fix(plan): use .specify/feature.json to allow /speckit.plan on custom git branches (#2305) (#2349)

* fix: allow plan setup to use feature metadata on custom branches

* fix: harden feature metadata validation

* fix: use portable feature metadata path

Made-with: Cursor

* fix: share feature.json parser and make path compare OS aware

* test: isolate setup plan subprocess environment

* fix: normalize feature metadata paths with pwd -P

scripts/powershell/common.ps1

@@ -164,6 +164,74 @@ function Test-FeatureBranch {
     return $true
 }
 
+# True when .specify/feature.json pins an existing feature directory that matches the
+# active FEATURE_DIR from Get-FeaturePathsEnv (so /speckit.plan can skip git branch pattern checks).
+function Test-FeatureJsonMatchesFeatureDir {
+    param(
+        [Parameter(Mandatory = $true)][string]$RepoRoot,
+        [Parameter(Mandatory = $true)][string]$ActiveFeatureDir
+    )
+
+    $featureJson = Join-Path (Join-Path $RepoRoot '.specify') 'feature.json'
+    if (-not (Test-Path -LiteralPath $featureJson -PathType Leaf)) {
+        return $false
+    }
+
+    try {
+        $raw = Get-Content -LiteralPath $featureJson -Raw
+        $cfg = $raw | ConvertFrom-Json
+    } catch {
+        return $false
+    }
+
+    $fd = $cfg.feature_directory
+    if ([string]::IsNullOrWhiteSpace([string]$fd)) {
+        return $false
+    }
+
+    if (-not [System.IO.Path]::IsPathRooted($fd)) {
+        $fd = Join-Path $RepoRoot $fd
+    }
+
+    if (-not (Test-Path -LiteralPath $fd -PathType Container)) {
+        return $false
+    }
+
+    # Resolve both paths to canonical absolute form. Prefer Resolve-Path (follows
+    # symlinks and is the canonical PS way); fall back to [Path]::GetFullPath when
+    # Resolve-Path can't produce a value. Mirrors the pattern used by Find-SpecifyRoot.
+    $resolvedJson = Resolve-Path -LiteralPath $fd -ErrorAction SilentlyContinue
+    if ($resolvedJson) {
+        $normJson = $resolvedJson.Path
+    } else {
+        $normJson = [System.IO.Path]::GetFullPath($fd)
+    }
+
+    $resolvedActive = Resolve-Path -LiteralPath $ActiveFeatureDir -ErrorAction SilentlyContinue
+    if ($resolvedActive) {
+        $normActive = $resolvedActive.Path
+    } else {
+        $normActive = [System.IO.Path]::GetFullPath($ActiveFeatureDir)
+    }
+
+    # Use case-insensitive compare only on Windows; POSIX filesystems are case-sensitive.
+    # PowerShell 5.1 is Windows-only and does not define $IsWindows, so treat its
+    # absence as "we're on Windows".
+    if ($null -ne $IsWindows) {
+        $onWindows = $IsWindows
+    } else {
+        $onWindows = $true
+    }
+
+    if ($onWindows) {
+        $comparison = [System.StringComparison]::OrdinalIgnoreCase
+    } else {
+        $comparison = [System.StringComparison]::Ordinal
+    }
+
+    return [string]::Equals($normJson, $normActive, $comparison)
+}
+
 # Resolve specs/<feature-dir> by numeric/timestamp prefix (mirrors scripts/bash/common.sh find_feature_dir_by_prefix).
 function Find-FeatureDirByPrefix {
     param(