Merge pull request #5848 from jennings/jennings/push-xolwzyoornps

fix(complete): Fix PowerShell dynamic completion

clap_complete/src/env/mod.rs

@@ -52,7 +52,9 @@
 //!
 //! Powershell
 //! ```powershell
-//! echo "COMPLETE=powershell your_program | Invoke-Expression" >> $PROFILE
+//! $env:COMPLETE = "powershell"
+//! echo "your_program | Out-String | Invoke-Expression" >> $PROFILE
+//! Remove-Item Env:\COMPLETE
 //! ```
 //!
 //! Zsh

clap_complete/src/env/shells.rs

@@ -274,13 +274,25 @@ impl EnvCompleter for Powershell {
         let completer =
             shlex::try_quote(completer).unwrap_or(std::borrow::Cow::Borrowed(completer));
 
+        // `completer` may or may not be surrounded by double quotes, enclosing
+        // the expression in a here-string ensures the whole thing is
+        // interpreted as the first argument to the call operator
         writeln!(
             buf,
             r#"
 Register-ArgumentCompleter -Native -CommandName {bin} -ScriptBlock {{
     param($wordToComplete, $commandAst, $cursorPosition)
 
-    $results = Invoke-Expression "{var}=powershell &{completer} -- $($commandAst.ToString())";
+    $prev = $env:{var};
+    $env:{var} = "powershell";
+    $results = Invoke-Expression @"
+& {completer} -- $commandAst
+"@;
+    if ($null -eq $prev) {{
+        Remove-Item Env:\{var};
+    }} else {{
+        $env:{var} = $prev;
+    }}
     $results | ForEach-Object {{
         $split = $_.Split("`t");
         $cmd = $split[0];