From a3eb7c2c448abb92e444aea3a61970635bfa1d81 Mon Sep 17 00:00:00 2001
From: galargh <piotr.galar@gmail.com>
Date: Thu, 20 Jun 2024 15:30:16 +0100
Subject: [PATCH] Added pull_number inference from workflow_run event context

---
 .github/workflows/comment.yml |  1 -
 .github/workflows/test.yml    |  2 +-
 CHANGELOG.md                  |  5 +++++
 README.md                     |  4 ++--
 action.yml                    |  3 +--
 index.js                      | 25 ++++++++++++++++++++++++-
 6 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/.github/workflows/comment.yml b/.github/workflows/comment.yml
index 9468bf0..835ac3a 100644
--- a/.github/workflows/comment.yml
+++ b/.github/workflows/comment.yml
@@ -11,7 +11,6 @@ on:
       pull_number:
         description: 'The pull request number'
         required: false
-        default: '${{ github.event.workflow_run.pull_requests[0].number }}'
         type: string
       template:
         description: 'The template name or a lodash style template to use for the comment'
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 77f4c8f..e0ecf2a 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -12,7 +12,7 @@ permissions:
   pull-requests: write
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.event.workflow_run.pull_requests[0].number }}
+  group: ${{ github.workflow }}-${{ github.event.workflow_run.id }}
   cancel-in-progress: true
 
 jobs:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c8c16b1..c1a18db 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## Unreleased
+### Added
+- Added `pull_number` inference from the `workflow_run` event context
+
+### Changed
+- Removed the default value for the `pull_number` input
 
 ## [1.0.2] - 2024-04-09
 ### Added
diff --git a/README.md b/README.md
index 12e850e..ddd766f 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@ permissions:
   pull-requests: write
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.event.workflow_run.pull_requests[0].number }}
+  group: ${{ github.workflow }}-${{ github.event.workflow_run.id }}
   cancel-in-progress: true
 
 jobs:
@@ -76,7 +76,7 @@ with:
   # The repository to comment on
   repository: '${{ github.repository }}'
   # The pull request number
-  pull_number: '${{ github.event.workflow_run.pull_requests[0].number }}'
+  pull_number: ''
   # The template name or a lodash style template to use for the comment
   template: 'sorted_by_result'
   # The identifier to use for the sticky comment
diff --git a/action.yml b/action.yml
index 60af1a2..56eb7ec 100644
--- a/action.yml
+++ b/action.yml
@@ -12,8 +12,7 @@ inputs:
     default: '${{ github.repository }}'
   pull_number:
     description: 'The pull request number'
-    required: true
-    default: '${{ github.event.workflow_run.pull_requests[0].number }}'
+    required: false
   template:
     description: 'The template name or a lodash style template to use for the comment'
     required: false
diff --git a/index.js b/index.js
index 7f1a3f0..ba7f982 100644
--- a/index.js
+++ b/index.js
@@ -40,7 +40,7 @@ async function run() {
     core.info('Retrieving the inputs...')
     const repository = core.getInput('repository')
     const [owner, repo] = repository.split('/').slice(-2)
-    const pull_number = core.getInput('pull_number')
+    const pull_number_option = core.getInput('pull_number')
     const template_name = core.getInput('template')
     const identifier = core.getInput('identifier')
     const token = core.getInput('token')
@@ -68,6 +68,29 @@ async function run() {
     core.info('Setting up the GitHub client...')
     const octokit = new github.getOctokit(token)
 
+    core.info('Inferring the pull request number...')
+    let pull_number
+    if (pull_number_option === '') {
+      if (github.context.eventName !== 'workflow_run' || github.context.payload.event !== 'pull_request') {
+        throw new Error('The pull request number must be provided when not running in a workflow run event (triggered by pull_request event) context.')
+      }
+      core.info('Finding matching pull requests...')
+      const pull_requests = await octokit.paginate(octokit.rest.issues.search, {
+        q: `is:pr repo:${owner}/${repo} head:${github.context.payload.head_branch} base:${github.context.payload.base_branch} ${github.context.payload.commit.id}`
+      })
+      core.debug(`Pull requests: ${JSON.stringify(pull_requests, null, 2)}`)
+      if (pull_requests.length === 0) {
+        throw new Error('No pull request found for the commit.')
+      }
+      if (pull_requests.length > 1) {
+        throw new Error('Multiple pull requests found for the commit.')
+      }
+      pull_number = pull_requests[0].number
+    } else {
+      pull_number = parseInt(pull_number_option)
+    }
+    core.info(`Pull request number: ${pull_number}`)
+
     core.info('Retrieving the pull request...')
     const pull = await octokit.rest.pulls.get({
       owner,