Dart API Tool

A tool to analyze the public API of a package and create a model of it. It also allows to use that model to compare the public API with a newer version and check if the version follows semver correctly.

CI pub package

Installation

To install activate the tool via dart pub:

dart pub global activate dart_apitool

Screenshot

dart-apitool screenshot of CI integration

Usage

After activation the tool is usable via

dart-apitool

A set of utilities for Package APIs

Usage: dart-apitool <command> [arguments]

Global options:
-h, --help    Print this usage information.

Available commands:
  diff      Creates a diff of 2 given packages.
  extract   Extracts the API from the given package ref.

Run "dart-apitool help <command>" for more information about a command.

extract

Extracts the API from the given package ref.

Usage: dart-apitool extract [arguments]
-h, --help                               Print this usage information.
    --input (mandatory)                  Input package ref. Package reference can be one of:
                                         - directory path pointing to a package on disk
                                           (e.g. /path/to/package)
                                         - any package from pub
                                           (e.g. pub://package_name/version)
-p, --[no-]include-path-dependencies     OBSOLETE: Has no effect anymore.
    --output                             Output file for the extracted Package API.
                                         If not specified the extracted API will be printed to the console.
    --no-analyze-platform-constraints    Disables analysis of platform constraints.
    --[no-]remove-example                Removes examples from the package to analyze.
                                         (defaults to on)
    --[no-]set-exit-on-missing-export    Sets exit code to != 0 if missing exports are detected in the API.

diff

Creates a diff of 2 given packages.

Usage: dart-apitool diff [arguments]
-h, --help                               Print this usage information.
    --old (mandatory)                    Old package reference. Package reference can be one of:
                                         - directory path pointing to a package on disk
                                           (e.g. /path/to/package)
                                         - any package from pub
                                           (e.g. pub://package_name/version)
    --new (mandatory)                    New package reference. Package reference can be one of:
                                         - directory path pointing to a package on disk
                                           (e.g. /path/to/package)
                                         - any package from pub
                                           (e.g. pub://package_name/version)
-p, --[no-]include-path-dependencies     OBSOLETE: Has no effect anymore.
    --version-check-mode                 Defines the mode the versions of the packages shall be compared.
                                         This affects the exit code of this program.
                                         [none, fully (default), onlyBreakingChanges]
    --[no-]check-sdk-version             Determines if the SDK version should be checked.
                                         (defaults to on)
    --[no-]ignore-prerelease             Determines if the pre-release aspect of the new version
                                         shall be ignored when checking versions.
                                         You may want to do this if you want to make sure
                                         (in your CI) that the version - once ready - matches semver.
                                         (defaults to on)
    --no-analyze-platform-constraints    Disables analysis of platform constraints.
    --dependency-check-mode              DEPRECATED - this option as no effect any more
                                         [none, allowAdding (default), strict]
    --[no-]remove-example                Removes examples from the package to analyze.
                                         (defaults to on)
    --[no-]ignore-requiredness           Whether to ignore the required aspect of interfaces (yielding less strict version bump requirements)
    --report-format                      Which output format should be used
                                         [cli (default), markdown, json]
    --report-file-path                   Where to store the report file (no effect on cli option)

Integration

How to best integrate dart-apitool in your CI and release process highly depends on your setup.

In general, you need to have a reference of what has been released before in order to do a diff to the new sources.

To do that you can either:

  • store the last released version next to your source code (via a separate file or by using tags)
  • or use whatever knowledge your release process has to get a copy of the previously released version

Depending on what you have as a reference you can call dart-apitool using the appropriate package ref for the old parameter:

  1. pub://package_name/package-version if you know the last released version and your package is hosted at pub
  2. path-to-copy to get the public API model from the obtained reference copy

CI

For an example how to integrate dart-apitool in your CI (to make sure that the current pre-release version is targeting the right version number) you can refer to the workflow used by this repository. dart-apitool uses approach 1 (use the tags to determine the last released version). It uses git describe to get the last tag and then uses the tag as the version for the pub:// reference.

tag=$(git describe --tags --abbrev=0)
version="${tag#releases/}" # to support the old tag format dart_apitool used (e.g. releases/0.12.0)
version="${version#v}" # the new tag format (e.g. v0.12.0)

You can see this in action in the workflow of this repository.

For your convenience there is a reusable workflow that you can integrate in your workflow.

  semver:
    uses: bmw-tech/dart_apitool/.github/workflows/check_version.yml@workflow/v1
    with:
      runs-on: [your build node] # defaults to ubuntu-latest
      old: [package ref to old] # required, e.g. "pub://dart_apitool/<old version>"
      new: [package ref to new] # e.g. "."
      ignore-prerelease: ['on' if you want to check against the future version (without pre-release), defaults to 'off'] # e.g. 'on'
      flutter-channel: [flutter channel to use, defaults to 'stable'] # e.g. 'stable'
      flutter-version: [flutter version to use, defaults to 'any'] # e.g. 'any'

Release

Your release process has to make sure that the reference is stored somehow. The easiest way to do that is to use git tags for this. You probably are creating tags for releases anyway so using them to get the last released version is a good idea. The release process can also use dart-apitool to make sure that the new version matches the changes it contains.

Contributions

Any kind of contribution is very welcome. Either you have found a false positive or you miss something in the public API model that needs to be analyzed or if you want to contribute directly. Feel free to use the issues to create requests.

Limitations

It doesn't cover all potential API changes that might lead to breaking changes.

It does not look into implementations

Imagine a class:

class MyClass<T> {
  String doSomething(T arg) {
    final castedArg = arg as SomeBaseClass;
    return castedArg.baseClassMethod();
  }
}

that got changed to

class MyClass<T> {
  String doSomething(T arg) {
    final castedArg = arg as SomeOtherBaseClass;
    return castedArg.otherBaseClassMethod();
  }
}

Changes in the implementation are not detected.

Verdict

You have to keep your eyes 👀 open and always remember the public API!

dart-apitool can help you find problematic changes on Dart API level, but it can't detect everything. 😉

Libraries

api_tool
api_tool_cli