fix!: validate directories before install

[chawyehsu]

An alternative implementation of #76, relates to #60

This COULD be a BREAKING CHANGE, as the behavior has changed. Before this downstreams may run the installer to install Scoop into a directory that's non-empty, and with this PR it'll fail. But it's certain a bad idea to install Scoop into a non-empty directory because serious problems will arise, we should not support such installation.

Closes ScoopInstaller/Scoop#6655

[coderabbitai]

Summary by CodeRabbit

• Bug Fixes
  • Improved setup path validation for invalid paths.
  • File paths and existing non-empty directories are now rejected where applicable.
  • Scoop root paths containing spaces are now supported.

Walkthrough

Test-ValidateParameter now validates Scoop, global, and cache paths for invalid paths and existing files. It rejects non-empty Scoop or global directories. Scoop roots containing spaces are no longer rejected. Tests cover each validation case.

Changes

Installation validation

Layer / File(s)	Summary
Installation path validation install.ps1	Test-ValidateParameter rejects invalid paths, existing files, and non-empty Scoop or global directories. Scoop roots may contain spaces.
Path validation tests test/install.Tests.ps1	Parameterized tests cover invalid characters, file-valued paths, and non-empty Scoop or global directories.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly summarizes the main change: validating installation directories before installation. It is concise and specific.
Description check	✅ Passed	The description directly explains the directory validation changes, the prevention of non-empty directory installations, the possible breaking behavior, and the related issue.

Full details: Docstring Coverage

Explanation

No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0 files. (2 skipped: 2 unsupported.)

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[coderabbitai]

Actionable comments posted: 1

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ℹ️ Review info

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Reviewing files that changed from the base of the PR and between 395043c and 2e5efa4.

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• install.ps1

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[coderabbitai]

♻️ Duplicate comments (1)

install.ps1 (1)

144-145: ⚠️ Potential issue | 🟡 Minor

Preserve literal, fail-closed directory validation.

Test-Path -Path "$DIR\*" interprets the path as a wildcard. It can miss hidden-only children, and path names containing wildcard characters can resolve incorrectly. The check can therefore allow installation into a non-empty directory. PowerShell documents this wildcard behavior, and hidden-item misses are documented in the PowerShell issue tracker. (learn.microsoft.com)

Use -LiteralPath for the directory check, enumerate with Get-ChildItem -Force, and treat enumeration errors as validation failures. This is the same unresolved issue reported previously.

$root = Join-Path $env:TEMP ("scoop-path-check-" + [guid]::NewGuid())
$hiddenDir = Join-Path $root 'hidden-only'
$specialDir = Join-Path $root 'name[1]'

[System.IO.Directory]::CreateDirectory($hiddenDir) | Out-Null
[System.IO.Directory]::CreateDirectory($specialDir) | Out-Null
$hiddenFile = Join-Path $hiddenDir '.keep'
[System.IO.File]::WriteAllText($hiddenFile, '')
[System.IO.File]::SetAttributes($hiddenFile, [System.IO.FileAttributes]::Hidden)
[System.IO.File]::WriteAllText((Join-Path $specialDir 'keep'), '')

try {
    [pscustomobject]@{
        HiddenOnly_TestPath = Test-Path -Path "$hiddenDir\*"
        HiddenOnly_ForceCount = @(Get-ChildItem -LiteralPath $hiddenDir -Force).Count
        WildcardName_TestPath = Test-Path -Path "$specialDir\*"
        WildcardName_LiteralCount = @(Get-ChildItem -LiteralPath $specialDir -Force).Count
    }
} finally {
    [System.IO.Directory]::Delete($root, $true)
}

Also applies to: 152-153

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[coderabbitai]

Actionable comments posted: 1

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• install.ps1
• test/install.Tests.ps1

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