Improve SplitVcfBySamples to correctly handle allele-specific annotat…

…ions (#357)

src/main/java/com/github/discvrseq/walkers/SplitVcfBySamples.java

@@ -8,11 +8,10 @@
 import com.opencsv.RFC4180ParserBuilder;
 import com.opencsv.exceptions.CsvValidationException;
 import htsjdk.samtools.util.IOUtil;
-import htsjdk.variant.variantcontext.VariantContext;
+import htsjdk.variant.variantcontext.*;
 import htsjdk.variant.variantcontext.writer.VariantContextWriter;
 import htsjdk.variant.variantcontext.writer.VariantContextWriterBuilder;
-import htsjdk.variant.vcf.VCFHeader;
-import htsjdk.variant.vcf.VCFHeaderLine;
+import htsjdk.variant.vcf.*;
 import org.apache.commons.collections4.list.UnmodifiableList;
 import org.apache.commons.io.FilenameUtils;
 import org.apache.commons.lang3.StringUtils;
@@ -22,11 +21,16 @@
 import org.broadinstitute.hellbender.cmdline.StandardArgumentDefinitions;
 import org.broadinstitute.hellbender.engine.*;
 import org.broadinstitute.hellbender.exceptions.GATKException;
+import org.broadinstitute.hellbender.tools.walkers.genotyper.AlleleSubsettingUtils;
+import org.broadinstitute.hellbender.tools.walkers.genotyper.GenotypeAssignmentMethod;
 import org.broadinstitute.hellbender.utils.Utils;
+import org.broadinstitute.hellbender.utils.variant.GATKVCFConstants;
+import org.broadinstitute.hellbender.utils.variant.GATKVariantContextUtils;
 
 import java.io.File;
 import java.io.IOException;
 import java.util.*;
+import java.util.stream.Collectors;
 
 /**
  * This takes an input VCF and subsets it into new VCFs where each contains a subset of the original samples. You can either provide samplesPerVcf, in which case it will be subset based on # of samples, or you can provide a
@@ -73,6 +77,15 @@ public class SplitVcfBySamples extends VariantWalker {
     @Argument(doc="This is a TSV file with two columns and no header, where column 1 is the filepath for an output VCF. Column 2 is a sample ID to write to this file. The file can contain multiple rows per output file. The purpose is to supply a list of samples->file, such that this tool can read the input VCF once, and write multiple output VCFs at the same time.", fullName = "sample-mapping-file", optional = true)
     public GATKPath sampleMappingFile = null;
 
+    @Argument(fullName="recalculate-ac", doc="This will recalculate the AC, AF, and AN values after subsetting. See also --keep-original-ac", optional=true)
+    private boolean recalculateChrCounts = false;
+
+    @Argument(fullName="keep-original-ac", doc="Store the original AC, AF, and AN values after subsetting", optional=true)
+    private boolean keepOriginalChrCounts = false;
+
+    @Argument(fullName="original-ac-suffix", doc="If --keep-original-ac is selected, the original AC, AF, and AN values will be stored, but with this suffix (e.g., a suffix of .Orig would result in AF -> AF.Orig)", optional=true)
+    private String originalChrCountsSuffix = ".Orig";
+
     List<List<String>> batches = new ArrayList<>();
     List<VariantContextWriter> writers = new ArrayList<>();
 
@@ -134,11 +147,37 @@ private void prepareOutputsForSampleFile(List<String> samples, VCFHeader header)
             writers.add(writer);
             batches.add(new UnmodifiableList<>(fileToSamples.get(outputFile).stream().toList()));
 
-            VCFHeader outputHeader = new VCFHeader(header.getMetaDataInInputOrder(), fileToSamples.get(outputFile));
+            VCFHeader outputHeader = new VCFHeader(getHeaderLines(header), fileToSamples.get(outputFile));
             writer.writeHeader(outputHeader);
         }
     }
 
+    private Set<VCFHeaderLine> getHeaderLines(VCFHeader header) {
+        Set<VCFHeaderLine> headerLines = new LinkedHashSet<>(header.getMetaDataInInputOrder());
+
+        if (recalculateChrCounts) {
+            if (header.getInfoHeaderLine(VCFConstants.ALLELE_COUNT_KEY) == null) {
+                headerLines.add(VCFStandardHeaderLines.getInfoLine(VCFConstants.ALLELE_COUNT_KEY));
+            }
+
+            if (header.getInfoHeaderLine(VCFConstants.ALLELE_FREQUENCY_KEY) == null) {
+                headerLines.add(VCFStandardHeaderLines.getInfoLine(VCFConstants.ALLELE_FREQUENCY_KEY));
+            }
+
+            if (header.getInfoHeaderLine(VCFConstants.ALLELE_NUMBER_KEY) == null) {
+                headerLines.add(VCFStandardHeaderLines.getInfoLine(VCFConstants.ALLELE_NUMBER_KEY));
+            }
+        }
+
+        if (recalculateChrCounts && keepOriginalChrCounts) {
+            headerLines.add(new VCFInfoHeaderLine(VCFConstants.ALLELE_COUNT_KEY + originalChrCountsSuffix, VCFHeaderLineCount.A, VCFHeaderLineType.Integer, "Original AC"));
+            headerLines.add(new VCFInfoHeaderLine(VCFConstants.ALLELE_FREQUENCY_KEY + originalChrCountsSuffix, VCFHeaderLineCount.A, VCFHeaderLineType.Float, "Original AF"));
+            headerLines.add(new VCFInfoHeaderLine(VCFConstants.ALLELE_NUMBER_KEY + originalChrCountsSuffix, 1, VCFHeaderLineType.Integer, "Original AN"));
+        }
+
+        return headerLines;
+    }
+
     private void prepareOutputsForBatches(List<String> samples, VCFHeader header) {
         Lists.partition(new ArrayList<>(samples), samplesPerVcf).forEach(l -> {
             batches.add(List.copyOf(l));  // this returns an unmodifiable list
@@ -161,7 +200,6 @@ private void prepareOutputsForBatches(List<String> samples, VCFHeader header) {
 
         int idx = 0;
         File inputFile = getDrivingVariantsFeatureInput().toPath().toFile();
-        final Set<VCFHeaderLine> headerLines = new LinkedHashSet<>(header.getMetaDataInInputOrder());
         for (List<String> batch : batches) {
             idx++;
             String name = inputFile.getName();
@@ -176,19 +214,19 @@ private void prepareOutputsForBatches(List<String> samples, VCFHeader header) {
             VariantContextWriter writer = new VariantContextWriterBuilder().setOutputFile(output).setReferenceDictionary(getReferenceDictionary()).build();
             writers.add(writer);
 
-            VCFHeader outputHeader = new VCFHeader(headerLines, new ArrayList<>(batch));
+            VCFHeader outputHeader = new VCFHeader(getHeaderLines(header), new ArrayList<>(batch));
             writer.writeHeader(outputHeader);
         }
     }
 
     @Override
     public void apply(VariantContext variant, ReadsContext readsContext, ReferenceContext referenceContext, FeatureContext featureContext) {
         int idx = 0;
-        for (List<String> batch : batches) {
+        for (List<String> sampleNames : batches) {
             final VariantContextWriter writer = writers.get(idx);
             idx++;
 
-            final VariantContext sub = variant.subContextFromSamples(new LinkedHashSet<>(batch), removeUnusedAlternates);
+            final VariantContext sub = subsetGenotypesBySampleNames(variant, new TreeSet<>(sampleNames), removeUnusedAlternates);
             if (discardNonVariantSites) {
                 if (sub.getCalledChrCount() == 0) {
                     continue;
@@ -202,6 +240,136 @@ else if (sub.getGenotypes().stream().noneMatch(g -> !g.isFiltered() && g.isCalle
         }
     }
 
+    // NOTE: this is basically copied from SelectVariants. This is necessary to ensure we also subset INFO fields correctly
+    private VariantContext subsetGenotypesBySampleNames(final VariantContext vc, final SortedSet<String> samples, final boolean removeUnusedAlternates) {
+        // If no subsetting of samples or alleles happened, exit now
+        if (!removeUnusedAlternates && samples.size() == vc.getNSamples()) {
+            return vc;
+        }
+
+        // strip out the alternate alleles that aren't being used
+        final VariantContext sub = vc.subContextFromSamples(samples, removeUnusedAlternates);
+
+        GenotypesContext newGC;
+        if (sub.getNAlleles() != vc.getNAlleles()) {
+            // fix the PL and AD values if sub has fewer alleles than original vc
+            final GenotypesContext subGenotypesWithOldAlleles = sub.getGenotypes();  //we need sub for the right samples, but PLs still go with old alleles
+            newGC = sub.getNAlleles() == vc.getNAlleles() ? subGenotypesWithOldAlleles :
+                    AlleleSubsettingUtils.subsetAlleles(subGenotypesWithOldAlleles, 0, vc.getAlleles(),
+                            sub.getAlleles(), null, GenotypeAssignmentMethod.DO_NOT_ASSIGN_GENOTYPES);
+        } else {
+            newGC = sub.getGenotypes();
+        }
+
+        // since the VC has been subset (either by sample or allele), we need to strip out the MLE tags
+        final VariantContextBuilder builder = new VariantContextBuilder(sub);
+        builder.rmAttributes(Arrays.asList(GATKVCFConstants.MLE_ALLELE_COUNT_KEY,GATKVCFConstants.MLE_ALLELE_FREQUENCY_KEY));
+        builder.genotypes(newGC);
+        addAnnotations(builder, vc, sub.getSampleNames());
+
+        if (!vc.getAlleles().equals(sub.getAlleles())) {
+            int[] oldToKeyNoRef = sub.getAlternateAlleles().stream().map(a -> vc.getAlleleIndex(a) - 1).mapToInt(Integer::intValue).toArray();
+            int[] oldToKeyWithRef = sub.getAlleles().stream().map(vc::getAlleleIndex).mapToInt(Integer::intValue).toArray();
+            for (String attr : builder.getAttributes().keySet()) {
+                VCFInfoHeaderLine line = getHeaderForVariants().getInfoHeaderLine(attr);
+                if (line == null) {
+                    continue;
+                }
+
+                if (line.getCountType() == VCFHeaderLineCount.A) {
+                    builder.attribute(attr, getReorderedAttributes(sub.getAttribute(attr), oldToKeyNoRef));
+                }
+                else if (line.getCountType() == VCFHeaderLineCount.R) {
+                    builder.attribute(attr, getReorderedAttributes(sub.getAttribute(attr), oldToKeyWithRef));
+                }
+            }
+        }
+
+        final VariantContext subset = builder.make();
+        return removeUnusedAlternates ? GATKVariantContextUtils.trimAlleles(subset,true,true) : subset;
+    }
+
+    private void addAnnotations(final VariantContextBuilder builder, final VariantContext originalVC, final Set<String> selectedSampleNames) {
+        if (recalculateChrCounts && keepOriginalChrCounts) {
+            final int[] indexOfOriginalAlleleForNewAllele;
+            final List<Allele> newAlleles = builder.getAlleles();
+            final int numOriginalAlleles = originalVC.getNAlleles();
+
+            // if the alleles already match up, we can just copy the previous list of counts
+            if (numOriginalAlleles == newAlleles.size()) {
+                indexOfOriginalAlleleForNewAllele = null;
+            }
+            // otherwise we need to parse them and select out the correct ones
+            else {
+                indexOfOriginalAlleleForNewAllele = new int[newAlleles.size() - 1];
+                Arrays.fill(indexOfOriginalAlleleForNewAllele, -1);
+
+                // note that we don't care about the reference allele at position 0
+                for (int newI = 1; newI < newAlleles.size(); newI++) {
+                    final Allele newAlt = newAlleles.get(newI);
+                    for (int oldI = 0; oldI < numOriginalAlleles - 1; oldI++) {
+                        if (newAlt.equals(originalVC.getAlternateAllele(oldI), false)) {
+                            indexOfOriginalAlleleForNewAllele[newI - 1] = oldI;
+                            break;
+                        }
+                    }
+                }
+            }
+
+            if (originalVC.hasAttribute(VCFConstants.ALLELE_COUNT_KEY)) {
+                builder.attribute(VCFConstants.ALLELE_COUNT_KEY + originalChrCountsSuffix,
+                        getReorderedAttributes(originalVC.getAttribute(VCFConstants.ALLELE_COUNT_KEY), indexOfOriginalAlleleForNewAllele));
+            }
+            if (originalVC.hasAttribute(VCFConstants.ALLELE_FREQUENCY_KEY)) {
+                builder.attribute(VCFConstants.ALLELE_FREQUENCY_KEY + originalChrCountsSuffix,
+                        getReorderedAttributes(originalVC.getAttribute(VCFConstants.ALLELE_FREQUENCY_KEY), indexOfOriginalAlleleForNewAllele));
+            }
+            if (originalVC.hasAttribute(VCFConstants.ALLELE_NUMBER_KEY)) {
+                builder.attribute(VCFConstants.ALLELE_NUMBER_KEY + originalChrCountsSuffix, originalVC.getAttribute(VCFConstants.ALLELE_NUMBER_KEY));
+            }
+        }
+
+        if (recalculateChrCounts) {
+            VariantContextUtils.calculateChromosomeCounts(builder, false);
+        }
+
+        boolean sawDP = false;
+        int depth = 0;
+        for (final String sample : selectedSampleNames ) {
+            final Genotype g = originalVC.getGenotype(sample);
+            if (!g.isFiltered()) {
+                if (g.hasDP()) {
+                    depth += g.getDP();
+                    sawDP = true;
+                }
+            }
+        }
+
+        if (sawDP) {
+            builder.attribute(VCFConstants.DEPTH_KEY, depth);
+        }
+    }
+
+    private Object getReorderedAttributes(final Object attribute, final int[] oldToNewIndexOrdering) {
+        if (oldToNewIndexOrdering == null || attribute == null) {
+            return attribute;
+        }
+
+        // break the original attributes into separate tokens; unfortunately, this means being smart about class types
+        final Object[] tokens;
+        if (attribute.getClass().isArray()) {
+            tokens = (Object[]) attribute;
+        } else if (List.class.isAssignableFrom(attribute.getClass())) {
+            tokens = ((List) attribute).toArray();
+        } else {
+            tokens = attribute.toString().split(VCFConstants.INFO_FIELD_ARRAY_SEPARATOR);
+        }
+
+        Utils.validateArg(Arrays.stream(oldToNewIndexOrdering).allMatch(index -> index < tokens.length), () ->
+                "the old attribute has an incorrect number of elements: " + attribute);
+        return Arrays.stream(oldToNewIndexOrdering).mapToObj(index -> tokens[index]).collect(Collectors.toList());
+    }
+
     @Override
     public void closeTool() {
         super.closeTool();

src/test/java/com/github/discvrseq/walkers/SplitVcfBySamplesIntegrationTest.java

@@ -98,11 +98,57 @@ private ArgumentsBuilder getBaseArgs(File outDir) {
         return getBaseArgs(outDir, 1);
     }
 
+    @Test
+    public void testInfoSubsetting() throws Exception {
+        final File outDir = IOUtils.createTempDir("splitVcfBySamples.");
+        ArgumentsBuilder args = getBaseArgs(outDir, 1, "mergeVcfWithAlts.vcf");
+        args.addRaw("--recalculate-ac");
+        args.addRaw("--keep-original-ac");
+        args.addRaw("--original-ac-suffix");
+        args.addRaw(".new");
+
+        runCommandLine(args);
+
+        String actualMD5 = Utils.calculateFileMD5(new File(outDir, "mergeVcfWithAlts.1of2.vcf"));
+        String expectedMD5 = Utils.calculateFileMD5(getTestFile("mergeVcfWithAlts.1of2.vcf"));
+        Assert.assertEquals(actualMD5, expectedMD5);
+
+        actualMD5 = Utils.calculateFileMD5(new File(outDir, "mergeVcfWithAlts.2of2.vcf"));
+        expectedMD5 = Utils.calculateFileMD5(getTestFile("mergeVcfWithAlts.2of2.vcf"));
+        Assert.assertEquals(actualMD5, expectedMD5);
+    }
+
+    @Test
+    public void testInfoSubsettingRemoveAlts() throws Exception {
+        final File outDir = IOUtils.createTempDir("splitVcfBySamples.");
+        ArgumentsBuilder args = getBaseArgs(outDir, 1, "mergeVcfWithAlts.vcf");
+        args.addRaw("--recalculate-ac");
+        args.addRaw("--keep-original-ac");
+        args.addRaw("--original-ac-suffix");
+        args.addRaw(".new");
+        args.addRaw("--remove-unused-alternates");
+        args.addFlag("discardNonVariantSites");
+
+        runCommandLine(args);
+
+        String actualMD5 = Utils.calculateFileMD5(new File(outDir, "mergeVcfWithAlts.1of2.vcf"));
+        String expectedMD5 = Utils.calculateFileMD5(getTestFile("mergeVcfWithAltsRemoveAlts.1of2.vcf"));
+        Assert.assertEquals(actualMD5, expectedMD5);
+
+        actualMD5 = Utils.calculateFileMD5(new File(outDir, "mergeVcfWithAlts.2of2.vcf"));
+        expectedMD5 = Utils.calculateFileMD5(getTestFile("mergeVcfWithAltsRemoveAlts.2of2.vcf"));
+        Assert.assertEquals(actualMD5, expectedMD5);
+    }
+
     private ArgumentsBuilder getBaseArgs(File outDir, @Nullable Integer samplesPerVcf) {
+        return getBaseArgs(outDir, samplesPerVcf, "mergeVcf3.vcf");
+    }
+
+    private ArgumentsBuilder getBaseArgs(File outDir, @Nullable Integer samplesPerVcf, String inputVcf) {
         ArgumentsBuilder args = new ArgumentsBuilder();
 
         args.addRaw("--variant");
-        File input = new File(testBaseDir, "mergeVcf3.vcf");
+        File input = new File(testBaseDir, inputVcf);
         ensureVcfIndex(input);
         args.addRaw(normalizePath(input));
 

src/test/resources/com/github/discvrseq/TestData/mergeVcfWithAlts.vcf

@@ -0,0 +1,10 @@
+##fileformat=VCFv4.2
+##INFO=<ID=RR,Number=R,Type=String,Description="Test REF annotation">
+##INFO=<ID=RA,Number=A,Type=String,Description="Test ALT annotation">
+##FORMAT=<ID=GT,Number=1,Type=String,Description="Genotype">
+##contig=<ID=1,length=16000>
+##contig=<ID=2,length=16000>
+#CHROM	POS	ID	REF	ALT	QUAL	FILTER	INFO	FORMAT	Sample1	Sample3
+1	61	.	GT	G	724.43	PASS	RR=GT,G;RA=G	GT	0/1	0/1
+1	72	.	T	A,C	100	PASS	RR=T,A,C;RA=A,C	GT	0/1	1/1
+1	73	.	TT	AG	100	PASS	RR=TT,AG;RA=AG	GT	0/1	0/0

src/test/resources/com/github/discvrseq/walkers/SplitVcfBySamples/mergeVcfWithAlts.1of2.vcf

@@ -0,0 +1,16 @@
+##fileformat=VCFv4.2
+##FORMAT=<ID=GT,Number=1,Type=String,Description="Genotype">
+##INFO=<ID=AC,Number=A,Type=Integer,Description="Allele count in genotypes, for each ALT allele, in the same order as listed">
+##INFO=<ID=AC.new,Number=A,Type=Integer,Description="Original AC">
+##INFO=<ID=AF,Number=A,Type=Float,Description="Allele Frequency, for each ALT allele, in the same order as listed">
+##INFO=<ID=AF.new,Number=A,Type=Float,Description="Original AF">
+##INFO=<ID=AN,Number=1,Type=Integer,Description="Total number of alleles in called genotypes">
+##INFO=<ID=AN.new,Number=1,Type=Integer,Description="Original AN">
+##INFO=<ID=RA,Number=A,Type=String,Description="Test ALT annotation">
+##INFO=<ID=RR,Number=R,Type=String,Description="Test REF annotation">
+##contig=<ID=1,length=16000>
+##contig=<ID=2,length=16000>
+#CHROM	POS	ID	REF	ALT	QUAL	FILTER	INFO	FORMAT	Sample1
+1	61	.	GT	G	724.43	PASS	AC=1;AF=0.500;AN=2;RA=G;RR=GT,G	GT	0/1
+1	72	.	T	A,C	100	PASS	AC=1,0;AF=0.500,0.00;AN=2;RA=A,C;RR=T,A,C	GT	0/1
+1	73	.	TT	AG	100	PASS	AC=1;AF=0.500;AN=2;RA=AG;RR=TT,AG	GT	0/1

src/test/resources/com/github/discvrseq/walkers/SplitVcfBySamples/mergeVcfWithAlts.2of2.vcf

@@ -0,0 +1,16 @@
+##fileformat=VCFv4.2
+##FORMAT=<ID=GT,Number=1,Type=String,Description="Genotype">
+##INFO=<ID=AC,Number=A,Type=Integer,Description="Allele count in genotypes, for each ALT allele, in the same order as listed">
+##INFO=<ID=AC.new,Number=A,Type=Integer,Description="Original AC">
+##INFO=<ID=AF,Number=A,Type=Float,Description="Allele Frequency, for each ALT allele, in the same order as listed">
+##INFO=<ID=AF.new,Number=A,Type=Float,Description="Original AF">
+##INFO=<ID=AN,Number=1,Type=Integer,Description="Total number of alleles in called genotypes">
+##INFO=<ID=AN.new,Number=1,Type=Integer,Description="Original AN">
+##INFO=<ID=RA,Number=A,Type=String,Description="Test ALT annotation">
+##INFO=<ID=RR,Number=R,Type=String,Description="Test REF annotation">
+##contig=<ID=1,length=16000>
+##contig=<ID=2,length=16000>
+#CHROM	POS	ID	REF	ALT	QUAL	FILTER	INFO	FORMAT	Sample3
+1	61	.	GT	G	724.43	PASS	AC=1;AF=0.500;AN=2;RA=G;RR=GT,G	GT	0/1
+1	72	.	T	A,C	100	PASS	AC=2,0;AF=1.00,0.00;AN=2;RA=A,C;RR=T,A,C	GT	1/1
+1	73	.	TT	AG	100	PASS	AC=0;AF=0.00;AN=2;RA=AG;RR=TT,AG	GT	0/0

src/test/resources/com/github/discvrseq/walkers/SplitVcfBySamples/mergeVcfWithAltsRemoveAlts.1of2.vcf

@@ -0,0 +1,16 @@
+##fileformat=VCFv4.2
+##FORMAT=<ID=GT,Number=1,Type=String,Description="Genotype">
+##INFO=<ID=AC,Number=A,Type=Integer,Description="Allele count in genotypes, for each ALT allele, in the same order as listed">
+##INFO=<ID=AC.new,Number=A,Type=Integer,Description="Original AC">
+##INFO=<ID=AF,Number=A,Type=Float,Description="Allele Frequency, for each ALT allele, in the same order as listed">
+##INFO=<ID=AF.new,Number=A,Type=Float,Description="Original AF">
+##INFO=<ID=AN,Number=1,Type=Integer,Description="Total number of alleles in called genotypes">
+##INFO=<ID=AN.new,Number=1,Type=Integer,Description="Original AN">
+##INFO=<ID=RA,Number=A,Type=String,Description="Test ALT annotation">
+##INFO=<ID=RR,Number=R,Type=String,Description="Test REF annotation">
+##contig=<ID=1,length=16000>
+##contig=<ID=2,length=16000>
+#CHROM	POS	ID	REF	ALT	QUAL	FILTER	INFO	FORMAT	Sample1
+1	61	.	GT	G	724.43	PASS	AC=1;AF=0.500;AN=2;RA=G;RR=GT,G	GT	0/1
+1	72	.	T	A	100	PASS	AC=1;AF=0.500;AN=2;RA=A;RR=T,A	GT	0/1
+1	73	.	TT	AG	100	PASS	AC=1;AF=0.500;AN=2;RA=AG;RR=TT,AG	GT	0/1