It turns out it was this thing: https://clojurians.slack.com/archives/C03S1KBA2/p1693908172883489

interesting--so you had some custom data readers being defined somewhere? For future reference, about Biff's reload functionality: Biff uses the https://github.com/nextjournal/beholder library to call an https://github.com/jacobobryant/biff/blob/d8c83c4cc25123b67e14751ff5d19e6b24f7317c/example/src/com/example.clj#L55 whenever a file is saved. By default, that on-save function includes a call to https://github.com/jacobobryant/biff/blob/d8c83c4cc25123b67e14751ff5d19e6b24f7317c/src/com/biffweb.clj#L201, which in turn https://github.com/jacobobryant/biff/blob/master/src/com/biffweb/impl/util/reload.clj to evaluate any files that have changed and all files which depend on them. It should give the same results as using your editor to evaluate all the files/buffers. e.g. if you have some vars that aren't getting updated, I'd start by just evaluating the file they're in with your editor and then see if that works/if you get any errors. You can also call biff/eval-files! from your editor, though note that it'll only pick up changes in files that have been saved.

> so you had some custom data readers being defined somewhere? I didn't define any. I didn't have any. I used a reader for something else in one other project but that was a very long time ago. And this shouldn't happen.

so were you able to fix the issue or is it still unresolved? I'm a little fuzzy on the details reading through that thread.

I was able to fix it by moving my .m2 directory and redownloading.

Then I removed that directory and moved on. And then vemv actually provided a good way of debugging it.

The interesting part is that the issue first partially appeared yesterday when the reloading mechanism stopped reloading reliably. For instance it would reload every 2 minutes or something. But if I edit hiccup then it would sometimes reload immediately... but then again wouldn't reload anything again. I thought I messed something up with symbol references and I was restarting the dev server once in a while. The interesting thing is that sometimes the update of UI still actually updated. So I thought that it was really my mistake. And today I thought that I could try to run the (reload) function that is provided in the top namespace of the example project. I ran it and then everything has hit the fan. My tests (they're located in src directory) started to crash on #inst symbols and I refactored them away. But then I had #inst which was harder to refactor. So now my clojure environment in me laptop was non-working. Then I asked a question in slack and later I tried it on a different project that uses tools.deps. It was the same problem. BUT Leiningen-based projects worked 😄 :man-shrugging:

that is a super weird bug ha ha

I now think that what could've happened was that the reader functions were loaded in the wrong order. It could've been a classpath bug where the dependencies were ordered in a different way than usual.