- introduce new configuration option, allowing to provide an empty_content for categories matching no PRs

- FIX https://github.com/mikepenz/release-changelog-builder-action/issues/804

README.md

@@ -163,13 +163,14 @@ This configuration is a `.json` file in the following format.
       },
       {
         "title": "## 🧪 Tests",
-        "labels": ["test"],
+        "labels": ["test"]
       },
       {
         "title": "## 🧪 Tests and some 🪄 Magic",
         "labels": ["test", "magic"],
         "exclude_labels": ["no-magic"],
         "exhaustive": true,
+        "empty_content": "- no matching PRs"
       }
     ],
     "ignore_labels": [
@@ -325,6 +326,7 @@ Table of descriptions for the `configuration.json` options to configure the resu
 | category.labels             | An array of labels, to match pull request labels against. If any PR label matches any category label, the pull request will show up under this category.                                                                           |
 | category.exclude_labels     | Similar to `labels`, an array of labels to match PRs against, but if a match occurs the PR is excluded from this category.                                                                                                         |
 | category.exhaustive         | Will require all labels defined within this category to be present on the matching PR.                                                                                                                                             |
+| category.empty_content         |  If the category has no matching PRs, this content will be used. When not set, the category will be skipped in the changelog.                                                                                                   |
 | ignore_labels               | An array of labels, to match pull request labels against. If any PR label overlaps, the pull request will be ignored from the changelog. This takes precedence over category labels                                                |
 | sort                        | A `sort` specification, offering the ability to define sort order and property.                                                                                                                                                    |
 | sort.order                  | The sort order. Allowed values: `ASC`, `DESC`                                                                                                                                                                                      |

__tests__/transform.test.ts

@@ -456,6 +456,38 @@ it('Deduplicate duplicated PRs DESC', async () => {
   )
 })
 
+
+it('Use empty_content for empty category', async () => {
+  const customConfig = Object.assign({}, DefaultConfiguration)
+  customConfig.categories = [
+    {
+      title: '## 🚀 Features and 🐛 Issues',
+      labels: ['Never-Matching-Category'],
+      empty_content: "- No PRs in this category"
+    },
+    {
+      title: '## 🚀 Features',
+      labels: ['Feature'],
+    }
+  ]
+
+  const resultChangelog = buildChangelog(pullRequestsWithLabels, {
+    owner: 'mikepenz',
+    repo: 'test-repo',
+    fromTag: '1.0.0',
+    toTag: '2.0.0',
+    includeOpen: false,
+    failOnError: false,
+    fetchReviewers: false,
+    commitMode: false,
+    configuration: customConfig
+  })
+
+  expect(resultChangelog).toStrictEqual(
+    `## 🚀 Features and 🐛 Issues\n\n- No PRs in this category\n\n## 🚀 Features\n\n- [ABC-1234] - this is a PR 1 title message\n   - PR: #1\n- [ABC-1234] - this is a PR 3 title message\n   - PR: #3\n\n`
+  )
+})
+
 it('Commit SHA-1 in commitMode', async () => {
   const customConfig = Object.assign({}, DefaultConfiguration)
   customConfig.sort = "DESC"

dist/index.js

@@ -1487,8 +1487,11 @@ function buildChangelog(prs, options) {
             for (const pr of pullRequests) {
                 changelog = `${changelog + pr}\n`;
             }
-            // add space between
-            changelog = `${changelog}\n`;
+            changelog = `${changelog}\n`; // add space between sections
+        }
+        else if (category.empty_content !== undefined) {
+            changelog = `${changelog + category.title}\n\n`;
+            changelog = `${changelog + category.empty_content}\n\n`;
         }
     }
     core.info(`✒️ Wrote ${categorizedPrs.length} categorized pull requests down`);

src/configuration.ts

@@ -21,6 +21,7 @@ export interface Category {
   labels: string[] // labels to associate PRs to this category
   exclude_labels?: string[] // if an exclude label is detected, the PR will be excluded from this category
   exhaustive?: boolean // requires all labels to be present in the PR
+  empty_content ?: string // if the category has no matching PRs, this content will be used. If not set, the category will be skipped in the changelog.
 }
 
 export interface Sort {

src/transform.ts

@@ -183,9 +183,10 @@ export function buildChangelog(
       for (const pr of pullRequests) {
         changelog = `${changelog + pr}\n`
       }
-
-      // add space between
-      changelog = `${changelog}\n`
+      changelog = `${changelog}\n` // add space between sections
+    } else if (category.empty_content !== undefined) {
+      changelog = `${changelog + category.title}\n\n`
+      changelog = `${changelog + category.empty_content}\n\n`
     }
   }
   core.info(`✒️ Wrote ${categorizedPrs.length} categorized pull requests down`)