Different indentation styles per filetype

For my hacking, I love to use the KDevelop IDE. Once in a while, I find myself working on a project that has different indentation styles depending on the filetype — in this case, C++ files, Makefiles, etc. use tabs, JavaScript and HTML files use 2 spaces. I haven’t found this to be straight-forward from KDevelop’s configuration dialog (though I just learnt that it does seem to be possible). I did find myself having to fix indentation before committing (annoying!) and even having to fix up the indentation of code committed by myself (embarrassing!). As that’s both stupid and repetitive work, it’s something I wanted to avoid. Here’s how it’s done using EditorConfig files:

  1. put a file called .editorconfig in the project’s root directory
  2. specify a default style and then a specialization for certain filetypes
  3. restart KDevelop

Here’s what my .editorconfig file looks like:

# EditorConfig is awesome: https://EditorConfig.org

# for the top-most EditorConfig file, set...
# root = true

# In general, tabs shown 2 spaces wide
indent_style = tab
indent_size = 2

# Matches multiple files with brace expansion notation
indent_style = space
indent_size = 2

This does the job nicely and has the following advantages:

  • It doesn’t affect my other projects, so I don’t have to run around in the configuration to switch when task-switching. (Editorconfigs cascade, so will be looked up up in the filesystem tree for fallback styles.
  • It works across different editors supporting the editorconfig standards, so not just KWrite, Kate, KDevelop, but also for entirely different products.
  • It allows me to spend less time on formalities and more time on actual coding (or diving).

(Thanks to Reddit.)