I was trying to construct a test for the problem that
patch1901 fixes. In this case, darcs (pre-patch1901)
fails if the tag in the context of the bundle is unclean.

I didn't manage to construct a case where it breaks if
tag is missing, rather than just reporting its absence.

1 patch for repository darcs-unstable@darcs.net:screened:

patch 4ff33b06e4dd5ad34c216233b230de58baca4129
Author: Ganesh Sittampalam <ganesh@earth.li>
Date:   Wed Sep 18 17:57:35 BST 2019
  * add a test for applying a patch with an unclean tag

Attachments

• add-a-test-for-applying-a-patch-with-an-unclean-tag.dpatch
• patch-preview.txt
• unnamed

> I didn't manage to construct a case where it breaks if
> tag is missing, rather than just reporting its absence.

I think this is because in case of a missing tag it is pretty unlikely
to actually crash. What it does in this case is to unwrap all
tags/inventories and then merge the complete history with the new
patches (plus their bogus context). If that doesn't already crash then
we detect the missing tag and fail cleanly.

To get a crash you need to ensure that there are common patches (in the
context of the bundle and our repo) that depend on patches that are not
in the bundle so their can't be commuted to the common trunk.

> patch 4ff33b06e4dd5ad34c216233b230de58baca4129
> Author: Ganesh Sittampalam <ganesh@earth.li>
> Date:   Wed Sep 18 17:57:35 BST 2019
>   * add a test for applying a patch with an unclean tag

Please remember to always rm -rf any file or directory created by a test
before creating them, otherwise we cannot easily re-run the test.

Last remark: I find it clearer and mroe reliable to use a match flag and
--all instead of echo yyyd | ... even if in your case this means we have
to do two pulls:

echo 'yyyd' | darcs pull ../R

->

darcs pull ../R -a --tag=initial
darcs pull ../R -a -p 'A'

Updated version, I'll screen it now.

It was a real pain to get the patch matching options right.
Unless I get better at doing it quickly I am skeptical
it is worth the effort.

1 patch for repository darcs-unstable@darcs.net:screened:

patch 4d3777ada9102e3b15a91612a2d160712e92f409
Author: Ganesh Sittampalam <ganesh@earth.li>
Date:   Sun Sep 22 21:33:04 BST 2019
  * add a test for applying a patch with an unclean tag

Attachments

• add-a-test-for-applying-a-patch-with-an-unclean-tag.dpatch
• patch-preview.txt
• unnamed

> It was a real pain to get the patch matching options right.
> Unless I get better at doing it quickly I am skeptical
> it is worth the effort.

Sorry about that. For the future, please regard my comment as a mere
recommendation not a strict requirement. More tests are always a good thing.

I also checked that without the recent fix for this the test fails.

One more comment re matching options: using them should be easy.
I know it isn't, currently, and I think we should work on that.