🐛 Fixes Error "Multiple ambiguous overloads found for ToString"

src/ConvertTo-NixMode.ps1

@@ -0,0 +1,89 @@
+#!/usr/bin/env pwsh
+$ErrorActionPreference = "Stop"
+Set-StrictMode -Version Latest
+
+
+if ([Type]::GetType("System.IO.UnixFileMode")) {
+    <#
+    .SYNOPSIS
+        Converts a value to a strongly-typed [System.IO.UnixFileMode] enum value.
+    .DESCRIPTION
+        Converts a value to a strongly-typed [System.IO.UnixFileMode] enum value.
+    .EXAMPLE
+        ConvertTo-NixMode -FromOctal 755
+    #>
+    function ConvertTo-NixMode() {
+        [System.Runtime.Versioning.SupportedOSPlatform("net7.0")]
+        [CmdletBinding()]
+        [OutputType([System.IO.UnixFileMode])]
+        param(
+            [Parameter(Mandatory = $true, Position = 0, ParameterSetName = 'FromOctal')]
+            [ValidateNotNullOrEmpty()]
+            [string] $FromOctal,
+
+            [Parameter(Mandatory = $true, Position = 0, ParameterSetName = 'FromDecimal')]
+            [ValidateNotNullOrEmpty()]
+            [int] $FromDecimal
+        )
+        Begin {
+            function Factor-EnumValue() {
+                [OutputType([System.IO.UnixFileMode])]
+                param(
+                    [Parameter(Mandatory = $true)]
+                    [int]
+                    $Value
+                )
+                $value = [int]$Value
+                $result = [System.IO.UnixFileMode]::None
+
+                foreach ($enumValue in [System.Enum]::GetValues([System.IO.UnixFileMode])) {
+                    if (($value -band $enumValue) -eq $enumValue) {
+                        $result = $result -bor $enumValue
+                        $value = $value -bxor $enumValue
+                    }
+                }
+
+                if ($value -ne 0) {
+                    throw [System.ArgumentException]::new("Unable to interpret value '$FromDecimal' as a value of [System.IO.UnixFileMode].")
+                } else {
+                    return $result
+                }
+            }
+
+            if ($FromOctal) {
+                $FromDecimal = [Convert]::ToInt32($FromOctal, 8)
+            }
+        }
+        Process {
+            return (Factor-EnumValue $FromDecimal)
+        }
+    }
+} else {
+    <#
+    .SYNOPSIS
+        Converts a value to a strongly-typed [System.IO.UnixFileMode] enum value.
+    .DESCRIPTION
+        Converts a value to a strongly-typed [System.IO.UnixFileMode] enum value.
+    .EXAMPLE
+        ConvertTo-NixMode -FromOctal 755
+    #>
+    function ConvertTo-NixMode() {
+        [System.Runtime.Versioning.SupportedOSPlatform("net7.0")]
+        [CmdletBinding()]
+        # [OutputType([System.IO.UnixFileMode])]
+        param(
+            [Parameter(Mandatory = $true, Position = 0, ParameterSetName = 'FromOctal')]
+            [ValidateNotNullOrEmpty()]
+            [string] $FromOctal,
+
+            [Parameter(Mandatory = $true, Position = 0, ParameterSetName = 'FromDecimal')]
+            [ValidateNotNullOrEmpty()]
+            [int] $FromDecimal
+        )
+        Begin {
+            throw [System.PlatformNotSupportedException]::new()
+        }
+        Process {
+        }
+    }
+}

src/Set-ItemNixMode.ps1

@@ -5,16 +5,38 @@ Set-StrictMode -Version Latest
 
 if ($IsLinux) {
     function Set-ItemNixMode() {
+        [System.Runtime.Versioning.UnsupportedOSPlatform("windows")]
         param(
             [Parameter(Mandatory = $true)]
             [string[]]
             $Path,
+
             [Parameter(Mandatory = $true)]
-            [System.IO.UnixFileMode]
-            $Mode
+            # [ValidateScript({ ConvertTo-NixMode -FromOctal $_ })]
+            [string] $ModeOctal
         )
-        [string] $modeInOctal = [Convert]::ToString($Mode, 8)
-        Get-Item $Path | ForEach-Object { chmod $modeInOctal $_.FullName } | Out-Null
+        DynamicParam {
+            # Add the ValidateScript attribute to the ModeOctal parameter, but
+            # only if the UnixFileMode type is available.
+            if ([Type]::GetType("System.IO.UnixFileMode")) {
+                $Attribute = [System.Management.Automation.ValidateScriptAttribute]::new(
+                    [ScriptBlock]::Create("ConvertTo-NixMode -FromOctal $_")
+                )
+                $RuntimeParameterDictionary = [System.Management.Automation.RuntimeDefinedParameterDictionary]::new()
+                $RuntimeParameterDictionary.Add(
+                    "ModeOctal",
+                    [System.Management.Automation.RuntimeDefinedParameter]::new(
+                        "ModeOctal",
+                        [string],
+                        [System.Collections.ObjectModel.Collection[System.Attribute]]::new($Attribute)
+                    )
+                )
+                return $RuntimeParameterDictionary
+            }
+        }
+        Process {
+            Get-Item $Path | ForEach-Object { chmod $ModeOctal $_.FullName } | Out-Null
+        }
     }
 } else {
     function Set-ItemNixMode() {

test/ConvertTo-NixMode.Tests.ps1

@@ -0,0 +1,85 @@
+#!/usr/bin/env pwsh
+#Requires -Modules "Pester"
+$ErrorActionPreference = "Stop"
+Set-StrictMode -Version Latest
+
+
+BeforeAll {
+    $SutFile = Get-Item "$PSScriptRoot/../src/ConvertTo-NixMode.ps1"
+    $SutName = $SutFile.BaseName
+}
+
+Describe "SUT file" {
+    It "should exist" {
+        $SutFile | Should -Exist
+    }
+
+    It "should be sourceable" {
+        { . $SutFile.FullName } | Should -Not -Throw
+    }
+
+    Context "when sourced" {
+        BeforeEach {
+            . $SutFile
+        }
+
+        Describe "function" {
+            BeforeDiscovery {
+                $FileModeSettingNotSupported = $IsWindows -or ($null -eq [Type]::GetType("System.IO.UnixFileMode"))
+            }
+
+            It "should be defined" {
+                Get-Command -Name $SutName -CommandType Function | Should -Not -BeNullOrEmpty
+            }
+
+            Context "when invoked" -Skip:$FileModeSettingNotSupported {
+                Context "with no arguments" {
+                    It "should throw" {
+                        { & $SutName } | Should -Throw
+                    }
+                }
+
+                Context "via parameter" {
+                    # single integer matching a UnixFileMode value
+                    Context "single input is integer-equivalent [System.IO.UnixFileMode] value" {
+                        It "should return the value as-is" {
+                            $parameterValue = [int][Convert]::ToString([int][System.IO.UnixFileMode]::GroupExecute, 8)
+                            $expectedResult = [System.IO.UnixFileMode]::GroupExecute
+
+                            $actualResult = ConvertTo-NixMode -FromOctal $parameterValue
+
+                            $actualResult | Should -BeOfType [System.IO.UnixFileMode]
+                            $actualResult | Should -Be $expectedResult
+                        }
+                    }
+
+                    # single integer that should have been parsed as base8
+                    Context "single input is integer wrongly parsed as base10 instead of base8" {
+                        It "should return the value converted" {
+                            $parameterValue = [int]700
+                            $expectedResult = [System.IO.UnixFileMode]([Convert]::ToInt32('700', 8))
+
+                            $actualResult = ConvertTo-NixMode -FromOctal $parameterValue
+
+                            $actualResult | Should -BeOfType [System.IO.UnixFileMode]
+                            $actualResult | Should -Be $expectedResult
+                        }
+                    }
+
+                    # single integer string matching a UnixFileMode value as-is
+                    Context "single input is an integer string matching a [System.IO.UnixFileMode] value as-is" {
+                        It "should return the value as-is" {
+                            $parameterValue = [Convert]::ToString([int][System.IO.UnixFileMode]::GroupExecute, 8)
+                            $expectedResult = [System.IO.UnixFileMode]::GroupExecute
+
+                            $actualResult = ConvertTo-NixMode -FromOctal $parameterValue
+
+                            $actualResult | Should -BeOfType [System.IO.UnixFileMode]
+                            $actualResult | Should -Be $expectedResult
+                        }
+                    }
+                }
+            }
+        }
+    }
+}

test/Set-ItemNixMode.Tests.ps1

@@ -0,0 +1,90 @@
+#!/usr/bin/env pwsh
+#Requires -Modules "Pester"
+$ErrorActionPreference = "Stop"
+Set-StrictMode -Version Latest
+
+
+BeforeAll {
+    $SutFile = Get-Item "$PSScriptRoot/../src/Set-ItemNixMode.ps1"
+    $SutName = $SutFile.BaseName
+}
+
+Describe "SUT file" {
+    It "should exist" {
+        $SutFile | Should -Exist
+    }
+
+    It "should be sourceable" {
+        { . $SutFile.FullName } | Should -Not -Throw
+    }
+
+    Context "when sourced" {
+        BeforeEach {
+            . $SutFile
+        }
+
+        Describe "function" {
+            BeforeDiscovery {
+                $FileModeSettingNotSupported = $IsWindows -or ($null -eq [Type]::GetType("System.IO.UnixFileMode"))
+            }
+
+            It "should be defined" {
+                Get-Command -Name $SutName -CommandType Function | Should -Not -BeNullOrEmpty
+            }
+
+            Context "when invoked" -Skip:$FileModeSettingNotSupported {
+                Context "with no arguments" {
+                    It "should throw" {
+                        { & $SutName } | Should -Throw
+                    }
+                }
+
+                Context "for an existing file" {
+                    BeforeEach {
+                        $targetFile = New-TemporaryFile
+                    }
+
+                    AfterEach {
+                        Remove-Item $targetFile.FullName -Force
+                    }
+
+                    Context "ModeOctal is 700" {
+                        It "should set the mode" {
+                            $modeOctalParameter = '700'
+                            [System.IO.UnixFileMode] $expectedMode = [System.IO.UnixFileMode]::OwnerRead -bor [System.IO.UnixFileMode]::OwnerWrite -bor [System.IO.UnixFileMode]::OwnerExecute
+
+                            Set-ItemNixMode -Path $targetFile -ModeOctal $modeOctalParameter
+
+                            $targetFile.Refresh()
+                            $targetFile.Mode | Should -Be $expectedMode
+                        }
+                    }
+
+                    Context "ModeOctal is 555" {
+                        It "should set the mode" {
+                            $modeOctalParameter = '555'
+                            [System.IO.UnixFileMode] $expectedMode = [System.IO.UnixFileMode]::OwnerRead -bor [System.IO.UnixFileMode]::OwnerExecute -bor [System.IO.UnixFileMode]::GroupRead -bor [System.IO.UnixFileMode]::GroupExecute -bor [System.IO.UnixFileMode]::OthersRead -bor [System.IO.UnixFileMode]::OthersExecute
+
+                            Set-ItemNixMode -Path $targetFile -ModeOctal $modeOctalParameter
+
+                            $targetFile.Refresh()
+                            $targetFile.Mode | Should -Be $expectedMode
+                        }
+                    }
+
+                    Context "ModeOctal is 644" {
+                        It "should set the mode" {
+                            $modeOctalParameter = '644'
+                            [System.IO.UnixFileMode] $expectedMode = [System.IO.UnixFileMode]::OwnerRead -bor [System.IO.UnixFileMode]::OwnerWrite -bor [System.IO.UnixFileMode]::GroupRead -bor [System.IO.UnixFileMode]::OthersRead
+
+                            Set-ItemNixMode -Path $targetFile -ModeOctal $modeOctalParameter
+
+                            $targetFile.Refresh()
+                            $targetFile.Mode | Should -Be $expectedMode
+                        }
+                    }
+                }
+            }
+        }
+    }
+}