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buildMavenPackage: Add overrideMavenAttrs function and `buildOfflin…
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…e` documentation (#313152)
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tomodachi94 authored Nov 27, 2024
2 parents b94e852 + 49a1189 commit d3f007d
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84 changes: 84 additions & 0 deletions doc/languages-frameworks/maven.section.md
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Expand Up @@ -49,6 +49,90 @@ This package calls `maven.buildMavenPackage` to do its work. The primary differe
After setting `maven.buildMavenPackage`, we then do standard Java `.jar` installation by saving the `.jar` to `$out/share/java` and then making a wrapper which allows executing that file; see [](#sec-language-java) for additional generic information about packaging Java applications.
:::

### Overriding Maven package attributes {#maven-overriding-package-attributes}

```
overrideMavenAttrs :: (AttrSet -> Derivation) | ((AttrSet -> Attrset) -> Derivation) -> Derivation
```

The output of `buildMavenPackage` has an `overrideMavenAttrs` attribute, which is a function that takes either
- any subset of the attributes that can be passed to `buildMavenPackage`

or
- a function that takes the argument passed to the previous invocation of `buildMavenPackage` (conventionally called `old`) and returns an attribute set that can be passed to `buildMavenPackage`

and returns a derivation that builds a Maven package based on the old and new arguments merged.

This is similar to [](#sec-pkg-overrideAttrs), but notably does not allow accessing the final value of the argument to `buildMavenPackage`.

:::{.example}
### `overrideMavenAttrs` Example

Use `overrideMavenAttrs` to build `jd-cli` version 1.2.0 and disable some flaky test:

```nix
jd-cli.overrideMavenAttrs (old: rec {
version = "1.2.0";
src = fetchFromGitHub {
owner = old.src.owner;
repo = old.src.repo;
rev = "${old.pname}-${version}";
# old source hash of 1.2.0 version
hash = "sha256-US7j6tQ6mh1libeHnQdFxPGoxHzbZHqehWSgCYynKx8=";
};
# tests can be disabled by prefixing it with `!`
# see Maven documentation for more details:
# https://maven.apache.org/surefire/maven-surefire-plugin/examples/single-test.html#Multiple_Formats_in_One
mvnParameters = lib.escapeShellArgs [
"-Dsurefire.failIfNoSpecifiedTests=false"
"-Dtest=!JavaDecompilerTest#basicTest,!JavaDecompilerTest#patternMatchingTest"
];
# old mvnHash of 1.2.0 maven dependencies
mvnHash = "sha256-N9XC1pg6Y4sUiBWIQUf16QSXCuiAPpXEHGlgApviF4I=";
});
```
:::

### Offline build {#maven-offline-build}

By default, `buildMavenPackage` does the following:

1. Run `mvn package -Dmaven.repo.local=$out/.m2 ${mvnParameters}` in the
`fetchedMavenDeps` [fixed-output derivation](https://nixos.org/manual/nix/stable/glossary.html#gloss-fixed-output-derivation).
2. Run `mvn package -o -nsu "-Dmaven.repo.local=$mvnDeps/.m2"
${mvnParameters}` again in the main derivation.

As a result, tests are run twice.
This also means that a failing test will trigger a new attempt to realise the fixed-output derivation, which in turn downloads all dependencies again.
For bigger Maven projects, this might lead to a long feedback cycle.

Use `buildOffline = true` to change the behaviour of `buildMavenPackage to the following:
1. Run `mvn de.qaware.maven:go-offline-maven-plugin:1.2.8:resolve-dependencies
-Dmaven.repo.local=$out/.m2 ${mvnDepsParameters}` in the fixed-output derivation.
2. Run `mvn package -o -nsu "-Dmaven.repo.local=$mvnDeps/.m2"
${mvnParameters}` in the main derivation.

As a result, all dependencies are downloaded in step 1 and the tests are executed in step 2.
A failing test only triggers a rebuild of step 2 as it can reuse the dependencies of step 1 because they have not changed.

::: {.warning}
Test dependencies are not downloaded in step 1 and are therefore missing in
step 2 which will most probably fail the build. The `go-offline` plugin cannot
handle these so-called [dynamic dependencies](https://github.com/qaware/go-offline-maven-plugin?tab=readme-ov-file#dynamic-dependencies).
In that case you must add these dynamic dependencies manually with:
```nix
maven.buildMavenPackage rec {
manualMvnArtifacts = [
# add dynamic test dependencies here
"org.apache.maven.surefire:surefire-junit-platform:3.1.2"
"org.junit.platform:junit-platform-launcher:1.10.0"
];
};
```
:::

### Stable Maven plugins {#stable-maven-plugins}

Maven defines default versions for its core plugins, e.g. `maven-compiler-plugin`. If your project does not override these versions, an upgrade of Maven will change the version of the used plugins, and therefore the derivation and hash.
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6 changes: 6 additions & 0 deletions doc/redirects.json
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Expand Up @@ -3190,6 +3190,12 @@
"maven-buildmavenpackage": [
"index.html#maven-buildmavenpackage"
],
"maven-overriding-package-attributes": [
"index.html#maven-overriding-package-attributes"
],
"maven-offline-build": [
"index.html#maven-offline-build"
],
"stable-maven-plugins": [
"index.html#stable-maven-plugins"
],
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34 changes: 25 additions & 9 deletions pkgs/by-name/ma/maven/package.nix
Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,6 @@
makeWrapper,
stdenvNoCC,
}:

stdenvNoCC.mkDerivation (finalAttrs: {
pname = "maven";
version = "3.9.9";
Expand Down Expand Up @@ -34,14 +33,31 @@ stdenvNoCC.mkDerivation (finalAttrs: {
runHook postInstall
'';

passthru = {
buildMaven = callPackage ./build-maven.nix {
maven = finalAttrs.finalPackage;
};
buildMavenPackage = callPackage ./build-maven-package.nix {
maven = finalAttrs.finalPackage;
passthru =
let
makeOverridableMavenPackage =
mavenRecipe: mavenArgs:
let
drv = mavenRecipe mavenArgs;
overrideWith =
newArgs: mavenArgs // (if lib.isFunction newArgs then newArgs mavenArgs else newArgs);
in
drv
// {
overrideMavenAttrs = newArgs: makeOverridableMavenPackage mavenRecipe (overrideWith newArgs);
};
in
{
buildMaven = callPackage ./build-maven.nix {
maven = finalAttrs.finalPackage;
};

buildMavenPackage = makeOverridableMavenPackage (
callPackage ./build-maven-package.nix {
maven = finalAttrs.finalPackage;
}
);
};
};

meta = {
homepage = "https://maven.apache.org/";
Expand All @@ -54,7 +70,7 @@ stdenvNoCC.mkDerivation (finalAttrs: {
'';
license = lib.licenses.asl20;
mainProgram = "mvn";
maintainers = [ ] ++ lib.teams.java.members;
maintainers = with lib.maintainers; [ tricktron ] ++ lib.teams.java.members;
inherit (jdk_headless.meta) platforms;
};
})

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