feat: Danger - Add inline changelog suggestions for GitHub PRs

danger/dangerfile-utils.js

@@ -86,8 +86,125 @@ function extractPRFlavor(prTitle, prBranchRef) {
   return "";
 }
 
+/// Find insertion point and determine what content needs to be inserted
+function findChangelogInsertionPoint(changelogContent, sectionName) {
+  const lines = changelogContent.split('\n');
+
+  // Find "## Unreleased" section
+  let unreleasedIndex = -1;
+  for (let i = 0; i < lines.length; i++) {
+    if (lines[i].trim().match(/^##\s+Unreleased/i)) {
+      unreleasedIndex = i;
+      break;
+    }
+  }
+
+  // Case 1: No Unreleased section exists
+  if (unreleasedIndex === -1) {
+    // Find first ## section or top of changelog to insert before it
+    let insertionPoint = 0;
+
+    // Skip title and initial content, look for first version section
+    for (let i = 0; i < lines.length; i++) {
+      if (lines[i].trim().match(/^##\s+/)) {
+        insertionPoint = i;
+        break;
+      }
+    }
+
+    // If no version sections exist, insert at end
+    if (insertionPoint === 0) {
+      insertionPoint = lines.length;
+    }
+
+    return {
+      lineNumber: insertionPoint + 1, // 1-indexed for GitHub API
+      insertContent: 'unreleased-and-section'
+    };
+  }
+
+  // Case 2: Unreleased section exists, find the target subsection
+  let sectionIndex = -1;
+  let nextSectionIndex = lines.length; // End of file by default
+
+  for (let i = unreleasedIndex + 1; i < lines.length; i++) {
+    // Stop if we hit another main section (##)
+    if (lines[i].trim().match(/^##\s+/)) {
+      nextSectionIndex = i;
+      break;
+    }
+
+    // Check for our target subsection
+    if (lines[i].trim().match(new RegExp(`^###\\s+${sectionName}`, 'i'))) {
+      sectionIndex = i;
+      break;
+    }
+  }
+
+  // Case 3: Subsection doesn't exist, need to create it within Unreleased
+  if (sectionIndex === -1) {
+    // Find insertion point after "## Unreleased" but before next main section
+    let insertAfter = unreleasedIndex;
+
+    // Skip empty lines after "## Unreleased"
+    while (insertAfter + 1 < nextSectionIndex && lines[insertAfter + 1].trim() === '') {
+      insertAfter++;
+    }
+
+    return {
+      lineNumber: insertAfter + 1, // 1-indexed for GitHub API
+      insertContent: 'section-and-entry'
+    };
+  }
+
+  // Case 4: Both Unreleased and subsection exist, just add entry
+  let insertionPoint = sectionIndex + 1;
+
+  // Skip empty lines after section header
+  while (insertionPoint < nextSectionIndex && lines[insertionPoint].trim() === '') {
+    insertionPoint++;
+  }
+
+  return {
+    lineNumber: insertionPoint + 1, // 1-indexed for GitHub API
+    insertContent: 'entry-only'
+  };
+}
+
+/// Generate suggestion text for changelog entry based on what needs to be inserted
+function generateChangelogSuggestion(prTitle, prNumber, prUrl, sectionName, insertionInfo) {
+  // Clean up PR title (remove conventional commit prefix if present)
+  const cleanTitle = prTitle
+    .split(": ")
+    .slice(-1)[0]
+    .trim()
+    .replace(/\.+$/, "");
+
+  const bulletPoint = `- ${cleanTitle} ([#${prNumber}](${prUrl}))`;
+
+  switch (insertionInfo.insertContent) {
+    case 'unreleased-and-section':
+      // Need to create both Unreleased section and subsection
+      return `## Unreleased\n\n### ${sectionName}\n\n${bulletPoint}\n`;
+
+    case 'section-and-entry':
+      // Need to create subsection within existing Unreleased
+      return `\n### ${sectionName}\n\n${bulletPoint}`;
+
+    case 'entry-only':
+      // Just add the bullet point to existing section
+      return bulletPoint;
+
+    default:
+      // Fallback to entry-only
+      return bulletPoint;
+  }
+}
+
 module.exports = {
   FLAVOR_CONFIG,
   getFlavorConfig,
-  extractPRFlavor
+  extractPRFlavor,
+  findChangelogInsertionPoint,
+  generateChangelogSuggestion
 };