Make the bot add branch labels/title-prefixes to the pull requests targeting non-main branch

README.md

@@ -140,6 +140,15 @@ pullRequestTasks:
       # Tasks specific to the improvement issue type:
       improvement:
          - improvement task1
+branches:
+  # Make the bot add a label with the name of base ref when a pull requests target a non-main branch.
+  enabled: true
+  # Prefix is only added when a prefix format is passed. Must contain a single %s that will be replaced with the base ref 
+  titlePrefix: "[%s]"
+  # Label is only added when a label format is passed. Must contain a single %s that will be replaced with the base ref
+  label: "branch-%s"
+  ignore:
+    # as other config sections, supports ignore rules
 ```
 
 ### Altering the infrastructure

src/main/java/org/hibernate/infra/bot/EditPullRequestAddBranchTagLabel.java

@@ -0,0 +1,111 @@
+package org.hibernate.infra.bot;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Locale;
+import java.util.Random;
+
+import org.hibernate.infra.bot.config.DeploymentConfig;
+import org.hibernate.infra.bot.config.RepositoryConfig;
+
+import org.jboss.logging.Logger;
+
+import io.quarkiverse.githubapp.ConfigFile;
+import io.quarkiverse.githubapp.event.PullRequest;
+import jakarta.inject.Inject;
+import org.kohsuke.github.GHEventPayload;
+import org.kohsuke.github.GHFileNotFoundException;
+import org.kohsuke.github.GHIssueState;
+import org.kohsuke.github.GHLabel;
+import org.kohsuke.github.GHPullRequest;
+import org.kohsuke.github.GHRepository;
+import org.kohsuke.github.GHUser;
+
+public class EditPullRequestAddBranchTagLabel {
+	private static final Logger LOG = Logger.getLogger( EditPullRequestAddBranchTagLabel.class );
+
+	@Inject
+	DeploymentConfig deploymentConfig;
+
+	void pullRequestChanged(
+			@PullRequest.Opened @PullRequest.Reopened @PullRequest.Edited @PullRequest.Synchronize
+			GHEventPayload.PullRequest payload,
+			@ConfigFile("hibernate-github-bot.yml") RepositoryConfig repositoryConfig
+	) throws IOException {
+		addTagOrLabel( payload.getRepository(), repositoryConfig, payload.getPullRequest() );
+	}
+
+	private void addTagOrLabel(
+			GHRepository repository,
+			RepositoryConfig repositoryConfig,
+			GHPullRequest pullRequest
+	) throws IOException {
+		if ( repositoryConfig == null || repositoryConfig.branches == null
+				|| !repositoryConfig.branches.getEnabled().orElse( Boolean.FALSE ) ) {
+			return;
+		}
+
+		if ( !shouldCheck( repository, pullRequest, repositoryConfig.branches.getIgnore() ) ) {
+			return;
+		}
+
+		String base = pullRequest.getBase().getRef();
+		if ( "main".equalsIgnoreCase( base ) ) {
+			return;
+		}
+
+		if ( repositoryConfig.branches.getTitlePrefix().isPresent() ) {
+			String prefix = String.format( Locale.ROOT, repositoryConfig.branches.getTitlePrefix().get(), base );
+			String title = pullRequest.getTitle();
+			if ( !title.startsWith( prefix ) ) {
+				if ( !deploymentConfig.isDryRun() ) {
+					pullRequest.setTitle( prefix + " " + title );
+				}
+				else {
+					LOG.info( "Pull request #" + pullRequest.getNumber() + " - Setting title to: " + title );
+				}
+			}
+		}
+
+		if ( repositoryConfig.branches.getLabel().isPresent() ) {
+			String labelName = String.format( Locale.ROOT, repositoryConfig.branches.getLabel().get(), base );
+			for ( GHLabel ghLabel : pullRequest.getLabels() ) {
+				if ( ghLabel.getName().equals( labelName ) ) {
+					return;
+				}
+			}
+
+			GHLabel label;
+			try {
+				label = repository.getLabel( base );
+			}
+			catch (GHFileNotFoundException e) {
+				label = repository.createLabel(
+						base,
+						String.format( Locale.ROOT, "%06x", new Random().nextInt( 0xffffff + 1 ) ),
+						"Label for pull requests targeting [" + base + "] branch."
+				);
+			}
+
+			if ( !deploymentConfig.isDryRun() ) {
+				pullRequest.addLabels( label );
+			}
+			else {
+				LOG.info( "Pull request #" + pullRequest.getNumber() + " - Adding label: " + label.getName() );
+			}
+		}
+	}
+
+	private boolean shouldCheck(GHRepository repository, GHPullRequest pullRequest, List<RepositoryConfig.IgnoreConfiguration> ignoredPRConfigurations) throws IOException {
+		GHUser author = pullRequest.getUser();
+		String title = pullRequest.getTitle();
+		for ( RepositoryConfig.IgnoreConfiguration ignore : ignoredPRConfigurations ) {
+			if ( ignore.getUser().equals( author.getLogin() )
+					&& ignore.getTitlePattern().matcher( title ).matches() ) {
+				return false;
+			}
+		}
+		return !GHIssueState.CLOSED.equals( pullRequest.getState() )
+				&& repository.getId() == pullRequest.getBase().getRepository().getId();
+	}
+}

src/main/java/org/hibernate/infra/bot/config/RepositoryConfig.java

@@ -20,6 +20,8 @@ public class RepositoryConfig {
 
 	public TaskList pullRequestTasks;
 
+	public BranchLabel branches;
+
 	public static class JiraConfig {
 		private Optional<Pattern> issueKeyPattern = Optional.empty();
 
@@ -229,4 +231,43 @@ public void setIgnore(List<IgnoreConfiguration> ignore) {
 			this.ignore = ignore;
 		}
 	}
+
+	public static class BranchLabel {
+		private Optional<Boolean> enabled = Optional.empty();
+		private List<IgnoreConfiguration> ignore = Collections.emptyList();
+		private Optional<String> label = Optional.empty();
+		private Optional<String> titlePrefix = Optional.empty();
+
+		public Optional<Boolean> getEnabled() {
+			return enabled;
+		}
+
+		public void setEnabled(Boolean enabled) {
+			this.enabled = Optional.of( enabled );
+		}
+
+		public List<IgnoreConfiguration> getIgnore() {
+			return ignore;
+		}
+
+		public void setIgnore(List<IgnoreConfiguration> ignore) {
+			this.ignore = ignore;
+		}
+
+		public Optional<String> getLabel() {
+			return label;
+		}
+
+		public void setLabel(String label) {
+			this.label = Optional.of( label );
+		}
+
+		public Optional<String> getTitlePrefix() {
+			return titlePrefix;
+		}
+
+		public void setTitlePrefix(String titlePrefix) {
+			this.titlePrefix = Optional.of( titlePrefix );
+		}
+	}
 }