Add git commit fallback for repositories without changelog files

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Features
+
+- Updater now supports repositories without changelog files by falling back to git commit messages ([#116](https://github.com/getsentry/github-workflows/pull/116))
+
 ### Breaking Changes
 
 Updater and Danger reusable workflows are now composite actions ([#114](https://github.com/getsentry/github-workflows/pull/114))

updater/scripts/get-changelog.ps1

@@ -45,24 +45,68 @@ function Get-ChangelogContent {
     return $false
 }
 
-try {
-    Write-Host 'Fetching CHANGELOG files for comparison...'
+# Function to generate changelog from git commits
+function Get-ChangelogFromCommits {
+    param($repoUrl, $oldTag, $newTag, $tmpDir)
 
-    # Fetch old changelog
-    $oldChangelogPath = Join-Path $tmpDir 'old-changelog.md'
-    if (-not (Get-ChangelogContent $OldTag $oldChangelogPath)) {
-        Write-Warning "Could not find changelog at $OldTag"
-        return
-    }
+    # Clone the repository
+    $repoDir = Join-Path $tmpDir 'repo'
+    Write-Host "Cloning repository to generate changelog from commits..."
 
-    # Fetch new changelog
-    $newChangelogPath = Join-Path $tmpDir 'new-changelog.md'
-    if (-not (Get-ChangelogContent $NewTag $newChangelogPath)) {
-        Write-Warning "Could not find changelog at $NewTag"
-        return
+    # Clone with limited depth for performance, but ensure we have both tags
+    git clone --depth=200 --no-single-branch --quiet $repoUrl $repoDir 2>&1 | Out-Null
+
+    Push-Location $repoDir
+    try {
+        # Ensure we have both tags
+        git fetch --tags --quiet 2>&1 | Out-Null
+
+        # Get commit messages between tags
+        Write-Host "Getting commits between $oldTag and $newTag..."
+        $commitMessages = git log "$oldTag..$newTag" --pretty=format:'%s' 2>&1
+
+        if ($LASTEXITCODE -ne 0) {
+            Write-Warning "Could not get commits between $oldTag and $newTag"
+            return $null
+        }
+
+        if ([string]::IsNullOrEmpty($commitMessages)) {
+            Write-Host "No commits found between $oldTag and $newTag"
+            return $null
+        }
+
+        # Filter out version tag commits and format as list
+        $commits = $commitMessages -split "`n" |
+            Where-Object {
+                $_ -and
+                $_ -notmatch '^\s*v?\d+\.\d+\.\d+' -and  # Skip version commits
+                $_.Trim().Length -gt 0
+            } |
+            ForEach-Object { "- $_" }
+
+        if ($commits.Count -eq 0) {
+            Write-Host "No meaningful commits found between $oldTag and $newTag"
+            return $null
+        }
+
+        # Create changelog from commits
+        $changelog = "## Changelog`n`n"
+        $changelog += "### Commits between $oldTag and $newTag`n`n"
+        $changelog += $commits -join "`n"
+
+        Write-Host "Generated changelog from $($commits.Count) commits"
+        return $changelog
+    }
+    finally {
+        Pop-Location
     }
+}
+
+# Function to generate changelog from diff between changelog files
+function Get-ChangelogFromDiff {
+    param($oldChangelogPath, $newChangelogPath, $oldTag, $newTag)
 
-    Write-Host "Generating changelog diff between $OldTag and $NewTag..."
+    Write-Host "Generating changelog diff between $oldTag and $newTag..."
 
     # Generate diff using git diff --no-index
     # git diff returns exit code 1 when differences are found, which is expected behavior
@@ -80,69 +124,121 @@ try {
     # The first lines are diff metadata, skip them
     $fullDiff = $fullDiff -split "`n" | Select-Object -Skip 4
     if ([string]::IsNullOrEmpty("$fullDiff")) {
-        Write-Host "No differences found between $OldTag and $NewTag"
-        return
+        Write-Host "No differences found between $oldTag and $newTag"
+        return $null
     } else {
         Write-Host "Successfully created a changelog diff - $($fullDiff.Count) lines"
     }
 
     # Extract only the added lines (lines starting with + but not ++)
     $addedLines = $fullDiff | Where-Object { $_ -match '^[+][^+]*' } | ForEach-Object { $_.Substring(1) }
 
-    if ($addedLines.Count -gt 0) {
-        # Create clean changelog from added lines
-        $changelog = ($addedLines -join "`n").Trim()
+    if ($addedLines.Count -eq 0) {
+        Write-Host "No changelog additions found between $oldTag and $newTag"
+        return $null
+    }
 
-        # Apply formatting to clean changelog
-        if ($changelog.Length -gt 0) {
-            # Add header
-            if (-not ($changelog -match '^(##|#) Changelog')) {
-                $changelog = "## Changelog`n`n$changelog"
-            }
+    # Create clean changelog from added lines
+    $changelog = ($addedLines -join "`n").Trim()
 
-            # Increase header level by one for content (not the main header)
-            $changelog = $changelog -replace '(^|\n)(#+) ', '$1$2# ' -replace '^### Changelog', '## Changelog'
+    if ($changelog.Length -eq 0) {
+        return $null
+    }
 
-            # Only add details section if there are deletions or modifications (not just additions)
-            $hasModifications = $fullDiff | Where-Object { $_ -match '^[-]' -and $_ -notmatch '^[-]{3}' }
-            if ($hasModifications) {
-                $changelog += "`n`n<details>`n<summary>Full CHANGELOG.md diff</summary>`n`n"
-                $changelog += '```diff' + "`n"
-                $changelog += $fullDiff -join "`n"
-                $changelog += "`n" + '```' + "`n`n</details>"
-            }
+    # Add header if needed
+    if (-not ($changelog -match '^(##|#) Changelog')) {
+        $changelog = "## Changelog`n`n$changelog"
+    }
 
-            # Apply standard formatting
-            # Remove at-mentions.
-            $changelog = $changelog -replace '@', ''
-            # Make PR/issue references into links to the original repository (unless they already are links).
-            $changelog = $changelog -replace '(?<!\[)#([0-9]+)(?![\]0-9])', ('[#$1](' + $RepoUrl + '/issues/$1)')
-            # Replace any links pointing to github.com so that the target PRs/Issues don't get na notification.
-            $changelog = $changelog -replace ('\(' + $prefix), '(https://github-redirect.dependabot.com/'
-
-            # Limit the changelog length to ~60k to allow for other text in the PR body (total PR limit is 65536 characters).
-            $limit = 60000
-            if ($changelog.Length -gt $limit) {
-                $oldLength = $changelog.Length
-                Write-Warning "Truncating changelog because it's $($changelog.Length - $limit) characters longer than the limit $limit."
-                while ($changelog.Length -gt $limit) {
-                    $lastNewlineIndex = $changelog.LastIndexOf("`n")
-                    if ($lastNewlineIndex -eq -1) {
-                        # No newlines found, just truncate to limit
-                        $changelog = $changelog.Substring(0, $limit)
-                        break
-                    }
-                    $changelog = $changelog.Substring(0, $lastNewlineIndex)
-                }
-                $changelog += "`n`n> :warning: **Changelog content truncated by $($oldLength - $changelog.Length) characters because it was over the limit ($limit) and wouldn't fit into PR description.**"
-            }
+    # Increase header level by one for content (not the main header)
+    $changelog = $changelog -replace '(^|\n)(#+) ', '$1$2# ' -replace '^### Changelog', '## Changelog'
 
-            Write-Host "Final changelog length: $($changelog.Length) characters"
-            Write-Output $changelog
+    # Only add details section if there are deletions or modifications (not just additions)
+    $hasModifications = $fullDiff | Where-Object { $_ -match '^[-]' -and $_ -notmatch '^[-]{3}' }
+    if ($hasModifications) {
+        $changelog += "`n`n<details>`n<summary>Full CHANGELOG.md diff</summary>`n`n"
+        $changelog += '```diff' + "`n"
+        $changelog += $fullDiff -join "`n"
+        $changelog += "`n" + '```' + "`n`n</details>"
+    }
+
+    return $changelog
+}
+
+# Function to sanitize and format changelog content
+function Format-ChangelogContent {
+    param($changelog, $repoUrl)
+
+    if ([string]::IsNullOrEmpty($changelog)) {
+        return $null
+    }
+
+    # Apply standard formatting
+    # Remove at-mentions
+    $changelog = $changelog -replace '@', ''
+
+    # Make PR/issue references into links to the original repository (unless they already are links)
+    $changelog = $changelog -replace '(?<!\[)#([0-9]+)(?![\]0-9])', ('[#$1](' + $repoUrl + '/issues/$1)')
+
+    # Replace any links pointing to github.com so that the target PRs/Issues don't get notification
+    $changelog = $changelog -replace ('\(' + $prefix), '(https://github-redirect.dependabot.com/'
+
+    # Limit the changelog length to ~60k to allow for other text in the PR body (total PR limit is 65536 characters)
+    $limit = 60000
+    if ($changelog.Length -gt $limit) {
+        $oldLength = $changelog.Length
+        Write-Warning "Truncating changelog because it's $($changelog.Length - $limit) characters longer than the limit $limit."
+        while ($changelog.Length -gt $limit) {
+            $lastNewlineIndex = $changelog.LastIndexOf("`n")
+            if ($lastNewlineIndex -eq -1) {
+                # No newlines found, just truncate to limit
+                $changelog = $changelog.Substring(0, $limit)
+                break
+            }
+            $changelog = $changelog.Substring(0, $lastNewlineIndex)
         }
+        $changelog += "`n`n> :warning: **Changelog content truncated by $($oldLength - $changelog.Length) characters because it was over the limit ($limit) and wouldn't fit into PR description.**"
+    }
+
+    Write-Host "Final changelog length: $($changelog.Length) characters"
+    return $changelog
+}
+
+try {
+    Write-Host 'Fetching CHANGELOG files for comparison...'
+
+    # Fetch old changelog
+    $oldChangelogPath = Join-Path $tmpDir 'old-changelog.md'
+    $hasOldChangelog = Get-ChangelogContent $OldTag $oldChangelogPath
+
+    # Fetch new changelog
+    $newChangelogPath = Join-Path $tmpDir 'new-changelog.md'
+    $hasNewChangelog = Get-ChangelogContent $NewTag $newChangelogPath
+
+    $changelog = $null
+
+    # Try changelog file diff first, fall back to git commits if not available
+    if ($hasOldChangelog -and $hasNewChangelog) {
+        $changelog = Get-ChangelogFromDiff $oldChangelogPath $newChangelogPath $OldTag $NewTag
+    }
+
+    # Fall back to git commits if no changelog files or no diff found
+    if (-not $changelog) {
+        Write-Host "No changelog files found or no changes detected, falling back to git commits..."
+        $changelog = Get-ChangelogFromCommits $RepoUrl $OldTag $NewTag $tmpDir
     }
 
-    Write-Host "No changelog additions found between $OldTag and $NewTag"
+    # Apply formatting and output result
+    if ($changelog) {
+        $formattedChangelog = Format-ChangelogContent $changelog $RepoUrl
+        if ($formattedChangelog) {
+            Write-Output $formattedChangelog
+        } else {
+            Write-Host "No changelog content to display after formatting"
+        }
+    } else {
+        Write-Host "No changelog found between $OldTag and $NewTag"
+    }
 } catch {
     Write-Warning "Failed to get changelog: $($_.Exception.Message)"
 } finally {

updater/tests/get-changelog.Tests.ps1

@@ -258,4 +258,59 @@ Features, fixes and improvements in this release have been contributed by:
             $actualLines[$i].Trim() | Should -Be $expectedLines[$i].Trim()
         }
     }
+
+    It 'falls back to git commits when no changelog files exist' {
+        # Test with a repository that doesn't have changelog files
+        $actual = & "$PSScriptRoot/../scripts/get-changelog.ps1" `
+            -RepoUrl 'https://github.com/catchorg/Catch2' -OldTag 'v3.9.1' -NewTag 'v3.10.0'
+
+        $expected = @'
+## Changelog
+
+### Commits between v3.9.1 and v3.10.0
+
+- Forbid deducing reference types for m_predicate in FilterGenerator ([#3005](https://github-redirect.dependabot.com/catchorg/Catch2/issues/3005))
+- Make message macros (FAIL, WARN, INFO, etc) thread safe
+- Improve performance of writing XML
+- Improve performance of writing JSON values
+- Don't add / to start of pkg-config file path when DESTDIR is unset
+- Fix color mode detection on FreeBSD by adding platform macro
+- Handle DESTDIR env var when generating pkgconfig files
+'@
+
+        $actual | Should -Be $expected
+    }
+
+    It 'git commit fallback handles PR references correctly' {
+        # Test with a known repository and tags that contain PR references
+        $actual = & "$PSScriptRoot/../scripts/get-changelog.ps1" `
+            -RepoUrl 'https://github.com/catchorg/Catch2' -OldTag 'v3.9.1' -NewTag 'v3.10.0'
+
+        # Check that PR references are converted to links with github-redirect
+        $actual | Should -Match '\[#3005\]\(https://github-redirect\.dependabot\.com/catchorg/Catch2/issues/3005\)'
+        # Should not contain raw @mentions
+        $actual | Should -Not -Match "@\w+"
+    }
+
+    It 'git commit fallback returns empty when no commits found' {
+        # Test with same tags (no commits between them)
+        $actual = & "$PSScriptRoot/../scripts/get-changelog.ps1" `
+            -RepoUrl 'https://github.com/catchorg/Catch2' -OldTag 'v3.10.0' -NewTag 'v3.10.0'
+
+        $actual | Should -BeNullOrEmpty
+    }
+
+    It 'git commit fallback filters out version tag commits' {
+        # Test that version commits like "v3.10.0" are filtered out
+        $actual = & "$PSScriptRoot/../scripts/get-changelog.ps1" `
+            -RepoUrl 'https://github.com/catchorg/Catch2' -OldTag 'v3.9.0' -NewTag 'v3.10.0'
+
+        # Should not contain version tag lines (v3.9.1 and v3.10.0 are version tags in this range)
+        $actual | Should -Not -Match "- v3\.9\.1"
+        $actual | Should -Not -Match "- v3\.10\.0"
+        $actual | Should -Not -Match "- 3\.9\.1"
+        $actual | Should -Not -Match "- 3\.10\.0"
+        # But should contain meaningful commits
+        $actual | Should -Match "- Forbid deducing reference types"
+    }
 }