merge: don't auto-pick destination with `hg merge 'wdir()'`...
merge: don't auto-pick destination with `hg merge 'wdir()'`
If the user doesn't specify a commit to merge with, we'll have
`node==None` in `commands.merge()`. We'll then try to find a good
commit to merge with. However, if the user, for some strange reason,
runs `hg merge 'wdir()'`, we'll also have `node==None` and we'll do
that same. That's clearly not the intent, so let's not do that.
It turns out we'd instead crash on that command after this patch, so I
added special handling of it too.
Differential Revision:
https://phab.mercurial-scm.org/D7996