Standalone ---------- Use `fatrace` to record all file access during an `sbuild` run and find those build dependencies which have their files never needed. You need superuser privileges to run this script because of `fatrace`. Run it like follows. In one terminal execute: $ ./findunusedbd.sh In another run sbuild like this: $ sbuild \ --chroot-setup-commands='/home/user/path/to/findunusedbd.sh chroot-setup' \ --pre-realbuild-commands='/home/user/path/to/findunusedbd.sh pre-realbuild' \ --post-realbuild-commands='/home/user/path/to/findunusedbd.sh post-realbuild' This needs the --pre-realbuild-commands and --post-realbuild-commands to exist which can be added to sbuild by applying `0001-add-pre-realbuild-commands-and-post-realbuild-comman.patch` to it. Any unused dependencies can then be found by investigating the file `unneededdepends.list`. Batch ----- The process can be automated for multiple packages by passing `dsc` files to `run.sh`: $ ./run.sh ../mysources/*.dsc This script will put the successful builds in `buildsuccess.list` and the found unused build dependencies as `*.unusedbd` for each `dsc` file in the current directory. A second pass on the successfully built `dsc` files will then check each of the found unused build dependencies for their validity by replacing them by an empty equivs package one after another. The results of that run are stored in `*.unusedbd.real` files for each `dsc` file in the current directory. The `run.sh` script expects to find `findunusedbd.sh` directly under `/home`. Best try this out in a chroot to not mess with the host system. Schroot setup ------------- Create the schroot: $ sudo sbuild-createchroot --make-sbuild-tarball=/var/lib/sbuild/sid-amd64.tar.gz sid `mktemp -d` http://127.0.0.1:3142/snapshot.debian.org/archive/debian/20140601T000000Z Enter the schroot: $ sbuild-shell source:sid-amd64-sbuild Make apt ignore the `Valid-Until` header: $ echo 'Acquire::Check-Valid-Until "false";' > /etc/apt/apt.conf.d/80-nocheckvaliduntil Install `equivs`: $ apt-get install equivs --no-install-recommends Bugs ---- - when investigating which build dependencies are unused, virtual packages are not taken into account - maybe the fake equivs package can be built outside the schroot to avoid the additional dependencies for installing equivs - maybe equivs can be avoided altogether by finding a way to edit debian/control on the fly License ------- Consider everything in this repository in the public domain. It is a gross hack and I do not care what you do with it.