Try to avoid Project GUID conflicts.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/branches/2.1@2260 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

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

@@ -120,7 +120,7 @@ namespace ICSharpCode.SharpDevelop.Project
 			Name = information.ProjectName;
 			FileName = information.OutputProjectFileName;
 			
-			IdGuid = "{" + Guid.NewGuid().ToString().ToUpperInvariant() + "}";
+			base.IdGuid = "{" + Guid.NewGuid().ToString().ToUpperInvariant() + "}";
 			MSBuild.BuildPropertyGroup group = project.AddNewPropertyGroup(false);
 			group.AddNewProperty(ProjectGuidPropertyName, IdGuid, true);
 			group.AddNewProperty("Configuration", "Debug", true).Condition = " '$(Configuration)' == '' ";
@@ -130,6 +130,15 @@ namespace ICSharpCode.SharpDevelop.Project
 			this.ActivePlatform = "AnyCPU";
 		}
 		
+		/// <summary>
+		/// The MSBuild property used to store the project's IdGuid.
+		/// The IdGuid is only stored in the project file to make multiple solutions use the same
+		/// GUID for the project when the project is added to multiple solutions. However, the actual
+		/// GUID used for the project in the solution can differ from the GUID in the project file -
+		/// SharpDevelop does not try to correct mismatches but simply always use the value from the solution.
+		/// SharpDevelop creates a new GUID for the solution when the project GUID cannot be used because it
+		/// would conflict with another project. This happens when one project is created by copying another project.
+		/// </summary>
 		public const string ProjectGuidPropertyName = "ProjectGuid";
 		
 		/// <summary>
@@ -849,18 +858,25 @@ namespace ICSharpCode.SharpDevelop.Project
 				CreateItemsListFromMSBuild();
 				LoadConfigurationPlatformNamesFromMSBuild();
 				
-				IdGuid = GetEvaluatedProperty(ProjectGuidPropertyName);
-				if (IdGuid == null) {
-					// Fix projects that have nb GUID
-					IdGuid = Guid.NewGuid().ToString();
-					SetPropertyInternal(null, null, ProjectGuidPropertyName, IdGuid, PropertyStorageLocations.Base, true);
+				base.IdGuid = GetEvaluatedProperty(ProjectGuidPropertyName);
+			} finally {
+				isLoading = false;
+			}
+		}
+		
+		[Browsable(false)]
+		public override string IdGuid {
+			get { return base.IdGuid; }
+			set {
+				if (base.IdGuid == null) {
+					// Save the GUID in the project if the project does not yet have a GUID.
+					SetPropertyInternal(null, null, ProjectGuidPropertyName, value, PropertyStorageLocations.Base, true);
 					try {
 						// save fixed project
-						project.Save(fileName);
+						project.Save(this.FileName);
 					} catch {}
 				}
-			} finally {
-				isLoading = false;
+				base.IdGuid = value;
 			}
 		}
 		#endregion

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

@@ -15,7 +15,6 @@ namespace ICSharpCode.SharpDevelop.Project
 		{
 			Name     = title;
 			FileName = fileName;
-			IdGuid = "{" + Guid.NewGuid().ToString() + "}";
 			TypeGuid = "{00000000-0000-0000-0000-000000000000}";
 		}
 	}

src/Main/Base/Project/Src/Project/Solution/AbstractSolutionFolder.cs

@@ -51,7 +51,7 @@ namespace ICSharpCode.SharpDevelop.Project
 		}
 		
 		[Browsable(false)]
-		public string IdGuid {
+		public virtual string IdGuid {
 			get {
 				return idGuid;
 			}

src/Main/Base/Project/Src/Project/Solution/SolutionFolder.cs

@@ -79,6 +79,10 @@ namespace ICSharpCode.SharpDevelop.Project
 		
 		public virtual void AddFolder(ISolutionFolder folder)
 		{
+			if (string.IsNullOrEmpty(folder.IdGuid)) {
+				folder.IdGuid = Guid.NewGuid().ToString().ToUpperInvariant();
+			}
+			
 			if (folder.Parent != null) {
 				folder.Parent.RemoveFolder(folder);
 			}

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

@@ -44,7 +44,6 @@ namespace ICSharpCode.SharpDevelop.Project
 		{
 			Name     = title;
 			FileName = fileName;
-			IdGuid = "{" + Guid.NewGuid().ToString() + "}";
 			TypeGuid = "{00000000-0000-0000-0000-000000000000}";
 		}
 	}

src/Main/Base/Project/Src/Services/ProjectService/ProjectService.cs

@@ -196,6 +196,14 @@ namespace ICSharpCode.SharpDevelop.Project
 		
 		public static void AddProject(ISolutionFolderNode solutionFolderNode, IProject newProject)
 		{
+			if (Linq.Exists(solutionFolderNode.Solution.SolutionFolders,
+			                delegate (ISolutionFolder folder) {
+			                	return string.Equals(folder.IdGuid, newProject.IdGuid, StringComparison.OrdinalIgnoreCase);
+			                }))
+			{
+				LoggingService.Warn("ProjectService.AddProject: Duplicate IdGuid detected");
+				newProject.IdGuid = Guid.NewGuid().ToString().ToUpperInvariant();
+			}
 			solutionFolderNode.Container.AddFolder(newProject);
 			ParserService.CreateProjectContentForAddedProject(newProject);
 			solutionFolderNode.Solution.FixSolutionConfiguration(new IProject[] { newProject });

src/Main/Base/Project/Src/Util/Linq.cs

@@ -75,6 +75,18 @@ namespace ICSharpCode.SharpDevelop
 			return default(T);
 		}
 		
+		/// <summary>
+		/// Gets if any element in the input matches the filter.
+		/// </summary>
+		public static bool Exists<T>(IEnumerable<T> input, Predicate<T> filter)
+		{
+			foreach (T element in input) {
+				if (filter(element))
+					return true;
+			}
+			return false;
+		}
+		
 		public static List<T> ToList<T>(IEnumerable<T> input)
 		{
 			return new List<T>(input);