fix(storage): initialize workspaces under the lock in one transaction

Follows PLAN 4.2: create .ykanban, take the lock, then build the database.
SqliteDatabase.Create writes every migration and the preset columns in a
single transaction and deletes the file again on failure, so no empty
version-0 database is left behind. WorkspaceSession.Initialize keeps the lock
into the session instead of releasing and re-acquiring it.

A lock conflict while initializing shows the lock-conflict page.

YKanBan.Tests/Storage/Workspace/WorkspacePresetTests.cs

@@ -29,8 +29,7 @@ public class WorkspacePresetTests
             ];
 
             using var directory = new TempDirectory();
-            WorkspaceInitializer.Initialize(directory.FullPath);
-            WorkspacePreset.AddPresetColumns(directory.FullPath);
+            WorkspaceSession.Initialize(directory.FullPath).Dispose();
 
             using SqliteConnection connection = SqliteTestHelper.OpenWorkspace(directory.FullPath);
             CollectionAssert.AreEqual(expected, SqliteTestHelper.GetColumnTitles(connection));
@@ -56,8 +55,7 @@ public class WorkspacePresetTests
             ];
 
             using var directory = new TempDirectory();
-            WorkspaceInitializer.Initialize(directory.FullPath);
-            WorkspacePreset.AddPresetColumns(directory.FullPath);
+            WorkspaceSession.Initialize(directory.FullPath).Dispose();
 
             using SqliteConnection connection = SqliteTestHelper.OpenWorkspace(directory.FullPath);
             CollectionAssert.AreEqual(expected, SqliteTestHelper.GetColumnTitles(connection));
@@ -83,8 +81,7 @@ public class WorkspacePresetTests
             ];
 
             using var directory = new TempDirectory();
-            WorkspaceInitializer.Initialize(directory.FullPath);
-            WorkspacePreset.AddPresetColumns(directory.FullPath);
+            WorkspaceSession.Initialize(directory.FullPath).Dispose();
 
             // Switching the language after adding the presets must not rewrite stored data.
             Resources.Culture = new CultureInfo("zh-Hans");

YKanBan.Tests/Storage/Workspace/WorkspaceSessionTests.cs

@@ -57,4 +57,36 @@ public class WorkspaceSessionTests
         Assert.AreEqual("bug", session.Repository.GetTags().Single().Name);
         Assert.AreEqual(tag.Id, session.Repository.GetTags().Single().Id);
     }
+
+    [TestMethod]
+    public void InitializeAddsPresetColumnsAndHoldsTheLock()
+    {
+        using var directory = new TempDirectory();
+
+        using WorkspaceSession session = WorkspaceSession.Initialize(directory.FullPath);
+        Assert.AreEqual(3, session.Repository.GetColumns().Count);
+        Assert.ThrowsExactly<WorkspaceLockException>(() => WorkspaceSession.Open(directory.FullPath));
+    }
+
+    [TestMethod]
+    public void InitializeWhileAnotherInstanceHoldsTheLockThrowsLockConflict()
+    {
+        using var directory = new TempDirectory();
+        Directory.CreateDirectory(WorkspacePaths.Root(directory.FullPath));
+        using WorkspaceLock held = WorkspaceLock.Acquire(directory.FullPath);
+
+        Assert.ThrowsExactly<WorkspaceLockException>(() => WorkspaceSession.Initialize(directory.FullPath));
+        Assert.IsFalse(File.Exists(WorkspacePaths.Database(directory.FullPath)));
+    }
+
+    [TestMethod]
+    public void FailedInitializeReleasesTheLock()
+    {
+        using var directory = new TempDirectory();
+        WorkspaceInitializer.Initialize(directory.FullPath);
+
+        // The database already exists, so initialization fails after taking the lock.
+        Assert.ThrowsExactly<InvalidOperationException>(() => WorkspaceSession.Initialize(directory.FullPath));
+        using WorkspaceSession reopened = WorkspaceSession.Open(directory.FullPath);
+    }
 }