Use Register-ArgumentCompleter to >= PS 6

Author: rkeithhill

src/GitTabExpansion.ps1

@@ -470,36 +470,45 @@ function GitTabExpansionInternal($lastBlock, $GitStatus = $null) {
     }
 }
 
-$PowerTab_RegisterTabExpansion = if (Get-Module -Name powertab) { Get-Command Register-TabExpansion -Module powertab -ErrorAction SilentlyContinue }
-if ($PowerTab_RegisterTabExpansion) {
-    & $PowerTab_RegisterTabExpansion "git.exe" -Type Command {
-        param($Context, [ref]$TabExpansionHasOutput, [ref]$QuoteSpaces)  # 1:
+if ($PSVersionTable.PSVersion.Major -ge 6) {
+    Register-ArgumentCompleter -CommandName git,tgit,gitk -Native -ScriptBlock {
+        param($wordToComplete, $commandAst, $cursorPosition)
 
-        $line = $Context.Line
-        $lastBlock = [regex]::Split($line, '[|;]')[-1].TrimStart()
-        $TabExpansionHasOutput.Value = $true
-        Expand-GitCommand $lastBlock
+        Expand-GitCommand $commandAst.Extent.Text
     }
-    return
 }
+else {
+    $PowerTab_RegisterTabExpansion = if (Get-Module -Name powertab) { Get-Command Register-TabExpansion -Module powertab -ErrorAction SilentlyContinue }
+    if ($PowerTab_RegisterTabExpansion) {
+        & $PowerTab_RegisterTabExpansion "git.exe" -Type Command {
+            param($Context, [ref]$TabExpansionHasOutput, [ref]$QuoteSpaces)  # 1:
 
-if (Test-Path Function:\TabExpansion) {
-    Rename-Item Function:\TabExpansion TabExpansionBackup
-}
+            $line = $Context.Line
+            $lastBlock = [regex]::Split($line, '[|;]')[-1].TrimStart()
+            $TabExpansionHasOutput.Value = $true
+            Expand-GitCommand $lastBlock
+        }
+        return
+    }
 
-function TabExpansion($line, $lastWord) {
-    $lastBlock = [regex]::Split($line, '[|;]')[-1].TrimStart()
+    if (Test-Path Function:\TabExpansion) {
+        Rename-Item Function:\TabExpansion TabExpansionBackup
+    }
 
-    switch -regex ($lastBlock) {
-        # Execute git tab completion for all git-related commands
-        "^$(Get-AliasPattern git) (.*)" { Expand-GitCommand $lastBlock }
-        "^$(Get-AliasPattern tgit) (.*)" { Expand-GitCommand $lastBlock }
-        "^$(Get-AliasPattern gitk) (.*)" { Expand-GitCommand $lastBlock }
+    function TabExpansion($line, $lastWord) {
+        $lastBlock = [regex]::Split($line, '[|;]')[-1].TrimStart()
 
-        # Fall back on existing tab expansion
-        default {
-            if (Test-Path Function:\TabExpansionBackup) {
-                TabExpansionBackup $line $lastWord
+        switch -regex ($lastBlock) {
+            # Execute git tab completion for all git-related commands
+            "^$(Get-AliasPattern git) (.*)" { Expand-GitCommand $lastBlock }
+            "^$(Get-AliasPattern tgit) (.*)" { Expand-GitCommand $lastBlock }
+            "^$(Get-AliasPattern gitk) (.*)" { Expand-GitCommand $lastBlock }
+
+            # Fall back on existing tab expansion
+            default {
+                if (Test-Path Function:\TabExpansionBackup) {
+                    TabExpansionBackup $line $lastWord
+                }
             }
         }
     }

test/TabExpansion.Tests.ps1

@@ -1,9 +1,17 @@
 . $PSScriptRoot\Shared.ps1
 
-Describe 'TabExpansion Tests' {
-    It 'Exports a TabExpansion function' {
+Describe 'TabExpansion function test' {
+    BeforeAll {
+        if ($PSVersionTable.PSVersion.Major -eq 5) {
+            $PSDefaultParameterValues["it:skip"] = $true
+        }
+    }
+    It 'Windows PowerShell v5 exports a TabExpansion function' {
         $module.ExportedFunctions.Keys -contains 'TabExpansion' | Should Be $true
     }
+}
+
+Describe 'TabExpansion Tests' {
     Context 'Subcommand TabExpansion Tests' {
         It 'Tab completes without subcommands' {
             $result = & $module GitTabExpansionInternal 'git whatever '