note that my v8 checkout is configured to use gerrit

My guess is that "git cl"'s guessing logic is broken.

WAI:

$ git cl patch --rietveld <url or issue>

is the right way to go since your default is Gerrit.

+ @agable maybe this should be added to FAQ?

Note: we can add guessing the codereview based on domain name, but IMO guessing is not a good approach since this is also used on bots.

That said, if current behavior bugs many users this perhaps should be reconsidered.

we can improve error message to indicate that it actually tried to access Gerrit's issue #xxxx, and suggest to use --rietveld or --gerrit.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/depot_tools/+/28d840eb31e84581608d43d8936646bc073ad2e1

commit 28d840eb31e84581608d43d8936646bc073ad2e1
Author: Andrii Shyshkalov <tandrii@chromium.org>
Date: Mon Apr 10 14:06:30 2017

git cl patch: when URL matches both codereview systems, choose rietveld.

This is temporary, and will be changed in subsequent CLs. For now,
it suffices to stop relying on pseudo-random dictionary order in tests
and prod.

R=jochen@chromium.org
BUG= 706406 

Change-Id: I26c467a28bc63b5f81d20fc222a2b6f0511c507f
Reviewed-on: https://chromium-review.googlesource.com/472750
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>

[modify] https://crrev.com/28d840eb31e84581608d43d8936646bc073ad2e1/tests/git_cl_test.py
[modify] https://crrev.com/28d840eb31e84581608d43d8936646bc073ad2e1/git_cl.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/depot_tools/+/90f3192799a37026cf58b8d52f8ac2771f0cba80

commit 90f3192799a37026cf58b8d52f8ac2771f0cba80
Author: Andrii Shyshkalov <tandrii@chromium.org>
Date: Mon Apr 10 14:14:00 2017

git cl: remember codereview type when parsing issue/change URL.

R=jochen@chromium.org
BUG= 706406 

Change-Id: I477d1cf629bb0bccebead6e5c0189830ea76be7e
Reviewed-on: https://chromium-review.googlesource.com/472867
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>

[modify] https://crrev.com/90f3192799a37026cf58b8d52f8ac2771f0cba80/tests/git_cl_test.py
[modify] https://crrev.com/90f3192799a37026cf58b8d52f8ac2771f0cba80/git_cl.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/depot_tools/+/c971239edd08292d4e9a45b68cce1e82cea382b2

commit c971239edd08292d4e9a45b68cce1e82cea382b2
Author: Andrii Shyshkalov <tandrii@chromium.org>
Date: Tue Apr 11 11:39:21 2017

git cl patch <url>: better handling of URLs.

* if --rietveld or --gerrit is given, parse only using appropriate
  parser.
* if url has '$HOST-review' in the beginning, assume it's Gerrit
* if type of codereview is detected based on URL, then print this
  information for the user.
  This also applies to `git cl description` but message is logged instead,
  because in '-d|--display' option git cl is supposed to print only description,
  and some tooling likely relies on this :(

R=jochen@chromium.org
BUG= 706406 

Change-Id: I21c9355c5334fd71db27618cda11287f75168b59
Reviewed-on: https://chromium-review.googlesource.com/473186
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>

[modify] https://crrev.com/c971239edd08292d4e9a45b68cce1e82cea382b2/tests/git_cl_test.py
[modify] https://crrev.com/c971239edd08292d4e9a45b68cce1e82cea382b2/git_cl.py

So, I've actually found bugs and fixed them - see last CL landed right above.

Jochen, thanks for reporting and persisting!