Avoid circular task dependency when build includes itself (#143)

Fixes #141

Author: bigdaz

plugin-test/src/test/groovy/org/gradle/github/dependencygraph/MultiProjectDependencyExtractorTest.groovy

@@ -2,6 +2,8 @@ package org.gradle.github.dependencygraph
 
 
 import org.gradle.test.fixtures.maven.MavenModule
+import org.gradle.util.GradleVersion
+import spock.lang.IgnoreIf
 
 class MultiProjectDependencyExtractorTest extends BaseExtractorTest {
     private MavenModule foo
@@ -250,4 +252,32 @@ class MultiProjectDependencyExtractorTest extends BaseExtractorTest {
             "org.test:foo:1.0": [package_url: purlFor(foo)]
         ])
     }
+
+    @IgnoreIf({
+        // `includeBuild('.')` is not possible with Gradle < 6.1
+        GradleVersion.version(testGradleVersion) < GradleVersion.version("6.1")
+    })
+    def "extracts dependencies from build that includes itself"() {
+        given:
+        settingsFile << """
+            includeBuild('.')
+"""
+        buildFile << """
+            apply plugin: 'java'
+            dependencies {
+                implementation 'org.test:bar:1.0'
+            }
+
+"""
+
+        when:
+        run(":ForceDependencyResolutionPlugin_resolveAllDependencies")
+
+        then:
+        def manifest = gitHubManifest()
+        manifest.sourceFile == "settings.gradle"
+        manifest.assertResolved([
+            "org.test:bar:1.0": [package_url: purlFor(bar)]
+        ])
+    }
 }

plugin/src/main/kotlin/org/gradle/forceresolve/ForceDependencyResolutionPlugin.kt

@@ -39,8 +39,10 @@ class ForceDependencyResolutionPlugin : Plugin<Gradle> {
 
             // Depend on all 'resolveBuildDependencies' task in each included build
             gradle.includedBuilds.forEach { includedBuild ->
-                resolveAllDeps.configure {
-                    it.dependsOn(includedBuild.task(":$RESOLVE_ALL_TASK"))
+                if (includedBuild.projectDir != gradle.rootProject.projectDir) {
+                    resolveAllDeps.configure {
+                        it.dependsOn(includedBuild.task(":$RESOLVE_ALL_TASK"))
+                    }
                 }
             }
         }