🐛 BUG: script reload duplicates all previous `console.log`s and uncaught errors

[mrbbot]

What version of Wrangler are you using?

2.0.29

What operating system are you using?

Mac

Describe the Bug

After uploading a new script on file change, Wrangler will re-log all previously logged messages and uncaught errors. It's possible this is intended behaviour, but to me it's a little confusing, as it makes it seem like old versions of the script are still running. Notably, the duplicated error stack traces will still use the most up-to-date source maps, leading to incorrect source location reporting.

Example

export default {
  async fetch(request) {
    const { pathname } = new URL(request.url);
    if (pathname === "/") {
      console.log("message1");
      return new Response();
    } else {
      return new Response(null, { status: 404 });
    }
  },
};

$ wrangler2 dev issue.js
 ⛅️ wrangler 2.0.29 
--------------------
Retrieving cached values for userId from node_modules/.cache/wrangler
⬣ Listening at http://0.0.0.0:8787
Total Upload: 0.35 KiB / gzip: 0.23 KiB
13:01:00 GET / 200
message1                                  # 1) Visit http://localhost:8787 in browser
13:01:00 GET /favicon.ico 404
⎔ Detected changes, restarted server.    # 2) Update `message1` to `message2`
Total Upload: 0.35 KiB / gzip: 0.23 KiB
message1                                  # 3) Unexpected, `message1` from previous request logged
Script modified; context reset.
message2                                  # 4) Visit http://localhost:8787 in browser
13:01:08 GET / 200
⎔ Detected changes, restarted server.    # 5) Update `message2` to `message3`
Total Upload: 0.35 KiB / gzip: 0.23 KiB
message1                                  # 6) Unexpected, `message1` and `message2` from previous
message2                                  #    requests logged
Script modified; context reset.
message3                                  # 7) Visit http://localhost:8787 in browser
13:01:16 GET / 200

---

For an example with uncaught errors:

export default {
  async fetch(request) {
    const { pathname } = new URL(request.url);
    if (pathname === "/") {
      throw new Error("message1");
    } else {
      return new Response(null, { status: 404 });
    }
  },
};

Following the same steps as above gives:

$ wrangler2 dev issue.js
 ⛅️ wrangler 2.0.29 
--------------------
Retrieving cached values for userId from node_modules/.cache/wrangler
⬣ Listening at http://0.0.0.0:8787
Total Upload: 0.33 KiB / gzip: 0.23 KiB
# 1) Visit http://localhost:8787 in browser
13:12:15 GET / 500
✘ [ERROR] Uncaught (in promise) Error: message1

  throw new Error("message1");
        ^
      at fetch (/Users/mrbbot/Desktop/wrangler-playground/ws-issues.js:5:12)


✘ [ERROR] Uncaught (in response) Error: message1


13:12:15 GET /cdn-cgi/styles/cf.errors.css 304
13:12:15 GET /favicon.ico 404
# 2) Update `message1` to `message2`
⎔ Detected changes, restarted server.
Total Upload: 0.33 KiB / gzip: 0.23 KiB
# 3) Unexpected, `message1` error from previous request logged
✘ [ERROR] Uncaught (in response) Error: message1


✘ [ERROR] Uncaught (in promise) Error: message1

  throw new Error("message2");  # Note incorrect source mapping here too
        ^
      at fetch (/Users/mrbbot/Desktop/wrangler-playground/ws-issues.js:5:12)


Script modified; context reset.
# 4) Visit http://localhost:8787 in browser
13:12:28 GET / 500
✘ [ERROR] Uncaught (in promise) Error: message2

  throw new Error("message2");
        ^
      at fetch (/Users/mrbbot/Desktop/wrangler-playground/ws-issues.js:5:12)


✘ [ERROR] Uncaught (in response) Error: message2


# 5) Update `message2` to `message3`
⎔ Detected changes, restarted server.
Total Upload: 0.33 KiB / gzip: 0.23 KiB
# 6a) Unexpected, `message1` error from previous request logged
✘ [ERROR] Uncaught Error: message1 

  throw new Error("message3");  # Note incorrect source mapping here too
        ^
      at fetch (/Users/mrbbot/Desktop/wrangler-playground/ws-issues.js:5:12)


✘ [ERROR] Uncaught Error: message1 


# 6b) Unexpected, `message2` error from previous request logged
✘ [ERROR] Uncaught (in promise) Error: message2

  throw new Error("message3");  # Note incorrect source mapping here too
        ^
      at fetch (/Users/mrbbot/Desktop/wrangler-playground/ws-issues.js:5:12)


✘ [ERROR] Uncaught (in response) Error: message2


Script modified; context reset.
# 7) Visit http://localhost:8787 in browser
✘ [ERROR] Uncaught (in promise) Error: message3

  throw new Error("message3");
        ^
      at fetch (/Users/mrbbot/Desktop/wrangler-playground/ws-issues.js:5:12)


✘ [ERROR] Uncaught (in response) Error: message3


13:12:38 GET / 500