feat: ✨ Automatically link pull-request with issue (#786)

README.md

@@ -339,23 +339,43 @@ gitReplaceChars: 'ab/'
 
 The above configuration replaces all occurences of the characters 'a', 'b' and '/' in the branch title.
 
+## Automatically link pull request with issue
+
+This app can automatically link a pull request to the issue for which the issue
+branch (of the pull request) was created. You can enable this feature with:
+
+```yaml
+autoLinkIssue: true
+```
+
+Be aware that the app needs to be able to find the issue number in the branch
+name, otherwise this feature will not work. This feature only works if one of
+the following is true for your app configuration:
+
+- You use the default `branchName` setting
+- Your `branchName` setting is `tiny`, `short` or `full`
+- Your branch name starts with the issue number
+- Your branch name contains the string `issue-` (case insensitive) followed by
+  the issue number, for example: `Project-A-Issue-123-Rewrite_in_Clojure`
+
 ## Automatically close issues after a pull request merge
 
-This app can close issues automatically for you when a pull request for an issue branch is merged. You can enable this
-feature with:
+This app can close issues automatically for you when a pull request for an
+issue branch is merged. You can enable this feature with:
 
 ```yaml
 autoCloseIssue: true
 ```
 
-Be aware that the app needs to be able to find the issue number in the branch name, otherwise this feature will not
-work. This feature only works if one of the following is true for your app configuration:
+Be aware that the app needs to be able to find the issue number in the branch
+name, otherwise this feature will not work. This feature only works if one of
+the following is true for your app configuration:
 
 - You use the default `branchName` setting
 - Your `branchName` setting is `tiny`, `short` or `full`
 - Your branch name starts with the issue number
-- Your branch name contains the string `issue-` (case insensitive) followed by the issue number, for
-  example: `Project-A-Issue-123-Rewrite_in_Clojure`
+- Your branch name contains the string `issue-` (case insensitive) followed by
+  the issue number, for example: `Project-A-Issue-123-Rewrite_in_Clojure`
 
 ## Default source branch
 

src/config.js

@@ -76,6 +76,10 @@ function isExperimentalBranchNameArgument (config) {
     config.experimental.branchNameArgument === true)
 }
 
+function autoLinkIssue (config) {
+  return 'autoLinkIssue' in config && config.autoLinkIssue === true
+}
+
 function autoCloseIssue (config) {
   return 'autoCloseIssue' in config && config.autoCloseIssue === true
 }
@@ -243,6 +247,7 @@ module.exports = {
   isModeImmediate: isModeImmediate,
   isModeChatOps: isModeChatOps,
   getChatOpsCommandArgument: getChatOpsCommandArgument,
+  autoLinkIssue: autoLinkIssue,
   autoCloseIssue: autoCloseIssue,
   isSilent: isSilent,
   isChatOpsCommand: isChatOpsCommand,

src/github.js

@@ -438,6 +438,14 @@ async function updatePrTitle (app, ctx, config, pr, issueTitle, labels) {
   }
 }
 
+async function updatePrBody (app, ctx, config, pr, body) {
+  const owner = context.getRepoOwnerLogin(ctx)
+  const repo = context.getRepoName(ctx)
+  const pullNumber = pr.number
+  app.log.info(`Updating body for PR #${pullNumber} in ${owner}/${repo}`)
+  await ctx.octokit.pulls.update({ owner: owner, repo: repo, pull_number: pullNumber, body: body })
+}
+
 module.exports = {
   createIssueBranch: createIssueBranch,
   addComment: addComment,
@@ -452,5 +460,6 @@ module.exports = {
   getBranchName: getBranchName,
   createBranch: createBranch,
   createPr: createPr,
-  updatePrTitle: updatePrTitle
+  updatePrTitle: updatePrTitle,
+  updatePrBody: updatePrBody
 }

src/webhooks/pull-request.js

@@ -20,6 +20,21 @@ async function handle (app, ctx) {
       }
     }
   }
+  if (Config.autoLinkIssue(config)) {
+    const pr = ctx.payload.pull_request
+    const branchName = pr.head.ref
+    const issueNumber = github.getIssueNumberFromBranchName(branchName)
+    if (issueNumber) {
+      const body = pr.body
+      const linkText = `closes #${issueNumber}`
+      if (!body) {
+        await github.updatePrBody(app, ctx, config, pr, linkText)
+      } else if (!body.includes(`closes #${issueNumber}`)) {
+        const updatedBody = body.length === 0 ? linkText : `${body}\n${linkText}`
+        await github.updatePrBody(app, ctx, config, pr, updatedBody)
+      }
+    }
+  }
 }
 
 module.exports = {