How to disable auto-indentation of new lines?

Question

I've recently upgraded emacs to version 24.4.1 and something has changed in the indentation of new lines. When I hit enter I expect just "bare" new line character at point where cursor was present, in particular if I'm in the middle of the line, that line should be splitted and none character be deleted including spaces. Unfortunately this is not the case.

Here is example:

a b

When I put the cursor just after a and hit enter I get:

a
b

while it should be

a
 b

I googled a bit and probably this is due to auto-indentation, how can I disable this? I'm talking about text or fundamental mode if that matters.

Answer 1

Disable electric-indent-mode:

(when (fboundp 'electric-indent-mode) (electric-indent-mode -1))

That works with any Emacs version. This annoyance or shiny-new-feature, depending on your point of view, was introduced as the default in Emacs 24.4.

See also this similar post on StackOverflow.

(However, it sounds like you are saying the reverse, and that you want RET to indent but are not getting that indentation. What has changed is that RET ("Enter") now indents automatically, and you need to hit C-j to get just a newline with no indentation. They swapped RET and C-j, in effect. If you want RET to indent, then the new default behavior should give you what you want. In any case, the mode is electric-indent-mode: turn it on or off, as you like.)

Answer 2

There is the possibility to insert a newline char with C-q C-j and there are 3 commands to split the line: open-line C-o, split-line C-M-o and the newline RET, C-m you used. If you position the cursor like you said after the a and press C-o the current line will be broken after the cursor and every char will be in the next line. split-line will keep the column-position so that an extra blank is inserted before the content.

Hmm, interesting, with C-M-o the current line also gets an extra blank in the end so that the b and the cursor positions line up after the change.

In fundamental mode C-j changes the buffer to your expectation on my machine, and C-j is bound to electric-newline-and-maybe-indent

Answer 3

You can effectively disable line indentation this way:

(defun singpolyma/indent-line ()
    "Don't auto indent lines."
    )

...

    (add-hook 'prog-mode-hook (lambda ()
        (setq indent-line-function 'singpolyma/indent-line)
    ))
    (add-hook 'text-mode-hook (lambda ()
        (setq indent-line-function 'singpolyma/indent-line)
    ))

Answer 4

When you want to disable electric-indent-mode for a particular major mode, you can add a hook as follows:

  (add-hook 'sml-mode-hook
            (lambda () (electric-indent-local-mode -1)))

Answer 5

In my case, this has happened when I added the next line in my configuration.

(setq indent-line-function 'insert-tab)

I have commented out to fix.