Hello.
Consider the following latex snippet with the cursor position indicated by |:
\begin{itemize}
\item My 1st item %%% comment |
\end{itemize}
At that point call `LaTeX-insert-item' (M-RET) to get the following:
\begin{itemize}
\item My 1st item %%% comment
%%% \item |
\end{itemize}
while I would have expected
\begin{itemize}
\item My 1st item %%% comment
\item |
\end{itemize}
I cannot think of a situation where the current version is desirable.
This happens because `LaTeX-insert-item' inserts a new line using `LaTeX-newline' instead of `TeX-newline.
In addition to the above, `LaTeX-insert-item' always inserts a new line unless the cursor is at the beginning of line:
(unless (bolp) (LaTeX-newline))
This is rarely the case. For example, if you enter a new line inside itemize, the line is indented. It would be better to replace the (bolp) check with a check that the line contains only whitespace characters. So my proposal is to replace the above line with
(unless (string-match-p "^[[:blank:]]*$" (buffer-substring-no-properties (line-beginning-position) (line-end-position))) (TeX-newline))