Fix incorrect reading of source files when generating an HTML report

src/main/groovy/org/scoverage/ScoverageAggregate.groovy

@@ -24,6 +24,9 @@ class ScoverageAggregate extends DefaultTask {
     @Input
     final Property<Boolean> deleteReportsOnAggregation = project.objects.property(Boolean)
 
+    @Input
+    final Property<String> sourceEncoding = project.objects.property(String)
+
     // TODO - consider separate options for `report` and `aggregate` tasks
     @Input
     final Property<Boolean> coverageOutputCobertura = project.objects.property(Boolean)
@@ -60,6 +63,7 @@ class ScoverageAggregate extends DefaultTask {
                         rootDir,
                         reportDir.get(),
                         coverage.get(),
+                        sourceEncoding.get(),
                         coverageOutputCobertura.get(),
                         coverageOutputXML.get(),
                         coverageOutputHTML.get(),

src/main/groovy/org/scoverage/ScoveragePlugin.groovy

@@ -104,7 +104,13 @@ class ScoveragePlugin implements Plugin<PluginAware> {
         def globalReportTask = project.tasks.register(REPORT_NAME, ScoverageAggregate)
         def globalCheckTask = project.tasks.register(CHECK_NAME, OverallCheckTask)
 
+
         project.afterEvaluate {
+            def detectedSourceEncoding = compileTask.scalaCompileOptions.encoding
+            if (detectedSourceEncoding == null) {
+                detectedSourceEncoding = "UTF-8"
+            }
+
             // calling toList() on TaskCollection is required
             // to avoid potential ConcurrentModificationException in multi-project builds
             def testTasks = project.tasks.withType(Test).toList()
@@ -123,6 +129,7 @@ class ScoveragePlugin implements Plugin<PluginAware> {
                     reportDir = taskReportDir
                     sources = extension.sources
                     dataDir = extension.dataDir
+                    sourceEncoding.set(detectedSourceEncoding)
                     coverageOutputCobertura = extension.coverageOutputCobertura
                     coverageOutputXML = extension.coverageOutputXML
                     coverageOutputHTML = extension.coverageOutputHTML
@@ -139,6 +146,7 @@ class ScoveragePlugin implements Plugin<PluginAware> {
                 group = 'verification'
                 runner = scoverageRunner
                 reportDir = extension.reportDir
+                sourceEncoding.set(detectedSourceEncoding)
                 dirsToAggregateFrom = reportDirs
                 deleteReportsOnAggregation = false
                 coverageOutputCobertura = extension.coverageOutputCobertura
@@ -171,6 +179,7 @@ class ScoveragePlugin implements Plugin<PluginAware> {
                     group = 'verification'
                     runner = scoverageRunner
                     reportDir = extension.reportDir
+                    sourceEncoding.set(detectedSourceEncoding)
                     deleteReportsOnAggregation = extension.deleteReportsOnAggregation
                     coverageOutputCobertura = extension.coverageOutputCobertura
                     coverageOutputXML = extension.coverageOutputXML

src/main/groovy/org/scoverage/ScoverageReport.groovy

@@ -28,6 +28,9 @@ class ScoverageReport extends DefaultTask {
     @OutputDirectory
     final Property<File> reportDir = project.objects.property(File)
 
+    @Input
+    final Property<String> sourceEncoding = project.objects.property(String)
+
     @Input
     final Property<Boolean> coverageOutputCobertura = project.objects.property(Boolean)
     @Input
@@ -59,6 +62,7 @@ class ScoverageReport extends DefaultTask {
                         sources.get(),
                         reportDir.get(),
                         coverage,
+                        sourceEncoding.get(),
                         coverageOutputCobertura.get(),
                         coverageOutputXML.get(),
                         coverageOutputHTML.get(),

src/main/groovy/org/scoverage/ScoverageWriter.java

@@ -1,13 +1,18 @@
 package org.scoverage;
 
 import org.gradle.api.logging.Logger;
+import scala.Some;
+import scala.collection.JavaConverters;
+import scala.collection.mutable.Buffer;
 import scoverage.Constants;
 import scoverage.Coverage;
 import scoverage.report.CoberturaXmlWriter;
 import scoverage.report.ScoverageHtmlWriter;
 import scoverage.report.ScoverageXmlWriter;
 
 import java.io.File;
+import java.nio.charset.Charset;
+import java.util.Arrays;
 
 /**
  * Util for generating and saving coverage files.
@@ -29,6 +34,7 @@ public ScoverageWriter(Logger logger) {
      * @param sourceDir               directory with project sources
      * @param reportDir               directory for generate reports
      * @param coverage                coverage data
+     * @param sourceEncoding          the encoding of the source files
      * @param coverageOutputCobertura switch for Cobertura output
      * @param coverageOutputXML       switch for Scoverage XML output
      * @param coverageOutputHTML      switch for Scoverage HTML output
@@ -37,6 +43,7 @@ public ScoverageWriter(Logger logger) {
     public void write(File sourceDir,
                              File reportDir,
                              Coverage coverage,
+                             String sourceEncoding,
                              Boolean coverageOutputCobertura,
                              Boolean coverageOutputXML,
                              Boolean coverageOutputHTML,
@@ -70,7 +77,8 @@ public void write(File sourceDir,
         }
 
         if (coverageOutputHTML) {
-            new ScoverageHtmlWriter(sourceDir, reportDir).write(coverage);
+            Buffer<File> sources = JavaConverters.asScalaBuffer(Arrays.asList(sourceDir));
+            new ScoverageHtmlWriter(sources, reportDir, new Some<>(sourceEncoding)).write(coverage);
             logger.info("[scoverage] Written HTML report to " +
                 reportDir.getAbsolutePath() +
                 File.separator +