Detector of unused BuildRequires of RPM builds.

Usage

[!NOTE] The current implementation requires that the mock chroot is not on a filesystem mounted with the noatime option. If relatime is used, the tool will still work but will spend some time rewriting filesystem metadata inside the build root. The tool works fastest with mount options strictatime,lazytime.

Enable it upon mock execution via a command line flag:

mock --enable-plugin=unbreq ...

Enable it permamently by adding / editing the configuration file in $HOME/.config/mock.cfg:

config_opts['plugin_conf']['unbreq_enable'] = True

In logs you should see messages like:

INFO: enabled unbreq plugin(...)

If Unbreq detects an unneeded BuildRequire it prints a message like:

WARNING: unbreq plugin: the following BuildRequires were not used:
...

Configuration

The configuration options for this plugin are listed below.

Configuration via the .cfg file is done this way:

config_opts['plugin_conf']['unbreq_opts']['${OPTION}'] = ${VALUE}

Configuration from the command line is done this way:

--plugin-option='unbreq:${OPTION}=${VALUE}'

Configuration options

• exclude_accessed_files - List[str]

  • A list of regular expressions that are used to ignore file accesses of certain files.

    Example: xmvn always reads all files inside /usr/share/maven-metadata/. The exclusion filter ^/usr/share/maven-metadata/ excludes these files from the listing.

How it works

Before the build

The tool reads the BuildRequires of the SRPM files (usually only one) in their standard location. This step is executed after resolving dynamic BuildRequires and this tool is able to recognize them.

It also marks a timestamp before executing the build for use as reference.

Depending of the detected filesystem mount options, if relatime options is detected, then all the files owned by all the installed dependencies have their access times and modify times set to 0, to make it possible to detect further file accesses during the build.

After the build

After executing the build, the relevant files have their access time compared to the saved timestamp.

Each BuildRequire field may cause the installation of multiple packages. These are obtained by iteratively executing dnf --assumeno remove ${BuildRequires}.

If any of the files owned by any of the package in this set was accessed, then this BuildRequires field can not be removed.

Each iteration of the remove query will also include all the BuildRequires fields for which were shown to be unnecessary. This is because the removal of multiple packages at once can produce a different result than removing them separately.

Output

The output of the tool is logged in the build log at the end of the build.

Available since version 6.4.