We seen in the last video, that patch queues allow you to apply and unapply patches.

What I didn't show you yet, is how to work with multiple different patches.

This video is going to try to cover that.

So let's say we have one patch applied,

and it's bug123456_whitespacefixes

And we want to create a new patch.

This patch will be independent of the last.

The first thing we're going to do is go make a change to a file.

And we're just going to add a pretty useless comment right now and say: This is a comment.

And we're going to save and quit.

And we're going to go hg qnew bug777777 comment changes dot diff

And hit enter.

So this is going to create a second patch.

If we would have wanted that change inside the last patch,

we would have just used hg qrefresh or hg qref.

So if we go look at hg qapplied now, you're going to see that there's 2 patches.

The first one being the whitespace patch. The second one being the comment change.

Now we can pop off the last change, using hg qpop.

And it says that we're now at the whitespace patch.

So if we go look at hg qapplied again, it's just going to show the one patch.

Now if we go modify the file that we just changed,

we'll notice that the comment is not there.

And that's because the patch is not applied.

As soon as we push it back on.

And we go modify that same file again,

we'll see that the comment is present now.

So what I want to explain now, is just the concept of how patch queues work.

Is that, it kind of works like a stack and not a queue.

So just like if you have a stack of plates, basically you have a stack of patches.

The current patch is always the very top. So if you put food on the stack of plate for example,

that food will only be on the very top plate.

Just like if you make changes to your current patch queue, those changes will only be made to the very top patch that's applied.

So hg qapplied, now you see that we're on the comment changes is the last patch there.

That's the top of your stack basically.

So if you go make a change, This is a, we're just going to put "good" comment.

Save it, and quit.

Now when we hg qref, that change is going to go inside your top of your stack, which is the bug777777 comment changes

So now I'm just going to go open that patch,

and you'll see that it says: This is a good comment

And that's all for this video.