introduce DETACHED_HEAD metadata

Author: McFoggy

src/main/java/fr/brouillard/oss/jgitver/impl/ScriptVersionStrategy.java

@@ -131,10 +131,6 @@ public Version build(Commit head, List<Commit> parents) throws VersionCalculatio
                 metaProps.put(Metadatas.COMMIT_TIMESTAMP.name(), GitUtils.getTimestamp(rc.getAuthorIdent().getWhen().toInstant()));
             }
 
-            // Extra convenient metadata
-            metaProps.put("DETACHED_HEAD",
-                          GitUtils.isDetachedHead(getRepository()));
-
             metaProps.put("BASE_COMMIT_ON_HEAD",
                           isBaseCommitOnHead(head, base));
 
@@ -283,6 +279,7 @@ public ScriptVersionStrategy setScript(String script) {
                 return TO_INTEGER;
             case DIRTY:
             case ANNOTATED:
+            case DETACHED_HEAD:
                 return TO_BOOLEAN;
             default: return IDENTITY;
         }

src/main/java/fr/brouillard/oss/jgitver/impl/VersionStrategy.java

@@ -15,6 +15,7 @@
  */
 package fr.brouillard.oss.jgitver.impl;
 
+import java.io.IOException;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Optional;
@@ -135,6 +136,11 @@ protected Version getBaseVersionAndRegisterMetadata(Commit base, Ref tagToUse) {
             getRegistrar().registerMetadata(Metadatas.BASE_TAG, tagName);
         }
 
+        try {
+            getRegistrar().registerMetadata(Metadatas.DETACHED_HEAD, "" + GitUtils.isDetachedHead(getRepository()));
+        } catch (IOException ioe) {
+            // ignore
+        }
         getRegistrar().registerMetadata(Metadatas.ANNOTATED,"" + GitUtils.isAnnotated(tagToUse));
         getRegistrar().registerMetadata(Metadatas.BASE_VERSION, baseVersion.toString());
         getRegistrar().registerMetadata(Metadatas.CURRENT_VERSION_MAJOR, Integer.toString(baseVersion.getMajor()));

src/main/java/fr/brouillard/oss/jgitver/metadata/Metadatas.java

@@ -166,6 +166,10 @@ public enum Metadatas {
     /**
      * True if the current HEAD is on an annotated tag, false otherwise
      */
-    ANNOTATED
+    ANNOTATED,
+    /**
+     * True if the current HEAD is detached, false otherwise
+     */
+    DETACHED_HEAD
     ;
 }