pg_upgrade test failure

Hi,

After my last rebase of the meson tree I encountered the following test
failure:

https://cirrus-ci.com/task/5532444261613568

[20:23:04.171] ------------------------------------- 8< -------------------------------------
[20:23:04.171] stderr:
[20:23:04.171] # Failed test 'pg_upgrade_output.d/ not removed after pg_upgrade --check success'
[20:23:04.171] # at C:/cirrus/src/bin/pg_upgrade/t/002_pg_upgrade.pl line 249.
[20:23:04.171] # Failed test 'pg_upgrade_output.d/ removed after pg_upgrade success'
[20:23:04.171] # at C:/cirrus/src/bin/pg_upgrade/t/002_pg_upgrade.pl line 261.
[20:23:04.171] # Looks like you failed 2 tests of 13.

regress_log:
https://api.cirrus-ci.com/v1/artifact/task/5532444261613568/testrun/build/testrun/pg_upgrade/002_pg_upgrade/log/regress_log_002_pg_upgrade

The pg_upgrade output contains these potentially relevant warnings:

...
*Clusters are compatible*
pg_upgrade: warning: could not remove file or directory "C:/cirrus/build/testrun/pg_upgrade/002_pg_upgrade/data/t_002_pg_upgrade_new_node_data/pgdata/pg_upgrade_output.d/20220919T201958.511/log": Directory not empty
pg_upgrade: warning: could not remove file or directory "C:/cirrus/build/testrun/pg_upgrade/002_pg_upgrade/data/t_002_pg_upgrade_new_node_data/pgdata/pg_upgrade_output.d/20220919T201958.511": Directory not empty
...

I don't know if actually related to the commit below, but there've been a
lot of runs of the pg_upgrade tests in the meson branch, and this is the first
failure of this kind. Unfortunately the error seems to be transient -
rerunning the tests succeeded.

On 2022-09-13 01:39:59 +0000, Michael Paquier wrote:
> Move any remaining files generated by pg_upgrade into an internal subdir
>
> This change concerns a couple of .txt files (for internal state checks)
> that were still written in the path where the binary is executed, and
> not in the subdirectory located in the target cluster. Like the other
> .txt files doing already so (like loadable_libraries.txt), these are
> saved in the base output directory. Note that on failure, the logs
> report the full path to the .txt file generated, so these are easy to
> find.
>
> Oversight in 38bfae3.
>
> Author: Daniel Gustafsson
> Reviewed-by: Michael Paquier, Justin Prysby
> Discussion: https://postgr.es/m/181A6DA8-3B7F-4B71-82D5-363FF0146820@yesql.se
> Backpatch-through: 15

Greetings,

Andres Freund