Optionally warn (once) if repository is shallow/sparse

license-maven-plugin-git/src/main/java/com/mycila/maven/plugin/license/git/CopyrightAuthorProvider.java

@@ -55,7 +55,7 @@ public Map<String, String> getAdditionalProperties(AbstractLicenseMojo mojo, Pro
 
     try {
       Map<String, String> result = new HashMap<String, String>(3);
-      GitLookup gitLookup = getGitLookup(document.getFile(), properties);
+      GitLookup gitLookup = getGitLookup(mojo, document.getFile(), properties);
 
       result.put(COPYRIGHT_CREATION_AUTHOR_NAME_KEY, gitLookup.getAuthorNameOfCreation(document.getFile()));
       result.put(COPYRIGHT_CREATION_AUTHOR_EMAIL_KEY, gitLookup.getAuthorEmailOfCreation(document.getFile()));

license-maven-plugin-git/src/main/java/com/mycila/maven/plugin/license/git/CopyrightRangeProvider.java

@@ -78,7 +78,7 @@ public Map<String, String> getAdditionalProperties(AbstractLicenseMojo mojo, Pro
     }
     try {
       Map<String, String> result = new HashMap<String, String>(4);
-      GitLookup gitLookup = getGitLookup(document.getFile(), properties);
+      GitLookup gitLookup = getGitLookup(mojo, document.getFile(), properties);
       int copyrightEnd = gitLookup.getYearOfLastChange(document.getFile());
       result.put(COPYRIGHT_LAST_YEAR_KEY, Integer.toString(copyrightEnd));
       final String copyrightYears;

license-maven-plugin-git/src/main/java/com/mycila/maven/plugin/license/git/GitLookup.java

@@ -59,6 +59,7 @@ public enum DateSource {
   private final GitPathResolver pathResolver;
   private final Repository repository;
   private final TimeZone timeZone;
+  private final boolean shallow;
 
   /**
    * Creates a new {@link GitLookup} for a repository that is detected from the supplied {@code anyFile}.
@@ -76,7 +77,8 @@ public GitLookup(File anyFile, DateSource dateSource, TimeZone timeZone, int che
     super();
     this.repository = new FileRepositoryBuilder().findGitDir(anyFile).build();
     /* A workaround for  https://bugs.eclipse.org/bugs/show_bug.cgi?id=457961 */
-    this.repository.getObjectDatabase().newReader().getShallowCommits();
+    // Also contains contents of .git/shallow and can detect shallow repo
+    this.shallow = !this.repository.getObjectDatabase().newReader().getShallowCommits().isEmpty();
 
     this.pathResolver = new GitPathResolver(repository.getWorkTree().getAbsolutePath());
     this.dateSource = dateSource;
@@ -184,6 +186,10 @@ String getAuthorEmailOfCreation(File file) throws IOException, GitAPIException {
     walk.dispose();
     return authorEmail;
   }
+
+  boolean isShallowRepository() {
+    return this.shallow;
+  }
 
   private boolean isFileModifiedOrUnstaged(String repoRelativePath) throws GitAPIException {
     @SuppressWarnings("resource")

license-maven-plugin-git/src/main/java/com/mycila/maven/plugin/license/git/GitPropertiesProvider.java

@@ -21,6 +21,8 @@
 import java.util.Properties;
 import java.util.TimeZone;
 
+import com.mycila.maven.plugin.license.AbstractLicenseMojo;
+
 /**
  * @author <a href="mailto:ppalaga@redhat.com">Peter Palaga</a>
  */
@@ -43,7 +45,7 @@ public GitPropertiesProvider() {}
    * @return
    * @throws IOException
    */
-  GitLookup getGitLookup(File file, Properties props) throws IOException {
+  GitLookup getGitLookup(AbstractLicenseMojo mojo, File file, Properties props) throws IOException {
     if (gitLookup == null) {
       synchronized (this) {
         if (gitLookup == null) {
@@ -74,6 +76,10 @@ GitLookup getGitLookup(File file, Properties props) throws IOException {
               throw new IllegalStateException("Unexpected " + GitLookup.DateSource.class.getName() + " " + dateSource);
           }
           gitLookup = new GitLookup(file, dateSource, timeZone, checkCommitsCount);
+          // One-time warning for shallow repo
+          if (mojo.warnIfShallow && gitLookup.isShallowRepository()) {
+            mojo.warn("Shallow git repository detected. Year and author property values may not be accurate.");
+          }
         }
       }
     }

license-maven-plugin-git/src/test/java/com/mycila/maven/plugin/license/git/CopyrightAuthorProviderTest.java

@@ -15,6 +15,7 @@
  */
 package com.mycila.maven.plugin.license.git;
 
+import com.mycila.maven.plugin.license.LicenseCheckMojo;
 import com.mycila.maven.plugin.license.document.Document;
 
 import java.io.File;
@@ -53,7 +54,7 @@ private void assertAuthor(CopyrightAuthorProvider provider, String path, String
     Properties props = new Properties();
 
     Document document = newDocument(path);
-    Map<String, String> actual = provider.getAdditionalProperties(null, props, document);
+    Map<String, String> actual = provider.getAdditionalProperties(new LicenseCheckMojo(), props, document);
 
     HashMap<String, String> expected = new HashMap<String, String>();
     expected.put(CopyrightAuthorProvider.COPYRIGHT_CREATION_AUTHOR_NAME_KEY, copyrightAuthorName);

license-maven-plugin-git/src/test/java/com/mycila/maven/plugin/license/git/CopyrightRangeProviderTest.java

@@ -15,6 +15,7 @@
  */
 package com.mycila.maven.plugin.license.git;
 
+import com.mycila.maven.plugin.license.LicenseCheckMojo;
 import com.mycila.maven.plugin.license.document.Document;
 
 import java.io.File;
@@ -71,7 +72,7 @@ private void assertRange(CopyrightRangeProvider provider, String path, String in
     props.put(CopyrightRangeProvider.INCEPTION_YEAR_KEY, inceptionYear);
 
     Document document = newDocument(path);
-    Map<String, String> actual = provider.getAdditionalProperties(null, props, document);
+    Map<String, String> actual = provider.getAdditionalProperties(new LicenseCheckMojo(), props, document);
 
     HashMap<String, String> expected = new HashMap<String, String>();
     expected.put(CopyrightRangeProvider.COPYRIGHT_CREATION_YEAR_KEY, copyrightStart);

license-maven-plugin-svn/src/main/java/com/mycila/maven/plugin/license/svn/SVNPropertiesProvider.java

@@ -20,10 +20,12 @@
 import com.mycila.maven.plugin.license.PropertiesProvider;
 import com.mycila.maven.plugin.license.document.Document;
 import org.tmatesoft.svn.core.ISVNLogEntryHandler;
+import org.tmatesoft.svn.core.SVNDepth;
 import org.tmatesoft.svn.core.SVNException;
 import org.tmatesoft.svn.core.SVNLogEntry;
 import org.tmatesoft.svn.core.internal.wc.DefaultSVNOptions;
 import org.tmatesoft.svn.core.wc.SVNClientManager;
+import org.tmatesoft.svn.core.wc.SVNInfo;
 import org.tmatesoft.svn.core.wc.SVNRevision;
 
 import java.io.File;
@@ -58,6 +60,8 @@ protected SimpleDateFormat initialValue() {
 
   public static final String SVN_SERVER_ID_PLUGIN_KEY = "license.svn.serverId";
 
+  private volatile boolean initialized = false;
+
   /**
    * Provides information on the given document. The information is put in the
    * returned map using: SVN_COPYRIGHT_LAST_YEAR_KEY the year of the latest
@@ -104,6 +108,20 @@ public void handleLogEntry(SVNLogEntry logEntry) throws SVNException {
     };
 
     try {
+      if (!this.initialized) {
+        synchronized (this) {
+          if (!this.initialized) {
+            this.initialized = true;
+            // One-time warning for shallow repo
+            if (mojo.warnIfShallow) {
+              SVNInfo info = clientManager.getWCClient().doInfo(documentFile, SVNRevision.HEAD);
+              if (info.getDepth() != SVNDepth.INFINITY) {
+                mojo.warn("Sparse svn repository detected. Year and author property values may not be accurate.");
+              }
+            }
+          }
+        }
+      }
       clientManager.getLogClient().doLog(new File[]{documentFile}, SVNRevision.HEAD, SVNRevision.create(0), true, true, 1, lastChangeDateLogEntryHandler);
     } catch (SVNException ex) {
       IllegalStateException ise = new IllegalStateException("cannot query SVN latest date information for file: " + documentFile, ex);

license-maven-plugin/src/main/java/com/mycila/maven/plugin/license/AbstractLicenseMojo.java

@@ -295,6 +295,16 @@ public abstract class AbstractLicenseMojo extends AbstractMojo {
   @Parameter(property = "license.skip", defaultValue = "false")
   public boolean skip = false;
 
+  /**
+   * Determination of the year and author of the first commit and last change year
+   * of a file requires a full git or svn history. By default the plugin will log
+   * warning when using these properties on a shallow or sparse repository. If you
+   * are certain the repository depth will permit accurate determination of these
+   * values, you can disable this check.
+   */
+  @Parameter(property = "license.warnIfShallow", defaultValue = "true")
+  public boolean warnIfShallow = true;
+
   /**
    * If you do not want to see the list of file having a missing header, you
    * can add the quiet flag that will shorten the output