I'm not sure how you got to that log, but if you click on the failed build in Rietveld, for me it takes me to

https://build.chromium.org/p/tryserver.chromium.mac/builders/ios-simulator/builds/191729

where the failing step says "Patch failure check the update step for details" and you can see on the line above the link to the failing patch output.

Is this good enough, or would you like to suggest that the patch failure step should also contain a link to the failing patch output? The latter seems like a good idea to me and I'm not sure why this is two different steps ...

+hinoka, dnj

The "bot_update" step contains the correct link to the patch failure and, as you noted, it also mentions this in the failing step:

Patch failure Patch failure
Check the bot_update step for details 

The actual patch failure log that is referenced contains a lot of useful information: https://luci-logdog.appspot.com/v/?s=chromium%2Fbb%2Ftryserver.chromium.mac%2Fios-simulator%2F191729%2F%2B%2Frecipes%2Fsteps%2Fbot_update%2F0%2Flogs%2Fpatch_error%2F0

Agreed that actually having the link there would be nice. hinoka@, any idea why we can't do that?

In the event of a patch failure, we did not want the build step text to display "failed bot_update", instead, we want it to say "failed patch failure".  There wasn't a way to do this in recipes without creating a new step.

I actually think "failed bot_update" plus some step text would be fine. Failing that, is there a way to copy the link to the patch failure down to the "patch failure" step?

problem with "failed bot_update" is that a user would see it, and then file a bug against me, and I'd have to point out that they need to rebase their checkout.  This has unfortunately happened many times in the past.

I don't think there is a way to refer to log links from one step in another step.

Hm. I can see the problem about filing bugs against bot_update ...

Aren't the buildbot links just annotations with URLs? I don't really see why we couldn't save the URL and then add it to the next step.

you can't get a buildbot URL because recipes just emit step cursors and step texts.  On the recipe side, there isn't a way to extract that URL (for a good reason too, it might change)

The log URL is generated by BuildBot / Annotee, which happens outside of the consciousness of the recipe engine. Changing direction of that information would require a reverse formation flow to be built and is probably non-trivial.

After some thought, I went ahead and took a swing at this: https://chromium-review.googlesource.com/c/475950/

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/depot_tools/+/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683

commit 8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683
Author: Dan Jacques <dnj@chromium.org>
Date: Wed Apr 12 19:05:48 2017

bot_update: Show failed patch in "Patch Failure".

Have "bot_update.py" export the failing patch body in its JSON. Have the
recipe actually emit the patch body in the "Patch Failure" step instead
of the "bot_update" step, and remove the "Patch Failure" step's
indirection to the "bot_update" step for patch failure.

This will provide a more straightforward user interface: the red step
that says "Patch Failure" now includes the details of the patch failure!

BUG= chromium:710477 
TEST=expectations

Change-Id: I6ad305f0b972de89e4f0b5eb70edf41980447abd
Reviewed-on: https://chromium-review.googlesource.com/475950
Commit-Queue: Daniel Jacques <dnj@chromium.org>
Reviewed-by: Ryan Tseng <hinoka@chromium.org>

[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/resources/bot_update.py
[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/example.expected/tryjob_fail_patch.json
[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/test_api.py
[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/api.py
[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/example.expected/tryjob_fail_patch_download.json

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/depot_tools/+/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683

commit 8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683
Author: Dan Jacques <dnj@chromium.org>
Date: Wed Apr 12 19:05:48 2017

bot_update: Show failed patch in "Patch Failure".

Have "bot_update.py" export the failing patch body in its JSON. Have the
recipe actually emit the patch body in the "Patch Failure" step instead
of the "bot_update" step, and remove the "Patch Failure" step's
indirection to the "bot_update" step for patch failure.

This will provide a more straightforward user interface: the red step
that says "Patch Failure" now includes the details of the patch failure!

BUG= chromium:710477 
TEST=expectations

Change-Id: I6ad305f0b972de89e4f0b5eb70edf41980447abd
Reviewed-on: https://chromium-review.googlesource.com/475950
Commit-Queue: Daniel Jacques <dnj@chromium.org>
Reviewed-by: Ryan Tseng <hinoka@chromium.org>

[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/resources/bot_update.py
[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/example.expected/tryjob_fail_patch.json
[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/test_api.py
[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/api.py
[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/example.expected/tryjob_fail_patch_download.json

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/depot_tools/+/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683

commit 8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683
Author: Dan Jacques <dnj@chromium.org>
Date: Wed Apr 12 19:05:48 2017

bot_update: Show failed patch in "Patch Failure".

Have "bot_update.py" export the failing patch body in its JSON. Have the
recipe actually emit the patch body in the "Patch Failure" step instead
of the "bot_update" step, and remove the "Patch Failure" step's
indirection to the "bot_update" step for patch failure.

This will provide a more straightforward user interface: the red step
that says "Patch Failure" now includes the details of the patch failure!

BUG= chromium:710477 
TEST=expectations

Change-Id: I6ad305f0b972de89e4f0b5eb70edf41980447abd
Reviewed-on: https://chromium-review.googlesource.com/475950
Commit-Queue: Daniel Jacques <dnj@chromium.org>
Reviewed-by: Ryan Tseng <hinoka@chromium.org>

[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/resources/bot_update.py
[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/example.expected/tryjob_fail_patch.json
[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/test_api.py
[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/api.py
[modify] https://crrev.com/8dd4edae992e3cd9cacb7ce36cf2fa48ab60d683/recipes/recipe_modules/bot_update/example.expected/tryjob_fail_patch_download.json

New patch failure message looks a lot better:

https://luci-milo.appspot.com/buildbot/tryserver.chromium.win/win_clang/206610

https://screenshot.googleplex.com/TOJ1DjnJGiF

Yup, definitely better. Thanks!

Ahh, my brain completely skipped the "Check the bot_update step for details".
The thing I attached in #0 was the result of clicking "stdout" on "patch error", where I was expecting to see the failed diff.
#14 looks great, thanks a lot!

I'll consider that Verified :D