mima-maven-plugin

This is a Maven plugin that allows you to check your Scala project against a previous version of the project for binary incompatibilities that you may have introduced. This plugin is just a shell; the heavy lifting is done by the core of MiMa.

Releases here will match the version of the corresponding MiMa release. If extra releases of this plugin are required for a given MiMa version, a fourth version component will be added to the plugin's version number.

Usage

<build>
  <plugins>
    <plugin>
      <groupId>org.spurint.maven.plugins</groupId>
      <artifactId>mima-maven-plugin</artifactId>
      <version>${mima-maven-plugin.version}</version>
      <executions>
        <execution>
          <id>check-abi</id>
          <goals>
            <goal>check-abi</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

In general, the out-of-the-box configuration should have sane defaults and will do what you want. The maven plugin differs a bit in configuration from the sbt plugin, since we can't write arbitrary code to provide as configuration as we could with sbt.

This plugin, by default, will figure out the previous version to use for comparison by fetching the maven-metadata.xml file for the artifact being built from whatever remote repositories are defined in your POM (which is just maven central if you haven't defined any). It finds the latest release version from that metadata file, and then attempts to fetch that version of the artifact from the remote repository.

For allowing/disallowing binary incompatibilities, the plugin's default configuration follows the rules set out in Semantic Versioning, namely:

1. If the version's major number is 0 (as in, 0.4.21), binary incompatibilities are only allowed if the minor version has been bumped (as in, 4 -> 5).
2. Otherwise (as in, 2.0.4), binary incompatibilities are only allowed if the major version has been bumped (as in, 2 -> 3).

Configuration

Name	Default	Description
previousArtifact	latest-release	If set to latest-release, will attempt to determine the most recent released version as described above; otherwise, this can be set to a specific version of an artifact.
failOnProblem	semver	If set to semver, the previous artifact version is compared with the current version, and whether or not incompatibilities will cause the build to fail is decided based on Semantic Versioning rules, as described above. If set to never or false, binary incompatibilities are never allowed, while always or true will put the plugin into warn-only mode.
failOnNoPrevious	false	Whether or not to fail the build if a previous artifact version is not supplied or cannot be found.
readTimeout	4000	Timeout in ms to fetch the previous artifact.
direction	backward	Whether to do backward compatibilities checks, forward compatibility checks, or both.
filters	(none)	A list of <filter> elements that allow you to ignore particular problems (see below).

Filters

Filters allow you to ignore particular problems (perhaps for changes in internal non-public classes that nevertheless need to be public). To specify a filter, you can add something like:

<configuration>
  ...
  <filters>
    <filter>
      <name>DirectMissingMethodProblem</name>
      <value>com.example.Foo.create</value>
    </filter>
  </filters>
  ...
</configuration>

The name property comes from one of the ProblemRef subclasses, which you can discover by taking a look at the MiMa core source.

When a binary issue is reported as an error, it will also print out a "filter with:" line that shows the exact filter definition to use to suppress the error.