JHBuild

From JHBuild's wiki:

JHBuild allows you to build and run GNOME platform and applications building the required modules in a sandbox environment, isolating the installation; so there is no need to build and run GNOME inside a virtual machine.

JHBuild is a tool that allows you to automatically download and compile "modules" (i.e. source code packages). It can pull modules from a variety of sources (CVS, Subversion, Git, Bazaar, tarballs, etc.) and handle dependencies. You can also choose which specific modules you want to build, instead of building the whole project.

JHBuild was originally written for building GNOME, but has since been extended to be usable with other projects.

Installation

Install the jhbuild^AUR package.

Configuration

There are two configuration files: the #Default configuration file installed by jhbuild^AUR package, and the #User-specific configuration file created by the user.

By default JHBuild uses the installed configuration file. Its configuration is overridden by the configuration in the user-specific configuration file if it exists.

These use Python syntax. See JHBuild Manual^{[dead link 2021-11-12 ⓘ]} for more information.

Default configuration file

The default configuration file is located at /usr/lib/python3.9/site-packages/jhbuild/defaults.jhbuildrc. It should have everything you need for start using JHBuild, as it sets the modulesets directory, the default moduleset, autogen/meson/cmake arguments for all modules that use it.

Some default values currently set:

moduleset = gnome-apps-latest
modules = meta-gnome-core
directory of downloaded tarball = $XDG_CACHE_HOME/jhbuild/downloads
buildroot = $XDG_CACHE_HOME/jhbuild/build

If believe you found a Arch-specific setting that should be set, feel free to suggest that in jhbuild^AUR comments. If not Arch-specific, consider filing an issue in the upstream.

User-specific configuration file

This configuration file is located at $XDG_CONFIG_HOME/jhbuildrc (e.g. ~/.config/jhbuildrc). It is optional, does not exist by default and overrides values set in the default JHBuild configuration file.

It is very useful for, e.g., set a different moduleset, or to add a compiler flag to debug and try to fix a build failure system.

See examples in /usr/share/jhbuild/examples/.

Sample configuration

This section shows a non-exhaustive list of key/value pairs that can be set in any of the configuration files.

Use a local moduleset file instead of downloading it again, making it possible to change something in the file and test it

use_local_modulesets = True
modulesets_dir = "~/.cache/jhbuild/"

Enable a wide-most moduleset, and also force GTK3 for modules that would use GTK2 by default

moduleset = ['gnome-world']
autogenargs = '--with-gtk3'

Or you may want to enable documentation build for autotools, even though it will slowdown module compilation

autogenargs = '--enable-gtk-doc'

Or you want some debug output from make command

makeargs = 'V=1'

Or you found out that a module requires a specific automake option (WebKit is already patched, there is no real need for this one)

module_autogenargs['WebKit'] = 'PYTHON=/usr/bin/python2'

Or you want to disable documentation build for a module that use meson build system

module_mesonargs['gstreamer'] = '-Ddisable_gtkdoc=true

Note: autotools and meson are different build systems, so make sure to add the desired flags for the correct option name

Usage

This topic provides some information and examples on how to use some JHBuild commands, but without intending to exhaust the subject. For a detailed information on each of JHBuild commands, please refer to JHBuild Manual^{[dead link 2021-11-12 ⓘ]}, learn from each command's help output or even read JHBuild's source code.

JHBuild provides a general --help which lists all the commands available, and also a help message for each sub-command, e.g. jhbuild sysdeps --help.

Checking and installing prerequisites

sysdeps can be used to get a detailed list of which dependencies you have installed and which ones you should install. In order to get this information, just run:

$ jhbuild sysdeps

To install missing dependencies, run use --install parameter:

$ jhbuild sysdeps --install

For dependencies that the above command is unable install, consider installing the correspondent package from official repositories or the AUR.

Note: jhbuild^AUR already lists some dependencies that sysdeps --install cannot install for some reason. If you find a package that should be listed in there, please report it in the comments of jhbuild^AUR.

Updating modules

It is possible to simply update the source code of the modules without building them, making it possible build another time without having to wait fetching the source code. There are three ways of simply updating modules:

update, without any arguments, will update all modules available in the moduleset/modules set in configuration file

$ jhbuild update

update, with one or more modules as arguments, will update all modules that the named modules depends on. e.g.:

$ jhbuild update gedit

updateone, with one or more modules, will update only the named module(s). e.g.:

$ jhbuild updateonly gedit

Building modules

This action will run the whole build process: it will update the source code (unless it is already up-to-date), configure & build, and install it in the proper directory.

Just like update, There are three ways of building modules in JHBuild:

build, without any arguments, will build all modules available in the moduleset/modules set in configuration file

$ jhbuild build

build, with one or more modules as arguments, will build all modules that the named modules depends on. e.g.:

$ jhbuild build gedit

buildone, with one or more modules, will build only the named module(s). e.g.:

$ jhbuild buildone gedit

Note: Please notice that since buildone do not also build the latest development version of a module's dependencies, it may fail due to dependency not being installed or being out-of-date; in this case, you should run build for the named module

Running modules

After a successfully installed application in JHBuild, use run to start the module you just built. e.g.:

$ jhbuild run gedit

Creating dependency graph

JHBuild can output graph contents which can by piped into graphviz in order to generate e.g. a PNG or PostScript file.

To generate a PNG file of e.g. gedit, run:

$ jhbuild dot gedit | dot -Tpng > dependencies.png

Troubleshooting

Note: If you encounter an issue that is not documented below, please report it in a comment on the jhbuild^AUR package.

Python issues

A module that depends on python2 may fail to build as software usually expect the binary filename of python 2.x to be /usr/bin/python and python 3.x to be /usr/bin/python3, which is not the case in Arch Linux: python 2.x is /usr/bin/python2 and python 3.x is /usr/bin/python.

For cases like that, force the modules to run /usr/bin/python2 using the one or more methods below:

set module_autoargs with PYTHON=/usr/bin/python2 for this specific module in ~/.config/jhbuildrc, as mentioned in the above Configuration section — this will run autogen.sh or configure with this value for variable PYTHON

if the configure or Makefile does not parse PYTHON variable, one approach is to manually find all lines in configure/Makefile that run python binary and rename python -> python2 — this will hard code python2 in the module's source code.

if only the above workarounds still do not work for you, consider editing module's .py files in order to replace python with python2 when the first line matches #!/usr/bin/env python or #!/usr/bin/python

Note: All edits and patches that are manually applied to the source code will be lost when you wipe the directory and checkout (download) it again, so it is not exactly a permanent solution

Note: If a module's configure/build process misuse PYTHON variable, or does not use at all, consider reporting it to the module's upstream and/or providing patch for JHBuild upstream

pkg-config issues

If you have a malformatted .pc file on your PKG_CONFIG_PATH, JHBuild will not be able to detect all the (valid) .pc files you have installed and will complain that the .pc files are missing. Look at the output of jhbuild sysdeps—there should be a message about the problematic .pc files.

Build failed due to incompatible meson versions

This article or section is out of date.

Reason: No longer an issue, as meson now regenerates the configuration from scratch when the meson's version used to generate the build directory has incompatible with the current version. (Discuss in Talk:JHBuild)

You may come across with a message similar to one of these below.

Meson encountered an error:
Build directory has been generated with Meson version 0.40.0, which is incompatible with current version 0.40.1.
Please delete this build directory AND create a new one.
FAILED: build.ninja 
'/usr/bin/python3' '/home/foobar/jhbuild/install/bin/meson' --internal regenerate '/home/foobar/jhbuild/checkout/gst-plugins-base' '/home/foobar/.cache/jhbuild/build/gst-plugins-base' --backend ninja
ninja: error: rebuilding 'build.ninja': subcommand failed

In the above example, the module was configured with meson 0.40.0 at on time, but a newer version (0.40.1, in the example) is now installed and is not compatible with the old one.

Solution: Run Configure phase again, in order to have this module configured with newer Meson version

Build failed due to GCC library or object not found

You may come across with a message similar to the one below.

cc: error: /usr/lib/gcc/x86_64-pc-linux-gnu/gcc_version/../../../../lib/name.so: No such file or directory

or

g++: error: /usr/lib/gcc/x86_64-pc-linux-gnu/gcc_version/../../../../lib/name.o: No such file or directory

where gcc_version is a GCC version older than the current one, and name is the name of the library (.so) or object (.o) that failed to be found.

This may happen if gcc was updated and the software was previously configured and built with the previous version of gcc.

Solution: Run Configure phase again, in order to have this module configured with newer GCC version

gst-plugin-bad fails on missing vulkan headers

When building the gst-plugins-bad module, You may come across with a number of messages similar to the one below:

In file included from ext/vulkan/gstvulkan-plugins-enumtypes.c:8:
../../../../jhbuild/checkout/gst-plugins-bad/ext/vulkan/vkviewconvert.h:26:10: fatal error: gst/vulkan/vulkan.h: No such file or directory
   26

It means gst-plugin-bad was automatically set to build its vulkan extension, but did not find all the dependecies it needs. As of the writing this subsection, ext/vulkan/meson.build looks for the binary glslc provided by shaderc, which several packages depend on directly or indirectly. Removing shaderc would solve this error, but this might not be an option if you want to keep one those packages the depends on it.

Solution: edit your jhbuild user configuration file to disable the vulkan extension:

~/.config/jhbuildrc

module_mesonargs['gst-plugins-bad'] = '-D vulkan=disabled'

and run Configure phase again, in order to have the gst-plugins-bad module successfully built.

Library missing and no known rule to make it

When building a module that uses meson build system you might come across an issue like this:

*** Checking out module_name *** [67/218]
some omitted checkout output
*** Building module_name *** [67/218]
ninja
ninja: error: 'path/to/missing_library.so', needed by 'path/to/module_file', missing and no known rule to make it
*** Error during the phase build of module_name: ########## Error running ninja   *** [67/218]

This happens because the module was previously configured and built in another commit of this module, and in that occasion it was configured to a previous version of the dependency path/to/missing_library.so. Since the file path/to/module_file was configured to and expects that missing library to be available, it fails.

Solution: Just run option 7 for the configure phase to reconfigure the module and build it again.

Building JHBuild from scratch

If you do not want to use the jhbuild^AUR package, and instead you want build JHBuild from scratch on your own, there are a few things you should pay attention too.

Make sure to install all the dependencies required by JHBuild and its target modules. Refer to list of dependencies for Arch Linux;

JHBuild itself used to depend on Python version 2 but it got migrated to python 3, so no specific configuration on python version;

Some modules might still depend on python2. Make sure to read the #Python issues section;

For detailed information downloading and building the source code of JHBuild, check JHBuild's "How Do I" at GNOME wiki.