from https://gerrit.libreoffice.org/c/core/+/158845


diff -ur clucene.org/src/core/CLucene/index/IndexWriter.cpp clucene/src/core/CLucene/index/IndexWriter.cpp
--- clucene.org/src/core/CLucene/index/IndexWriter.cpp	2023-11-02 17:31:00.110168174 +0100
+++ clucene/src/core/CLucene/index/IndexWriter.cpp	2023-11-02 17:33:22.507665912 +0100
@@ -366,6 +366,10 @@
   }
 }
 
+void IndexWriter::setSegmentInfoStartVersion(int64_t startVersion) {
+  this->segmentInfos->setStartVersion(startVersion);
+}
+
 int32_t IndexWriter::getMaxBufferedDocs() {
   ensureOpen();
   return docWriter->getMaxBufferedDocs();
diff -ur clucene.org/src/core/CLucene/index/IndexWriter.h clucene/src/core/CLucene/index/IndexWriter.h
--- clucene.org/src/core/CLucene/index/IndexWriter.h	2023-11-02 17:31:00.113501525 +0100
+++ clucene/src/core/CLucene/index/IndexWriter.h	2023-11-02 17:33:43.547787510 +0100
@@ -336,6 +336,12 @@
   int64_t getWriteLockTimeout();
 
   /**
+   * Sets the 0th segmentinfo version. Default is current system time
+   * in milliseconds
+   */
+  void setSegmentInfoStartVersion(int64_t startVersion);
+
+  /**
    * Sets the maximum time to wait for a commit lock (in milliseconds).
    */
   void setCommitLockTimeout(int64_t commitLockTimeout);
diff -ur clucene.org/src/core/CLucene/index/SegmentInfos.cpp clucene/src/core/CLucene/index/SegmentInfos.cpp
--- clucene.org/src/core/CLucene/index/SegmentInfos.cpp	2023-11-02 17:31:00.110168174 +0100
+++ clucene/src/core/CLucene/index/SegmentInfos.cpp	2023-11-02 18:04:43.855243418 +0100
@@ -662,6 +662,10 @@
 	  return IndexFileNames::fileNameFromGeneration( IndexFileNames::SEGMENTS, "", nextGeneration );
   }
 
+  void SegmentInfos::setStartVersion(int64_t version) {
+      this->version = version;
+  }
+
   void SegmentInfos::clearto(size_t from, size_t end){
 	size_t range = end - from;
       if ( (infos.size() - from) >= range) { // Make sure we actually need to remove
diff -ur clucene.org/src/core/CLucene/index/_SegmentInfos.h clucene/src/core/CLucene/index/_SegmentInfos.h
--- clucene.org/src/core/CLucene/index/_SegmentInfos.h	2023-11-02 17:31:00.106834824 +0100
+++ clucene/src/core/CLucene/index/_SegmentInfos.h	2023-11-02 18:04:51.178598463 +0100
@@ -347,6 +347,13 @@
 		*/
 		std::string getNextSegmentFileName();
 
+		/**
+		* Set version value to start from
+
+          Defaults to current time in milliseconds
+		*/
+        void setStartVersion(int64_t version);
+
 		/* public vector-like operations */
 		//delete and clears objects 'from' from to 'to'
 		void clearto(size_t to, size_t end);