I had trouble installing the patch with Drupal 10.3.10, apparently some of the modifications on the content_access.module file can not be applied (the changed order in the use statements). I recreated a patch by changing just that and it works for me. I leave the patch here in case someone stumbles upon the same issue.
I found what was causing the issue for me. I had
this patch →
applied and updating the module while still having this patch in my composer.json messed things up. Hope this helps! And thanks @garphy for the hint.
I had the same issue while updating from 4.0.0-alpha5 to 4.0.0-alpha6. For some reason, the conditional_fields_get_simpler_id() function in the conditional_fields.module file was duplicated, with one small difference, the dot in the end of this line was present in the first declaration of the function and not the second:
// preg_match('/.*([-]{2,}[a-zA-Z0-9]+)$/', $id, $matches);.
I checked and the code in the repo is fine, the function is only here once. So that's a bit weird. What I did to fix the issue was deleting the conditional_fields directory in my contrib modules and run composer install again.