Page MenuHomePhabricator

darwin: use vim, not vi, to avoid data-loss inducing posix behavior
ClosedPublic

Authored by spectral on Mar 23 2020, 6:12 PM.

Details

Summary

Apple's version of vim, available at
opensource.apple.com/release/macos-1015.html (for Catalina, but this behavior
has been there for a while) has several tweaks from the version of vim from
vim.org. Most of these tweaks appear to be for "Unix2003" compatibility.

One of the tweaks is that if any ex command raises an error, the entire
process will (when you exit, possibly minutes/hours later) also exit non-zero.
Ex commands are things like :foo.

Luckily, they only enabled this if vim was executed (via a symlink or copying
the binary) as vi or ex. If you start it as vim, it doesn't have this
behavior, so let's do that.

To see this in action, run the following two commands on macOS:

$ vi -c ':unknown' -c ':qa' ; echo $?
1
$ vim -c ':unknown' -c ':qa' ; echo $?
0

We don't want to start ignoring non-zero return types from the editor because
that will mean you can't use :cquit to intentionally exit 1 (which,
shows up as 2 if you combine an ex command error and a cquit, but only a 1 if
you just use cquit, so we can't differentiate between the two statuses). Since
we can't differentiate, we have to assume that all non-zero exit codes are
intentional and an indication of the user's desire to not continue with whatever
we're doing. If this was a complicated hg split or hg histedit, this is
especially disastrous :(

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Event Timeline

spectral created this revision.Mar 23 2020, 6:12 PM
This revision was not accepted when it landed; it landed in state Needs Review.
This revision was automatically updated to reflect the committed changes.