Multi-line input truncated when comint-use-prompt-regexp and comint-eol-on-send are both t

[dpom]

Description

Multi-line input containing blank lines is truncated to just the first line when comint-use-prompt-regexp and comint-eol-on-send are both t.

Example: sending "First sentence\n\nSecond sentence" results in only "First sentence" being sent to the process.

Root cause

In Emacs 30's comint-send-input, when comint-use-prompt-regexp is t and comint-eol-on-send is t, the function calls (end-of-line) (instead of (goto-char (field-end))) to position point before capturing input. If point starts at the process mark (not at point-max), (end-of-line) only moves to the end of the first line, truncating the rest.

;; comint-send-input in Emacs 30:
(if comint-eol-on-send
    (if comint-use-prompt-regexp
        (end-of-line)               ;; ← truncates at first newline
      (goto-char (field-end))))     ;; ← works correctly

In shell-maker-submit, point is conditionally moved to point-max only when (shell-maker-point-at-last-prompt-p) returns nil. When point is at the process mark (right after the prompt, before the input text), the predicate returns t, so goto-char is skipped. This leaves point at the process mark, where (end-of-line) only captures the first line.

Fix

PR #37: unconditionally move to point-max before calling comint-send-input in shell-maker-submit.

Workaround

Users can set comint-use-prompt-regexp to nil in the shell-maker buffer, or ensure point is at point-max before submitting.