Update debhelper (#13594)

* Update debian packaging to debhelper version 12

Don't call dh_installinit anymore, because it has been deprecated, and use
dh_installsystemd instead of dh_systemd_enable for the same reason.

Signed-off-by: Jörg Behrmann <behrmann@physik.fu-berlin.de>

* Drop preinst script

It was used for reasons of interactions of dh_systemd_start and dh_installinit,
which have both be deprecated

Signed-off-by: Jörg Behrmann <behrmann@physik.fu-berlin.de>

* Drop /etc/default file

It was no longer being installed.

* Remove debian/compat file

This is managed by the control file nowadays

7 files changed, 15 insertions, 41 deletions

diff --git a/debian/changelog b/debian/changelog
index 605e660928..3257adef77 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,5 +1,7 @@
 matrix-synapse-py3 (1.66.0~rc1+nmu1) UNRELEASED; urgency=medium
 
+  * Update debhelper to compatibility level 12.
+  * Drop the preinst script stopping synapse.
   * Allocate a group for the system user.
 
  -- Jörg Behrmann <behrmann@physik.fu-berlin.de>  Tue, 23 Aug 2022 17:17:00 +0100
diff --git a/debian/compat b/debian/compat
deleted file mode 100644
index f599e28b8a..0000000000
--- a/debian/compat
+++ /dev/null
@@ -1 +0,0 @@
-10
diff --git a/debian/control b/debian/control
index 412a9e1d4c..86f5a66d02 100644
--- a/debian/control
+++ b/debian/control
@@ -4,7 +4,7 @@ Priority: extra
 Maintainer: Synapse Packaging team <packages@matrix.org>
 # keep this list in sync with the build dependencies in docker/Dockerfile-dhvirtualenv.
 Build-Depends:
- debhelper (>= 10),
+ debhelper-compat (= 12),
  dh-virtualenv (>= 1.1),
  libsystemd-dev,
  libpq-dev,
diff --git a/debian/matrix-synapse-py3.preinst b/debian/matrix-synapse-py3.preinst
deleted file mode 100644
index 4b5612f050..0000000000
--- a/debian/matrix-synapse-py3.preinst
+++ /dev/null
@@ -1,31 +0,0 @@
-#!/bin/sh -e
-
-# Attempt to undo some of the braindamage caused by
-# https://github.com/matrix-org/package-synapse-debian/issues/18.
-#
-# Due to reasons [1], the old python2 matrix-synapse package will not stop the
-# service when the package is uninstalled. Our maintainer scripts will do the
-# right thing in terms of ensuring the service is enabled and unmasked, but
-# then do a `systemctl start matrix-synapse`, which of course does nothing -
-# leaving the old (py2) service running.
-#
-# There should normally be no reason for the service to be running during our
-# preinst, so we assume that if it *is* running, it's due to that situation,
-# and stop it.
-#
-# [1] dh_systemd_start doesn't do anything because it sees that there is an
-#     init.d script with the same name, so leaves it to dh_installinit.
-#
-#     dh_installinit doesn't do anything because somebody gave it a --no-start
-#     for unknown reasons.
-
-if [ -x /bin/systemctl ]; then
-    if /bin/systemctl --quiet is-active -- matrix-synapse; then
-        echo >&2 "stopping existing matrix-synapse service"
-        /bin/systemctl stop matrix-synapse || true
-    fi
-fi
-
-#DEBHELPER#
-
-exit 0
diff --git a/debian/matrix-synapse.default b/debian/matrix-synapse.default
deleted file mode 100644
index f402d73bbf..0000000000
--- a/debian/matrix-synapse.default
+++ /dev/null
@@ -1,2 +0,0 @@
-# Specify environment variables used when running Synapse
-# SYNAPSE_CACHE_FACTOR=0.5 (default)
diff --git a/debian/matrix-synapse.service b/debian/matrix-synapse.service
index bde1c6cb9f..c3f9660283 100644
--- a/debian/matrix-synapse.service
+++ b/debian/matrix-synapse.service
@@ -5,7 +5,6 @@ Description=Synapse Matrix homeserver
 Type=notify
 User=matrix-synapse
 WorkingDirectory=/var/lib/matrix-synapse
-EnvironmentFile=-/etc/default/matrix-synapse
 ExecStartPre=/opt/venvs/matrix-synapse/bin/python -m synapse.app.homeserver --config-path=/etc/matrix-synapse/homeserver.yaml --config-path=/etc/matrix-synapse/conf.d/ --generate-keys
 ExecStart=/opt/venvs/matrix-synapse/bin/python -m synapse.app.homeserver --config-path=/etc/matrix-synapse/homeserver.yaml --config-path=/etc/matrix-synapse/conf.d/
 ExecReload=/bin/kill -HUP $MAINPID
@@ -13,5 +12,10 @@ Restart=always
 RestartSec=3
 SyslogIdentifier=matrix-synapse
 
+# The environment file is not shipped by default anymore and the below directive
+# is for backwards compatibility only. Please use your homeserver.yaml if
+# possible.
+EnvironmentFile=-/etc/default/matrix-synapse
+
 [Install]
 WantedBy=multi-user.target
diff --git a/debian/rules b/debian/rules
index 5baf2475f0..3b79d56074 100755
--- a/debian/rules
+++ b/debian/rules
@@ -6,15 +6,17 @@
 # assume we only have one package
 PACKAGE_NAME:=`dh_listpackages`
 
-override_dh_systemd_enable:
-	dh_systemd_enable --name=matrix-synapse
-
-override_dh_installinit:
-	dh_installinit --name=matrix-synapse
+override_dh_installsystemd:
+	dh_installsystemd --name=matrix-synapse
 
 # we don't really want to strip the symbols from our object files.
 override_dh_strip:
 
+# many libraries pulled from PyPI have allocatable sections after
+# non-allocatable ones on which dwz errors out. For those without the issue the
+# gains are only marginal
+override_dh_dwz:
+
 # dh_shlibdeps calls dpkg-shlibdeps, which finds all the binary files
 # (executables and shared libs) in the package, and looks for the shared
 # libraries that they depend on. It then adds a dependency on the package that