rdf validate: fix comparisons with empty frames

src/main/scala/eu/neverblink/jelly/cli/command/rdf/RdfValidate.scala

@@ -8,7 +8,7 @@ import eu.neverblink.jelly.cli.util.io.IoUtil
 import eu.neverblink.jelly.cli.util.jena.*
 import eu.ostrzyciel.jelly.convert.jena.JenaConverterFactory
 import eu.ostrzyciel.jelly.core.JellyOptions
-import eu.ostrzyciel.jelly.core.proto.v1.RdfStreamFrame
+import eu.ostrzyciel.jelly.core.proto.v1.{RdfStreamFrame, RdfStreamOptions}
 import org.apache.jena.graph.Triple
 import org.apache.jena.riot.RDFParser
 import org.apache.jena.riot.system.StreamRDFLib
@@ -92,10 +92,10 @@ object RdfValidate extends JellyCommand[RdfValidateOptions]:
     // Step 1: Validate delimiting
     validateDelimiting(delimiting, delimited)
     // Step 2: Validate basic stream structure & the stream options
-    val framesSeq = skipEmptyFrames(frameIterator.toSeq)
-    validateOptions(framesSeq)
+    val framesSeq = frameIterator.toSeq
+    val streamOptions = validateOptions(skipEmptyFrames(framesSeq))
     // Step 3: Validate the content
-    validateContent(framesSeq, frameIndices, rdfComparison)
+    validateContent(framesSeq, frameIndices, rdfComparison, streamOptions)
 
   private def validateDelimiting(
       expected: Delimiting,
@@ -109,7 +109,7 @@ object RdfValidate extends JellyCommand[RdfValidateOptions]:
       if delimited then
         throw CriticalException("Expected undelimited input, but the file was delimited")
 
-  private def validateOptions(frames: Seq[RdfStreamFrame]): Unit =
+  private def validateOptions(frames: Seq[RdfStreamFrame]): RdfStreamOptions =
     if !frames.head.rows.head.row.isOptions then
       throw CriticalException("First row in the input stream does not contain stream options")
     val streamOptions = frames.head.rows.head.row.options
@@ -134,17 +134,18 @@ object RdfValidate extends JellyCommand[RdfValidateOptions]:
       streamOptions,
       expectedOptions.getOrElse(JellyOptions.defaultSupportedOptions),
     )
+    streamOptions
 
   private def validateContent(
       frames: Seq[RdfStreamFrame],
       frameIndices: IndexRange,
       maybeRdfComparison: Option[StreamRdfCollector],
+      opt: RdfStreamOptions,
   ): Unit =
     // Prepare data structures
     val jellyStreamConsumer =
       if maybeRdfComparison.isDefined then StreamRdfCollector()
       else StreamRDFLib.sinkNull()
-    val opt = frames.head.rows.head.row.options
     val dec = JenaConverterFactory.anyStatementDecoder(
       None,
       (prefix, iri) => jellyStreamConsumer.prefix(prefix, iri.getURI),

src/test/scala/eu/neverblink/jelly/cli/command/rdf/RdfValidateSpec.scala

@@ -443,6 +443,36 @@ class RdfValidateSpec extends AnyWordSpec, Matchers, TestFixtureHelper:
         }
       }
 
+      "content matches the reference RDF file, empty frames in the stream, sliced comparison" in withFullJenaFile {
+        jenaF =>
+          withEmptyJenaFile { emptyJenaF =>
+            withFullJellyFile { jellyF =>
+              // Three empty frames and the start and end
+              val input =
+                Array[Byte](0, 0, 0) ++ FileInputStream(jellyF).readAllBytes() ++ Array[Byte](
+                  0,
+                  0,
+                  0,
+                )
+              val params = Seq(
+                (jenaF, "3"),
+                (emptyJenaF, "0..=2"),
+                (emptyJenaF, "4..=6"),
+              )
+              for (comparisonFile, frameIndices) <- params do
+                RdfValidate.setStdIn(ByteArrayInputStream(input))
+                RdfValidate.runTestCommand(
+                  List(
+                    "rdf",
+                    "validate",
+                    "--compare-to-rdf-file=" + comparisonFile,
+                    "--compare-frame-indices=" + frameIndices,
+                  ),
+                )
+            }
+          }
+      }
+
       "content matches the reference RDF file, using a slice of the stream" in withFullJenaFile {
         jenaF =>
           withFullJellyFile { jellyF =>