Offer new API to reference parent / child PR relations

README.md

@@ -259,6 +259,12 @@ This configuration is a `JSON` in the following format. (The below showcases *ex
       "on_property": "title",
       "method": "match"
     },
+    "reference": {
+      "pattern": ".*\\ \\#(.).*",
+      "on_property": "body",
+      "method": "replace",
+      "target": "$1"
+    },
     "transformers": [
       {
         "pattern": "[\\-\\*] (\\[(...|TEST|CI|SKIP)\\])( )?(.+?)\n(.+?[\\-\\*] )(.+)",
@@ -371,8 +377,10 @@ When using `*` values are joined by `,`.
 | `${{REVIEWERS[*]}}` | GitHub Login names of specified reviewers. Requires `fetchReviewers` to be enabled. |
 | `${{APPROVERS[*]}}` | GitHub Login names of users who approved the PR.                                    |
 
-Additionally there is a special array placeholder `REVIEWS` which allows access to it's properties:
-`(KEY)[(*/index)].(property)` for example: `REVIEWS[*].author` or `REVIEWS[*].body`
+Additionally there are special array placeholders like `REVIEWS` which allows access to it's properties via
+`(KEY)[(*/index)].(property)`.
+
+For example: `REVIEWS[*].author` or `REVIEWS[*].body`
 
 | **Placeholder**               | **Description**                            |
 |-------------------------------|--------------------------------------------|
@@ -382,6 +390,14 @@ Additionally there is a special array placeholder `REVIEWS` which allows access
 | `${{REVIEWS[*].submittedAt}}` | The date whent he review was submitted.    |
 | `${{REVIEWS[*].state}}`       | The state of the given review.             |
 
+Similar to `REVIEWS`, `REFERENCED` PRs also offer special placeholders. 
+
+| **Placeholder**               | **Description**                                                           |
+|-------------------------------|---------------------------------------------------------------------------|
+| `${{REFERENCED[*].number}}`   | The PR number of the referenced PR.                                       |
+| `${{REFERENCED[*].title}}`    | The title of the referenced PR.                                           |
+| `${{REFERENCED[*]."..."}}`    | Allows to use most other PR properties as placeholder.                    |
+
 </p>
 </details>
 
@@ -448,6 +464,7 @@ Table of descriptions for the `configuration.json` options to configure the resu
 | label_extractor.flags       | Defines the regex flags specified for the pattern. Default: `gu`.                                                                                                                                                                  |
 | label_extractor.on_empty    | Defines the placeholder to be filled in, if the regex does not lead to a result.                                                                                                                                                   |
 | duplicate_filter            | Defines the `Extractor` to use for retrieving the identifier for a PR. In case of duplicates will keep the last matching pull request (depends on `sort`). See `label_extractor` for details on `Extractor` properties.            |
+| reference                   | Defines the `Extractor` to use for resolving the "PR-number" for a parent PR. In case of a match, the child PR will not be included in the release notes. See `label_extractor` for details on `Extractor` properties.            |
 | transformers                | An array of `transform` specifications, offering a flexible API to modify the text per pull request. This is applied on the change text created with `pr_template`. `transformers` are executed per change, in the order specified |
 | transformer.pattern         | A `regex` pattern, extracting values of the change message.                                                                                                                                                                        |
 | transformer.target          | The result pattern, the regex groups will be filled into. Allows for full transformation of a pull request message. Including potentially specified texts                                                                          |

__tests__/transform.test.ts

@@ -266,7 +266,7 @@ pullRequestsWithLabels.push(
     repoName: 'test-repo',
     labels: ['issue', 'fix'],
     milestone: '',
-    body: 'no magic body for this matter',
+    body: 'no magic body for this matter - #1',
     assignees: [],
     requestedReviewers: [],
     approvedReviewers: [],
@@ -399,6 +399,26 @@ it('Deduplicate duplicated PRs DESC', async () => {
   )
 })
 
+it('Reference PRs', async () => {
+  const customConfig = Object.assign({}, DefaultConfiguration)
+  customConfig.categories = [
+    {
+      title: '',
+      labels: []
+    }
+  ]
+  customConfig.pr_template = "${{NUMBER}} -- ${{REFERENCED[*].number}}"
+  customConfig.reference = {
+    pattern: '.*\ \#(.).*', // matches the 1 from "abcdefg #1 adfasdf"
+    on_property: 'body',
+    method: 'replace',
+    target: '$1'
+  }
+  expect(buildChangelogTest(customConfig, pullRequestsWithLabels)).toStrictEqual(
+    `1 -- 2\n4 -- \n3 -- \n\n`
+  )
+})
+
 it('Use empty_content for empty category', async () => {
   const customConfig = Object.assign({}, DefaultConfiguration)
   customConfig.categories = [

pr-collector/src/pullRequests.ts

@@ -36,6 +36,25 @@ export interface CommentInfo {
   state: string | undefined
 }
 
+export const EMPTY_PULL_REQUEST_INFO: PullRequestInfo = {
+  number: 0,
+  title: "",
+  htmlURL: "",
+  baseBranch: "",
+  mergedAt: undefined,
+  createdAt: moment(),
+  mergeCommitSha: "",
+  author: "",
+  repoName: "",
+  labels: [],
+  milestone: "",
+  body: "",
+  assignees: [],
+  requestedReviewers: [],
+  approvedReviewers: [],
+  status: 'open'
+}
+
 export const EMPTY_COMMENT_INFO: CommentInfo = {
   id: 0,
   htmlURL: '',

src/configuration.ts

@@ -13,6 +13,7 @@ export interface Configuration extends PullConfiguration {
   ignore_labels: string[]
   label_extractor: Extractor[]
   duplicate_filter?: Extractor // extract an identifier from a PR used to detect duplicates, will keep the last match (depends on `sort`)
+  reference?: Extractor // extracts a reference from a PR, used to establish parent child relations. This will remove the child from the main PR list.
   transformers: Transformer[]
   tag_resolver: TagResolver
   base_branches: string[]