From ae13cd8412aeda022300f2923b29c0471936389e Mon Sep 17 00:00:00 2001
From: Eugene Yokota <eed3si9n@gmail.com>
Date: Thu, 10 Jul 2014 17:49:52 -0400
Subject: [PATCH] Improves unresolved dependencies error by displaying the deps
 nodes. fixes #1422, #381

---
 ivy/src/main/scala/sbt/IvyActions.scala  | 30 ++++++++++++++++++---
 ivy/src/main/scala/sbt/IvyRetrieve.scala | 34 ++++++++++++++++++++++--
 2 files changed, 59 insertions(+), 5 deletions(-)

diff --git a/ivy/src/main/scala/sbt/IvyActions.scala b/ivy/src/main/scala/sbt/IvyActions.scala
index c87666373..bdbf5fe1c 100644
--- a/ivy/src/main/scala/sbt/IvyActions.scala
+++ b/ivy/src/main/scala/sbt/IvyActions.scala
@@ -146,6 +146,17 @@ object IvyActions {
       withExtra foreach { id => log.warn("\t\t" + id) }
       log.warn("")
     }
+    err.failed foreach { x =>
+      val failedPaths = err.failedPaths(x)
+      if (!failedPaths.isEmpty) {
+        log.warn("\n\tNote: Unresolved dependencies path:")
+        val reverseFailedPaths = (failedPaths.toList map { _.toString }).reverse
+        log.warn("\t\t" + reverseFailedPaths.head)
+        reverseFailedPaths.tail foreach { id =>
+          log.warn("\t\t  +- " + id)
+        }
+      }
+    }
   }
   def groupedConflicts[T](moduleFilter: ModuleFilter, grouping: ModuleID => T)(report: UpdateReport): Map[T, Set[String]] =
     report.configurations.flatMap { confReport =>
@@ -209,8 +220,15 @@ object IvyActions {
       val err =
         if (resolveReport.hasError) {
           val messages = resolveReport.getAllProblemMessages.toArray.map(_.toString).distinct
-          val failed = resolveReport.getUnresolvedDependencies.map(node => IvyRetrieve.toModuleID(node.getId))
-          Some(new ResolveException(messages, failed))
+          val failedPaths = Map(resolveReport.getUnresolvedDependencies map { node =>
+            val m = IvyRetrieve.toModuleID(node.getId)
+            val path = IvyRetrieve.findPath(node, module.getModuleRevisionId) map { x =>
+              IvyRetrieve.toModuleID(x.getId)
+            }
+            m -> path
+          }: _*)
+          val failed = failedPaths.keys.toSeq
+          Some(new ResolveException(messages, failed, failedPaths))
         } else None
       (resolveReport, err)
     }
@@ -269,4 +287,10 @@ object IvyActions {
       error("Missing files for publishing:\n\t" + missing.map(_._2.getAbsolutePath).mkString("\n\t"))
   }
 }
-final class ResolveException(val messages: Seq[String], val failed: Seq[ModuleID]) extends RuntimeException(messages.mkString("\n"))
+final class ResolveException(
+    val messages: Seq[String],
+    val failed: Seq[ModuleID],
+    val failedPaths: Map[ModuleID, Seq[ModuleID]]) extends RuntimeException(messages.mkString("\n")) {
+  def this(messages: Seq[String], failed: Seq[ModuleID]) =
+    this(messages, failed, Map(failed map { m => m -> Nil }: _*))
+}
diff --git a/ivy/src/main/scala/sbt/IvyRetrieve.scala b/ivy/src/main/scala/sbt/IvyRetrieve.scala
index 5d0f3f6ec..e863d6723 100644
--- a/ivy/src/main/scala/sbt/IvyRetrieve.scala
+++ b/ivy/src/main/scala/sbt/IvyRetrieve.scala
@@ -5,10 +5,10 @@ package sbt
 
 import java.io.File
 import collection.mutable
-
-import org.apache.ivy.core.{ module, report }
+import org.apache.ivy.core.{ module, report, resolve }
 import module.descriptor.{ Artifact => IvyArtifact }
 import module.id.ModuleRevisionId
+import resolve.IvyNode
 import report.{ ArtifactDownloadReport, ConfigurationResolveReport, ResolveReport }
 
 object IvyRetrieve {
@@ -51,4 +51,34 @@ object IvyRetrieve {
     new UpdateStats(report.getResolveTime, report.getDownloadTime, report.getDownloadSize, false)
   def configurationReport(confReport: ConfigurationResolveReport): ConfigurationReport =
     new ConfigurationReport(confReport.getConfiguration, moduleReports(confReport), evicted(confReport))
+
+  /**
+   * Tries to find Ivy graph path the from node to target.
+   */
+  def findPath(target: IvyNode, from: ModuleRevisionId): List[IvyNode] = {
+    def doFindPath(current: IvyNode, path: List[IvyNode]): List[IvyNode] = {
+      val callers = current.getAllRealCallers.toList
+      // Ivy actually returns non-direct callers here.
+      // that's why we have to calculate all possible paths below and pick the longest path.
+      val directCallers = callers filter { caller =>
+        val md = caller.getModuleDescriptor
+        val dd = md.getDependencies.toList find { dd =>
+          (dd.getDependencyRevisionId == current.getId) &&
+            (dd.getParentRevisionId == caller.getModuleRevisionId)
+        }
+        dd.isDefined
+      }
+      val directCallersRevId = (directCallers map { _.getModuleRevisionId }).distinct
+      val paths: List[List[IvyNode]] = ((directCallersRevId map { revId =>
+        val node = current.findNode(revId)
+        if (revId == from) node :: path
+        else if (node == node.getRoot) Nil
+        else if (path contains node) path
+        else doFindPath(node, node :: path)
+      }) sortBy { _.size }).reverse
+      paths.headOption getOrElse Nil
+    }
+    if (target.getId == from) List(target)
+    else doFindPath(target, List(target))
+  }
 }