+});