This is a list of issues found while making the D ecosystem available on Linux distributions such as Debian and Fedora. It is a smaller, but priorized list of the general list of issues I find while working with D that can be viewed at dlang-quirks.md.
This list is ordered by priority, more pressing issues being at the top.
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D has no stable ABI. This kind of enforces recompiling all D shared libraries and binaries in a Linux distribution with every new compiler version. This is possible, but a major pain which requires quite some amount of manpower (Debian does this for OCaml and Haskell) - getting people to use D if it is that much extra work is harder. It also means that you can not use the libraries which were compiled with LDC in an application that is compiled with GDC and vice versa. This is a real PITA for distros and users who might have binaries compiled with the "wrong" compiler. It reduces the usefulness of development D packages in distributions a lot, if you need to recompile everything again anyway. Static linking is also frowned upon by distributions, because it triggers rebuild cascades on every bugfix that we introduce, making devlivering security updates much harder and error-prone (embedded code copies are very difficult to handle). A stable D ABI, or at least a guarantee that the ABI will not change unless there is a good reason (and the ABI change will be announced in the release notes) would help a lot. Having a D ABI that is shared between DMD, LDC and GDC would be even better.
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Dub doesn't use packages installed to system locations (dlang/dub#838) - this renders dub pretty much unusable for using it as part of the Linux distribution package tooling. Dub also writes into
$HOME
as part of the build process which is considered bad practice and is disallowed on build daemons at Debian (you need to add a hack for tools which expect$HOME
to be available) -
Dub: Can not version dependencies on other libraries (dlang/dub#906) - this makes it hard to determine compatibility if we package software written in D.
-
dub test
overrides the binary created bydub build
(prevents automatically running tests as part of the build process) (dlang/dub#840) -
No working Make/Ninja compatible depfile generation in LDC, DMD or GDC - this is especially important when not using dub (see the dub issues) and some other build system (Automake/CMake/Meson/..) is used instead. See ldc-developers/ldc#1802 for the LDC bug report.
-
There is no
dub install
command (dlang/dub#839) -
LDC doesn't support a lot of architectures / architecture support breaks from time to time. It would be quite nice to have D tools available on as many architectures as possible. (see ldc-developers/ldc#1636 for a bug report, build logs are here: https://buildd.debian.org/status/package.php?p=ldc)
The GDC issues have been separated out to not clutter the priorized overview.
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GDC is not part of official GCC. This makes it difficult (or actually sometimes impossible) to ship it with some Linux distributions, e.g. RHEL and Fedora. On Debian, we inject GDC into the GCC build, which is also a bit weird. Having GDC in GCC proper would also give D much higher visibility.
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GDC only supports an ancient version of the D standard library, which has many nice classes and also bugfixes missing. Because of that, it is almost impossible to compile modern D applications with GDC, and when developing a new application, support for GDC needs to be added explicitly and handled with a lot of care. This is an issue LDC doesn't have, and which is fragmenting the D ecosystem.
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GDC does not support creating shared libraries at time, which is a big deal for distros which need it to reduce duplicate code and make security fixes easier.
- DMD is completely free software now, there is no obstacle to ship it in distributions anymore.
Please keep in mind that this list is probably now extremely out-of-date and would really need an update!
Rust is also a real pain, but the short of it is that all Rust code is built statically, and since cargo supports local repositories packages just install the source code into system locations and it's then used from there. There is also some quite insane tooling available in form of debcargo to automate as much of the busywork as possible (a perk when a language is popular like Rust and people invest time into creating solutions like this)
See https://wiki.debian.org/Teams/RustPackaging/Policy and https://salsa.debian.org/rust-team/debcargo-conf/blob/master/README.rst for details.
The primary difference is really cargo allowing for a first-class system-wide repository of packages, while dub does not (or did not - I think dub has this now but last time I tested it it tried to place files in a read-only location and crashed).
Also, a ton of Rust-using projects, like Mesa and many GNOME projects like librsvg, use Meson as buildsystem, which simplifies things a lot. Packaging Rust still is pretty painful though, compared to a language like Python which also has a native package manager but also plays very well with packaging.