ci(release): guard empty changelog notes and unreadable CHANGELOG (review)

Addresses Copilot review on #31:
- UpdateReleaseNotes: if the matched CHANGELOG entry is empty/whitespace, warn and
  leave ReleaseNotes unchanged rather than overwriting the built manifest with an
  empty string.
- Create GitHub Release: read CHANGELOG.md defensively (Test-Path + try/catch). A
  missing or unreadable file now falls back to --generate-notes instead of failing
  the publish (GitHub's pwsh runs with $ErrorActionPreference = 'Stop').

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: tablackburn

.github/workflows/PublishModuleToPowerShellGallery.yaml

@@ -99,16 +99,29 @@ jobs:
           # Build release notes from this version's CHANGELOG.md section so the release
           # body carries only the curated, user-facing entries (not the full PR list that
           # --generate-notes produces, which is dominated by bot/CI/chore PRs).
-          $headerPattern = '^##\s+\[' + [regex]::Escape($version) + '\]'
-          $capturing = $false
+          # Read defensively: a missing/unreadable CHANGELOG.md must fall back to
+          # --generate-notes (below), never fail the publish.
+          $changelogLines = $null
+          if (Test-Path -LiteralPath './CHANGELOG.md') {
+              try {
+                  $changelogLines = Get-Content -LiteralPath './CHANGELOG.md' -ErrorAction Stop
+              }
+              catch {
+                  Write-Host "::warning::Could not read CHANGELOG.md ($($_.Exception.Message)); falling back to auto-generated notes."
+              }
+          }
           $captured = [System.Collections.Generic.List[string]]::new()
-          foreach ($line in (Get-Content -LiteralPath './CHANGELOG.md')) {
-              if (-not $capturing) {
-                  if ($line -match $headerPattern) { $capturing = $true }
-                  continue
+          if ($changelogLines) {
+              $headerPattern = '^##\s+\[' + [regex]::Escape($version) + '\]'
+              $capturing = $false
+              foreach ($line in $changelogLines) {
+                  if (-not $capturing) {
+                      if ($line -match $headerPattern) { $capturing = $true }
+                      continue
+                  }
+                  if ($line -match '^##\s+\[') { break }   # next version header ends the section
+                  $captured.Add($line)
               }
-              if ($line -match '^##\s+\[') { break }   # next version header ends the section
-              $captured.Add($line)
           }
           $body = ($captured -join "`n").Trim()
 

build.psake.ps1

@@ -77,6 +77,10 @@ Task -Name 'UpdateReleaseNotes' -Depends 'Build' -Description 'Set built manifes
     }
 
     $releaseNotes = $releaseEntry.RawData.Trim()
+    if ([string]::IsNullOrWhiteSpace($releaseNotes)) {
+        Write-Warning "CHANGELOG.md entry for version $moduleVersion is empty; leaving ReleaseNotes unchanged."
+        return
+    }
     $builtManifest = Join-Path -Path $PSBPreference.Build.ModuleOutDir -ChildPath "$($PSBPreference.General.ModuleName).psd1"
     Update-ModuleManifest -Path $builtManifest -ReleaseNotes $releaseNotes -ErrorAction Stop
     Write-Host "  Set ReleaseNotes on built manifest from CHANGELOG [$($releaseEntry.Version)] ($($releaseNotes.Length) chars)" -ForegroundColor Gray