Completely disable all auto-indentation

Question

How do I completely disable all auto-indentation in Emacs? I need to disable it at least for Fundamental mode, but I'm fine with it being disabled globally for the current session.

Please read the rest of this question before declaring it a duplicate. All the other answers I've found are for much more targeted disabling of indentation. I really want to completely disable all auto-indentation for the whole session.

Setting electric-layout-mode to nil does not work.

Details

Sometimes I like to compose large Git commit messages with my Windows ASCII text editor. These messages frequently have bullet lists, code blocks, or other things where the precise formatting in my source document is meaningful. My codebase is on Linux, and I connect to the box using a text-only SSH client. When Git enters Emacs for editing the commit message, I want to be able to copy the source commit message to the Windows clipboard then paste it using Windows paste commands. From the perspective of Emacs, I'm typing what was found in the Windows text file. Unfortunately, when Emacs sees indented lines, it adds its own auto-indentation, so I get this huge triangle of whitespace along the left edge of the buffer.

I'm using GNU Emacs 24.3.1.

Workaround

My current workaround is to transfer my Windows text file to a filesystem that's mounted by my Linux host, load the file into Emacs, then use kill and yank to transfer the content. This is a bit clunky.

Example

Here's an example block of text:

a

  - b
    c
    d

Here is how it appears when I paste that into Emacs-under-ssh via MSWin paste:

a

  - b
      c
          d

If I press C-h l after doing the paste, here is what I see. Note that the newlines are input using C-j, not RET.

a C-j C-j SPC SPC - SPC b C-j SPC SPC SPC SPC c C-j
SPC SPC SPC SPC d C-j C-h l

Answer 1

Emacs ≤24.3

Pressing RET doesn't indent by default (except in some programming modes, for which you need to check mode-specific configuration, e.g. “electric” settings).

Unix terminals normally paste a carriage return character when the clipboard contents contains a newline (represented by the line feed character). In Emacs, a carriage return looks like the RET key (in fact, RET is the carriage return character), while a line feed looks like (is) C-j.

However, in your case, pasting a newline results in a C-j, which in Emacs is bound to the command newline-and-indent. As the name indicates, this command indents. I don't know if PuTTY has a setting you can change. If you want to fix the problem on the Emacs end, there's an easy workaround which I think you won't mind: bind C-j to newline (same as RET).

(global-set-key "\C-j" 'newline)

Emacs ≥24.4

In Emacs 24.4, Electric Indent mode is switched on by default. It's a global minor mode, so you can turn it off everywhere by calling (electric-indent-mode 0) and you can toggle it interactively with M-x electric-indent-mode RET.

You can find this information in the manual, or by looking at the documentation of the command invoked by pressing Return (press C-h k RET).

You can turn it on in a specific buffer with electric-indent-local-mode. Some programming modes (especially third-party ones) may have their own automatic indentation features that don't follow the settings of Electric Indent mode.

Answer 2

You might also try bracketed paste mode. This is a feature of your terminal emulator (PuTTY in this case, versions 0.63 and up) which uses escape sequences to signal that the user is pasting something, and then again when the paste ends. There's an Emacs package called bracketed-paste which you can install, it enables Emacs to recognize the escape sequences and transition to a safer keymap for the duration of the paste. Not only does this prevent the indentation from getting messed up, it also prevents a rogue paste from running commands in your emacs session using M-x.