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josch 2014-06-25 12:04:42 +02:00
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README.md
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@ -3,43 +3,36 @@ 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`.
privileges to run this script because of `fatrace`. You need to copy
`findunusedbd.sh` into `/home` so best run all of this inside a chroot to
prevent a mess.
Run it like follows. In one terminal execute:
Run it like follows:
$ ./findunusedbd.sh
$ ./run.sh foo.dsc bar.dsc [...]
In another run sbuild like this:
This will call sbuild like this for each `dsc` given:
$ 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'
--chroot-setup-commands='/home/findunusedbd.sh chroot-setup' \
--pre-realbuild-commands='/home/findunusedbd.sh pre-realbuild' \
--post-realbuild-commands='/home/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`.
The first pass will use `fatrace` to find build dependencies on packages with
files that are never used during the whole build. Since many of these are gonna
be meta packages, a second pass replaces the candidate package with a fake
equivs package of same name and version but without dependencies and tries to
rebuild.
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 with no dependencies 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.
Both passes are done for `--arch-all` and `--no-arch-all`. Any unused
dependencies can then be found by investigating the `*.arch-all.unusedbd.real`
and `*.no-arch-all.unusedbd.real`. The result from the former can permanently
be dropped from the `Build-Depends`. The result from the latter can be added to
`Build-Depends-Indep`.
Schroot setup
-------------
@ -65,6 +58,12 @@ 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
- fatrace suffers from [bug#722901](https://bugs.debian.org/722901)
Feature Requests
----------------
- build with `DEB_BUILD_OPTIONS=nocheck` once it is possible to add `<!profile.nocheck>`
License
-------