Fix tab close, Debug startup crash, Iseberg empty-line completion and first-tab startup

docs/iseberg.md

@@ -92,11 +92,14 @@ PowerShell 7.4.0 through 7.4.5 cannot load the patched SDK's
 `System.Management.Automation` 7.4.6.500 assembly reference and are rejected up front.
 The child architecture does not need to match DT. Make `pwsh` available on PATH, or set
 `DT_ISEBERG_PSHOME` to its absolute installation directory before starting DT.
-DT checks its version and child-runtime compatibility. A short noninteractive
-`pwsh -NoProfile` probe discovers and validates the installation. DT then starts
-an owned `pwsh -NoLogo -NoProfile` child and imports the absolute path to its
-`Devolutions.Iseberg.PowerShell.dll` binary module. The module creates a custom-host execution
-runspace; it does not replace PowerShell's bootstrap console host.
+DT checks its version and child-runtime compatibility without a separate probe
+process: DT starts an owned `pwsh -NoLogo -NoProfile` child whose bootstrap first
+prints one line describing `$PSHOME`, its version, .NET runtime and architecture,
+then imports the absolute path to its `Devolutions.Iseberg.PowerShell.dll` binary
+module. DT validates that description while the module loads, so an installation
+too old to load the module still fails with the version it found. The module
+creates a custom-host execution runspace; it does not replace PowerShell's
+bootstrap console host.
 
 Parser analysis, completion, execution, host input, debugging and portable
 `$psISE` proxies run in that child. The NativeAOT parent uses typed, source-generated

scripts/Install-IsebergTestPowerShell.ps1

@@ -55,7 +55,9 @@ if (-not (Test-Path -LiteralPath $executable -PathType Leaf)) {
     New-Item -ItemType Directory -Path $engineDirectory -Force | Out-Null
     $asset = if ($IsWindows) { "PowerShell-$version-$rid.zip" } else { "powershell-$version-$rid.tar.gz" }
     $archive = Join-Path $root $asset
-    Invoke-WebRequest "https://github.com/PowerShell/PowerShell/releases/download/v$version/$asset" -OutFile $archive
+    # GitHub release downloads intermittently return 5xx pages; retry before failing the job.
+    Invoke-WebRequest "https://github.com/PowerShell/PowerShell/releases/download/v$version/$asset" -OutFile $archive `
+        -MaximumRetryCount 4 -RetryIntervalSec 15
     if ((Get-FileHash -LiteralPath $archive -Algorithm SHA256).Hash -ne $hashes[$rid]) {
         throw "PowerShell test runtime checksum mismatch: $archive"
     }

src/Devolutions.Terminal.App/Devolutions.Terminal.App.csproj

@@ -8,9 +8,6 @@
   <PropertyGroup Condition="'$(EnablePowerShellIse)' == 'true'">
     <DefineConstants>$(DefineConstants);POWERSHELL_ISE</DefineConstants>
   </PropertyGroup>
-  <ItemGroup Condition="'$(EnablePowerShellIse)' != 'true'">
-    <Compile Remove="Connections\PowerShellInstallation.cs" />
-  </ItemGroup>
 
   <ItemGroup>
     <PackageReference Include="Avalonia" />

src/Devolutions.Terminal.App/Views/MainWindow.PowerShellIse.cs

@@ -23,7 +23,7 @@ private async Task<TerminalTab> CreatePowerShellIseTabAsync(
 #if POWERSHELL_ISE
         if (_isClosed || _closeConfirmationPending || _applicationClosePending)
             throw new InvalidOperationException("Cannot open Iseberg while DT is closing.");
-        await PowerShellIseRuntime.InitializeAsync().ConfigureAwait(true);
+        // The session's own pwsh reports and validates its installation during startup.
         return await CreatePowerShellIseTabCoreAsync(profile, restored, regenerateIdentities).ConfigureAwait(true);
 #else
         await Task.CompletedTask;

src/Devolutions.Terminal.App/Views/MainWindow.axaml.cs

@@ -1801,6 +1801,16 @@ private void BeginTabDrag(TerminalTab tab, Control control, PointerPressedEventA
             return;
         }
 
+        // A press on a nested button (the close X) belongs to that button. This
+        // handler also sees handled events, so capturing here would steal the
+        // nested button's pointer capture and it would never raise Click.
+        if (e.Source is Visual source &&
+            Avalonia.VisualTree.VisualExtensions.FindAncestorOfType<Button>(source, includeSelf: true) is { } pressed &&
+            !ReferenceEquals(pressed, control))
+        {
+            return;
+        }
+
         _draggedTab = tab;
         _dragStart = e.GetPosition(TabStrip);
         e.Pointer.Capture(control);

src/Devolutions.Terminal.Ise/Iseberg.Core/PowerShellInstallation.cs

@@ -0,0 +1,61 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Iseberg.Core;
+
+/// <summary>What the bridge's pwsh reports about itself before it loads the bridge module.</summary>
+public sealed record PowerShellInstallation(string Home, string Version, string RuntimeVersion, string Architecture)
+{
+    public const string HomeVariable = "DT_ISEBERG_PSHOME";
+    /// <summary>Prefix of the single stdout line written by <see cref="ReportScript"/>.</summary>
+    public const string ReportPrefix = "DT-ISEBERG-INSTALLATION:";
+    public static Version MinimumVersion => PowerShellCompatibility.MinimumVersion;
+
+    /// <summary>
+    /// Runs first in the bridge bootstrap, before the net8.0 module is imported, so a pwsh that cannot
+    /// load the module still describes itself and fails with an actionable message.
+    /// </summary>
+    public static string ReportScript { get; } =
+        "[Console]::Out.WriteLine('" + ReportPrefix + "' + ([pscustomobject]@{ " +
+        "Home = $PSHOME; " +
+        "Version = $PSVersionTable.PSVersion.ToString(); " +
+        "RuntimeVersion = [Environment]::Version.ToString(); " +
+        "Architecture = [System.Runtime.InteropServices.RuntimeInformation]::ProcessArchitecture.ToString() " +
+        "} | ConvertTo-Json -Compress))";
+
+    public static string MissingMessage =>
+        $"Install PowerShell {PowerShellCompatibility.SupportedVersions} on PATH, or set {HomeVariable} to its installation directory.";
+
+    public static PowerShellInstallation Parse(string json)
+    {
+        try
+        {
+            return JsonSerializer.Deserialize(json, PowerShellInstallationJsonContext.Default.PowerShellInstallation)
+                ?? throw new InvalidOperationException("PowerShell returned an empty installation description.");
+        }
+        catch (JsonException exception)
+        {
+            throw new InvalidOperationException("PowerShell returned an invalid installation description.", exception);
+        }
+    }
+
+    public void Validate()
+    {
+        if (!System.Version.TryParse(Version, out var version) ||
+            !PowerShellCompatibility.IsSupportedVersion(version))
+            throw new InvalidOperationException($"Iseberg requires PowerShell {PowerShellCompatibility.SupportedVersions}; found {Version}.");
+        if (!System.Version.TryParse(RuntimeVersion, out var runtime) ||
+            !PowerShellCompatibility.IsSupportedRuntime(version, runtime))
+            throw new InvalidOperationException($"PowerShell {version.Major}.{version.Minor} requires its bundled .NET {PowerShellCompatibility.RuntimeMajor(version)} runtime; found {RuntimeVersion}.");
+        if (!Enum.TryParse<System.Runtime.InteropServices.Architecture>(Architecture, out var architecture) ||
+            !Enum.IsDefined(architecture))
+            throw new InvalidOperationException($"PowerShell returned an unknown process architecture: {Architecture}.");
+        if (string.IsNullOrWhiteSpace(Home) || !Path.IsPathFullyQualified(Home) ||
+            !File.Exists(Path.Combine(Home, "System.Management.Automation.dll")) ||
+            !File.Exists(Path.Combine(Home, "pwsh.dll")))
+            throw new InvalidOperationException($"PowerShell installation is incomplete: {Home}.");
+    }
+}
+
+[JsonSerializable(typeof(PowerShellInstallation))]
+internal sealed partial class PowerShellInstallationJsonContext : JsonSerializerContext;

src/Devolutions.Terminal.Ise/Iseberg.Core/PowerShellSession.cs

@@ -13,6 +13,7 @@ public sealed class PowerShellSession : IAsyncDisposable
     private readonly object sync = new();
     private readonly CancellationTokenSource lifetime = new();
     private readonly StringBuilder diagnostics = new();
+    private readonly TaskCompletionSource<string?> installationReport = new(TaskCreationOptions.RunContinuationsAsynchronously);
     private BridgeConnection? connection;
     private NamedPipeServerStream? pipe;
     private Process? child;
@@ -75,7 +76,9 @@ public async Task InitializeAsync()
         {
             if (!Path.IsPathFullyQualified(ModulePath) || !File.Exists(ModulePath))
                 throw new FileNotFoundException("The DT-owned Iseberg PowerShell bridge module is missing.", ModulePath);
-            var executable = ExecutablePath ?? PowerShellProcessDiscovery.FindExecutable();
+            string executable;
+            try { executable = ExecutablePath ?? PowerShellProcessDiscovery.FindExecutable(); }
+            catch (FileNotFoundException exception) { throw new InvalidOperationException(PowerShellInstallation.MissingMessage, exception); }
             var endpoint = "dt-iseberg-" + Guid.NewGuid().ToString("N");
             var authentication = Convert.ToHexString(RandomNumberGenerator.GetBytes(32));
             var challenge = Convert.ToHexString(RandomNumberGenerator.GetBytes(32));
@@ -87,19 +90,22 @@ public async Task InitializeAsync()
                 RedirectStandardInput = true, RedirectStandardOutput = true, RedirectStandardError = true
             };
             using var parent = Process.GetCurrentProcess();
-            var bootstrap = "Import-Module -Name '" + ModulePath.Replace("'", "''") +
+            var bootstrap = PowerShellInstallation.ReportScript + "; Import-Module -Name '" + ModulePath.Replace("'", "''") +
                 "' -ErrorAction Stop; Start-IsebergBridge -PipeName '" + endpoint +
                 "' -ParentProcessId " + Environment.ProcessId +
                 " -ParentStartTimeUtcTicks " + parent.StartTime.ToUniversalTime().Ticks;
             foreach (var argument in new[] { "-NoLogo", "-NoProfile", "-NonInteractive", "-Command", bootstrap })
                 start.ArgumentList.Add(argument);
             start.Environment[IseBridgeProtocol.AuthenticationEnvironment] = authentication;
-            child = Process.Start(start) ?? throw new InvalidOperationException("The PowerShell bridge did not start.");
+            try { child = Process.Start(start) ?? throw new InvalidOperationException("The PowerShell bridge did not start."); }
+            catch (System.ComponentModel.Win32Exception exception) { throw new InvalidOperationException(PowerShellInstallation.MissingMessage, exception); }
             // Native programs inherit this stdin: give them end-of-input rather than DT's (or a hidden) console.
             child.StandardInput.Close();
-            outputDrain = DrainAsync(child.StandardOutput);
+            outputDrain = DrainOutputAsync(child.StandardOutput);
             errorDrain = DrainAsync(child.StandardError);
             exitObservation = ObserveExitAsync(child);
+            // The bootstrap describes pwsh before importing the module, so this overlaps the module load.
+            (await ReadInstallationAsync().ConfigureAwait(false)).Validate();
             await pipe.WaitForConnectionAsync(lifetime.Token).WaitAsync(TimeSpan.FromSeconds(30), lifetime.Token).ConfigureAwait(false);
             connection = new(pipe) { Request = HandleRequestAsync, Event = HandleEvent };
             connection.Disconnected += OnDisconnected;
@@ -399,24 +405,57 @@ private async Task<JsonElement> HandleRequestAsync(string operation, JsonElement
         }
     }
 
+    private async Task<PowerShellInstallation> ReadInstallationAsync()
+    {
+        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(15));
+        string? report;
+        try { report = await installationReport.Task.WaitAsync(timeout.Token).ConfigureAwait(false); }
+        catch (OperationCanceledException) when (timeout.IsCancellationRequested)
+        {
+            throw new InvalidOperationException("PowerShell did not respond to the installation check within 15 seconds.");
+        }
+        // Without a report, pwsh failed before it could describe itself.
+        return report is null
+            ? throw new InvalidOperationException($"PowerShell installation check failed: {StartupDiagnostics()}")
+            : PowerShellInstallation.Parse(report);
+    }
+    private async Task DrainOutputAsync(StreamReader reader)
+    {
+        try
+        {
+            while (await reader.ReadLineAsync(lifetime.Token).ConfigureAwait(false) is { } line)
+            {
+                // The bootstrap's installation report is the only stdout line with meaning.
+                if (!installationReport.Task.IsCompleted &&
+                    line.StartsWith(PowerShellInstallation.ReportPrefix, StringComparison.Ordinal))
+                    installationReport.TrySetResult(line[PowerShellInstallation.ReportPrefix.Length..]);
+                else
+                    AppendDiagnostics(line + Environment.NewLine);
+            }
+        }
+        catch (Exception exception) when (exception is IOException or OperationCanceledException or ObjectDisposedException) { }
+        finally { installationReport.TrySetResult(null); }
+    }
     private async Task DrainAsync(StreamReader reader)
     {
         try
         {
             var buffer = new char[4096];
             int read;
             while ((read = await reader.ReadAsync(buffer, lifetime.Token).ConfigureAwait(false)) != 0)
-            {
-                // Raw stdout/stderr is diagnostics, never a second script-output transport.
-                lock (sync)
-                {
-                    if (diagnostics.Length + read > 16384) diagnostics.Remove(0, Math.Min(diagnostics.Length, read));
-                    diagnostics.Append(buffer, 0, read);
-                }
-            }
+                AppendDiagnostics(buffer.AsSpan(0, read));
         }
         catch (Exception exception) when (exception is IOException or OperationCanceledException or ObjectDisposedException) { }
     }
+    // Raw stdout/stderr is diagnostics, never a second script-output transport.
+    private void AppendDiagnostics(ReadOnlySpan<char> text)
+    {
+        lock (sync)
+        {
+            if (diagnostics.Length + text.Length > 16384) diagnostics.Remove(0, Math.Min(diagnostics.Length, text.Length));
+            diagnostics.Append(text);
+        }
+    }
     private async Task ObserveExitAsync(Process process)
     {
         await process.WaitForExitAsync().ConfigureAwait(false);