Check for both destinationDir and toDir when calculating destination

Newer versions of AsciidoctorJ deprecated destinationDir and only use
toDir, which caused the plugin to report paths being overwritten incorrectly.

Closes asciidoctor#728

src/main/java/org/asciidoctor/maven/AsciidoctorMojo.java

@@ -244,8 +244,9 @@ public void processSources(List<File> sourceFiles, ResourcesProcessor resourcesP
         final Set<File> uniquePaths = new HashSet<>();
         for (final File source : sourceFiles) {
             final File destinationPath = setDestinationPaths(source, optionsBuilder, sourceDir, this);
-            if (!uniquePaths.add(destinationPath))
+            if (!uniquePaths.add(destinationPath)) {
                 getLog().warn("Duplicated destination found: overwriting file: " + destinationPath.getAbsolutePath());
+            }
 
             convertFile(asciidoctor, optionsBuilder.asMap(), source);
 
@@ -379,9 +380,8 @@ public File setDestinationPaths(final File sourceFile, final OptionsBuilder opti
                 optionsBuilder.toDir(outputDir).destinationDir(outputDir);
             }
             final File outputFile = configuration.getOutputFile();
-            final String destinationDir = (String) optionsBuilder.asMap().get(Options.DESTINATION_DIR);
+            final String destinationDir = getDestinationDir(optionsBuilder);
             if (outputFile != null) {
-                // allow overriding the output file name
                 optionsBuilder.toFile(outputFile);
                 return outputFile.isAbsolute() ? outputFile : new File(destinationDir, outputFile.getPath());
             } else {
@@ -392,6 +392,12 @@ public File setDestinationPaths(final File sourceFile, final OptionsBuilder opti
         }
     }
 
+    private static String getDestinationDir(OptionsBuilder optionsBuilder) {
+        final Map<String, Object> options = optionsBuilder.asMap();
+        return (String) Optional.ofNullable(options.get(Options.DESTINATION_DIR))
+                .orElse(options.get(Options.TO_DIR));
+    }
+
     protected Asciidoctor getAsciidoctorInstance(String gemPath) throws MojoExecutionException {
         Asciidoctor asciidoctor = null;
         if (gemPath == null) {

src/test/java/org/asciidoctor/maven/AsciidoctorMojoTest.java

@@ -5,12 +5,17 @@
 import org.apache.maven.model.Resource;
 import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugin.MojoFailureException;
+import org.asciidoctor.Options;
+import org.asciidoctor.OptionsBuilder;
 import org.asciidoctor.maven.extensions.ExtensionConfiguration;
 import org.asciidoctor.maven.io.AsciidoctorFileScanner;
 import org.asciidoctor.maven.io.ConsoleHolder;
 import org.asciidoctor.maven.test.processors.RequireCheckerTreeprocessor;
 import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.NullAndEmptySource;
+import org.junit.jupiter.params.provider.ValueSource;
 
 import java.io.*;
 import java.nio.file.Files;
@@ -1069,4 +1074,22 @@ public void should_not_show_message_when_overwriting_files_using_outputFile_and_
         consoleHolder.release();
     }
 
+    @ParameterizedTest
+    @NullAndEmptySource
+    @ValueSource(strings = {"output.html"})
+    public void should_return_absolute_path_when_calculating_destination(String outputFile) throws MojoExecutionException {
+        // given
+        final AsciidoctorMojo mojo = mockAsciidoctorMojo();
+        mojo.setOutputDirectory(newOutputTestDirectory("overlapping-outputFile"));
+        if (outputFile != null) mojo.setOutputFile(outputFile);
+        final File source = new File("source.adoc");
+        final OptionsBuilder builder = Options.builder();
+        final File sourceDir = new File(".");
+
+        // when
+        File file = mojo.setDestinationPaths(source, builder, sourceDir, mojo);
+
+        // then
+        Assertions.assertThat(file).isAbsolute();
+    }
 }