Handle empty-string and null-value results returned from custom argument completer more properly (#27398)

2026-06-08 12:12:50 +00:00 · 2026-05-11 11:59:37 -07:00
parent 7164700777
commit c9ac205fda
4 changed files with 188 additions and 12 deletions
@@ -149,4 +149,150 @@ Describe "Tab completion bug fix" -Tags "CI" {
            Pop-Location
        }
    }
+
+    Context 'Native CLI argument completion' {
+        BeforeAll {
+            $testDir = Join-Path $TestDrive "TempTestDir"
+            $file1 = Join-Path $testDir "abc.ps1"
+            $file2 = Join-Path $testDir "def.py"
+
+            New-Item -ItemType Directory -Path $testDir > $null
+            New-Item -ItemType File -Path $file1 > $null
+            New-Item -ItemType File -Path $file2 > $null
+
+            $dirSep = [System.IO.Path]::DirectorySeparatorChar
+            $relative_name_abc = ".${dirSep}abc.ps1"
+            $relative_name_def = ".${dirSep}def.py"
+        }
+
+        AfterAll {
+            ## Unregister the completer for 'ping' to avoid affecting other tests.
+            register-ArgumentCompleter -Native -CommandName ping -ScriptBlock $null
+        }
+
+        It 'Completer script block returning nothing should fall back to file name completion' {
+            register-ArgumentCompleter -Native -CommandName ping -ScriptBlock {
+                param($WordToComplete, $CommandAst, $CursorPosition)
+            }
+
+            try {
+                Push-Location -Path $testDir
+                $cmd = "ping "
+                $result = TabExpansion2 -inputScript $cmd -cursorColumn $cmd.Length
+                $result.CompletionMatches | Should -Not -BeNullOrEmpty
+                $result.CompletionMatches.Count | Should -Be 2
+                $result.CompletionMatches[0].CompletionText | Should -BeExactly $relative_name_abc
+                $result.CompletionMatches[1].CompletionText | Should -BeExactly $relative_name_def
+            } finally {
+                Pop-Location
+            }
+        }
+
+        It 'Completer script block returning $null should suppress default completion fallback' {
+            register-ArgumentCompleter -Native -CommandName ping -ScriptBlock {
+                param($WordToComplete, $CommandAst, $CursorPosition)
+                return $null
+            }
+
+            try {
+                Push-Location -Path $testDir
+                $cmd = "ping "
+                ## This call should not throw, and should suppress the default file name completion fallback, returning no results.
+                $result = TabExpansion2 -inputScript $cmd -cursorColumn $cmd.Length
+                $result.CompletionMatches.Count | Should -Be 0
+            } finally {
+                Pop-Location
+            }
+        }
+
+        It 'Completer script block returning empty string should suppress default completion fallback' {
+            register-ArgumentCompleter -Native -CommandName ping -ScriptBlock {
+                param($WordToComplete, $CommandAst, $CursorPosition)
+                return ''
+            }
+
+            try {
+                Push-Location -Path $testDir
+                $cmd = "ping "
+                ## This call should not throw, and should suppress the default file name completion fallback, returning no results.
+                $result = TabExpansion2 -inputScript $cmd -cursorColumn $cmd.Length
+                $result.CompletionMatches.Count | Should -Be 0
+            } finally {
+                Pop-Location
+            }
+        }
+
+        It 'Completer script block returning empty-string-only array should fall back to default completion' {
+            register-ArgumentCompleter -Native -CommandName ping -ScriptBlock {
+                param($WordToComplete, $CommandAst, $CursorPosition)
+                return '', ''
+            }
+
+            try {
+                Push-Location -Path $testDir
+                $cmd = "ping "
+                ## This call should not throw, and should fall back to the default completion.
+                $result = TabExpansion2 -inputScript $cmd -cursorColumn $cmd.Length
+                $result.CompletionMatches.Count | Should -Be 2
+                $result.CompletionMatches[0].CompletionText | Should -BeExactly $relative_name_abc
+                $result.CompletionMatches[1].CompletionText | Should -BeExactly $relative_name_def
+            } finally {
+                Pop-Location
+            }
+        }
+
+        It 'Completer script block returning null-value-only array should fall back to default completion' {
+            register-ArgumentCompleter -Native -CommandName ping -ScriptBlock {
+                param($WordToComplete, $CommandAst, $CursorPosition)
+                return $null, $null
+            }
+
+            try {
+                Push-Location -Path $testDir
+                $cmd = "ping "
+                ## This call should not throw, and should fall back to the default completion.
+                $result = TabExpansion2 -inputScript $cmd -cursorColumn $cmd.Length
+                $result.CompletionMatches.Count | Should -Be 2
+                $result.CompletionMatches[0].CompletionText | Should -BeExactly $relative_name_abc
+                $result.CompletionMatches[1].CompletionText | Should -BeExactly $relative_name_def
+            } finally {
+                Pop-Location
+            }
+        }
+
+        It 'Completer script block returning a single string works as expected' {
+            register-ArgumentCompleter -Native -CommandName ping -ScriptBlock {
+                param($WordToComplete, $CommandAst, $CursorPosition)
+                return 'hello'
+            }
+
+            try {
+                Push-Location -Path $testDir
+                $cmd = "ping "
+                $result = TabExpansion2 -inputScript $cmd -cursorColumn $cmd.Length
+                $result.CompletionMatches.Count | Should -Be 1
+                $result.CompletionMatches[0].CompletionText | Should -BeExactly "hello"
+            } finally {
+                Pop-Location
+            }
+        }
+
+        It 'Completer script block returning an array that contains non-empty-or-null strings works as expected' {
+            register-ArgumentCompleter -Native -CommandName ping -ScriptBlock {
+                param($WordToComplete, $CommandAst, $CursorPosition)
+                return '', 'hello', $null, 'world'
+            }
+
+            try {
+                Push-Location -Path $testDir
+                $cmd = "ping "
+                $result = TabExpansion2 -inputScript $cmd -cursorColumn $cmd.Length
+                $result.CompletionMatches.Count | Should -Be 2
+                $result.CompletionMatches[0].CompletionText | Should -BeExactly "hello"
+                $result.CompletionMatches[1].CompletionText | Should -BeExactly "world"
+            } finally {
+                Pop-Location
+            }
+        }
+    }
 }