Add Git object information marker to all source files (#1081)

* Add Git object information marker to all source files

* Update to capture file mode from Git

* Switch to storing raw int for fileMode

---------

Co-authored-by: Tim te Beek <tim@moderne.io>

Author: shanman190

src/main/java/org/openrewrite/maven/MavenMojoProjectParser.java

@@ -36,6 +36,7 @@
 import org.jspecify.annotations.Nullable;
 import org.openrewrite.ExecutionContext;
 import org.openrewrite.ParseExceptionResult;
+import org.openrewrite.PathUtils;
 import org.openrewrite.SourceFile;
 import org.openrewrite.internal.StringUtils;
 import org.openrewrite.java.JavaParser;
@@ -45,9 +46,13 @@
 import org.openrewrite.java.marker.JavaVersion;
 import org.openrewrite.jgit.api.Git;
 import org.openrewrite.jgit.lib.FileMode;
+import org.openrewrite.jgit.lib.ObjectId;
+import org.openrewrite.jgit.revwalk.RevCommit;
+import org.openrewrite.jgit.revwalk.RevWalk;
 import org.openrewrite.jgit.treewalk.FileTreeIterator;
 import org.openrewrite.jgit.treewalk.TreeWalk;
 import org.openrewrite.jgit.treewalk.WorkingTreeIterator;
+import org.openrewrite.jgit.treewalk.filter.PathFilter;
 import org.openrewrite.jgit.treewalk.filter.PathFilterGroup;
 import org.openrewrite.kotlin.KotlinParser;
 import org.openrewrite.marker.*;
@@ -226,6 +231,7 @@ public Stream<SourceFile> listSourceFiles(MavenProject mavenProject, Xml.@Nullab
         sourceFiles = Stream.concat(sourceFiles, nonProjectResources);
 
         return sourceFiles.map(addProvenance(projectProvenance))
+                .map(addGitTreeEntryInformation())
                 .map(this::logParseErrors);
     }
 
@@ -830,6 +836,36 @@ private <T extends SourceFile> UnaryOperator<T> addProvenance(List<Marker> prove
         };
     }
 
+    private <T extends SourceFile> UnaryOperator<T> addGitTreeEntryInformation() {
+        return s -> {
+            if (repository == null) {
+                return s;
+            }
+
+            try {
+                ObjectId head = repository.resolve("HEAD");
+                if (head == null) {
+                    return s;
+                }
+
+                try (RevWalk revWalk = new RevWalk(repository);
+                     TreeWalk treeWalk = new TreeWalk(repository)) {
+                    RevCommit commit = revWalk.parseCommit(head);
+                    treeWalk.addTree(commit.getTree());
+                    treeWalk.setRecursive(true);
+                    treeWalk.setFilter(PathFilter.create(PathUtils.separatorsToUnix(s.getSourcePath().toString())));
+
+                    if (treeWalk.next()) {
+                        return s.withMarkers(s.getMarkers().add(new GitTreeEntry(randomId(), treeWalk.getObjectId(0).name(), treeWalk.getRawMode(0))));
+                    }
+                    return s;
+                }
+            } catch (IOException e) {
+                throw new UncheckedIOException(e);
+            }
+        };
+    }
+
     private static Collection<Path> listJavaSources(MavenProject mavenProject, List<String> compileSourceRoots) throws MojoExecutionException {
         Set<Path> javaSources = new LinkedHashSet<>();
         for (String compileSourceRoot : compileSourceRoots) {