With php 8.1.10 and the diff module I am seeing the following:
Deprecated function: str_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in diff_diffs_show() (line 176 of \modules\diff\diff.pages.inc).
Deprecated function: explode(): Passing null to parameter #2 ($string) of type string is deprecated in diff_get_rows() (line 501 of \modules\diff\diff.module).
Deprecated function: explode(): Passing null to parameter #2 ($string) of type string is deprecated in diff_get_rows() (line 502 of \modules\diff\diff.module).
With php 8.1.10 and the diff module I am seeing the following:
This may be similar to https://github.com/backdrop-contrib/diff/issues/8