diff: analyse working tree when dirty

[pared]

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Fixes #3386

[pared]

The change in this test is in order to actually test diff when there is no dir cache, and not intermix it with dirty repo diff.

[pared]

I have a problem with deleted, because user will not be able to commit stage file when there is no output. But I presumed that its better to just log deleted instead some ambiguous warning saying "Output is deleted but stage file still exists, so you will not be able to commit current state of file".

[pmrowla]

deleted seems ok to me, since it's consistent with what dvc status reports for this case

file.dvc:
        changed outs:
                deleted:            file

[pmrowla]

deleted seems ok to me, since it's consistent with what dvc status reports for this case

file.dvc:
        changed outs:
                deleted:            file

[efiop]

Thanks!

[jorgeorpinel]

Hi! I don't completely understand this change but I'm pretty sure it requires some changes to the docs, right?

[efiop]

@jorgeorpinel

It defaults to comparing the current workspace and the last commit (HEAD), if arguments a_rev and b_rev are not specified.
is still relevant, we're just using actual workspace state here and not only what is recorded in the dvc-file.

This is an interesting topic whether or not we should stick to what is recorded in the dvc files or what is actually lying there (e.g. for cached files for any commit those would match, as cached files are determined by their hash in respective dvc-file, but for non-cached or git files/dirs it might be different), but in this case with dirty workspace we now clearly do the right thing.