Prevent IO_FAILURE by checking for conflicts in ref name validation

E.g. "a/1" is a conflict if "a" already exists, "b" is a conflict if
"b/1" already exists.

With the JGit change that this depends on, we can even show the user
which existing refs cause the conflict.

Bug: 393914
JGit-Dependency: I11e0ba2f300adb8b3612943c304ba68bbe73db8a
Change-Id: Ibea9984121ae88c488858b8a8e73b593195b15e0
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

3 files changed, 20 insertions, 1 deletions

diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java
index 800cb018fc..7e48a5fc42 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/UIText.java
@@ -4315,6 +4315,9 @@ public class UIText extends NLS {
 	public static String ValidationUtils_RefAlreadyExistsMessage;
 
 	/** */
+	public static String ValidationUtils_RefNameConflictsWithExistingMessage;
+
+	/** */
 	public static String ValidationUtils_PleaseEnterNameMessage;
 
 	/** */
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/ValidationUtils.java b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/ValidationUtils.java
index 2cc2ffe13e..f1b298608b 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/ValidationUtils.java
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/internal/ValidationUtils.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (C) 2010, 2012 Dariusz Luksza <dariusz@luksza.org> and others.
+ * Copyright (C) 2010, 2013 Dariusz Luksza <dariusz@luksza.org> and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
@@ -10,11 +10,16 @@
 package org.eclipse.egit.ui.internal;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
 
 import org.eclipse.egit.ui.Activator;
 import org.eclipse.egit.ui.UIText;
 import org.eclipse.jface.dialogs.IInputValidator;
+import org.eclipse.jgit.lib.RefDatabase;
 import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.util.StringUtils;
 import org.eclipse.osgi.util.NLS;
 
 /**
@@ -50,6 +55,16 @@ public class ValidationUtils {
 						return NLS.bind(
 								UIText.ValidationUtils_RefAlreadyExistsMessage,
 								testFor);
+					RefDatabase refDatabase = repo.getRefDatabase();
+					Collection<String> conflictingNames = refDatabase.getConflictingNames(testFor);
+					if (!conflictingNames.isEmpty()) {
+						ArrayList<String> names = new ArrayList<String>(conflictingNames);
+						Collections.sort(names);
+						String joined = StringUtils.join(names, ", "); //$NON-NLS-1$
+						return NLS.bind(
+								UIText.ValidationUtils_RefNameConflictsWithExistingMessage,
+								joined);
+					}
 				} catch (IOException e1) {
 					Activator.logError(NLS.bind(
 							UIText.ValidationUtils_CanNotResolveRefMessage,
diff --git a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties
index 9057973121..88e88ea704 100644
--- a/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties
+++ b/org.eclipse.egit.ui/src/org/eclipse/egit/ui/uitext.properties
@@ -1505,6 +1505,7 @@ SkipRebaseCommand_JobName=Skipping Rebase
 ValidationUtils_CanNotResolveRefMessage=Can not resolve {0}
 ValidationUtils_InvalidRefNameMessage={0} is not a valid name for a ref
 ValidationUtils_RefAlreadyExistsMessage=Ref {0} already exists
+ValidationUtils_RefNameConflictsWithExistingMessage=Name conflicts with existing refs: {0}
 ValidationUtils_PleaseEnterNameMessage=Please enter a name
 
 GitMergeEditorInput_CalculatingDiffTaskName=Calculating Differences