Limit debug logs to 4096 bytes on vercel to avoid errors

.changeset/mean-walls-press.md

@@ -0,0 +1,5 @@
+---
+'@clerk/nextjs': patch
+---
+
+Logs that exceed maximum allowed length on Vercel deployments will now be truncated to max length exactly

packages/nextjs/src/utils/debugLogger.test.ts

@@ -111,4 +111,24 @@ describe('withLogger', () => {
       expect(logger.commit).toHaveBeenCalled();
     }
   });
+
+  it('should truncate bytes to 4096 when deploying on vercel', () => {
+    // setup: mock vercel environment, mock console log so we can intercept its value
+    process.env.VERCEL = 'true';
+    const oldConsoleLog = console.log.bind(console);
+    const log = jest.fn();
+    console.log = log;
+
+    const veryLongString = new Array(6000).join('a');
+    const handler = withLogger('test-logger', logger => () => {
+      logger.enable();
+      logger.debug(veryLongString);
+    });
+    handler();
+    expect(log.mock.calls[0][0]).toHaveLength(4096);
+
+    // restore original console log and reset environment value
+    process.env.VERCEL = undefined;
+    console.log = oldConsoleLog;
+  });
 });

packages/nextjs/src/utils/debugLogger.ts

@@ -25,12 +25,15 @@ export const createDebugLogger = (name: string, formatter: (val: LogEntry) => st
     },
     commit: () => {
       if (isEnabled) {
-        console.log(
-          `Clerk debug start :: ${name}\n${entries
-            .map(log => formatter(log))
-            .map(e => `-- ${e}\n`)
-            .join('')}`,
-        );
+        const log = `Clerk debug start :: ${name}\n${entries
+          .map(log => formatter(log))
+          .map(e => `-- ${e}\n`)
+          .join('')}`;
+        if (process.env.VERCEL) {
+          console.log(truncate(log, 4096));
+        } else {
+          console.log(log);
+        }
       }
     },
   };
@@ -73,3 +76,15 @@ export const withLogger: WithLogger = (loggerFactoryOrName, handlerCtor) => {
     }
   }) as ReturnType<typeof handlerCtor>;
 };
+
+// ref: https://stackoverflow.com/questions/57769465/javascript-truncate-text-by-bytes-length
+function truncate(str: string, maxLength: number) {
+  const encoder = new TextEncoder();
+  const decoder = new TextDecoder('utf-8');
+
+  const encodedString = encoder.encode(str);
+  const truncatedString = encodedString.slice(0, maxLength);
+
+  // return the truncated string, removing any replacement characters that result from partially truncated characters
+  return decoder.decode(truncatedString).replace(/\uFFFD/g, '');
+}