Hi,
I've opened a tentative fix for this [1]. I've included a (hopefully!)
comprehensive write-up in the description of the MR, but for the sake of
completeness here's an e-mail friendly copy:
There are two bugs addressed in this request; mostly it undoes the
original fix for #989155, and then fixes that in such a way that #994204
does not occur.
The original issue (#989155) dealt with moving a package from the new
default restart behaviour ("--restart-after-upgrade", indicating
services should be restarted in a single step after file unpacking) to
the older restart behaviour ("--no-restart-after-upgrade", indicating
services should be stopped prior to unpacking, then started again at the
end of installation. The crux of this issue is, with the
"--no-restart-after-upgrade" option, *two* versions of the package are
involved in stopping and restarting the service. Specifically, the
"prerm" script of the *old* version of the package stops services, then
the "postinst" script of the *new* version of the package starts
services.
The original fix for this issue (in commit 6067bc2f [2] and 5b27a541
[3]), handled this by leaving the stop behaviour in "prerm" and
modifying the start behaviour in "postinst" to always *restart* (with
the unfortunate consequence found in #994204).
I think it may be preferable to instead move the stop behaviour to the
"preinst" script of the *new* version of the package so that both stop
and start behaviours are encapsulated in a *single* version of the
package (and hence can be freely moved between). This also means that
"postinst" script's prior behaviour can be restored.
To that end, the MR first reverts the two commits associated with
#989155, then adds a third commit that adds a "preinst" script for
"dh_installinit" and "dh_installsystemd" (and tidies up a little of the
substitution handling in the former). The test suite still passes for
me, and in a few test packages I've attempted building with the patched
version I *think* the restart behaviour is now fixed in the various
scenarios outlined above ("--no-stop-on-upgrade" for #994204, and moving
"--restart-after-upgrade" to "--no-restart-after-upgrade" for #989155).
However, my Perl skills are extremely rusty, and this is not an area I'm
overly familiar with, so any additional scrutiny is very welcome!
[1]: https://salsa.debian.org/debian/debhelper/-/merge_requests/61
[2]: https://salsa.debian.org/debian/debhelper/-/commit/6067bc2f
[3]: https://salsa.debian.org/debian/debhelper/-/commit/5b27a541
Best regards,
Dave Jones.
