[jampekka]

For example with vim (debian) defaults, if you happen to have a 2-space indented Python (the first two spaces are for HN formatting, the first if should start at zero indent):

  if True:
    # Two space indent

And continue to add another if block in that, the autoindent will give you four spaces:

  if True:
    # Two space indent
    if True:
        # Four space autoindent

And if you make a new line after the last row there and hit a backspace, it'll erase one space instead of four, giving an indentation of 3 (+2) spaces. And if you start a new line after that, you'll get an indentation of 8 spaces in total. Ending up with:

  if True:
    # Two space indent
    if True:
        # Four space autoindent
      # Hitting backspace gives this
          # Hitting a tab gives this

This is just a one case, but things like this tend to happen quite often when editing code. Even if it's been originally PEP-8 indented. Usually it's not what the Tab does, but what the Backspace or Autoindent does. I'm not exactly sure what exact Tab/Backspace/Autoindent rules underlie the behavior, but I can imagine there having to be quite a bit of hackery to support soft-tabs.

For me this kind of Tab/Autoindent/Backspace confusion is frequent enough that I'd be very surprised if others don't find themselves having to manually fix the number of spaces every now and then. And when watching over the shoulder I see others too occasionally having to micromanage space-indents (or accidentally ending up with three space indented blocks etc), also with other editors than vim.

[arp242]

This is because ftplugin/python.vim does:

  if !exists("g:python_recommended_style") || g:python_recommended_style != 0
    " As suggested by PEP8.
    setlocal expandtab tabstop=4 softtabstop=4 shiftwidth=4
  endif

So if you use "set sw=2" then it leaves tabstop and softtabstop at 4.

You can set that g:python_recommended_style to disable it.

Also sw=0 uses the tabstop value, and softtabstop=-1 uses the shiftwidth value.

I agree Vim's behaviour there is a bit annoying and confusing, but it doesn't really have anything to do with tabs vs. spaces. I strongly prefer tabs myself as well by the way.

Even when you DO use tabs Vim will use spaces if sw/ts/sts differ by the way. Try sw=2 and using >>, or sts=2 with noexpandtab.

[WorldMaker]

As with most things in vim, it is definitely manageable in settings such as tw=2 (tab width) and sts=2 (soft tab stop). This is why a lot of older Python files, in particular, are littered with vim modelines with settings like these.

The nice modern twist is .editorconfig files and the plugins that support them including for vim. You can use those to set such standard language-specific config concerns in a general way for an entire "workspace" for every editor that supports or has a plugin that supports .editorconfig.

[jampekka]

Well, yes. But that's one more small thing to config and manage. Not a big deal in isolation but such small things add up to significant yank.

With Tabs we wouldn't have this yet another papercut to tool over.

[Dylan16807]

Of course you can override it, but is there any excuse for that default behavior? It sounds ridiculous.

[WorldMaker]

The defaults are either 4-space or 8-space soft tab stops. 8 spaces it the oldest soft tab behavior. 4-space soft tabs have been common for C code among other languages for nearly as many decades. It is only relatively recently that Python and JS and several Lisp-family derivatives have made 2-space tab stops much more common of a style choice. Unfortunately there is no "perfect" default as these are as aesthetic preferences as anything else.

(It is one of the arguments for using hard tabs instead of soft ones in the eternal tabs versus spaces debates because editors can show hard tabs as different space equivalents as a user "style choice" without affecting the underlying text format.)

[Dylan16807]

Soft tabs at 4 would be fine, though worse than autodetect. But that is not the behavior described in the above post.

[WorldMaker]

The behavior described above seems to me to be exactly soft tabs at 4 in a 2-space tab document with autoindent turned on (often the default).

Vim has no autodetect by default. (I'm sure there's a plugin somewhere.)

[Dylan16807]

The part where the user is on a line indented by 2, hits return, and gets a line indented by 2+4=6 doesn't sound like soft tabs at 4 to me. And I wouldn't expect hitting backspace to then only remove 1 space (if it actually removed 2 that makes more sense, but is inconsistent with what what it just added). At that point, hitting return and getting a line indented by 8 might make sense but is weird.

Another comment suggests it's using 2 and 4 for different settings and that's causing problems.