Fix GC for FileRepo in case packfile renames fail

Only on Windows the rename operation which renames temporary Packfiles
(and index-files and bitmap-files) sometime fails. This happens only
when renaming a temporary Packfile to a Packfile which already exists.
Such situations occur if you run GC twice on a repo without modifying
the repo inbetween.

In such situations there was bug in GC which led to a corrupted repo
whithout any packfiles anymore. This commit fixes the problem by
introducing a utility method which renames a file and throws an
IOException if it fails. This method also takes care to repeat a
failing rename if our FS class has found out we are running on a
platform with a unreliable File.renameTo() method.

I am searching for a better solution because even with this utility
method in hand a GC on a already GC'ed repo will fail on Windows. But
at least with this fix we will not produce corrupted repos anymore.

Bug: 389305
Change-Id: Iac1ab3e0b8c419c90404f2e2f3559672eb8f6d28
Signed-off-by: Christian Halstrick <christian.halstrick@sap.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GCTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GCTest.java
index bc60f64886..d5c8f12ef6 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GCTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/GCTest.java
@@ -435,6 +435,13 @@ public class GCTest extends LocalDiskRepositoryTestCase {
 		assertEquals(0, stats.numberOfLooseObjects);
 		assertEquals(4, stats.numberOfPackedObjects);
 		assertEquals(1, stats.numberOfPackFiles);
+
+		// Do the gc again and check that it hasn't changed anything
+		gc.gc();
+		stats = gc.getStatistics();
+		assertEquals(0, stats.numberOfLooseObjects);
+		assertEquals(4, stats.numberOfPackedObjects);
+		assertEquals(1, stats.numberOfPackFiles);
 	}
 
 	@Test