Fix error propagation (#82)

src/headers.test.ts

@@ -34,11 +34,24 @@ describe('getHeaders', () => {
     });
 
     it('should require the request context if next/headers is not available', () => {
+        const error = new Error('next/headers requires app router');
+
         mockHeaders.mockImplementation(() => {
-            throw new Error('next/headers requires app router');
+            throw error;
         });
 
-        expect(() => getHeaders()).toThrow('No route context found.');
+        let actualError: unknown;
+
+        try {
+            getHeaders();
+        } catch (caughtError) {
+            actualError = caughtError;
+        }
+
+        // Ensure it rethrows the exact same error.
+        // It is important because Next uses the error type to detect dynamic routes based
+        // on usage of headers or cookies
+        expect(actualError).toBe(error);
     });
 
     type RequestContextScenario = {
@@ -138,11 +151,24 @@ describe('getCookies', () => {
     });
 
     it('should require the request context if next/headers is not available', () => {
+        const error = new Error('next/headers requires app router');
+
         mockCookies.mockImplementation(() => {
-            throw new Error('next/headers requires app router');
+            throw error;
         });
 
-        expect(() => getCookies()).toThrow('No route context found.');
+        let actualError: unknown;
+
+        try {
+            getCookies();
+        } catch (caughtError) {
+            actualError = caughtError;
+        }
+
+        // Ensure it rethrows the exact same error.
+        // It is important because Next uses the error type to detect dynamic routes based
+        // on usage of headers or cookies
+        expect(actualError).toBe(error);
     });
 
     type RequestContextScenario = {

src/headers.ts

@@ -36,9 +36,9 @@ export function getHeaders(route?: RouteContext): HeaderReader {
         const {headers} = importNextHeaders();
 
         return headers();
-    } catch {
+    } catch (error) {
         if (route === undefined) {
-            throw new Error('No route context found.');
+            throw error;
         }
     }
 
@@ -70,9 +70,9 @@ export function getCookies(route?: RouteContext): CookieAccessor {
         const {cookies} = importNextHeaders();
 
         return cookies();
-    } catch {
+    } catch (error) {
         if (route === undefined) {
-            throw new Error('No route context found.');
+            throw error;
         }
     }
 

src/server/evaluate.test.ts

@@ -4,6 +4,7 @@ import {ApiKey, ApiKey as MockApiKey} from '@croct/sdk/apiKey';
 import {FilteredLogger} from '@croct/sdk/logging/filteredLogger';
 import {headers} from 'next/headers';
 import {NextRequest, NextResponse} from 'next/server';
+import {DynamicServerError} from 'next/dist/client/components/hooks-server-context';
 import {cql, evaluate, EvaluationOptions} from './evaluate';
 import {resolveRequestContext, RequestContext} from '@/config/context';
 import {getDefaultFetchTimeout} from '@/config/timeout';
@@ -186,15 +187,25 @@ describe('evaluation', () => {
             expect(resolveRequestContext).toHaveBeenCalledWith(route);
         });
 
+        it('should rethrow dynamic server errors', async () => {
+            const error = new DynamicServerError('cause');
+
+            jest.mocked(resolveRequestContext).mockImplementation(() => {
+                throw error;
+            });
+
+            await expect(evaluate('true')).rejects.toBe(error);
+        });
+
         it('should report an error if the route context is missing', async () => {
             jest.mocked(resolveRequestContext).mockImplementation(() => {
                 throw new Error('next/headers requires app router');
             });
 
             await expect(evaluate('true')).rejects.toThrow(
                 'Error resolving request context: next/headers requires app router. '
-                + 'This error usually occurs when no `route` option is specified when evaluate() '
-                + 'is called outside of app routes. '
+                + 'This error typically occurs when evaluate() is called outside of app routes '
+                + 'without specifying the `route` option. '
                 + 'For help, see: https://croct.help/sdk/nextjs/missing-route-context',
             );
         });

src/server/evaluate.ts

@@ -3,6 +3,7 @@ import type {JsonValue} from '@croct/plug-react';
 import {FilteredLogger} from '@croct/sdk/logging/filteredLogger';
 import {ConsoleLogger} from '@croct/sdk/logging/consoleLogger';
 import {formatCause} from '@croct/sdk/error';
+import {isDynamicServerError} from 'next/dist/client/components/hooks-server-context';
 import {getApiKey} from '@/config/security';
 import {RequestContext, resolveRequestContext} from '@/config/context';
 import {getDefaultFetchTimeout} from '@/config/timeout';
@@ -21,18 +22,18 @@ export function evaluate<T extends JsonValue>(query: string, options: Evaluation
     try {
         context = resolveRequestContext(route);
     } catch (error) {
-        if (route === undefined) {
-            return Promise.reject(
-                new Error(
-                    `Error resolving request context: ${formatCause(error)}. `
-                    + 'This error usually occurs when no `route` option is specified when evaluate() '
-                    + 'is called outside of app routes. '
-                    + 'For help, see: https://croct.help/sdk/nextjs/missing-route-context',
-                ),
-            );
+        if (isDynamicServerError(error) || route !== undefined) {
+            return Promise.reject(error);
         }
 
-        return Promise.reject(error);
+        return Promise.reject(
+            new Error(
+                `Error resolving request context: ${formatCause(error)}. `
+                + 'This error typically occurs when evaluate() is called outside of app routes '
+                + 'without specifying the `route` option. '
+                + 'For help, see: https://croct.help/sdk/nextjs/missing-route-context',
+            ),
+        );
     }
 
     const timeout = getDefaultFetchTimeout();

src/server/fetchContent.test.ts

@@ -4,6 +4,7 @@ import {FetchResponse} from '@croct/plug/plug';
 import {ApiKey, ApiKey as MockApiKey} from '@croct/sdk/apiKey';
 import {FilteredLogger} from '@croct/sdk/logging/filteredLogger';
 import type {NextRequest, NextResponse} from 'next/server';
+import {DynamicServerError} from 'next/dist/client/components/hooks-server-context';
 import {fetchContent, FetchOptions} from './fetchContent';
 import {RequestContext, resolvePreferredLocale, resolveRequestContext} from '@/config/context';
 import {getDefaultFetchTimeout} from '@/config/timeout';
@@ -289,15 +290,25 @@ describe('fetchContent', () => {
         expect(resolvePreferredLocale).toHaveBeenCalledWith(route);
     });
 
+    it('should rethrow dynamic server errors', async () => {
+        const error = new DynamicServerError('cause');
+
+        jest.mocked(resolveRequestContext).mockImplementation(() => {
+            throw error;
+        });
+
+        await expect(fetchContent('slot-id')).rejects.toBe(error);
+    });
+
     it('should report an error if the route context is missing', async () => {
         jest.mocked(resolveRequestContext).mockImplementation(() => {
             throw new Error('next/headers requires app router');
         });
 
         await expect(fetchContent('slot-id')).rejects.toThrow(
             'Error resolving request context: next/headers requires app router. '
-            + 'This error usually occurs when no `route` option is specified when fetchContent() '
-            + 'is called outside of app routes. '
+            + 'This error typically occurs when fetchContent() is called outside of app routes without '
+            + 'specifying the `route` option. '
             + 'For help, see: https://croct.help/sdk/nextjs/missing-route-context',
         );
     });

src/server/fetchContent.ts

@@ -8,6 +8,7 @@ import type {SlotContent, VersionedSlotId, JsonObject} from '@croct/plug-react';
 import {FilteredLogger} from '@croct/sdk/logging/filteredLogger';
 import {ConsoleLogger} from '@croct/sdk/logging/consoleLogger';
 import {formatCause} from '@croct/sdk/error';
+import {isDynamicServerError} from 'next/dist/client/components/hooks-server-context';
 import {getApiKey} from '@/config/security';
 import {RequestContext, resolvePreferredLocale, resolveRequestContext} from '@/config/context';
 import {getDefaultFetchTimeout} from '@/config/timeout';
@@ -63,18 +64,18 @@ export function fetchContent<I extends VersionedSlotId, C extends JsonObject>(
     try {
         context = resolveRequestContext(route);
     } catch (error) {
-        if (route === undefined) {
-            return Promise.reject(
-                new Error(
-                    `Error resolving request context: ${formatCause(error)}. `
-                    + 'This error usually occurs when no `route` option is specified when fetchContent() '
-                    + 'is called outside of app routes. '
-                    + 'For help, see: https://croct.help/sdk/nextjs/missing-route-context',
-                ),
-            );
+        if (isDynamicServerError(error) || route !== undefined) {
+            return Promise.reject(error);
         }
 
-        return Promise.reject(error);
+        return Promise.reject(
+            new Error(
+                `Error resolving request context: ${formatCause(error)}. `
+                + 'This error typically occurs when fetchContent() is called outside of app routes '
+                + 'without specifying the `route` option. '
+                + 'For help, see: https://croct.help/sdk/nextjs/missing-route-context',
+            ),
+        );
     }
 
     return loadContent<I, C>(slotId, {