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