Improved WindowTitle customization experience

src/GitPrompt.ps1

@@ -1,7 +1,7 @@
 # Inspired by Mark Embling
 # http://www.markembling.info/view/my-ideal-powershell-prompt-with-git-integration
 
-$global:GitPromptSettings = [GitPromptSettings]::new()
+$global:GitPromptSettings = [PoshGitPromptSettings]::new()
 
 # Override some of the normal colors if the background color is set to the default DarkMagenta.
 $s = $global:GitPromptSettings
@@ -13,15 +13,19 @@ if ($Host.UI.RawUI.BackgroundColor -eq [ConsoleColor]::DarkMagenta) {
     $s.WorkingColor.ForegroundColor             = 'Red'
 }
 
-$isAdminProcess = Test-Administrator
-$adminHeader = if ($isAdminProcess) { 'Administrator: ' } else { '' }
+$IsAdmin = Test-Administrator
 
-$WindowTitleSupported = $true
-# TODO: Hmm, this is a curious way to detemine window title supported
-# Could do $host.Name -eq "Package Manager Host" but that is kinda specific
-# Could attempt to change it and catch any exception and then set this to $false
-if (Get-Module NuGet) {
-    $WindowTitleSupported = $false
+# Probe $Host.UI.RawUI.WindowTitle to see if it can be set without errors
+$WindowTitleSupported = $false
+try {
+    $global:PreviousWindowTitle = $Host.UI.RawUI.WindowTitle
+    $newTitle = "$origTitle "
+    $Host.UI.RawUI.WindowTitle = $newTitle
+    $WindowTitleSupported = $Host.UI.RawUI.WindowTitle -eq $newTitle
+    $Host.UI.RawUI.WindowTitle = $global:PreviousWindowTitle
+}
+catch {
+    Write-Debug "Probing for WindowTitleSupported errored: $_"
 }
 
 <#
@@ -218,14 +222,28 @@ function Write-GitStatus {
 
     $sb | Write-Prompt $s.AfterText > $null
 
-    if ($WindowTitleSupported -and $s.EnableWindowTitle) {
-        if (!$global:PreviousWindowTitle) {
-            $global:PreviousWindowTitle = $Host.UI.RawUI.WindowTitle
+    if ($WindowTitleSupported) {
+        if (!$s.EnableWindowTitle) {
+            if ($global:PreviousWindowTitle) {
+                $Host.UI.RawUI.WindowTitle = $global:PreviousWindowTitle
+            }
+        }
+        else {
+            try {
+                if ($s.WindowTitle -is [scriptblock]) {
+                    $windowTitleText = & $s.WindowTitle $Status $IsAdmin
+                }
+                else {
+                    $windowTitleText = $ExecutionContext.SessionState.InvokeCommand.ExpandString("$($s.WindowTitle)")
+                }
+
+                # Put $windowTitleText in a string to ensure results returned by scriptblock are flattened to a string
+                $Host.UI.RawUI.WindowTitle = "$windowTitleText"
+            }
+            catch {
+                Write-Debug "Error occurred during evaluation of `$GitPromptSettings.WindowTitle: $_"
+            }
         }
-
-        $repoName = Split-Path -Leaf (Split-Path $status.GitDir)
-        $prefix = if ($s.EnableWindowTitle -is [string]) { $s.EnableWindowTitle } else { '' }
-        $Host.UI.RawUI.WindowTitle = "${script:adminHeader}${prefix}${repoName} [$($Status.Branch)]"
     }
 
     return $sb.ToString()

src/GitUtils.ps1

@@ -340,6 +340,7 @@ function Get-GitStatus {
 
         $result = New-Object PSObject -Property @{
             GitDir          = $GitDir
+            RepoName        = Split-Path (Split-Path $GitDir -Parent) -Leaf
             Branch          = $branch
             AheadBy         = $aheadBy
             BehindBy        = $behindBy

src/PoshGitTypes.ps1

@@ -197,7 +197,7 @@ class PoshGitTextSpan {
     }
 }
 
-class GitPromptSettings {
+class PoshGitPromptSettings {
     [bool]$AnsiConsole = $Host.UI.SupportsVirtualTerminal -or ($Env:ConEmuANSI -eq "ON")
 
     [PoshGitCellColor]$DefaultColor = [PoshGitCellColor]::new()
@@ -244,8 +244,9 @@ class GitPromptSettings {
     [Nullable[bool]]$EnableFileStatusFromCache        = $null
     [string[]]$RepositoriesInWhichToDisableFileStatus = @()
 
-    [string]$DescribeStyle       = ''
-    [psobject]$EnableWindowTitle = 'posh~git ~ '
+    [string]$DescribeStyle   = ''
+    [bool]$EnableWindowTitle = $true
+    [psobject]$WindowTitle   = {param($GitStatus, [bool]$IsAdmin) "$(if ($IsAdmin) {'Admin: '})posh~git ~ $($GitStatus.RepoName) [$($GitStatus.Branch)]"}
 
     [PoshGitTextSpan]$DefaultPromptPrefix       = ''
     [PoshGitTextSpan]$DefaultPromptSuffix       = '$(''>'' * ($nestedPromptLevel + 1)) '

test/DefaultPrompt.Tests.ps1

@@ -7,7 +7,7 @@ Describe 'Default Prompt Tests - NO ANSI' {
     }
     BeforeEach {
         # Ensure these settings start out set to the default values
-        $global:GitPromptSettings = & $module.NewBoundScriptBlock({[GitPromptSettings]::new()})
+        $global:GitPromptSettings = & $module.NewBoundScriptBlock({[PoshGitPromptSettings]::new()})
         $GitPromptSettings.AnsiConsole = $false
     }
 
@@ -99,7 +99,7 @@ Describe 'Default Prompt Tests - ANSI' {
     }
     BeforeEach {
         # Ensure these settings start out set to the default values
-        $global:GitPromptSettings = & $module.NewBoundScriptBlock({[GitPromptSettings]::new()})
+        $global:GitPromptSettings = & $module.NewBoundScriptBlock({[PoshGitPromptSettings]::new()})
         $GitPromptSettings.AnsiConsole = $true
     }
 
@@ -194,3 +194,61 @@ A  test/Foo.Tests.ps1
         }
     }
 }
+
+Describe 'Default Prompt Window Title Tests' {
+    BeforeEach {
+        # Ensure these settings start out set to the default values
+        $defaultTitle = if ($IsWindows) { "Windows PowerShell" } else { "PowerShell-$($PSVersionTable.PSVersion)" }
+        $Host.UI.RawUI.WindowTitle = $defaultTitle
+        $global:PreviousWindowTitle = $defaultTitle
+        $global:GitPromptSettings = & $module.NewBoundScriptBlock({[PoshGitPromptSettings]::new()})
+    }
+
+    Context 'Default WindowTitle / EnableWindowTitle work ' {
+        It 'Sets the expected Window title text' {
+            Mock -ModuleName posh-git -CommandName git {
+                $OFS = " "
+                if ($args -contains 'rev-parse') {
+                    $res = Invoke-Expression "&$gitbin $args"
+                    return $res
+                }
+                Convert-NativeLineEnding -SplitLines @'
+## master
+A  test/Foo.Tests.ps1
+ D test/Bar.Tests.ps1
+ M test/Baz.Tests.ps1
+
+'@
+            }
+
+            Set-Location $PSScriptRoot
+            & $GitPromptScriptBlock *>$null
+            Assert-MockCalled git -ModuleName posh-git -Scope It
+            $title = $Host.UI.RawUI.WindowTitle
+            $title | Should Match '(Admin: )?posh~git ~ posh-git \[master\]'
+        }
+        It 'Does not set Window title when EnableWindowText is $false' {
+            Mock -ModuleName posh-git -CommandName git {
+                $OFS = " "
+                if ($args -contains 'rev-parse') {
+                    $res = Invoke-Expression "&$gitbin $args"
+                    return $res
+                }
+                Convert-NativeLineEnding -SplitLines @'
+## master
+A  test/Foo.Tests.ps1
+ D test/Bar.Tests.ps1
+ M test/Baz.Tests.ps1
+
+'@
+            }
+
+            Set-Location $PSScriptRoot
+            $GitPromptSettings.EnableWindowTitle = 0
+            & $GitPromptScriptBlock *>$null
+            Assert-MockCalled git -ModuleName posh-git -Scope It
+            $title = $Host.UI.RawUI.WindowTitle
+            $title | Should Match '^(Windows )?PowerShell'
+        }
+    }
+}