Don't re-add suppressed Gradle API to compileOnly configuration (#1422)

As part of Gradle's experiments with publishing an external Gradle API (gradle/gradle issue 29483), they are beginning to look at suppressing the local Gradle API dependency that is usually used when the `java-gradle-plugin` plugin is applied. Because of this, though, the current strategy that the Shadow plugin uses to move it from `api` to `compileOnly` doesn't check if it exists to begin with. This PR aims to solve that problem. I've added tests as needed.

Gradle's Plugin Publish plugin has a similar issue which I've gone into detail in gradle/plugin-portal-requests issue 260.


* Add tests for checking presence of Gradle API in dependencies

* Clean up tests

* Less diff in configureJavaGradlePlugin

* Remove afterEvaluate

* Apply suggestions from code review

* Update changelog

* Try `named`

* Revert "Try `named`"

This reverts commit 0cae38e.

---------

Co-authored-by: Goooler <[email protected]>

Author: Jonathing

docs/changes/README.md

@@ -4,6 +4,7 @@
 
 **Changed**
 
+- Don't re-add suppressed Gradle API to `compileOnly` configuration. ([#1422](https://github.com/GradleUp/shadow/pull/1422))
 - Bump the min Gradle requirement to 8.11. ([#1479](https://github.com/GradleUp/shadow/pull/1479))
 - Expose Ant as `compile` scope. ([#1488](https://github.com/GradleUp/shadow/pull/1488))
 

src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/JavaPluginTest.kt

@@ -5,6 +5,7 @@ import assertk.assertThat
 import assertk.assertions.contains
 import assertk.assertions.containsMatch
 import assertk.assertions.containsOnly
+import assertk.assertions.doesNotContain
 import assertk.assertions.isEqualTo
 import assertk.assertions.isFalse
 import assertk.assertions.isGreaterThan
@@ -35,6 +36,8 @@ import kotlin.io.path.name
 import kotlin.io.path.outputStream
 import kotlin.io.path.writeText
 import org.gradle.api.plugins.JavaPlugin
+import org.gradle.api.plugins.JavaPlugin.API_CONFIGURATION_NAME
+import org.gradle.api.plugins.JavaPlugin.COMPILE_ONLY_CONFIGURATION_NAME
 import org.gradle.api.tasks.bundling.Jar
 import org.gradle.testfixtures.ProjectBuilder
 import org.junit.jupiter.api.Test
@@ -489,6 +492,47 @@ class JavaPluginTest : BasePluginTest() {
     }
   }
 
+  @Issue(
+    "https://github.com/GradleUp/shadow/issues/1422",
+  )
+  @Test
+  fun movesLocalGradleApiToCompileOnly() {
+    projectScriptPath.writeText(
+      """
+        ${getDefaultProjectBuildScript("java-gradle-plugin")}
+      """.trimIndent() + System.lineSeparator(),
+    )
+
+    val outputCompileOnly = dependencies(COMPILE_ONLY_CONFIGURATION_NAME)
+    val outputApi = dependencies(API_CONFIGURATION_NAME)
+
+    // "unspecified" is the local Gradle API.
+    assertThat(outputCompileOnly).contains("unspecified")
+    assertThat(outputApi).doesNotContain("unspecified")
+  }
+
+  @Issue(
+    "https://github.com/GradleUp/shadow/issues/1422",
+  )
+  @ParameterizedTest
+  @ValueSource(strings = [COMPILE_ONLY_CONFIGURATION_NAME, API_CONFIGURATION_NAME])
+  fun doesNotReAddSuppressedGradleApi(configuration: String) {
+    projectScriptPath.writeText(
+      """
+        ${getDefaultProjectBuildScript("java-gradle-plugin")}
+      """.trimIndent() + System.lineSeparator(),
+    )
+
+    val output = dependencies(
+      configuration = configuration,
+      // Internal flag added in 8.14 to experiment with suppressing local Gradle API.
+      "-Dorg.gradle.unsafe.suppress-gradle-api=true",
+    )
+
+    // "unspecified" is the local Gradle API.
+    assertThat(output).doesNotContain("unspecified")
+  }
+
   @Issue(
     "https://github.com/GradleUp/shadow/issues/1070",
   )
@@ -734,4 +778,8 @@ class JavaPluginTest : BasePluginTest() {
       containsOnly(*entriesInAB, *manifestEntries)
     }
   }
+
+  private fun dependencies(configuration: String, vararg flags: String): String {
+    return run("dependencies", "--configuration", configuration, *flags).output
+  }
 }

src/main/kotlin/com/github/jengelman/gradle/plugins/shadow/ShadowJavaPlugin.kt

@@ -101,15 +101,16 @@ public abstract class ShadowJavaPlugin @Inject constructor(
 
   protected open fun Project.configureJavaGradlePlugin() {
     plugins.withType(JavaGradlePluginPlugin::class.java).configureEach {
+      val gradleApi = dependencies.gradleApi()
       // Remove the gradleApi so it isn't merged into the jar file.
       // This is required because 'java-gradle-plugin' adds gradleApi() to the 'api' configuration.
       // See https://github.com/gradle/gradle/blob/972c3e5c6ef990dd2190769c1ce31998a9402a79/subprojects/plugin-development/src/main/java/org/gradle/plugin/devel/plugins/JavaGradlePluginPlugin.java#L161.
-      configurations.named(JavaPlugin.API_CONFIGURATION_NAME) {
-        it.dependencies.remove(dependencies.gradleApi())
-      }
-      // Compile only gradleApi() to make sure the plugin can compile against Gradle API.
-      configurations.named(JavaPlugin.COMPILE_ONLY_CONFIGURATION_NAME) {
-        it.dependencies.add(dependencies.gradleApi())
+      configurations.named(JavaPlugin.API_CONFIGURATION_NAME) { api ->
+        // Only proceed if the removal is successful.
+        if (!api.dependencies.remove(gradleApi)) return@named
+        // Compile only gradleApi() to make sure the plugin can compile against Gradle API.
+        configurations.getByName(JavaPlugin.COMPILE_ONLY_CONFIGURATION_NAME)
+          .dependencies.add(dependencies.gradleApi())
       }
     }
   }