feature: initial version if no tags are created

README.md

@@ -49,11 +49,12 @@ versioning {
 
 Below are all the available settings and what they do.
 
-| Name        | Default value | Description |
-| ----------- | ------------- | ----------- |
-| tagPrefix   | `null`        | A prefix that tags must start with in order to be considered a version tag. The prefix is removed from the final version string. |
-| excludeTags | `null`        | A regular expression for tags that should be ignored. |
-| dirtyMark   | `true`        | Whether a `-dirty` suffix should be added to the version string if the Git working directory is dirty. |
+| Name           | Default value | Description |
+| -------------- | ------------- | ----------- |
+| initialVersion | `"0.0.0"`     | An initial version number to use if no tags are available. Can also be overridden by setting `version` manually. |
+| tagPrefix      | `null`        | A prefix that tags must start with in order to be considered a version tag. The prefix is removed from the final version string. |
+| excludeTags    | `null`        | A regular expression for tags that should be ignored. |
+| dirtyMark      | `true`        | Whether a `-dirty` suffix should be added to the version string if the Git working directory is dirty. |
 
 ### Automatic publishing
 If you are using Travis, the following configuration works quite nicely:

src/main/java/com/widen/versioning/Settings.java

@@ -1,7 +1,23 @@
 package com.widen.versioning;
 
 public class Settings {
+    /**
+     * An initial version number to use if no tags are available.
+     */
+    public String initialVersion = "0.0.0";
+
+    /**
+     * A prefix that tags must start with in order to be considered a version tag.
+     */
     public String tagPrefix;
+
+    /**
+     * A regular expression for tags that should be ignored.
+     */
     public String excludeTags;
+
+    /**
+     * Whether a `-dirty` suffix should be added to the version string if the Git working directory is dirty.
+     */
     public boolean dirtyMark = true;
 }

src/main/java/com/widen/versioning/VersioningPlugin.java

@@ -21,6 +21,9 @@ public void apply(final Project project) {
             if (version != null) {
                 p.setVersion(version);
             }
+            else if ("unspecified".equals(p.getVersion())) {
+                p.setVersion(settings.initialVersion);
+            }
         });
     }
 }