Fix a regression where VcfWriter would not write a regular file index

src/main/scala/com/fulcrumgenomics/vcf/api/VcfWriter.scala

@@ -31,7 +31,7 @@ import htsjdk.samtools.Defaults
 import htsjdk.variant.variantcontext.writer.{Options, VariantContextWriter, VariantContextWriterBuilder}
 
 import java.nio.file.Files
-import java.nio.file.LinkOption.NOFOLLOW_LINKS
+import java.nio.file.attribute.BasicFileAttributes
 
 /**
   * Writes [[Variant]]s to a file or other storage mechanism.
@@ -49,33 +49,42 @@ object VcfWriter {
   var DefaultUseAsyncIo: Boolean = Defaults.USE_ASYNC_IO_WRITE_FOR_TRIBBLE
 
   /**
-    * Creates a [[VcfWriter]] that will write to the give path.  The path must end in either
-    *   - `.vcf` to create an uncompressed VCF file
-    *   - `.vcf.gz` to create a block-gzipped VCF file
-    *   - `.bcf` to create a binary BCF file
+    * Creates a [[VcfWriter]] that will write to the given path. If the path is meant to point to a regular file, then
+    * the path must end in either:
+    *
+    *   - `.vcf`: to create an uncompressed VCF file
+    *   - `.vcf.gz`: to create a block-gzipped VCF file
+    *   - `.bcf`: to create a binary BCF file
+    *
+    * If the path is meant to point to a regular file, then indexing will occur automatically. However, if the path
+    * already exists and the path is not a file or symbolic link, then this function will assume the path is a named
+    * pipe (such as `/dev/null`) and indexing will not occur.
     *
     * @param path the path to write to
     * @param header the header of the VCF
-    * @return a VariantWriter to write to the given path
+    * @return a VCF writer to write to the given path
     */
   def apply(path: PathToVcf, header: VcfHeader, async: Boolean = DefaultUseAsyncIo): VcfWriter = {
     import com.fulcrumgenomics.fasta.Converters.ToSAMSequenceDictionary
     val javaHeader = VcfConversions.toJavaHeader(header)
+    require(!Files.isDirectory(path), "Input path cannot be a directory!")
 
     val builder = new VariantContextWriterBuilder()
       .setOutputPath(path)
       .setReferenceDictionary(header.dict.asSam)
       .setOption(Options.ALLOW_MISSING_FIELDS_IN_HEADER)
       .setBuffer(Io.bufferSize)
 
-    if (Files.isRegularFile(path, NOFOLLOW_LINKS)) {
-      builder.setOption(Options.INDEX_ON_THE_FLY)
-    } else {
+    if (async) builder.setOption(Options.USE_ASYNC_IO) else builder.unsetOption(Options.USE_ASYNC_IO)
+
+    // If the path exists and is not a file or symbolic link, then assume it is a named pipe and do not index.
+    if (Files.exists(path) && Files.readAttributes(path, classOf[BasicFileAttributes]).isOther) {
       builder.unsetOption(Options.INDEX_ON_THE_FLY)
       builder.setIndexCreator(null)
+    } else {
+      builder.setOption(Options.INDEX_ON_THE_FLY)
     }
 
-    if (async) builder.setOption(Options.USE_ASYNC_IO) else builder.unsetOption(Options.USE_ASYNC_IO)
     val writer = builder.build()
     writer.writeHeader(javaHeader)
     new VcfWriter(writer, header)

src/test/scala/com/fulcrumgenomics/vcf/api/VcfIoTest.scala

@@ -24,12 +24,14 @@
 
 package com.fulcrumgenomics.vcf.api
 
-import com.fulcrumgenomics.commons.io.Io
-import com.fulcrumgenomics.testing.{UnitSpec, VcfBuilder}
+import com.fulcrumgenomics.commons.io.{Io, PathUtil}
 import com.fulcrumgenomics.testing.VcfBuilder.Gt
+import com.fulcrumgenomics.testing.{UnitSpec, VcfBuilder}
 import com.fulcrumgenomics.vcf.api.Allele.NoCallAllele
+import htsjdk.samtools.util.FileExtensions.{BCF => BcfExtension, COMPRESSED_VCF => VcfGzExtension, TABIX_INDEX => TbiExtension, TRIBBLE_INDEX => IdxExtension, VCF => VcfExtension}
 import org.scalatest.OptionValues
 
+import java.nio.file.Files
 import scala.collection.compat._
 import scala.collection.immutable.ListMap
 
@@ -67,7 +69,7 @@ class VcfIoTest extends UnitSpec with OptionValues {
 
   /** Writes out the variants to a file and reads them back, returning the header and the variants. */
   @inline private def roundtrip(variants: IterableOnce[Variant], header: VcfHeader = VcfIoTest.Header): Result = {
-    val vcf = makeTempFile("test.", ".vcf")
+    val vcf = makeTempFile(getClass.getSimpleName, VcfExtension)
     val out = VcfWriter(vcf, header)
     out ++= variants
     out.close()
@@ -167,7 +169,7 @@ class VcfIoTest extends UnitSpec with OptionValues {
     val variants = Range.inclusive(1000, 2000, step=10).map { s =>
       Variant(chrom="chr1", pos=s, alleles=alleles, genotypes=Map("s1" -> Genotype(alleles, "s1", alleles.alts)))
     }
-    val vcf = makeTempFile("queryable.", ".vcf.gz")
+    val vcf = makeTempFile("queryable.", VcfGzExtension)
     val out = VcfWriter(vcf, VcfIoTest.Header)
     out ++= variants
     out.close()
@@ -227,12 +229,51 @@ class VcfIoTest extends UnitSpec with OptionValues {
     v.gt("0").callIndices.mkString("/") shouldBe "2/3"
   }
 
-  it should "not attempt to index a VCF when streaming to a file handle or other kind of non-regular file" in {
+  it should "not allow a VCF writer to write to a directory path" in {
     val samples = Seq("sample")
-    val builder = VcfBuilder(samples=samples)
-    val writer  = VcfWriter(Io.DevNull, header = builder.header)
-    builder.add(chrom = "chr1", pos = 100, alleles = Seq("A", "C"), gts = Seq(Gt(sample="sample", gt="0/1")))
-    noException shouldBe thrownBy { writer.write(builder.toSeq) }
+    val builder = VcfBuilder(samples = samples)
+    val output  = Io.makeTempDir(getClass.getSimpleName)
+    output.toFile.deleteOnExit()
+    an[IllegalArgumentException] shouldBe thrownBy { VcfWriter(output, header = builder.header) }
+  }
+
+  it should "write a sibling index when writing to a plaintext VCF file" in {
+    val samples = Seq("sample")
+    val builder = VcfBuilder(samples = samples)
+    val output  = makeTempFile(getClass.getSimpleName, VcfExtension)
+    val writer  = VcfWriter(output, header = builder.header)
+    builder.add(chrom = "chr1", pos = 100, alleles = Seq("A", "C"), gts = Seq(Gt(sample = "sample", gt = "0/1")))
     writer.close()
+    Files.exists(PathUtil.replaceExtension(output, VcfExtension + IdxExtension)) shouldBe true
+  }
+
+  it should "write a sibling index when writing to a compressed VCF file" in {
+    val samples = Seq("sample")
+    val builder = VcfBuilder(samples = samples)
+    val output  = makeTempFile(getClass.getSimpleName, VcfGzExtension)
+    val writer  = VcfWriter(output, header = builder.header)
+    builder.add(chrom = "chr1", pos = 100, alleles = Seq("A", "C"), gts = Seq(Gt(sample = "sample", gt = "0/1")))
+    writer.close()
+    Files.exists(PathUtil.replaceExtension(PathUtil.removeExtension(output), VcfGzExtension + TbiExtension)) shouldBe true
+  }
+
+  it should "write a sibling index when writing to a BCF file" in {
+    val samples = Seq("sample")
+    val builder = VcfBuilder(samples = samples)
+    val output  = makeTempFile(getClass.getSimpleName, BcfExtension)
+    val writer  = VcfWriter(output, header = builder.header)
+    builder.add(chrom = "chr1", pos = 100, alleles = Seq("A", "C"), gts = Seq(Gt(sample = "sample", gt = "0/1")))
+    writer.close()
+    Files.exists(PathUtil.replaceExtension(output, BcfExtension + IdxExtension)) shouldBe true
+  }
+
+  it should "not attempt to write a sibling index when streaming to a named pipe like '/dev/null'" in {
+    val samples = Seq("sample")
+    val builder = VcfBuilder(samples = samples)
+    val writer  = VcfWriter(Io.DevNull, header = builder.header)
+    builder.add(chrom = "chr1", pos = 100, alleles = Seq("A", "C"), gts = Seq(Gt(sample = "sample", gt = "0/1")))
+    noException shouldBe thrownBy { writer.write(builder.toSeq); writer.close() }
+    Files.exists(PathUtil.pathTo(Io.DevNull.getFileName.toString + IdxExtension)) shouldBe false
+    Files.exists(PathUtil.pathTo(Io.DevNull.getFileName.toString + TbiExtension)) shouldBe false
   }
 }