Fix deadlock caused by GitProjectData.logAndUnmapGoneMappedResource

Deadlock could occur as follows:

Thread 1: In GitProjectData.get/load, the class object is locked. In
case a mapped resource is gone, RepositoryProvider.unmap is called,
which waits for job run.

Thread 2: In a job run, GitProvider.getData is called, which waits to
lock the GitProjectData class.

There are also other situations, all of which are caused by
logAndUnmapGoneMappedResource calling RepositoryProvider.unmap. By doing
that in a job where the GitProjectData class is no longer locked, this
should be solved.

Bug: 425973
Change-Id: I74ecc26d696057896ac2790974e9c2e9687c783e
Signed-off-by: Robin Stocker <robin@nibor.org>

3 files changed, 28 insertions, 5 deletions

diff --git a/org.eclipse.egit.core/src/org/eclipse/egit/core/internal/CoreText.java b/org.eclipse.egit.core/src/org/eclipse/egit/core/internal/CoreText.java
index 4ff0ce284b..ba0a383a56 100644
--- a/org.eclipse.egit.core/src/org/eclipse/egit/core/internal/CoreText.java
+++ b/org.eclipse.egit.core/src/org/eclipse/egit/core/internal/CoreText.java
@@ -373,6 +373,9 @@ public class CoreText extends NLS {
 	public static String GitProjectData_repositoryChangedTaskName;
 
 	/** */
+	public static String GitProjectData_UnmapJobName;
+
+	/** */
 	public static String GitProjectData_UnmappingGoneResourceFailed;
 
 	/** */
diff --git a/org.eclipse.egit.core/src/org/eclipse/egit/core/internal/coretext.properties b/org.eclipse.egit.core/src/org/eclipse/egit/core/internal/coretext.properties
index af2de271a2..2039eb66ee 100644
--- a/org.eclipse.egit.core/src/org/eclipse/egit/core/internal/coretext.properties
+++ b/org.eclipse.egit.core/src/org/eclipse/egit/core/internal/coretext.properties
@@ -149,6 +149,7 @@ GitSubscriberMergeContext_FailedRefreshSyncView=Failed to refresh synchronize vi
 
 GitProjectData_repositoryChangedJobName=Git repository changed
 GitProjectData_repositoryChangedTaskName=Git repository changed
+GitProjectData_UnmapJobName=Disconnecting project {0} from Git repository
 GitProjectData_UnmappingGoneResourceFailed=Unmapping gone mapped resource {0} failed
 
 GitResourceVariantTreeSubscriber_fetchTaskName=Fetching data from git repositories
diff --git a/org.eclipse.egit.core/src/org/eclipse/egit/core/project/GitProjectData.java b/org.eclipse.egit.core/src/org/eclipse/egit/core/project/GitProjectData.java
index 5ad2ba451b..d62e5c5abd 100644
--- a/org.eclipse.egit.core/src/org/eclipse/egit/core/project/GitProjectData.java
+++ b/org.eclipse.egit.core/src/org/eclipse/egit/core/project/GitProjectData.java
@@ -530,11 +530,8 @@ public class GitProjectData {
 				CoreText.GitProjectData_mappedResourceGone, m.toString()),
 				new FileNotFoundException(m.getContainerPath().toString()));
 		m.clear();
-		try {
-			RepositoryProvider.unmap(getProject());
-		} catch (TeamException e) {
-			Activator.logError(CoreText.GitProjectData_UnmappingGoneResourceFailed, e);
-		}
+		UnmapJob unmapJob = new UnmapJob(getProject());
+		unmapJob.schedule();
 	}
 
 	private void protect(IResource resource) {
@@ -553,4 +550,26 @@ public class GitProjectData {
 			c = c.getParent();
 		}
 	}
+
+	private static class UnmapJob extends Job {
+
+		private final IProject project;
+
+		private UnmapJob(IProject project) {
+			super(MessageFormat.format(CoreText.GitProjectData_UnmapJobName,
+					project.getName()));
+			this.project = project;
+		}
+
+		@Override
+		protected IStatus run(IProgressMonitor monitor) {
+			try {
+				RepositoryProvider.unmap(project);
+				return Status.OK_STATUS;
+			} catch (TeamException e) {
+				return new Status(IStatus.ERROR, Activator.getPluginId(),
+						CoreText.GitProjectData_UnmappingGoneResourceFailed, e);
+			}
+		}
+	}
 }