Fix #252 - Adding an existing project to a solution uses a new GUID instead of the <ProjectGuid>

Also adds code to detect+fix duplicate GUIDs. (which might exist due to users creating new projects by copying old ones)

src/Main/Base/Project/Editor/CodeCompletion/ICompletionItem.cs

@@ -56,6 +56,7 @@ namespace ICSharpCode.SharpDevelop.Editor.CodeCompletion
 		public virtual void Complete(CompletionContext context)
 		{
 			context.Editor.Document.Replace(context.StartOffset, context.Length, this.Text);
+			// In case someone calls base.Complete() and then continues using the context, update EndOffset:
 			context.EndOffset = context.StartOffset + this.Text.Length;
 		}
 	}

src/Main/Base/Project/Project/ISolutionItem.cs

@@ -36,7 +36,8 @@ namespace ICSharpCode.SharpDevelop.Project
 		/// <summary>
 		/// Gets the ID GUID of this solution item.
 		/// </summary>
-		Guid IdGuid { get; }
+		/// <remarks>SharpDevelop will change an item's GUID in order to automatically solve GUID conflicts.</remarks>
+		Guid IdGuid { get; set; }
 		
 		/// <summary>
 		/// Gets the type GUID of this solution item.

src/Main/Base/Project/Src/Project/MSBuildBasedProject.cs

@@ -122,6 +122,19 @@ namespace ICSharpCode.SharpDevelop.Project
 		
 		public event EventHandler MinimumSolutionVersionChanged;
 		
+		public override Guid IdGuid {
+			get {
+				return base.IdGuid;
+			}
+			set {
+				if (base.IdGuid != value) {
+					base.IdGuid = value;
+					// Save changed GUID to project file
+					SetPropertyInternal(null, null, ProjectGuidPropertyName, value.ToString("B").ToUpperInvariant(), PropertyStorageLocations.Base, true);
+				}
+			}
+		}
+		
 		public string ToolsVersion {
 			get { return projectFile.ToolsVersion; }
 			protected internal set {
@@ -181,6 +194,7 @@ namespace ICSharpCode.SharpDevelop.Project
 			else
 				SetProperty(null, platform, "PlatformTarget", "AnyCPU", PropertyStorageLocations.PlatformSpecific, false);
 			LoadConfigurationPlatformNamesFromMSBuild();
+			isLoading = false;
 		}
 		
 		/// <summary>
@@ -914,7 +928,7 @@ namespace ICSharpCode.SharpDevelop.Project
 						propertyRemoved = true;
 					}
 				}
-				if (propertyRemoved && propertyGroup.Children.Count() == 0)
+				if (propertyRemoved && propertyGroup.Children.Count == 0)
 					project.RemoveChild(propertyGroup);
 			}
 		}
@@ -1188,7 +1202,7 @@ namespace ICSharpCode.SharpDevelop.Project
 		#endregion
 		
 		#region Loading
-		protected bool isLoading;
+		protected bool isLoading = true;
 		
 		public MSBuildBasedProject(ProjectLoadInformation loadInformation)
 			: base(loadInformation)
@@ -1197,7 +1211,6 @@ namespace ICSharpCode.SharpDevelop.Project
 			this.configurationNames = new MSBuildConfigurationOrPlatformNameCollection(this, false);
 			this.platformNames = new MSBuildConfigurationOrPlatformNameCollection(this, true);
 			
-			isLoading = true;
 			bool success = false;
 			try {
 				try {
@@ -1277,6 +1290,15 @@ namespace ICSharpCode.SharpDevelop.Project
 				userProjectFile = ProjectRootElement.Create(userFileName, MSBuildProjectCollection);
 			}
 			
+			// Read IdGuid from project file.
+			string idGuidString = GetEvaluatedProperty(ProjectGuidPropertyName);
+			if (idGuidString != null) {
+				Guid idGuid;
+				if (Guid.TryParse(idGuidString, out idGuid)) {
+					// Use 'base.' to avoid writing the changed ID back into the project file
+					base.IdGuid = idGuid;
+				}
+			}
 			CreateItemsListFromMSBuild();
 			LoadConfigurationPlatformNamesFromMSBuild();
 		}

src/Main/Base/Test/Project/AddExistingProjectTests.cs

@@ -30,7 +30,8 @@ namespace ICSharpCode.SharpDevelop.Project
 		IProject LoadProject(ProjectLoadInformation info)
 		{
 			var project = MockRepository.GenerateStrictMock<IProject>();
-			project.Stub(p => p.IdGuid).Return(projectGuid);
+			project.Stub(p => p.IdGuid).PropertyBehavior();
+			project.IdGuid = projectGuid;
 			project.Stub(p => p.FileName).Return(info.FileName);
 			project.Stub(p => p.ParentSolution).Return(info.Solution);
 			project.Stub(p => p.ParentFolder).PropertyBehavior();
@@ -67,10 +68,14 @@ namespace ICSharpCode.SharpDevelop.Project
 			solution.AddExistingProject(project1FileName);
 		}
 		
-//		[Test]
-//		public void AddTwoProjectsWithSameGUID()
-//		{
-//			
-//		}
+		[Test]
+		public void AddTwoProjectsWithSameGUID()
+		{
+			var solution = CreateSolution();
+			var project1 = solution.AddExistingProject(project1FileName);
+			var project2 = solution.AddExistingProject(project2FileName);
+			Assert.AreEqual(projectGuid, project1.IdGuid);
+			Assert.AreNotEqual(projectGuid, project2.IdGuid);
+		}
 	}
 }

src/Main/SharpDevelop/Project/SolutionFileItem.cs

@@ -9,12 +9,11 @@ namespace ICSharpCode.SharpDevelop.Project
 	class SolutionFileItem : ISolutionFileItem
 	{
 		readonly Solution parentSolution;
-		readonly Guid idGuid;
 		
 		public SolutionFileItem(Solution parentSolution)
 		{
 			this.parentSolution = parentSolution;
-			this.idGuid = Guid.NewGuid();
+			this.IdGuid = Guid.NewGuid();
 		}
 		
 		FileName fileName;
@@ -35,9 +34,7 @@ namespace ICSharpCode.SharpDevelop.Project
 			get { return parentSolution; }
 		}
 
-		public Guid IdGuid {
-			get { return idGuid; }
-		}
+		public Guid IdGuid { get; set; }
 
 		public Guid TypeGuid {
 			get { return Guid.Empty; }

src/Main/SharpDevelop/Project/SolutionFolder.cs

@@ -16,7 +16,7 @@ namespace ICSharpCode.SharpDevelop.Project
 	class SolutionFolder : ISolutionFolder
 	{
 		readonly Solution parentSolution;
-		readonly Guid idGuid;
+		Guid idGuid;
 		
 		public SolutionFolder(Solution parentSolution, Guid idGuid)
 		{
@@ -114,6 +114,7 @@ namespace ICSharpCode.SharpDevelop.Project
 		
 		public Guid IdGuid {
 			get { return idGuid; }
+			set { idGuid = value; }
 		}
 		
 		public Guid TypeGuid {
@@ -135,7 +136,10 @@ namespace ICSharpCode.SharpDevelop.Project
 				throw new ProjectLoadException("Project " + fileName + " is already part of this solution.");
 			ProjectLoadInformation loadInfo = new ProjectLoadInformation(parentSolution, fileName, fileName.GetFileNameWithoutExtension());
 			IProject project = SD.ProjectService.LoadProject(loadInfo);
-			Debug.Assert(project.IdGuid != Guid.Empty);
+			if (parentSolution.GetItemByGuid(project.IdGuid) != null) {
+				SD.Log.Warn("Added project has duplicate GUID; a new GUID will be generated.");
+				project.IdGuid = Guid.NewGuid();
+			}
 			this.Items.Add(project);
 			project.ProjectLoaded();
 			ProjectBrowserPad.RefreshViewAsync();

src/Main/SharpDevelop/Project/SolutionLoader.cs

@@ -74,6 +74,7 @@ namespace ICSharpCode.SharpDevelop.Project
 				solutionEntries.Add(information);
 				if (projectInfoDict.ContainsKey(information.IdGuid)) {
 					// resolve GUID conflicts
+					SD.Log.WarnFormatted("Detected duplicate GUID in .sln file: {0} is used for {1} and {2}", information.IdGuid, information.ProjectName, projectInfoDict[information.IdGuid].ProjectName);
 					information.IdGuid = Guid.NewGuid();
 					fixedGuidConflicts = true;
 				}
@@ -131,9 +132,11 @@ namespace ICSharpCode.SharpDevelop.Project
 			// Now that the project configurations have been set, we can actually load the projects:
 			int projectsLoaded = 0;
 			foreach (var projectInfo in solutionEntries) {
+				// Make copy of IdGuid just in case the project binding writes to projectInfo.IdGuid
+				Guid idGuid = projectInfo.IdGuid;
 				ISolutionItem solutionItem;
 				if (projectInfo.TypeGuid == ProjectTypeGuids.SolutionFolder) {
-					solutionItem = solutionFolderDict[projectInfo.IdGuid];
+					solutionItem = solutionFolderDict[idGuid];
 				} else {
 					// Load project:
 					projectInfo.ActiveProjectConfiguration = projectInfo.ConfigurationMapping.GetProjectConfiguration(solution.ActiveConfiguration);
@@ -141,12 +144,29 @@ namespace ICSharpCode.SharpDevelop.Project
 					using (projectInfo.ProgressMonitor = progress.CreateSubTask(1.0 / projectCount)) {
 						solutionItem = LoadProjectWithErrorHandling(projectInfo);
 					}
+					if (solutionItem.IdGuid != idGuid) {
+						Guid projectFileGuid = solutionItem.IdGuid;
+						if (!projectInfoDict.ContainsKey(projectFileGuid)) {
+							// We'll use the GUID from the project file.
+							// Register that GUID in the dictionary to avoid its use by multiple projects.
+							projectInfoDict.Add(projectFileGuid, projectInfo);
+						} else {
+							// Cannot use GUID from project file due to conflict.
+							// To fix the problem without potentially introducing new conflicts in other .sln files that contain the project,
+							// we generate a brand new GUID:
+							solutionItem.IdGuid = Guid.NewGuid();
+						}
+						SD.Log.WarnFormatted("<ProjectGuid> in project '{0}' is '{1}' and does not match the GUID stored in the solution ({2}). "
+						                     + "The conflict was resolved using the GUID {3}",
+						                     projectInfo.ProjectName, projectFileGuid, idGuid, solutionItem.IdGuid);
+						fixedGuidConflicts = true;
+					}
 					projectsLoaded++;
 					progress.Progress = (double)projectsLoaded / projectCount;
 				}
 				// Add solutionItem to solution:
 				SolutionFolder folder;
-				if (guidToParentFolderDict != null && guidToParentFolderDict.TryGetValue(projectInfo.IdGuid, out folder)) {
+				if (guidToParentFolderDict != null && guidToParentFolderDict.TryGetValue(idGuid, out folder)) {
 					folder.Items.Add(solutionItem);
 				} else {
 					solution.Items.Add(solutionItem);