Emacs minor-mode that ensures pasted (yanked) text has the correct indentation level.

Do you often find yourself fixing the indentation of a code snippet right after pasting it somewhere? Never again! yank-indent is the answer.

• yank-indent-mode minor-mode that automatically calls indent-region on yanked/pasted text.
• global-yank-indent-mode which is a set-it-and-forget-it style global mode that enables yank-indent-mode in relevant buffers, with a sensible default list of major-modes to exclude.
• By default does not trigger indent-region if pasted text is longer than 5000 characters. This threshold can be can be customized with yank-indent-threshold.

(use-package yank-indent
  :straight (:host github :repo "jimeh/yank-indent")
  :config (global-yank-indent-mode t))

Place yank-indent.el somewhere in your load-path and require it. For example ~/.emacs.d/vendor:

(add-to-list 'load-path "~/.emacs.d/vendor")
(require 'yank-indent)
(global-yank-indent-mode t)

With global-yank-indent-mode enabled, you will find that yank-indent-mode is automatically enabled in relevant buffers. The defaults will specifically exclude common languages which are indentation sensitive like Python, YAML, Makefile, etc.

For fine-grained control over which major-modes it is enabled in or not, see customization options with M-x customize-group RET yank-indent.

If you prefer not to use the global mode, you can add yank-indent-mode as a hook to relevant major-modes, or even manually toggle it on and off with M-x yank-indent-mode.

To skip the indent operation for a single yank command, use a prefix command, so C-u C-y instead of just C-y.

Keep in mind that the include/exclude major-mode customizations only affect the global mode and which buffers it enables yank-indent-mode in. If you explicitly enable yank-indent-mode in a buffer, it will operate like normal regardless of what major-mode the buffer is using.

• snap-indent (melpa): Very similar with the addition of being able to trigger indentation on save, and extra custom formatting functions to run right after indentation.
• auto-indent-mode (melpa): Triggers indentation in a whole suite of scenarios, more or less trying to ensure everything is always correctly indented. This also includes indenting any yanked regions. Does not seem to support any thresholds to avoid triggering indentation for large buffers/yanked text.