rust*: add docs for testing packages

See also https://discourse.nixos.org/t/rust-build-speed-improvements/7225
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Maximilian Bosch 2020-05-24 18:37:34 +02:00
parent 913dcddb68
commit 6574ba1946
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2 changed files with 81 additions and 3 deletions

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@ -75,6 +75,72 @@ pkgs.rustPlatform.buildRustPackage {
}
```
### Running package tests
When using `buildRustPackage`, the `checkPhase` is enabled by default and runs
`cargo test` on the package to build. To make sure that we don't compile the
sources twice and to actually test the artifacts that will be used after that,
the tests will be ran in the `release`-mode by default.
However, in some cases the test-suite of a package doesn't work properly in the
`release` mode. In that case, the mode for `checkPhase` can be changed like this:
```nix
rustPlatform.buildRustPackage {
/* ... */
checkType = "debug";
}
```
#### Tests relying on the structure of the `target/`-directory
Some tests may rely on the structure of the `target/`-directory. Those tests
are likely to fail since we use `cargo --target` during build. This means that
the artifacts
[are stored in `target/<architecture>/release/`](https://doc.rust-lang.org/cargo/guide/build-cache.html)
rather than `target/release/`.
This can only be circumvented by patching the affected tests accordingly.
#### Disabling package-tests
In some cases it's necessary to disable the tests (which can be done by declaring
`doCheck = false;`) which is fine in the following cases:
* If no tests exist, the `checkPhase` should be explicitly disabled to skip
unnecessary build-steps to speed-up the build.
* If tests are highly impure (e.g. due to heavy network usage), it's also fine
disable tests.
There are obviously some other corner-cases where it's sensible to disable tests,
those aren't hard-rules, in the end this is a case-by-case decision.
Please check however if it's possible to disable a problematic subset of the
test-suite and leave comment which explains why that's needed.
### Building a package in the `debug` mode
By default, `buildRustPackage` will use the `release`-mode for building. If a package
should be built in the `debug`-mode however, it can be configured like this:
```nix
rustPlatform.buildRustPackage {
/* ... */
buildType = "debug";
}
```
Obviously, the `checkPhase` will be ran in `debug`-mode as well in this case.
### Custom `build`/`install`-procedures
Some packages may use custom scripts for building/installing, e.g. with a `Makefile`.
In that case it's recommended to always override the `build-`/`install-`/`checkPhase`.
Otherwise, it may be possible that one of the internal steps fails because of the
modified directory structure of `target/`.
## Compiling Rust crates using Nix instead of Cargo
### Simple operation

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@ -354,9 +354,21 @@ php.override {
</para>
</listitem>
<listitem>
<para>
The default output of <literal>buildGoPackage</literal> is now <literal>$out</literal> instead of <literal>$bin</literal>.
</para>
<para>
The default output of <literal>buildGoPackage</literal> is now <literal>$out</literal> instead of <literal>$bin</literal>.
</para>
</listitem>
<listitem>
<para>
Packages built using <literal>buildRustPackage</literal> now use the <literal>release</literal>
mode for the <literal>checkPhase</literal> by default.
</para>
<para>
Please note that <literal>rust</literal>-packages utilizing a custom build/install-procedure
(e.g. by using a <filename>Makefile</filename>) or test-suites that rely on the
structure in the <filename>target/</filename>-directory may break because of that.
For further information, please read the rust-section in the nixpkgs manual.
</para>
</listitem>
</itemizedlist>
</section>