From the go 1.19 release notes:
Command and LookPath no longer allow results from a PATH search to be found relative to the current directory. This removes a common source of security problems but may also break existing programs that depend on using, say, exec.Command("prog") to run a binary named prog (or, on Windows, prog.exe) in the current directory. See the os/exec package documentation for information about how best to update such programs.
We've been sometimes using lo and sometimes using my slices package, and we need to pick one
for consistency. Lo is more extensive and better maintained so we're going with that.
My slices package was a superset of go's own slices package so in some places I've just used
the official one (the methods were just wrappers anyway).
I've also moved the remaining methods into the utils package.
This fixes two problems with the "amend commit with staged changes" command:
1. Amending to a fixup commit didn't work (this would create a commmit with the
title "fixup! fixup! original title" and keep that at the top of the branch)
2. Unrelated fixup commits would be squashed too.
The added integration test verifies that both of these problems are fixed.
Instead of passing a bunch of different options in
PrepareInteractiveRebaseCommandOpts, where it was unclear how they interact if
several are set, have only a single field "instruction" which can be set to one
of various different instructions.
The functionality of replacing the entire todo file with our own is no longer
available; it is only possible to prepend todos to the existing file.
Also, instead of using different env vars for the various rebase operations that
we want to tell the daemon to do, use a single one that contains a json-encoded
struct with all available instructions. This makes the protocol much clearer,
and makes it easier to extend in the future.
