GitOrigin-RevId: 9b19f5e77dd906cb52dade0b7bd280339d2a1f3d
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Dart
Dart applications
The function buildDartApplication
builds Dart applications managed with pub.
It fetches its Dart dependencies automatically through pub2nix
, and (through a series of hooks) builds and installs the executables specified in the pubspec file. The hooks can be used in other derivations, if needed. The phases can also be overridden to do something different from installing binaries.
If you are packaging a Flutter desktop application, use buildFlutterApplication
instead.
pubspecLock
is the parsed pubspec.lock file. pub2nix uses this to download required packages.
This can be converted to JSON from YAML with something like yq . pubspec.lock
, and then read by Nix.
Alternatively, autoPubspecLock
can be used instead, and set to a path to a regular pubspec.lock
file. This relies on import-from-derivation, and is not permitted in Nixpkgs, but can be useful at other times.
::: {.warning}
When using autoPubspecLock
with a local source directory, make sure to use a
concatenation operator (e.g. autoPubspecLock = src + "/pubspec.lock";
), and
not string interpolation.
String interpolation will copy your entire source directory to the Nix store and
use its store path, meaning that unrelated changes to your source tree will
cause the generated pubspec.lock
derivation to rebuild!
:::
If the package has Git package dependencies, the hashes must be provided in the gitHashes
set. If a hash is missing, an error message prompting you to add it will be shown.
The dart
commands run can be overridden through pubGetScript
and dartCompileCommand
, you can also add flags using dartCompileFlags
or dartJitFlags
.
Dart supports multiple outputs types, you can choose between them using dartOutputType
(defaults to exe
). If you want to override the binaries path or the source path they come from, you can use dartEntryPoints
. Outputs that require a runtime will automatically be wrapped with the relevant runtime (dartaotruntime
for aot-snapshot
, dart run
for jit-snapshot
and kernel
, node
for js
), this can be overridden through dartRuntimeCommand
.
{ lib, buildDartApplication, fetchFromGitHub }:
buildDartApplication rec {
pname = "dart-sass";
version = "1.62.1";
src = fetchFromGitHub {
owner = "sass";
repo = pname;
rev = version;
hash = "sha256-U6enz8yJcc4Wf8m54eYIAnVg/jsGi247Wy8lp1r1wg4=";
};
pubspecLock = lib.importJSON ./pubspec.lock.json;
}
Patching dependencies
Some Dart packages require patches or build environment changes. Package derivations can be customised with the customSourceBuilders
argument.
A collection of such customisations can be found in Nixpkgs, in the development/compilers/dart/package-source-builders
directory.
This allows fixes for packages to be shared between all applications that use them. It is strongly recommended to add to this collection instead of including fixes in your application derivation itself.
Running executables from dev_dependencies
Many Dart applications require executables from the dev_dependencies
section in pubspec.yaml
to be run before building them.
This can be done in preBuild
, in one of two ways:
- Packaging the tool with
buildDartApplication
, adding it to Nixpkgs, and running it like any other application - Running the tool from the package cache
Of these methods, the first is recommended when using a tool that does not need to be of a specific version.
For the second method, the packageRun
function from the dartConfigHook
can be used.
This is an alternative to dart run
that does not rely on Pub.
e.g., for build_runner
:
packageRun build_runner build
Do not use dart run <package_name>
, as this will attempt to download dependencies with Pub.
Usage with nix-shell
As buildDartApplication
provides dependencies instead of pub get
, Dart needs to be explicitly told where to find them.
Run the following commands in the source directory to configure Dart appropriately.
Do not use pub
after doing so; it will download the dependencies itself and overwrite these changes.
cp --no-preserve=all "$pubspecLockFilePath" pubspec.lock
mkdir -p .dart_tool && cp --no-preserve=all "$packageConfig" .dart_tool/package_config.json
Flutter applications
The function buildFlutterApplication
builds Flutter applications.
See the Dart documentation for more details on required files and arguments.
{ flutter, fetchFromGitHub }:
flutter.buildFlutterApplication {
pname = "firmware-updater";
version = "unstable-2023-04-30";
src = fetchFromGitHub {
owner = "canonical";
repo = "firmware-updater";
rev = "6e7dbdb64e344633ea62874b54ff3990bd3b8440";
sha256 = "sha256-s5mwtr5MSPqLMN+k851+pFIFFPa0N1hqz97ys050tFA=";
fetchSubmodules = true;
};
pubspecLock = lib.importJSON ./pubspec.lock.json;
}
Usage with nix-shell
See the Dart documentation for nix-shell instructions.