Improve tracking of unattached dependencies

subprojects/dependency-management/src/integTest/groovy/org/gradle/integtests/resolve/platforms/JavaPlatformResolveIntegrationTest.groovy

@@ -640,6 +640,84 @@ class JavaPlatformResolveIntegrationTest extends AbstractHttpDependencyResolutio
         platform << ["project(':platform')", "'org:other-platform:1.0'", "'org:bom-platform:1.0'"]
     }
 
+    def 'platform deselection / reselection does not cause orphan edges'() {
+        given:
+        def depExcluded = mavenHttpRepo.module('org.test', 'excluded', '1.0').publish()
+        def depA = mavenHttpRepo.module('org.test', 'depA', '1.0').publish()
+        def platform = mavenHttpRepo.module('org.test', 'platform', '1.0').withModuleMetadata().withoutDefaultVariants()
+            .withVariant('apiElements') {
+                useDefaultArtifacts = false
+                attribute(Usage.USAGE_ATTRIBUTE.name, Usage.JAVA_API)
+                attribute(Category.CATEGORY_ATTRIBUTE.name, Category.REGULAR_PLATFORM)
+                constraint('org.test', 'depA', '1.0')
+                constraint('org.test', 'excluded', '1.0')
+            }
+            .withVariant('runtimeElements') {
+                useDefaultArtifacts = false
+                attribute(Usage.USAGE_ATTRIBUTE.name, Usage.JAVA_RUNTIME)
+                attribute(Category.CATEGORY_ATTRIBUTE.name, Category.REGULAR_PLATFORM)
+                constraint('org.test', 'depA', '1.0')
+                constraint('org.test', 'excluded', '1.0')
+            }.publish()
+        def depC = mavenHttpRepo.module('org.test', 'depC', '1.0').withModuleMetadata()
+            .withVariant('runtime') {
+                dependsOn('org.test', 'platform', '1.0', null, [(Category.CATEGORY_ATTRIBUTE.name): Category.REGULAR_PLATFORM])
+            }.publish()
+        def depB = mavenHttpRepo.module('org.test', 'depB', '1.0').dependsOn([exclusions: [[module: 'excluded']]], depC).publish()
+        def depF = mavenHttpRepo.module('org.test', 'depF', '1.0').dependsOn(depC).publish()
+        def depE = mavenHttpRepo.module('org.test', 'depE', '1.0').dependsOn(depF).publish()
+        def depD = mavenHttpRepo.module('org.test', 'depD', '1.0').dependsOn(depE).publish()
+
+        depExcluded.allowAll()
+        depA.allowAll()
+        depB.allowAll()
+        depC.allowAll()
+        depD.allowAll()
+        depE.allowAll()
+        depF.allowAll()
+        platform.allowAll()
+
+        buildFile << """
+            configurations {
+                conf.dependencies.clear()
+            }
+
+            dependencies {
+                conf 'org.test:depA'
+                conf 'org.test:depB:1.0'
+                conf 'org.test:depD:1.0'
+            }
+"""
+        checkConfiguration("conf")
+        resolve.expectDefaultConfiguration("runtime")
+
+        when:
+        succeeds 'checkDeps'
+
+        then:
+        resolve.expectGraph {
+            root(":", "org.test:test:1.9") {
+                edge("org.test:depA", "org.test:depA:1.0")
+                module("org.test:depB:1.0") {
+                    module("org.test:depC:1.0") {
+                        module('org.test:platform:1.0') {
+                            noArtifacts()
+                            constraint('org.test:depA:1.0')
+                        }
+                    }
+                }
+                module('org.test:depD:1.0') {
+                    module('org.test:depE:1.0') {
+                        module('org.test:depF:1.0') {
+                            module('org.test:depC:1.0')
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+
     private void checkConfiguration(String configuration) {
         resolve = new ResolveTestFixture(buildFile, configuration)
         resolve.expectDefaultConfiguration("compile")

subprojects/dependency-management/src/main/java/org/gradle/api/internal/artifacts/ivyservice/resolveengine/graph/builder/EdgeState.java

@@ -66,6 +66,7 @@ class EdgeState implements DependencyGraphEdge {
     private ExcludeSpec cachedExclusions;
 
     private ResolvedVariantResult resolvedVariant;
+    private boolean unattached;
 
     EdgeState(NodeState from, DependencyState dependencyState, ExcludeSpec transitiveExclusions, ResolveState resolveState) {
         this.from = from;
@@ -181,9 +182,13 @@ void failWith(Throwable err) {
         targetNodeSelectionFailure = new ModuleVersionResolveException(dependencyState.getRequested(), err);
     }
 
-    public void restart() {
+    public void restart(boolean checkUnattached) {
         if (from.isSelected()) {
             removeFromTargetConfigurations();
+            // We now have corner cases that can lead to this restart not succeeding
+            if (checkUnattached && !isUnattached()) {
+                selector.getTargetModule().addUnattachedDependency(this);
+            }
             attachToTargetConfigurations();
         }
     }
@@ -430,4 +435,16 @@ public void updateTransitiveExcludes(ExcludeSpec newResolutionFilter) {
             targetNode.updateTransitiveExcludes();
         }
     }
+
+    public void markUnattached() {
+        this.unattached = true;
+    }
+
+    public void markAttached() {
+        this.unattached = false;
+    }
+
+    public boolean isUnattached() {
+        return unattached;
+    }
 }

subprojects/dependency-management/src/main/java/org/gradle/api/internal/artifacts/ivyservice/resolveengine/graph/builder/ModuleResolveState.java

@@ -262,20 +262,23 @@ private void doRestart(ComponentState selected) {
     private void restartUnattachedDependencies() {
         if (unattachedDependencies.size() == 1) {
             EdgeState singleDependency = unattachedDependencies.get(0);
-            singleDependency.restart();
+            singleDependency.restart(false);
         } else {
             for (EdgeState dependency : new ArrayList<>(unattachedDependencies)) {
-                dependency.restart();
+                dependency.restart(false);
             }
         }
     }
 
     public void addUnattachedDependency(EdgeState edge) {
         unattachedDependencies.add(edge);
+        edge.markUnattached();
     }
 
     public void removeUnattachedDependency(EdgeState edge) {
-        unattachedDependencies.remove(edge);
+        if (unattachedDependencies.remove(edge)) {
+            edge.markAttached();
+        }
     }
 
     public ComponentState getVersion(ModuleVersionIdentifier id, ComponentIdentifier componentIdentifier) {

subprojects/dependency-management/src/main/java/org/gradle/api/internal/artifacts/ivyservice/resolveengine/graph/builder/NodeState.java

@@ -615,7 +615,7 @@ public boolean isSelected() {
 
     public void evict() {
         evicted = true;
-        restartIncomingEdges();
+        restartIncomingEdges(false);
     }
 
     boolean shouldIncludedInGraphResult() {
@@ -976,18 +976,18 @@ public void restart(ComponentState selected) {
             }
         } else {
             if (!incomingEdges.isEmpty()) {
-                restartIncomingEdges();
+                restartIncomingEdges(true);
             }
         }
     }
 
-    private void restartIncomingEdges() {
+    private void restartIncomingEdges(boolean checkUnattached) {
         if (incomingEdges.size() == 1) {
             EdgeState singleEdge = incomingEdges.get(0);
-            singleEdge.restart();
+            singleEdge.restart(checkUnattached);
         } else {
             for (EdgeState dependency : new ArrayList<>(incomingEdges)) {
-                dependency.restart();
+                dependency.restart(checkUnattached);
             }
         }
         clearIncomingEdges();