[Delta] Support absolute path in Clone (delta-io#4729)

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#### Which Delta project/connector is this regarding?
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- [x] Spark
- [ ] Standalone
- [ ] Flink
- [ ] Kernel
- [ ] Other (fill in here)

## Description
This change allows CLONE Iceberg to accept Iceberg tables with data
files not under the table path.

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## How was this patch tested?
Unit test
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## Does this PR introduce _any_ user-facing changes?

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NO

Author: harperjiang

iceberg/src/main/scala/org/apache/spark/sql/delta/IcebergFileManifest.scala

@@ -79,6 +79,8 @@ class IcebergFileManifest(
     _sizeInBytes.get
   }
 
+  override def supportAbsolutePath: Boolean = true
+
   def allFiles: Dataset[ConvertTargetFile] = {
     if (fileSparkResults.isEmpty) fileSparkResults = Some(getFileSparkResults())
     fileSparkResults.get

spark/src/main/scala/org/apache/spark/sql/delta/commands/CloneTableCommand.scala

@@ -239,11 +239,14 @@ abstract class CloneConvertedSource(spark: SparkSession) extends CloneSource {
     val partitionSchema = convertTargetTable.partitionSchema
 
     {
-      convertTargetTable.fileManifest.allFiles.mapPartitions { targetFile =>
+      val fileManifest = convertTargetTable.fileManifest
+      val supportAbsolutePath = fileManifest.supportAbsolutePath
+      fileManifest.allFiles.mapPartitions { targetFile =>
         val basePath = new Path(baseDir)
         val fs = basePath.getFileSystem(conf.value.value)
         targetFile.map(ConvertUtils.createAddFile(
-          _, basePath, fs, SQLConf.get, Some(partitionSchema)))
+          _, basePath, fs, SQLConf.get, Some(partitionSchema),
+          supportAbsolutePath))
       }
     }
   }

spark/src/main/scala/org/apache/spark/sql/delta/commands/ConvertToDeltaCommand.scala

@@ -305,10 +305,13 @@ abstract class ConvertToDeltaCommandBase(
     val shouldCollectStats = collectStats && statsEnabled
     val statsBatchSize = conf.getConf(DeltaSQLConf.DELTA_IMPORT_BATCH_SIZE_STATS_COLLECTION)
     var numFiles = 0L
+    val useAbsolutePath = manifest.supportAbsolutePath
     manifest.getFiles.grouped(statsBatchSize).flatMap { batch =>
       val adds = batch.map(
         ConvertUtils.createAddFile(
-          _, txn.deltaLog.dataPath, fs, conf, Some(partitionSchema), deltaPath.isDefined))
+          _, txn.deltaLog.dataPath, fs, conf, Some(partitionSchema),
+          useAbsolutePath || deltaPath.isDefined
+        ))
       if (shouldCollectStats) {
         logInfo(
           log"Collecting stats for a batch of " +

spark/src/main/scala/org/apache/spark/sql/delta/commands/convert/ConvertUtils.scala

@@ -221,7 +221,7 @@ trait ConvertUtilsBase extends DeltaLogging {
         s"Fail to relativize path $path against base path $basePath.")
       relativePath.toUri.toString
     } else {
-      path.toUri.toString
+      fs.makeQualified(path).toUri.toString
     }
 
     AddFile(pathStrForAddFile, partition, file.length, file.modificationTime, dataChange = true,

spark/src/main/scala/org/apache/spark/sql/delta/commands/convert/interfaces.scala

@@ -67,6 +67,8 @@ trait ConvertTargetFileManifest extends Closeable {
   /** Return the active files for a table in sequence */
   def getFiles: Iterator[ConvertTargetFile] = allFiles.toLocalIterator().asScala
 
+  /** All data file paths are required to be relative to table path when false */
+  def supportAbsolutePath: Boolean = false
   /** Return the number of files for the table */
   def numFiles: Long = allFiles.count()