SONAR-8835 support NULL in column file_sources.line_hashes

The column can be null on Oracle if source content is empty.
Other databases do not store NULL but empty string.

7 files changed, 49 insertions, 33 deletions

diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/FileMoveDetectionStep.java b/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/FileMoveDetectionStep.java
index 182e4232455..df6c144f05f 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/FileMoveDetectionStep.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/FileMoveDetectionStep.java
@@ -56,6 +56,7 @@ import org.sonar.server.computation.task.projectanalysis.filemove.FileSimilarity
 import org.sonar.server.computation.task.projectanalysis.source.SourceLinesRepository;
 import org.sonar.server.computation.task.step.ComputationStep;
 
+import static com.google.common.base.MoreObjects.firstNonNull;
 import static com.google.common.base.Splitter.on;
 import static com.google.common.collect.FluentIterable.from;
 import static java.util.Arrays.asList;
@@ -233,7 +234,8 @@ public class FileMoveDetectionStep implements ComputationStep {
     if (fileSourceDto == null) {
       return null;
     }
-    return new File(dbComponent.getPath(), LINES_HASHES_SPLITTER.splitToList(fileSourceDto.getLineHashes()));
+    String lineHashes = firstNonNull(fileSourceDto.getLineHashes(), "");
+    return new File(dbComponent.getPath(), LINES_HASHES_SPLITTER.splitToList(lineHashes));
   }
 
   private static void printIfDebug(ScoreMatrix scoreMatrix) {
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/FileSimilarity.java b/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/FileSimilarity.java
index 86743b06906..7f3547b904e 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/FileSimilarity.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/FileSimilarity.java
@@ -20,8 +20,6 @@
 package org.sonar.server.computation.task.projectanalysis.filemove;
 
 import java.util.List;
-import javax.annotation.CheckForNull;
-import javax.annotation.Nullable;
 
 import static java.util.Objects.requireNonNull;
 
@@ -31,16 +29,19 @@ public interface FileSimilarity {
     private final String path;
     private final List<String> lineHashes;
 
-    public File(String path, @Nullable List<String> lineHashes) {
+    public File(String path, List<String> lineHashes) {
       this.path = requireNonNull(path, "path can not be null");
-      this.lineHashes = lineHashes;
+      this.lineHashes = requireNonNull(lineHashes, "lineHashes can not be null");
     }
 
     public String getPath() {
       return path;
     }
 
-    @CheckForNull
+    /**
+     * List of hash of each line. An empty list is returned
+     * if file content is empty.
+     */
     public List<String> getLineHashes() {
       return lineHashes;
     }
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/FileSimilarityImpl.java b/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/FileSimilarityImpl.java
index c34bf8c1564..d059c0ac182 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/FileSimilarityImpl.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/FileSimilarityImpl.java
@@ -19,8 +19,6 @@
  */
 package org.sonar.server.computation.task.projectanalysis.filemove;
 
-import java.util.List;
-
 public class FileSimilarityImpl implements FileSimilarity {
 
   private final SourceSimilarity sourceSimilarity;
@@ -31,15 +29,10 @@ public class FileSimilarityImpl implements FileSimilarity {
 
   @Override
   public int score(File file1, File file2) {
-    int score = 0;
-
-    // TODO check filenames
+    // Algorithm could be improved by increasing score
+    // depending on filename similarity
+    // Current implementation relies on file content only.
 
-    List<String> lineHashes1 = file1.getLineHashes();
-    List<String> lineHashes2 = file2.getLineHashes();
-    if (lineHashes1 != null && lineHashes2 != null) {
-      score += sourceSimilarity.score(lineHashes1, lineHashes2);
-    }
-    return score;
+    return sourceSimilarity.score(file1.getLineHashes(), file2.getLineHashes());
   }
 }
diff --git a/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/SourceSimilarityImpl.java b/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/SourceSimilarityImpl.java
index bb9da71e5ef..bdbc91d3b25 100644
--- a/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/SourceSimilarityImpl.java
+++ b/server/sonar-server/src/main/java/org/sonar/server/computation/task/projectanalysis/filemove/SourceSimilarityImpl.java
@@ -27,12 +27,15 @@ import static java.lang.Math.min;
 public class SourceSimilarityImpl implements SourceSimilarity {
 
   @Override
-  public <T extends Object> int score(List<T> left, List<T> right) {
+  public <T> int score(List<T> left, List<T> right) {
+    if (left.isEmpty() && right.isEmpty()) {
+      return 0;
+    }
     int distance = levenshteinDistance(left, right);
     return (int) (100 * (1.0 - ((double) distance) / (max(left.size(), right.size()))));
   }
 
-  <T extends Object> int levenshteinDistance(List<T> left, List<T> right) {
+  private static <T> int levenshteinDistance(List<T> left, List<T> right) {
     int len0 = left.size() + 1;
     int len1 = right.size() + 1;
 
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/task/projectanalysis/filemove/FileMoveDetectionStepTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/task/projectanalysis/filemove/FileMoveDetectionStepTest.java
index 6f67fd94847..68af5bc8837 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/task/projectanalysis/filemove/FileMoveDetectionStepTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/task/projectanalysis/filemove/FileMoveDetectionStepTest.java
@@ -23,13 +23,12 @@ import java.io.File;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
+import javax.annotation.Nullable;
 import org.apache.commons.io.FileUtils;
 import org.junit.Before;
 import org.junit.Rule;
@@ -410,6 +409,18 @@ public class FileMoveDetectionStepTest {
   }
 
   @Test
+  public void execute_detects_no_move_if_two_files_are_empty() {
+    analysisMetadataHolder.setBaseAnalysis(ANALYSIS);
+    mockComponents(FILE_1.getKey(), FILE_2.getKey());
+    mockContentOfFileInDb(FILE_1.getKey(), null);
+    mockContentOfFileInDb(FILE_2.getKey(), null);
+
+    underTest.execute();
+
+    assertThat(movedFilesRepository.getComponentsWithOriginal()).isEmpty();
+  }
+
+  @Test
   public void execute_detects_several_moves() {
     // testing:
     // - file1 renamed to file3
@@ -496,17 +507,15 @@ public class FileMoveDetectionStepTest {
     sourceLinesRepository.addLines(ref, content);
   }
 
-  private void mockContentOfFileInDb(String key, String[] content) {
-    SourceLinesHashesComputer linesHashesComputer = new SourceLinesHashesComputer();
-    Iterator<String> lineIterator = Arrays.asList(content).iterator();
-    while (lineIterator.hasNext()) {
-      String line = lineIterator.next();
-      linesHashesComputer.addLine(line);
+  private void mockContentOfFileInDb(String key, @Nullable String[] content) {
+    FileSourceDto dto = new FileSourceDto();
+    if (content != null) {
+      SourceLinesHashesComputer linesHashesComputer = new SourceLinesHashesComputer();
+      stream(content).forEach(linesHashesComputer::addLine);
+      dto.setLineHashes(on('\n').join(linesHashesComputer.getLineHashes()));
     }
 
-    when(fileSourceDao.selectSourceByFileUuid(dbSession, componentUuidOf(key)))
-      .thenReturn(new FileSourceDto()
-        .setLineHashes(on('\n').join(linesHashesComputer.getLineHashes())));
+    when(fileSourceDao.selectSourceByFileUuid(dbSession, componentUuidOf(key))).thenReturn(dto);
   }
 
   private void setFilesInReport(Component... files) {
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/task/projectanalysis/filemove/MatchesByScoreTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/task/projectanalysis/filemove/MatchesByScoreTest.java
index cbd96aac878..4007a357a7c 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/task/projectanalysis/filemove/MatchesByScoreTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/task/projectanalysis/filemove/MatchesByScoreTest.java
@@ -30,6 +30,8 @@ import java.util.Set;
 import org.junit.Test;
 
 import static com.google.common.collect.ImmutableSet.of;
+import static java.util.Collections.emptyList;
+import static java.util.Collections.emptySet;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.sonar.server.computation.task.projectanalysis.filemove.FileMoveDetectionStep.MIN_REQUIRED_SCORE;
 
@@ -39,7 +41,7 @@ public class MatchesByScoreTest {
 
   @Test
   public void creates_returns_always_the_same_instance_of_maxScore_is_less_than_min_required_score() {
-    Set<String> doesNotMatterDbFileKeys = Collections.emptySet();
+    Set<String> doesNotMatterDbFileKeys = emptySet();
     Map<String, FileSimilarity.File> doesNotMatterReportFiles = Collections.emptyMap();
     int[][] doesNotMatterScores = new int[0][0];
 
@@ -78,6 +80,6 @@ public class MatchesByScoreTest {
   }
 
   private static FileSimilarity.File fileOf(String key) {
-    return new FileSimilarity.File("path of " + key, null);
+    return new FileSimilarity.File("path of " + key, emptyList());
   }
 }
diff --git a/server/sonar-server/src/test/java/org/sonar/server/computation/task/projectanalysis/filemove/SourceSimilarityImplTest.java b/server/sonar-server/src/test/java/org/sonar/server/computation/task/projectanalysis/filemove/SourceSimilarityImplTest.java
index 1c50bddbdb5..11ae0481655 100644
--- a/server/sonar-server/src/test/java/org/sonar/server/computation/task/projectanalysis/filemove/SourceSimilarityImplTest.java
+++ b/server/sonar-server/src/test/java/org/sonar/server/computation/task/projectanalysis/filemove/SourceSimilarityImplTest.java
@@ -25,6 +25,7 @@ import org.junit.Test;
 import org.junit.rules.ExpectedException;
 
 import static java.util.Arrays.asList;
+import static java.util.Collections.emptyList;
 import static org.assertj.core.api.Assertions.assertThat;
 
 public class SourceSimilarityImplTest {
@@ -32,7 +33,7 @@ public class SourceSimilarityImplTest {
   @Rule
   public ExpectedException expectedException = ExpectedException.none();
 
-  SourceSimilarityImpl underTest = new SourceSimilarityImpl();
+  private SourceSimilarityImpl underTest = new SourceSimilarityImpl();
 
   @Test
   public void zero_if_fully_different() {
@@ -53,4 +54,9 @@ public class SourceSimilarityImplTest {
     assertThat(underTest.score(asList("a"), asList("a", "b", "c"))).isEqualTo(33);
     assertThat(underTest.score(asList("a", "b", "c"), asList("a"))).isEqualTo(33);
   }
+
+  @Test
+  public void two_empty_lists_are_not_considered_as_equal() {
+    assertThat(underTest.score(emptyList(), emptyList())).isEqualTo(0);
+  }
 }