From d2630117b82b9c04726c544a1a6a96ff38f02384 Mon Sep 17 00:00:00 2001
From: George Gastaldi <gegastaldi@gmail.com>
Date: Thu, 9 Jun 2022 17:59:14 -0300
Subject: [PATCH] Affect `triage/needs-rebase` on Pull Requests with merge
 conflicts

This adds the `triage/needs-rebase` label (or removes it) on opened pull-requests, making it easier to find pull-requests that require a rebase to be merged

Apply suggestions from code review

Co-authored-by: Guillaume Smet <guillaume.smet@gmail.com>
---
 README.adoc                                   |  5 ++
 ...AffectNeedsRebaseToOpenedPullRequests.java | 51 +++++++++++++++++++
 src/main/java/io/quarkus/bot/util/Labels.java |  1 +
 3 files changed, 57 insertions(+)
 create mode 100644 src/main/java/io/quarkus/bot/AffectNeedsRebaseToOpenedPullRequests.java

diff --git a/README.adoc b/README.adoc
index 0f78f3f..51bd0fa 100644
--- a/README.adoc
+++ b/README.adoc
@@ -167,6 +167,11 @@ The bot will automatically remove these labels when they are outdated:
 
 The bot enforces a specific color for any label created that starts with `area/` so that all these labels are consistent.
 
+=== Include `triage/needs-rebase` on unmergeable pull-requests
+
+Pull requests may require a rebase when conflicts appear. The bot adds a `triage/needs-rebase` label on pull requests that cannot be merged and removes it when the pull request is in a mergeable state again.
+
+
 == Contributing
 
 To participate to the development of this GitHub App, create a playground project in your own org and
diff --git a/src/main/java/io/quarkus/bot/AffectNeedsRebaseToOpenedPullRequests.java b/src/main/java/io/quarkus/bot/AffectNeedsRebaseToOpenedPullRequests.java
new file mode 100644
index 0000000..58700f8
--- /dev/null
+++ b/src/main/java/io/quarkus/bot/AffectNeedsRebaseToOpenedPullRequests.java
@@ -0,0 +1,51 @@
+package io.quarkus.bot;
+
+import io.quarkiverse.githubapp.event.PullRequest;
+import io.quarkiverse.githubapp.event.Push;
+import io.quarkus.bot.util.Labels;
+import org.kohsuke.github.GHEventPayload;
+import org.kohsuke.github.GHIssueState;
+import org.kohsuke.github.GHPullRequest;
+import org.kohsuke.github.GHRepository;
+
+import java.io.IOException;
+
+public class AffectNeedsRebaseToOpenedPullRequests {
+
+    /**
+     * Affect triage/needs-rebase label on pull request events
+     */
+    void triageNeedsRebaseOnPullRequest(
+            @PullRequest.Opened @PullRequest.Reopened @PullRequest.Synchronize GHEventPayload.PullRequest pullRequestPayload)
+            throws IOException {
+        affectNeedsRebaseLabel(pullRequestPayload.getPullRequest());
+    }
+
+    void triageNeedsRebaseOnRepositoryPush(@Push GHEventPayload.Push pushRequestPayload) throws IOException {
+        GHRepository repository = pushRequestPayload.getRepository();
+        String defaultBranch = repository.getDefaultBranch();
+        for (GHPullRequest pullRequest : repository.getPullRequests(GHIssueState.OPEN)) {
+            if (!defaultBranch.equals(pullRequest.getBase().getRef())) {
+                continue;
+            }
+            affectNeedsRebaseLabel(pullRequest);
+        }
+    }
+
+    private void affectNeedsRebaseLabel(GHPullRequest pullRequest) throws IOException {
+        Boolean mergeable = pullRequest.getMergeable();
+        boolean hasNeedsRebaseLabel = pullRequest.getLabels().stream()
+                .anyMatch(label -> Labels.TRIAGE_NEEDS_REBASE.equals(label.getName()));
+        if (mergeable != null) {
+            if (mergeable) {
+                if (hasNeedsRebaseLabel) {
+                    pullRequest.removeLabels(Labels.TRIAGE_NEEDS_REBASE);
+                }
+            } else {
+                if (!hasNeedsRebaseLabel) {
+                    pullRequest.addLabels(Labels.TRIAGE_NEEDS_REBASE);
+                }
+            }
+        }
+    }
+}
diff --git a/src/main/java/io/quarkus/bot/util/Labels.java b/src/main/java/io/quarkus/bot/util/Labels.java
index 083cb45..bc71b8e 100644
--- a/src/main/java/io/quarkus/bot/util/Labels.java
+++ b/src/main/java/io/quarkus/bot/util/Labels.java
@@ -14,6 +14,7 @@ public class Labels {
     public static final String AREA_PREFIX = "area/";
     public static final String AREA_INFRA = "area/infra";
     public static final String TRIAGE_INVALID = "triage/invalid";
+    public static final String TRIAGE_NEEDS_REBASE = "triage/needs-rebase";
     public static final String TRIAGE_NEEDS_TRIAGE = "triage/needs-triage";
     public static final String TRIAGE_WAITING_FOR_CI = "triage/waiting-for-ci";
     public static final String TRIAGE_QE = "triage/qe?";