From 45a502aa1280743e8feb6f828e4e65b6ab12837c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christoph=20L=C3=A4ubrich?= <christoph@laeubi-soft.de>
Date: Wed, 6 Mar 2024 15:34:40 +0100
Subject: [PATCH] MNG-8069 - add failing projects if a project is banned from
 reactor

Currently if a multimodule build fails (either fast or at the end), the
user gets a message in the log that reads:

"This project has been banned from the build due to previous failures."

this is correct but does not give a hint what has failed and one needs
to investigate the build logs to get more details.

This now instead shows as part of the message the actual project that
make it impossible to build this  one and is the reason for this project
being banned.
---
 .../maven/cli/event/ExecutionEventLogger.java | 39 ++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/maven-embedder/src/main/java/org/apache/maven/cli/event/ExecutionEventLogger.java b/maven-embedder/src/main/java/org/apache/maven/cli/event/ExecutionEventLogger.java
index f7e2b48633e3..9f2169a7fc8f 100644
--- a/maven-embedder/src/main/java/org/apache/maven/cli/event/ExecutionEventLogger.java
+++ b/maven-embedder/src/main/java/org/apache/maven/cli/event/ExecutionEventLogger.java
@@ -20,6 +20,7 @@
 
 import java.io.File;
 import java.nio.file.Path;
+import java.util.Comparator;
 import java.util.List;
 import java.util.Objects;
 
@@ -28,8 +29,10 @@
 import org.apache.maven.execution.BuildSuccess;
 import org.apache.maven.execution.BuildSummary;
 import org.apache.maven.execution.ExecutionEvent;
+import org.apache.maven.execution.MavenExecutionRequest;
 import org.apache.maven.execution.MavenExecutionResult;
 import org.apache.maven.execution.MavenSession;
+import org.apache.maven.execution.ProjectDependencyGraph;
 import org.apache.maven.plugin.MojoExecution;
 import org.apache.maven.plugin.descriptor.MojoDescriptor;
 import org.apache.maven.project.MavenProject;
@@ -243,10 +246,44 @@ public void projectSkipped(ExecutionEvent event) {
         if (logger.isInfoEnabled()) {
             logger.info("");
             infoLine('-');
+            MavenSession session = event.getSession();
+            MavenExecutionResult result = session.getResult();
+            ProjectDependencyGraph projectDependencyGraph = session.getProjectDependencyGraph();
+            List<MavenProject> upstreamProjects;
+            if (MavenExecutionRequest.REACTOR_FAIL_AT_END.equals(session.getReactorFailureBehavior())
+                    && projectDependencyGraph != null) {
+
+                // the project is blacklisted only so one of its upstreams must have failed here...
+                upstreamProjects = projectDependencyGraph.getUpstreamProjects(event.getProject(), true);
+            } else {
+                // any other failure must have lead to this so any projects is eligible
+                upstreamProjects = session.getProjects();
+            }
+            // now collect all failing projects order by their ID
 
             infoMain("Skipping " + event.getProject().getName());
             logger.info("This project has been banned from the build due to previous failures.");
-
+            upstreamProjects.stream()
+                    .map(result::getBuildSummary)
+                    .filter(BuildFailure.class::isInstance)
+                    .map(BuildFailure.class::cast)
+                    .sorted(Comparator.comparing(
+                            BuildFailure::getProject,
+                            Comparator.comparing(MavenProject::getId, String.CASE_INSENSITIVE_ORDER)))
+                    .forEach(buildfailure -> {
+                        String reason;
+                        Throwable cause = buildfailure.getCause();
+                        if (cause == null) {
+                            reason = "failed!";
+                        } else {
+                            reason = cause.getClass().getSimpleName();
+                            String message = cause.getMessage();
+                            if (message != null) {
+                                message += ": " + message;
+                            }
+                        }
+                        logger.info(" - " + buildfailure.getProject().getId() + ": " + reason);
+                    });
             infoLine('-');
         }
     }