Thanks David, using --with-sources is exactly what I needed. As a starting point I have the *.deb I've built. In the same directory I create a Packages file with: apt-ftparchive packages . > ./Packages
Then I install using it: apt install --with-source ./Packages -s mariadb-server mariadb-client libmariadbclient18 Between each attempt I can edit the Packages file and it immediately takes effect. While the Packages file does not have the exact same format as the debian/control file, it is close enough so I can simulate small depends/breaks/replaces changes without having to rebuild anything, just editing this one file directly. Nice! The debugging options produce a ton of output which I did not yet learn to ready, but I'll paste it here below for reference for others to see what the resolver debug output looks like: # apt install --with-source ./Packages -s mariadb-server mariadb-client libmariadbclient18 -o Debug::pkgDepCache::Marker=1 -o Debug::pkgDepCache::AutoInstall=1 -o Debug::pkgProblemResolver=1 Reading package lists... Done Building dependency tree Reading state information... Done MarkInstall mariadb-server:amd64 < none -> 1:10.5.10+maria~bionic @un puN Ib > FU=1 Installing mariadb-server-10.5 as Depends of mariadb-server MarkInstall mariadb-server-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > FU=0 Installing mariadb-common as PreDepends of mariadb-server-10.5 MarkInstall mariadb-common:amd64 < none -> 1:10.5.10+maria~bionic @un uN > FU=0 Installing galera-4 as Depends of mariadb-server-10.5 MarkInstall galera-4:amd64 < none -> 26.4.5~ubuntu18.04.1~1588883342.189a33e7+4.x.debian.packaging.update @un uN > FU=0 Installing gawk as Depends of mariadb-server-10.5 MarkInstall gawk:amd64 < none -> 1:4.1.4+dfsg-1build1 @un uN Ib > FU=0 Installing libmpfr6 as PreDepends of gawk MarkInstall libmpfr6:amd64 < none -> 4.0.1-1 @un uN > FU=0 Installing libreadline7 as PreDepends of gawk MarkInstall libreadline7:amd64 < none -> 7.0-3 @un uN Ib > FU=0 Installing readline-common as Depends of libreadline7 MarkInstall readline-common:amd64 < none -> 7.0-3 @un uN > FU=0 Installing libsigsegv2 as PreDepends of gawk MarkInstall libsigsegv2:amd64 < none -> 2.12-1 @un uN > FU=0 Installing iproute2 as Depends of mariadb-server-10.5 MarkInstall iproute2:amd64 < none -> 4.15.0-2ubuntu1.3 @un uN Ib > FU=0 Installing libelf1 as Depends of iproute2 MarkInstall libelf1:amd64 < none -> 0.170-0.4ubuntu0.1 @un uN > FU=0 Installing libmnl0 as Depends of iproute2 MarkInstall libmnl0:amd64 < none -> 1.0.4-2 @un uN > FU=0 Installing libatm1 as Recommends of iproute2 MarkInstall libatm1:amd64 < none -> 1:2.5.1-2build1 @un uN > FU=0 Installing libxtables12 as Recommends of iproute2 MarkInstall libxtables12:amd64 < none -> 1.6.1-2ubuntu2 @un uN > FU=0 Installing libdbi-perl as Depends of mariadb-server-10.5 MarkInstall libdbi-perl:amd64 < none -> 1.640-1ubuntu0.2 @un uN > FU=0 Installing lsof as Depends of mariadb-server-10.5 MarkInstall lsof:amd64 < none -> 4.89+dfsg-0.1 @un uN > FU=0 Installing mariadb-client-10.5 as Depends of mariadb-server-10.5 MarkInstall mariadb-client-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > FU=0 Installing mariadb-client-core-10.5 as Depends of mariadb-client-10.5 MarkInstall mariadb-client-core-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > FU=0 Installing libmariadb3 as Depends of mariadb-client-core-10.5 MarkInstall libmariadb3:amd64 < none -> 1:10.5.10+maria~bionic @un uN > FU=0 Installing libreadline5 as Depends of mariadb-client-core-10.5 MarkInstall libreadline5:amd64 < none -> 5.2+dfsg-3build1 @un uN > FU=0 Removing: mysql-client-core-5.7 MarkDelete mysql-client-core-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 | 5.7.33-0ubuntu0.18.04.1 @ii umH Ib > FU=0 Removing: mysql-client-5.7 MarkDelete mysql-client-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 | 5.7.33-0ubuntu0.18.04.1 @ii umH Ib > FU=0 Installing libdbd-mysql-perl as Recommends of mariadb-client-10.5 MarkInstall libdbd-mysql-perl:amd64 < none -> 4.046-1 @un uN Ib > FU=0 Installing libmysqlclient20 as Depends of libdbd-mysql-perl MarkInstall libmysqlclient20:amd64 < none -> 5.7.33-0ubuntu0.18.04.1 @un uN > FU=0 Installing libterm-readkey-perl as Recommends of mariadb-client-10.5 MarkInstall libterm-readkey-perl:amd64 < none -> 2.37-1build1 @un uN > FU=0 Installing mariadb-server-core-10.5 as Depends of mariadb-server-10.5 MarkInstall mariadb-server-core-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > FU=0 Installing libpcre2-8-0 as Depends of mariadb-server-core-10.5 MarkInstall libpcre2-8-0:amd64 < none -> 10.31-2 @un uN > FU=0 Removing: mysql-server-core-5.7 MarkDelete mysql-server-core-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 | 5.7.33-0ubuntu0.18.04.1 @ii umH Ib > FU=0 Removing: mysql-server-5.7 MarkDelete mysql-server-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 | 5.7.33-0ubuntu0.18.04.1 @ii umH Ib > FU=0 Installing rsync as Depends of mariadb-server-10.5 MarkInstall rsync:amd64 < none -> 3.1.2-2.1ubuntu1.1 @un uN Ib > FU=0 Installing libpopt0 as Depends of rsync MarkInstall libpopt0:amd64 < none -> 1.16-11 @un uN > FU=0 Installing socat as Depends of mariadb-server-10.5 MarkInstall socat:amd64 < none -> 1.7.3.2-2ubuntu2 @un uN > FU=0 MarkInstall mysql-server:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > FU=0 Installing mysql-server-5.7 as Depends of mysql-server MarkInstall mysql-server-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > FU=0 Installing mysql-client-5.7 as Depends of mysql-server-5.7 MarkInstall mysql-client-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > FU=0 Installing mysql-client-core-5.7 as Depends of mysql-client-5.7 MarkInstall mysql-client-core-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > FU=0 Removing: mariadb-client-core-10.5 MarkDelete mariadb-client-core-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > FU=0 Removing: mariadb-client-10.5 MarkDelete mariadb-client-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > FU=0 Installing mysql-server-core-5.7 as Depends of mysql-server-5.7 MarkInstall mysql-server-core-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > FU=0 Removing: mariadb-server-core-10.5 MarkDelete mariadb-server-core-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > FU=0 Removing: mariadb-server-10.5 MarkDelete mariadb-server-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > FU=0 Removing: mysql-server-5.7 MarkDelete mysql-server-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU > FU=0 Removing: mysql-server-core-5.7 MarkDelete mysql-server-core-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU > FU=0 MarkInstall mariadb-client:amd64 < none -> 1:10.5.10+maria~bionic @un puN Ib > FU=1 Installing mariadb-client-10.5 as Depends of mariadb-client MarkInstall mariadb-client-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > FU=0 Installing mariadb-client-core-10.5 as Depends of mariadb-client-10.5 MarkInstall mariadb-client-core-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > FU=0 Removing: mysql-client-core-5.7 MarkDelete mysql-client-core-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > FU=0 Removing: mysql-client-5.7 MarkDelete mysql-client-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > FU=0 Starting pkgProblemResolver with broken count: 2 Starting 2 pkgProblemResolver with broken count: 2 Investigating (0) mariadb-server:amd64 < none -> 1:10.5.10+maria~bionic @un puN Ib > Broken mariadb-server:amd64 Depends on mariadb-server-10.5:amd64 < none | 1:10.5.10+maria~bionic @un uH > (>= 1:10.5.10+maria~bionic) Considering mariadb-server-10.5:amd64 0 as a solution to mariadb-server:amd64 9999 Re-Instated mariadb-server-core-10.5:amd64 Re-Instated mariadb-server-10.5:amd64 Investigating (0) mysql-server:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > Broken mysql-server:amd64 Depends on mysql-server-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 | 5.7.33-0ubuntu0.18.04.1 @ii umR > Considering mysql-server-5.7:amd64 1 as a solution to mysql-server:amd64 0 MarkKeep mysql-server:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > FU=0 Re-Instated mysql-client-core-5.7:amd64 Re-Instated mysql-client-5.7:amd64 Re-Instated mysql-server-core-5.7:amd64 Re-Instated mysql-server-5.7:amd64 Re-Instated mysql-server:amd64 Investigating (0) mariadb-server-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > Broken mariadb-server-10.5:amd64 Conflicts on mysql-client-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > Considering mysql-client-5.7:amd64 -1 as a solution to mariadb-server-10.5:amd64 0 Added mysql-client-5.7:amd64 to the remove list Conflicts//Breaks against version 5.7.30-0ubuntu0.18.04.1 for mysql-client-5.7 but that is not InstVer, ignoring Conflicts//Breaks against version 5.7.21-1ubuntu1 for mysql-client-5.7 but that is not InstVer, ignoring Broken mariadb-server-10.5:amd64 Conflicts on mysql-server:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU > (< 1:10.5.10+maria~bionic) Considering mysql-server:amd64 0 as a solution to mariadb-server-10.5:amd64 0 MarkKeep mariadb-server-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > FU=0 Holding Back mariadb-server-10.5:amd64 rather than change mysql-server:amd64 Investigating (0) mariadb-server-core-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > Broken mariadb-server-core-10.5:amd64 Conflicts on mysql-server-core-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > Considering mysql-server-core-5.7:amd64 0 as a solution to mariadb-server-core-10.5:amd64 0 MarkKeep mariadb-server-core-10.5:amd64 < none -> 1:10.5.10+maria~bionic @un uN Ib > FU=0 Holding Back mariadb-server-core-10.5:amd64 rather than change mysql-server-core-5.7:amd64 Investigating (0) mysql-client-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > Broken mysql-client-5.7:amd64 Conflicts on virtual-mysql-client:amd64 < none @un H > Considering mariadb-client-10.5:amd64 0 as a solution to mysql-client-5.7:amd64 -1 MarkKeep mysql-client-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > FU=0 Removing mysql-client-5.7:amd64 rather than change virtual-mysql-client:amd64 MarkDelete mysql-client-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 | 5.7.33-0ubuntu0.18.04.1 @ii umH Ib > FU=0 Investigating (0) mysql-client-core-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > Broken mysql-client-core-5.7:amd64 Conflicts on virtual-mysql-client-core:amd64 < none @un H > Considering mariadb-client-core-10.5:amd64 0 as a solution to mysql-client-core-5.7:amd64 -1 MarkKeep mysql-client-core-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > FU=0 Removing mysql-client-core-5.7:amd64 rather than change virtual-mysql-client-core:amd64 MarkDelete mysql-client-core-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 | 5.7.33-0ubuntu0.18.04.1 @ii umH Ib > FU=0 Investigating (1) mariadb-server:amd64 < none -> 1:10.5.10+maria~bionic @un puN Ib > Broken mariadb-server:amd64 Depends on mariadb-server-10.5:amd64 < none | 1:10.5.10+maria~bionic @un uH > (>= 1:10.5.10+maria~bionic) Considering mariadb-server-10.5:amd64 0 as a solution to mariadb-server:amd64 9999 Investigating (1) mysql-server-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > Broken mysql-server-5.7:amd64 Depends on mysql-client-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 | 5.7.33-0ubuntu0.18.04.1 @ii umR > (>= 5.7.33-0ubuntu0.18.04.1) Considering mysql-client-5.7:amd64 -1 as a solution to mysql-server-5.7:amd64 1 MarkKeep mysql-server-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > FU=0 Removing mysql-server-5.7:amd64 rather than change mysql-client-5.7:amd64 MarkDelete mysql-server-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 | 5.7.33-0ubuntu0.18.04.1 @ii umH Ib > FU=0 Investigating (1) mysql-server:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > Broken mysql-server:amd64 Depends on mysql-server-5.7:amd64 < 5.7.30-0ubuntu0.18.04.1 | 5.7.33-0ubuntu0.18.04.1 @ii umR > Considering mysql-server-5.7:amd64 1 as a solution to mysql-server:amd64 0 MarkKeep mysql-server:amd64 < 5.7.30-0ubuntu0.18.04.1 -> 5.7.33-0ubuntu0.18.04.1 @ii umU Ib > FU=0 Removing mysql-server:amd64 rather than change mysql-server-5.7:amd64 MarkDelete mysql-server:amd64 < 5.7.30-0ubuntu0.18.04.1 | 5.7.33-0ubuntu0.18.04.1 @ii umH Ib > FU=0 Investigating (2) mariadb-server:amd64 < none -> 1:10.5.10+maria~bionic @un puN Ib > Broken mariadb-server:amd64 Depends on mariadb-server-10.5:amd64 < none | 1:10.5.10+maria~bionic @un uH > (>= 1:10.5.10+maria~bionic) Considering mariadb-server-10.5:amd64 0 as a solution to mariadb-server:amd64 9999 Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: mariadb-server : Depends: mariadb-server-10.5 (>= 1:10.5.10+maria~bionic) but it is not going to be installed E: Unable to correct problems, you have held broken packages.