Fix DiffFormatter NPEs for DiffEntry without content change

DiffEntry.getOldId() returns null for a diff without an index line (e.g.
only mode changed, rename without content change).

Bug: 407743
Change-Id: I42eac87421f2a53c985af260a253338f578492bc

1 files changed, 30 insertions, 1 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/DiffFormatterTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/DiffFormatterTest.java
index 820c0c6d78..00e5f06747 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/DiffFormatterTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/DiffFormatterTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2010, Google Inc.
+ * Copyright (C) 2010, 2013 Google Inc.
  * and other copyright owners as documented in the project's IP log.
  *
  * This program and the accompanying materials are made available
@@ -257,6 +257,35 @@ public class DiffFormatterTest extends RepositoryTestCase {
 	}
 
 	@Test
+	public void testCreateFileHeaderWithoutIndexLine() throws Exception {
+		DiffEntry m = DiffEntry.modify(PATH_A);
+		m.oldMode = FileMode.REGULAR_FILE;
+		m.newMode = FileMode.EXECUTABLE_FILE;
+
+		FileHeader fh = df.toFileHeader(m);
+		String expected = DIFF + "a/src/a b/src/a\n" + //
+				"old mode 100644\n" + //
+				"new mode 100755\n";
+		assertEquals(expected, fh.getScriptText());
+	}
+
+	@Test
+	public void testCreateFileHeaderForRenameWithoutContentChange() throws Exception {
+		DiffEntry a = DiffEntry.delete(PATH_A, ObjectId.zeroId());
+		DiffEntry b = DiffEntry.add(PATH_B, ObjectId.zeroId());
+		DiffEntry m = DiffEntry.pair(ChangeType.RENAME, a, b, 100);
+		m.oldId = null;
+		m.newId = null;
+
+		FileHeader fh = df.toFileHeader(m);
+		String expected = DIFF + "a/src/a b/src/b\n" + //
+				"similarity index 100%\n" + //
+				"rename from src/a\n" + //
+				"rename to src/b\n";
+		assertEquals(expected, fh.getScriptText());
+	}
+
+	@Test
 	public void testDiff() throws Exception {
 		write(new File(db.getDirectory().getParent(), "test.txt"), "test");
 		File folder = new File(db.getDirectory().getParent(), "folder");