# Why Rebuild

To avoid common pitfalls between switching to ifupdown2, like, for example, the removal of the
networking units link, effectively disabling it.o

# How is the Source Tracked

We're using git's subtree functionality, which is basically just a convenience wrapper around the
age old subtree merge strategy.

The initial addition was done with the following command:
```
git subtree add -P src --squash https://salsa.debian.org/debian/ifupdown.git 0.8.36
```

## Subtree Rules

* We squash update commits to avoid making the git log explode here, one can always checkout the
  upstream repo for details.

* We try to keep change in the subtree copy contained to packaging as much as possible, anything
  else should be upstreamed first, and only applied locally afterwards.

* We're fine with merges, as they're required anyway. Especially d/changelog and the pre/post
  scripts will need to be adapted. Checkout upstream changes closely and ensure that our main goal
  (switching from ifupdown to ifupdown2 seamlessly) can still be achieved.

# Separate Subtree Changes from Parent

Quoting a tip from `man git-subtree`:

> In order to keep your commit messages clean, we recommend that people split their
> commits between the subtrees and the main project as much as possible. That is, if you
> make a change that affects both the library and the main application, commit it in two
> pieces. That way, when you split the library commits out later, their descriptions
> will still make sense. But if this isn't important to you, it’s not necessary. git
> subtree will simply leave out the non-library-related parts of the commit when it
> splits it out into the subproject later.

## Pull in New Version

Use something like the followign command (adapt the refspec at the end) to pull
and merge in a new upstream revision:

```
git subtree pull -P src --squash https://salsa.debian.org/debian/ifupdown.git 0.8.X
```

Handle merge conflicts and ensure that the *build* post/pre rm scripts don't do anything that would
interfere with switching to ifupdown2 or purging this package later.