DirCache: Do not create duplicate tree entries

If a file (e.g.  "A") and a subtree file (e.g. "A/foo.c") both appear
in the DirCache this cache should not be written out as a tree object.
The "A" file and "A" subtree conflict with each other in the same tree
and will fail fsck.

Detect this condition during DirCacheBuilder and DirCacheEditor
finish() so the application can be halted early before it updates a
DirCache that might later write an invalid tree structure.

Change-Id: I95660787e88df336297949b383f4c5fda52e75f5

1 files changed, 46 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/dircache/DirCachePathEditTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/dircache/DirCachePathEditTest.java
index 3988f6a4c4..39a0cdac5f 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/dircache/DirCachePathEditTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/dircache/DirCachePathEditTest.java
@@ -43,11 +43,13 @@
 package org.eclipse.jgit.dircache;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
 
 import java.util.ArrayList;
 import java.util.List;
 
 import org.eclipse.jgit.dircache.DirCacheEditor.PathEdit;
+import org.eclipse.jgit.errors.DirCacheNameConflictException;
 import org.eclipse.jgit.lib.FileMode;
 import org.eclipse.jgit.lib.ObjectId;
 import org.junit.Test;
@@ -212,6 +214,50 @@ public class DirCachePathEditTest {
 		assertEquals("e", dc.getEntry(4).getPathString());
 	}
 
+	@Test
+	public void testFileOverlapsTree() throws Exception {
+		DirCache dc = DirCache.newInCore();
+		DirCacheEditor editor = dc.editor();
+		editor.add(new AddEdit("a"));
+		editor.add(new AddEdit("a/b").setReplace(false));
+		try {
+			editor.finish();
+			fail("Expected DirCacheNameConflictException to be thrown");
+		} catch (DirCacheNameConflictException e) {
+			assertEquals("a a/b", e.getMessage());
+			assertEquals("a", e.getPath1());
+			assertEquals("a/b", e.getPath2());
+		}
+
+		editor = dc.editor();
+		editor.add(new AddEdit("A.c"));
+		editor.add(new AddEdit("A/c").setReplace(false));
+		editor.add(new AddEdit("A0c"));
+		editor.add(new AddEdit("A"));
+		try {
+			editor.finish();
+			fail("Expected DirCacheNameConflictException to be thrown");
+		} catch (DirCacheNameConflictException e) {
+			assertEquals("A A/c", e.getMessage());
+			assertEquals("A", e.getPath1());
+			assertEquals("A/c", e.getPath2());
+		}
+
+		editor = dc.editor();
+		editor.add(new AddEdit("A.c"));
+		editor.add(new AddEdit("A/b/c/d").setReplace(false));
+		editor.add(new AddEdit("A/b/c"));
+		editor.add(new AddEdit("A0c"));
+		try {
+			editor.finish();
+			fail("Expected DirCacheNameConflictException to be thrown");
+		} catch (DirCacheNameConflictException e) {
+			assertEquals("A/b/c A/b/c/d", e.getMessage());
+			assertEquals("A/b/c", e.getPath1());
+			assertEquals("A/b/c/d", e.getPath2());
+		}
+	}
+
 	private static DirCacheEntry createEntry(String path, int stage) {
 		DirCacheEntry entry = new DirCacheEntry(path, stage);
 		entry.setFileMode(FileMode.REGULAR_FILE);