tree 3eca4045e92c0c6a5cb86ca14be6f422b6de415a
parent f7e6779c382d2f6f68488662a6cbd6093764f821
author Barret Rhoden <brho@cs.berkeley.edu> 1552434110 -0400
committer Barret Rhoden <brho@cs.berkeley.edu> 1553395420 -0400

Treat tabs as having eight spaces instead of four

For whatever bad reason, we chose to treat tabs as four spaces instead
of eight.  e.g. in vim, tabstop=4.

That's a huge pain - both when dealing with other tools and when
switching between projects.  I don't particularly like having
per-project vim settings and whatnot.  Plus, that's a bit harder for
other people who look at our code and have their vim/emacs set to 8
space tabs.

I had regretted that for a long time, but I didn't want to make the
change for two reasons:

1) With other people working on the project, changes of this sort can
lead to merge conflicts.  Since I'm the only one working on it, for the
most part, this isn't a concern.

2) The bigger reason is that major reformatting changes break git blame.
However, there are tools that can ignore commits when running git blame.
Chromium has git hyper-blame.  I thought that feature ought to be baked
into git, so I have a patchset out for git to do so.  Either way, I'll
either have my own patched git or the feature will get merged.  In a
future commit, I'll have instructions for how to use that feature.

A lot of our files didn't need too much attention, due to our old
"spaces for formatting" policy.  I didn't change those to use tabs
instead of spaces for the formatting either.  I expect newer code will
just do whatever people's editors do.  I didn't want to change more
lines than were needed, and the code looks the same either way.

The biggest offenders were indented comments.  Structs with
column-aligned members needed some work too.  I did most of that stuff
manually, since the tools do a mediocre job.

Since I was making changes, I also fixed up the switch-case indenting:
don't do an extra level of indentation for the case keywords.  Doing
this now actually helped with the 8-space tab change, since switch
statements got a few spaces to work with.

A few of the kernel's C files were so badly messed up that I just used
clang-format on them.  Same for Plan 9 files that had been
clang-formatted before and hadn't been heavily modified by us.
Clang-format caused a few problems with its "alphabetized headers"
policy.  That was fun.

Higher-quality (subjectively) code didn't need as much work as older,
poorer code.  Specifically, code with way too many levels of indentation
looks even worse than before - that's actually a benefit of 8-space
tabs: it tells you when your code is bad.  A lot of that older code
needs a more serious refactoring, which this commit does not do.

Signed-off-by: Barret Rhoden <brho@cs.berkeley.edu>