github-yangbo
diff --git a/‎src/main/java/difflib/DiffUtils.java
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+8Lines changed: 8 additions & 0 deletions b/‎src/main/java/difflib/DiffUtils.java
Copy file name to clipboardExpand all lines: src/main/java/difflib/DiffUtils.java
+8Lines changed: 8 additions & 0 deletions
diff --git a/‎src/test/java/diffutils/EmptyContextUnifiedDiffTest.java
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+57-32Lines changed: 57 additions & 32 deletions b/‎src/test/java/diffutils/EmptyContextUnifiedDiffTest.java
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+57-32Lines changed: 57 additions & 32 deletions
diff --git a/‎src/test/resources/mocks/uc_original.txt renamed to ‎src/test/resources/mocks/unified_empty_context_original.txt
Copy file name to clipboard b/‎src/test/resources/mocks/uc_original.txt renamed to ‎src/test/resources/mocks/unified_empty_context_original.txt
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diff --git a/‎src/test/resources/mocks/uc_insert_patch.txt renamed to ‎src/test/resources/mocks/unified_empty_context_patch.txt
Copy file name to clipboard b/‎src/test/resources/mocks/uc_insert_patch.txt renamed to ‎src/test/resources/mocks/unified_empty_context_patch.txt
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diff --git a/‎src/test/resources/mocks/uc_insert_revised.txt renamed to ‎src/test/resources/mocks/unified_empty_context_revised.txt
Copy file name to clipboard b/‎src/test/resources/mocks/uc_insert_revised.txt renamed to ‎src/test/resources/mocks/unified_empty_context_revised.txt
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@@ -384,6 +384,14 @@ private static List<String> processDeltas(List<String> origLines,
 			revTotal++;
 		}
 
+		// In case of empty chunk and context
+		if (origTotal == 0 && origStart > 1)
+			--origStart;
+
+		// In case of empty chunk and context
+		if (revTotal == 0 && revStart > 1)
+			--revStart;
+
 		// Create and insert the block header, conforming to the Unified Diff
 		// standard
 		StringBuffer header = new StringBuffer();
 
@@ -1,7 +1,6 @@
 package diffutils;
 
 import java.io.BufferedReader;
-import java.io.File;
 import java.io.FileReader;
 import java.io.IOException;
 import java.util.LinkedList;
@@ -18,48 +17,74 @@ public class EmptyContextUnifiedDiffTest extends TestCase {
 	public List<String> fileToLines(String filename) {
 		List<String> lines = new LinkedList<String>();
 		String line = "";
+		BufferedReader in = null;
 		try {
-			BufferedReader in = new BufferedReader(new FileReader(filename));
+			in = new BufferedReader(new FileReader(filename));
 			while ((line = in.readLine()) != null) {
 				lines.add(line);
 			}
 		} catch (IOException e) {
 			e.printStackTrace();
 			fail(e.getMessage());
+		} finally {
+			if (in != null) {
+				try {
+					in.close();
+				} catch (IOException e) {
+					// ignore ... any errors should already have been
+					// reported via an IOException from the final flush.
+				}
+			}
 		}
 		return lines;
 	}
 
-	public void testUnifiedContextInsert() {
-		testUnifiedContextXXX(TestConstants.MOCK_FOLDER + "uc_insert_patch.txt", TestConstants.MOCK_FOLDER
-				+ "uc_insert_revised.txt");
+	public void testEmptyUnifiedContextPatch() {
+		List<String> origLines = fileToLines(TestConstants.MOCK_FOLDER + "unified_empty_context_original.txt");
+		List<String> revLines = fileToLines(TestConstants.MOCK_FOLDER + "unified_empty_context_revised.txt");
+		List<String> unifiedDiff = fileToLines(TestConstants.MOCK_FOLDER + "unified_empty_context_patch.txt");
+
+		List<String> patchedLines = null;
+		Patch patch = DiffUtils.parseUnifiedDiff(unifiedDiff);
+
+		try {
+			patchedLines = (List<String>) patch.applyTo(origLines);
+		} catch (PatchFailedException e) {
+			fail(e.getMessage());
+		}
+
+		verifyLinesEqual(patchedLines, revLines);
+	}
+
+	public void testEmptyUnifiedContextDiff() {
+		List<String> origLines = fileToLines(TestConstants.MOCK_FOLDER + "unified_empty_context_original.txt");
+		List<String> revLines = fileToLines(TestConstants.MOCK_FOLDER + "unified_empty_context_revised.txt");
+
+		List<String> patchedLines = null;
+
+		// Generate a 0-context diff then reapply
+		Patch generatedPatch = DiffUtils.diff(origLines, revLines);
+		List<String> generatedDiff = DiffUtils.generateUnifiedDiff("original", "revised", origLines, generatedPatch, 0);
+		Patch newPatch = DiffUtils.parseUnifiedDiff(generatedDiff);
+
+		try {
+			patchedLines = (List<String>) newPatch.applyTo(origLines);
+		} catch (PatchFailedException e) {
+			fail(e.getMessage());
+		}
+
+		verifyLinesEqual(patchedLines, revLines);
+	}
+
+	public void verifyLinesEqual(List<String> patchedLines, List<String> revLines) {
+		assertTrue(revLines.size() == patchedLines.size());
+		for (int i = 0; i < revLines.size(); i++) {
+			String l1 = revLines.get(i);
+			String l2 = patchedLines.get(i);
+			if (!l1.equals(l2)) {
+				fail("Line " + (i + 1) + " of the patched file did not match the revised original");
+			}
+		}
 	}
 
-	public void testUnifiedContextXXX(String patch_file, String revised_file) {
-    	List<String> origLines = fileToLines(TestConstants.MOCK_FOLDER + "uc_original.txt");
-    	List<String> revLines = fileToLines(revised_file);
-    	List<String> unifiedDiff = fileToLines(patch_file);
-    	List<String> patchedLines = null;
-    	Patch patch = DiffUtils.parseUnifiedDiff(unifiedDiff);
-    	    	
-    	 try {
-    		 patchedLines = (List<String>) patch.applyTo(origLines);
-         } catch (PatchFailedException e) {
-             fail(e.getMessage());
-         }
-         
-         verifyLinesEqual(patchedLines, revLines);
-    }
-    
-    public void verifyLinesEqual(List<String> patchedLines, List<String> revLines) {
-    	assertTrue(revLines.size() == patchedLines.size());
-        for (int i = 0; i < revLines.size(); i++) {
-            String l1 = revLines.get(i);
-            String l2 = patchedLines.get(i);
-            if (!l1.equals(l2)) {
-                fail("Line " + (i + 1) + " of the patched file did not match the revised original");
-            }
-        }
-    }
-    
 }