feat: support pull_request_number variable on push events

added support for pull_request_number dynamic variable when
push event is occurred on pull request merge.

upstream issue: #1353

https://issues.redhat.com/browse/SRVKP-7834

Signed-off-by: Zaki Shaikh <[email protected]>

Author: zakisk

docs/content/docs/guide/authoringprs.md

@@ -53,7 +53,7 @@ check out the code that is being tested.
 | event_type          | The event type (eg: `pull_request` or `push`)                                                                                                                                   | `{{event_type}}`                    | pull_request          (see the note for GitOps Comments [here]({{< relref "/docs/guide/gitops_commands.md#event-type-annotation-and-dynamic-variables" >}}) ) |
 | git_auth_secret     | The secret name auto-generated with provider token to check out private repos.                                                                                                  | `{{git_auth_secret}}`               | pac-gitauth-xkxkx                                                                                                                                             |
 | headers             | The request headers (see [below](#using-the-body-and-headers-in-a-pipelines-as-code-parameter))                                                                                 | `{{headers['x-github-event']}}`     | push                                                                                                                                                          |
-| pull_request_number | The pull or merge request number, only defined when we are in a `pull_request` event type.                                                                                      | `{{pull_request_number}}`           | 1                                                                                                                                                             |
+| pull_request_number | The pull or merge request number, only defined when we are in a `pull_request` event or push event occurred when pull request is merged.                                        | `{{pull_request_number}}`           | 1                                                                                                                                                             |
 | repo_name           | The repository name.                                                                                                                                                            | `{{repo_name}}`                     | pipelines-as-code                                                                                                                                             |
 | repo_owner          | The repository owner.                                                                                                                                                           | `{{repo_owner}}`                    | openshift-pipelines                                                                                                                                           |
 | repo_url            | The repository full URL.                                                                                                                                                        | `{{repo_url}}`                      | https:/github.com/repo/owner                                                                                                                                  |
@@ -67,6 +67,11 @@ check out the code that is being tested.
 | trigger_comment     | The comment triggering the PipelineRun when using a [GitOps command]({{< relref "/docs/guide/running.md#gitops-command-on-pull-or-merge-request" >}}) (like `/test`, `/retest`) | `{{trigger_comment}}`               | /merge-pr branch                                                                                                                                              |
 | pull_request_labels | The labels of the pull request separated by a newline                                                                                                                           | `{{pull_request_labels}}`           | bugs\nenhancement                                                                                                                                             |
 
+Note: When using the `{{ pull_request_number }}` variable in a push-triggered PipelineRun when a pull request is merged and the commit is associated with multiple pull requests
+the git provider API may return more than one pull request. In such cases, the `{{ pull_request_number }}` variable will contain the number of the first pull request returned by the API.
+
+The `{{ pull_request_number }}` variable is currently supported only for the GitHub provider when used in a push event.
+
 ### Defining Parameters with Object Values in YAML
 
 When working with YAML, particularly when defining parameters, you might encounter situations where you need to pass an object or a dynamic variable (e.g., `{{ body }}`) as the value of a parameter. However, YAML's validation rules prevent such values from being defined inline.

pkg/provider/github/github_test.go

@@ -1416,7 +1416,7 @@ func TestSkipPushEventForPRCommits(t *testing.T) {
 			},
 			isPartOfPR:          false,
 			wantErr:             false,
-			skipWarnLogContains: "Error checking if push commit is part of PR",
+			skipWarnLogContains: "Error getting pull requests associated with the commit in this push event",
 		},
 	}
 

pkg/provider/github/parse_payload.go

@@ -208,45 +208,39 @@ func (v *Provider) ParsePayload(ctx context.Context, run *params.Run, request *h
 	return processedEvent, nil
 }
 
-// isCommitPartOfPullRequest checks if the commit from a push event is part of an open pull request
-// If it is, it returns true and the PR number.
-func (v *Provider) isCommitPartOfPullRequest(ctx context.Context, sha, org, repo string) (bool, int, error) {
+// getPullRequestsWithCommit lists the all pull requests associated with given commit.
+func (v *Provider) getPullRequestsWithCommit(ctx context.Context, sha, org, repo string) ([]*github.PullRequest, error) {
 	if v.ghClient == nil {
-		return false, 0, fmt.Errorf("github client is not initialized")
+		return nil, fmt.Errorf("github client is not initialized")
 	}
 
 	// Validate input parameters
 	if sha == "" {
-		return false, 0, fmt.Errorf("sha cannot be empty")
+		return nil, fmt.Errorf("sha cannot be empty")
 	}
 	if org == "" {
-		return false, 0, fmt.Errorf("organization cannot be empty")
+		return nil, fmt.Errorf("organization cannot be empty")
 	}
 	if repo == "" {
-		return false, 0, fmt.Errorf("repository cannot be empty")
+		return nil, fmt.Errorf("repository cannot be empty")
 	}
 
-	// Use pagination to handle repositories with many PRs
 	opts := &github.ListOptions{
 		PerPage: 100, // GitHub's maximum per page
 	}
 
+	pullRequests := []*github.PullRequest{}
+
 	for {
 		// Use the "List pull requests associated with a commit" API to check if the commit is part of any open PR
 		prs, resp, err := v.ghClient.PullRequests.ListPullRequestsWithCommit(ctx, org, repo, sha, opts)
 		if err != nil {
 			// Log the error for debugging purposes
 			v.Logger.Debugf("Failed to list pull requests for commit %s in %s/%s: %v", sha, org, repo, err)
-			return false, 0, fmt.Errorf("failed to list pull requests for commit %s: %w", sha, err)
+			return nil, fmt.Errorf("failed to list pull requests for commit %s: %w", sha, err)
 		}
 
-		// Check if any of the returned PRs are open
-		for _, pr := range prs {
-			if pr.GetState() == "open" {
-				v.Logger.Debugf("Commit %s is part of open PR #%d in %s/%s", sha, pr.GetNumber(), org, repo)
-				return true, pr.GetNumber(), nil
-			}
-		}
+		pullRequests = append(pullRequests, prs...)
 
 		// Check if there are more pages
 		if resp.NextPage == 0 {
@@ -255,8 +249,22 @@ func (v *Provider) isCommitPartOfPullRequest(ctx context.Context, sha, org, repo
 		opts.Page = resp.NextPage
 	}
 
+	return pullRequests, nil
+}
+
+// isCommitPartOfPullRequest checks if the commit from a push event is part of an open pull request
+// If it is, it returns true and the PR number.
+func (v *Provider) isCommitPartOfPullRequest(sha, org, repo string, prs []*github.PullRequest) (bool, int) {
+	// Check if any of the returned PRs are open
+	for _, pr := range prs {
+		if pr.GetState() == "open" {
+			v.Logger.Debugf("Commit %s is part of open PR #%d in %s/%s", sha, pr.GetNumber(), org, repo)
+			return true, pr.GetNumber()
+		}
+	}
+
 	v.Logger.Debugf("Commit %s is not part of any open pull request in %s/%s", sha, org, repo)
-	return false, 0, nil
+	return false, 0
 }
 
 func (v *Provider) processEvent(ctx context.Context, event *info.Event, eventInt any) (*info.Event, error) {
@@ -327,12 +335,17 @@ func (v *Provider) processEvent(ctx context.Context, event *info.Event, eventInt
 		org := gitEvent.GetRepo().GetOwner().GetLogin()
 		repoName := gitEvent.GetRepo().GetName()
 
-		// Only check if the flag is enabled
-		if v.pacInfo.SkipPushEventForPRCommits {
-			isPartOfPR, prNumber, err := v.isCommitPartOfPullRequest(ctx, sha, org, repoName)
-			if err != nil {
-				v.Logger.Warnf("Error checking if push commit is part of PR: %v", err)
-			}
+		// First get all the pull requests associated with this commit so that we can reuse the output to check
+		// whether the commit is included in any PR or not, and if this push is generated on PR merge event, we can
+		// assign PR number to `pull_request_number` variable.
+		prs, err := v.getPullRequestsWithCommit(ctx, sha, org, repoName)
+		if err != nil {
+			v.Logger.Warnf("Error getting pull requests associated with the commit in this push event: %v", err)
+		}
+
+		// Only check if the flag is enabled and there are pull requests associated with this commit.
+		if v.pacInfo.SkipPushEventForPRCommits && len(prs) > 0 {
+			isPartOfPR, prNumber := v.isCommitPartOfPullRequest(sha, org, repoName, prs)
 
 			// If the commit is part of a PR, skip processing the push event
 			if isPartOfPR {
@@ -341,6 +354,12 @@ func (v *Provider) processEvent(ctx context.Context, event *info.Event, eventInt
 			}
 		}
 
+		// if there are pull requests associated with this commit, first pull request number will be used
+		// for `pull_request_number` dynamic variable.
+		if len(prs) > 0 {
+			processedEvent.PullRequestNumber = *prs[0].Number
+		}
+
 		processedEvent.Organization = gitEvent.GetRepo().GetOwner().GetLogin()
 		processedEvent.Repository = gitEvent.GetRepo().GetName()
 		processedEvent.DefaultBranch = gitEvent.GetRepo().GetDefaultBranch()