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Revision as of 10:35, 9 August 2018 by Ignatenkobrain (talk | contribs) (https://pagure.io/packaging-committee/issue/787)

Referencing Source

One of the design goals of rpm is to cleanly separate upstream source from vendor modifications. For the Fedora packager, this means that sources used to build a package should be the vanilla sources available from upstream. To help reviewers and QA scripts verify this, the packager needs to indicate where a reviewer can find the source that was used to make the rpm.

The most common case is where upstream distributes source as a tar.gz, tar.bz2 or zip archive that we can download from an upstream website. In these cases you must use a full URL to the package in the SourceX: line. For example:

Source0: https://downloads.sourceforge.net/%{name}/%{name}-%{version}.tar.gz

Source0: http://ftp.gnome.org/pub/GNOME/sources/gnome-common/2.12/gnome-common-2.12.0.tar.bz2
Idea.png
Smallest Compressed Archive
If the upstream source archive is available in multiple compressed formats that our tools can decompress it's best to use the one that is smallest in size. This ensures the smallest source rpm to save space on the mirrors and downloads of source RPM packages.

There are several cases where upstream is not providing the source to you in an upstream tarball. In these cases you must document how to generate the tarball used in the rpm either through a spec file comment or a script included as a separate SourceX:.

Here are some specific examples:

Using Revision Control

In some cases you may want to pull sources from upstream's revision control system because there have been many changes since the last release and you think that a tarball that you generate from there will more accurately show how the package relates to upstream's development. Here's how you can use a comment to show where the source came from:

# The source for this package was pulled from upstream's vcs.  Use the
# following commands to generate the tarball:
#  svn export -r 250 http://www.example.com/svn/foo/trunk foo-20070221
#  tar -cJvf foo-20070221.tar.xz foo-20070221
Source0: foo-20070221.tar.xz

When pulling from revision control, please remember to use a Name-version-release compatible with the Version and Release Guidelines. In particular, check the section on Naming Snapshots.

When Upstream uses Prohibited Code

Some upstream packages include patents or trademarks that we are not allowed to ship even as source code. In these cases you have to modify the source tarball to remove this code before you even upload it to the build system. Here's an example of using a script to document how you went from the upstream tarball to the one included in the package:

From the spec:

Source0: libfoo-1.0-nopatents.tar.gz
# libfoo contains patented code that we cannot ship.  Therefore we use
# this script to remove the patented code before shipping it.
# Download the upstream tarball and invoke this script while in the
# tarball's directory:
# ./generate-tarball.sh 1.0
Source1: generate-tarball.sh

generate-tarball.sh:

#!/bin/sh

VERSION=$1

tar -xzvf libfoo-$VERSION.tar.gz
rm libfoo-$VERSION/src/patentedcodec.c
sed -i -e 's/patentedcodec.c//' libfoo-$VERSION/src/Makefile

tar -czvf libfoo-$VERSION-nopatents.tar.gz libfoo-$VERSION

Python Packages (pypi)

As Pypi has moved to storing files in directories which change depending on the file being stored, it is rather unpleasant to use in a Source: URL. Instead, files.pythonhosted.org can be used as follows, where %srcname is the project's name on pypi and <first_letter> is the first letter of that name. (See also the sample python spec here).

Source0: https://files.pythonhosted.org/packages/source/<first_letter>/%{srcname}/%{srcname}-%{version}.tar.gz

Sourceforge.net

For packages hosted on sourceforge, use

Source0: https://downloads.sourceforge.net/%{name}/%{name}-%{version}.tar.gz

changing ".tar.gz" to whatever matches the upstream distribution. Note that we are using downloads.sourceforge.net instead of an arbitrarily chosen mirror. You may use the package name/package version instead of the %{name} and %{version} macros, of course.

Please note that the correct url is downloads.sourceforge.net, and NOT download.sourceforge.net.

Git Hosting Services

If the upstream does create tarballs you should use them as tarballs provide an easier trail for people auditing the packages.

Git web-based hosting services provide a mechanism to create tarballs on demand, either from a specific commit revision, or from a specific tag. If the upstream does not create tarballs for releases, you can use this mechanism to produce them.

The full 40-character hash and associated git tag may be obtained by issuing the following git command:

git ls-remote https://HOSTING-SERVICE/OWNER/%{name}.git

HOSTING-SERVICE:  name of the service, i.e. "github.com", "bitbucket.org", "gitlab.com", etc.
OWNER:            username for the repository owner

You may also obtain the 40-character hash and associated git tag via the web-interface of the HOSTING-SERVICE, or by cloning the repository and issuing the git show-ref command.

Once the commit hash and git tag are known, you can define them in your spec file as follows:

%global commit 40-CHARACTER-HASH-VALUE
%global gittag GIT-TAG
%global shortcommit %(c=%{commit}; echo ${c:0:7})    [GitHub]
%global shortcommit %(c=%{commit}; echo ${c:0:11})   [Bitbucket]
%global shortcommit %(c=%{commit}; echo ${c:0:7})    [GitLab]

Commit Revision

For the source tarball, you can use the following syntax:

Source0:  https://github.com/OWNER/%{name}/archive/%{commit}/%{name}-%{shortcommit}.tar.gz
Source0:  https://bitbucket.org/OWNER/%{name}/get/%{commit}.tar.gz#/%{name}-%{shortcommit}.tar.gz
Source0:  https://gitlab.com/OWNER/%{name}/repository/archive.tar.gz?ref=%{commit}#/%{name}-%{shortcommit}.tar.gz
...

%prep
%autosetup -n %{name}-%{commit}              [GitHub]
%autosetup -n OWNER-%{name}-%{shortcommit}   [BitBucket]
%autosetup -n %{name}.git                    [GitLab]

If the release corresponds to a git tag with a sane numeric version, you must use that version to populate the Version: tag in the spec file. If it does not, look at the source code to see if a version is indicated there, and use that value. If no numeric version is indicated in the code, you may set Version to 0, and treat the package as a "pre-release" package (and make use of the %{shortcommit} macro). See Pre-Release packages for details.

Alternately, if you are using a specific revision that is either a pre-release revision or a post-release revision, you must follow the "snapshot" guidelines. They are documented here: Snapshot packages. You can substitute %{shortcommit} for the git hash in %{checkout} in that section.

Git Tags

Git tags represent a particular code point that upstream deems important; and are typically used to mark release points.

Bitbucket uses the %{shortcommit} identifier as part of the archive directory structure; regardless of whether you use git tag or Commit Revision to retrieve it. This is shown in the %prep section example.

For the source tarball, you can use the following syntax:

Source0:  https://github.com/OWNER/%{name}/archive/%{gittag}/%{name}-%{version}.tar.gz
Source0:  https://bitbucket.org/OWNER/%{name}/get/%{gittag}.tar.gz#/%{name}-%{version}.tar.gz
Source0:  https://gitlab.com/OWNER/%{name}/repository/archive.tar.gz?ref=GIT-TAG#/%{name}-%{version}.tar.gz
...

%prep
%autosetup -n %{name}-%{gittag}               [GitHub]
%autosetup -n OWNER-%{name}-%{shortcommit}    [BitBucket]
%autosetup -n %{name}.git                     [GitLab]

Git Submodules

Some projects may use the Git submodule capability. If so, please note that the submodule will not be included in the tarball. Instead, it will appear in the tarball as an empty directory. In this situation, you will need to manually incorporate the submodule into the project.

The simplest method is to incorporate the submodule within the %prep section of the spec file. In this instance you will follow the preceding instructions to obtain the tarball for the submodule project. Instead of Source0, %commit, %gittag and %shortcommit; you will use Source1, %commit1, %gittag1 and %shortcommit1. An example %prep section would be:

%prep
%autosetup -n %{name}-%{commit} -a 1               [GitHub]
%autosetup -n OWNER-%{name}-%{shortcommit} -a 1    [BitBucket]
%autosetup -n %{name}.git -a 1                     [GitLab]
rmdir SUBMODULE                                    [Remove SUBMODULE]
mv %{name}-%{commit1} SUBMODULE                    [Move SUBMODULE TO %{name}]

If for some reason that isn't feasible, an alternative is to rebuild the tarball prior to its inclusion in the spec file. This involves cloning the project, issuing the Git commands to incorporate the submodule, then building a tarball of the newly created project directory structure. You will then need to comment as described in the Using Revision Control section. The following is an example specific to Git submodules:

# The source of this package was pulled from upstreams's vcs.
# Use the following command to generate the tar ball:
# git clone --recursive http://HOSTING-SERVICE/OWNER/%{name}.git
# tar cvjf %{name}-%{version}.tar.gz %{name}/

Keep in mind that the version specified reflects that of the project and NOT the submodule.

Using %{version}

Using %{version} in the SourceX: makes it easier for you to bump the version of a package, because most of the time you do not need to edit SourceX: when editing the spec file for the new package.

Troublesome URLs

When upstream has URLs for the download that do not end with the tarball name rpm will be unable to parse the tarball out of the source URL. One workaround for many cases is to construct a URL where the tarball is listed in a "URL fragment":

Source0: http://example.com/foo/1.0/download.cgi#/%{name}-%{version}.tar.gz

rpm will then use %{name}-%{version}.tar.gz as the tarball name. If you use spectool -g foo.spec to download the tarball, it will rename the tarball for you.

Sometimes this does not work because the upstream cgi tries to parse the fragment or because you need to login or fill in a form to access the tarball. In these cases, you have to put just the tarball's filename into the Source: tag. To make clear where you got the tarball, you should leave notes in comments above the Source: line to explain the situation to reviewers and future packagers. For example:

 # Mysql has a mirror redirector for its downloads
 # You can get this tarball by following a link from:
 # http://dev.mysql.com/downloads/mysql/5.1.html
 Source0: mysql-5.1.31.tar.gz