NOTE This is a port from Clojure to Java of the original code from: https://github.com/code54/buildversion-plugin

This is a maven plugin that extracts current build information from git projects, including: the latest commit hash, timestamp, most recent tag, number of commits since most recent tag. It also implements a "follow first parent" flavor of git describe (see "About git-describe" below for details).

Similar in intent to buildnumber-maven-plugin, this plugin sets Maven project properties intended to be used in later phases of the Maven lifecycle. You may use this to include build version information on property files, manifests and generated sources.

Simply add buildversion-plugin to your pom, executing the set-properties goal. Example:

  ...
  <build>
    <plugins>
      <plugin>
        <groupId>com.evolvedbinary.maven.plugins</groupId>
        <artifactId>buildversion-maven-plugin</artifactId>
        <version>2.0.0</version>
        <executions>
          <execution>
            <goals><goal>set-properties</goal></goals>
          </execution>
        </executions>
      </plugin>
  ...

By default, the plugin runs on Maven's initialize phase. Any plugin running after that phase will see the following properties:

• build-tag: Closest repository tag (in commit history following "first parents"). NOTE: Only tags starting with v are considered, and the v is stripped. Example: 1.2.0-SNAPSHOT (tag on git: v1.2.0-SNAPSHOT).
• build-tag-delta: Number of commits since the closest tag until HEAD. Example: 2
• build-commit: Full hash of current commit (HEAD). Example: c154712b8cea9da812c52f269578a458911f24cc
• build-commit-abbrev: Abbreviated hash of current commit (HEAD). Example: c154712
• build-version: Descriptive version of current build. If a tag points to HEAD (that is, build-tag-delta is "0") then build-version equals build-tag; otherwise, it'll include: the closest tag, tag delta, and abbreviated commit hash. Examples: 1.2.0-SNAPSHOT (tag points to HEAD), 1.2.0-SNAPSHOT-2-c154712 (HEAD is two commits ahead of tag)
• build-tstamp: A date and time stamp of the current commit (HEAD). The pattern is configurable. Example: 20120407001823.

Example:

  <plugin>
    <groupId>com.code54.mojo</groupId>
    <artifactId>buildversion-plugin</artifactId>
    <version>1.0.3</version>
    <executions>
      <execution>
        <goals><goal>set-properties</goal></goals>
        <configuration>
          <!-- use only the day for the timestamp -->
          <tstampFormat>yyyy-MM-dd</tstampFormat>

          <!-- Define a new project property 'build-tag-lowercase', based on 'build-tag'
               Note how 'build-tag' is available to the script as a local variable. -->
          <customProperties>
            { :build-tag-lowercase (clojure.string/lower-case build-tag) }
          </customProperties>
        </configuration>
      </execution>
    </executions>
  </plugin>

Before writing this plugin, I used to rely on a simple script which called git describe to obtain a descriptive version number including most recent tag and commits since such a tag.

Unfortunately, the logic behind git describe searches for the closest tag back in history following all parent commits on merges. This means it may select tags you originally put on another branch. So, if you are working on a development branch and merge back a fix made on a release branch, calling git describe on the development branch may shield a description that includes a tag you placed on the release branch.

Until git describe accepts a --first-parent argument to prevent this problem, this plugin implements its own logic, which basically relies on git log --first-parent to traverse history on the current "line of development".

Reference:

• Another explanation of this same issue with git describe.
• GIT mailing list discussion about git describe's logic and lack of --first-parent.
• Here's a working patch to add --first-parent to git describe

• Why don't you just use buildnumber-maven-plugin? Because it does not provide information about tagging and number of commits since tag. See "About git-describe" above for details.