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Bug 321712

Summary:	ConcurrentRefUpdateException on merge, leaves repository in inconsistent state
Product:	[Technology] JGit	Reporter:	Simon Kaufmann <simon.kaufmann>
Component:	JGit	Assignee:	Christian Halstrick <christian.halstrick>
Status:	CLOSED WORKSFORME	QA Contact:
Severity:	critical
Priority:	P3	CC:	simon, stefan.lay
Version:	unspecified
Target Milestone:	0.9.0
Hardware:	PC
OS:	Windows Vista
Whiteboard:

Description Simon Kaufmann

2010-08-04 09:07:40 EDT

Build Identifier: Helios (20100617-1415), JGit 0.9.0.201007291517

While merging from origin/master into my master branch, I happened to get the following Exception:

org.eclipse.jgit.api.ConcurrentRefUpdateException: Could not lock HEAD. RefUpdate return code was: LOCK_FAILURE
at org.eclipse.jgit.api.MergeCommand.updateHead(MergeCommand.java:201)
at org.eclipse.jgit.api.MergeCommand.call(MergeCommand.java:144)
at org.eclipse.egit.core.op.MergeOperation$1.run(MergeOperation.java:103)
at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:1975)
at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:1957)
at org.eclipse.egit.core.op.MergeOperation.execute(MergeOperation.java:124)
at org.eclipse.egit.ui.internal.repository.tree.command.MergeCommand$1.run(MergeCommand.java:90)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)

As a result my master branch is not visible anymore (neither in msysgit nor in egit) and gitk complains about "unknown revision HEAD", so apparently this reference is lost as well.
Whatever caused this concurrent access, I wasn't using anything else than egit (i.e. not command line tools in parallel etc.).

Reproducible: Couldn't Reproduce

Steps to Reproduce:
In EGit:
1. checkout master
2. fetch origin
3. merge from origin/master into master

Comment 1 Simon Kaufmann

2010-08-04 12:13:28 EDT

just another detail that might be helpful: the .git/refs/heads/master file got lost. 
The .git/HEAD file still exists and is pointing to refs/heads/master

Comment 2 Christian Halstrick

2010-12-01 09:15:03 EST

Simon: is this one still valid? We talked about one bug but I don't think that is this one.

Comment 3 Simon Kaufmann

2010-12-01 09:22:42 EST

Indeed, it's not the one we talked about. This one isn't reproducible, so I cannot really tell if it's still valid. It didn't happen again, so it doesn't really bother me.