Fail build when run with unsupported Gradle version

- Test more gradle versions, including minimum supported
- Fail build when run with Gradle < 5.2
- Fail build when run with Gradle 7.0
- Update README.md for Gradle compatibility

Author: bigdaz

.github/workflows/gradle.yml

@@ -30,9 +30,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        # Test latest version 5.x, 6.x and 7.x, as well as all patched minor versions of 8.x
-        # Latest 8.x is tested in 'quick-check' job
-        gradle-version: [ "5.6.4", "6.9.4", "7.6.3", "8.0.2", "8.1.1", "8.2.1", "8.3"]
+        # Test earliest and latest supported version of 5.x, 6.x and 7.x, as well as all patched minor versions of 8.x
+        # Latest 8.x is tested in 'quick-check' job using the wrapper
+        gradle-version: [ "5.2.1", "5.6.4", "6.0.1", "6.9.4", "7.1.1", "7.6.3", "8.0.2", "8.1.1", "8.2.1", "8.3", "8.4", "8.5"]
     runs-on: ubuntu-latest
     env:
       GRADLE_ENTERPRISE_ACCESS_KEY: ${{ secrets.GRADLE_ENTERPRISE_ACCESS_KEY }}

README.md

@@ -53,16 +53,23 @@ You can provide this value via the `DEPENDENCY_GRAPH_INCLUDE_CONFIGURATIONS` env
 
 ### Gradle compatibility
 
-The plugin should be compatible with all versions of Gradle >= 5.0, and has been tested against 
-Gradle versions "5.6.4", "6.9.4", "7.0.2", "7.6.2", "8.0.2" and the current Gradle release.
-
-The plugin is compatible with running Gradle with the configuration-cache enabled. However, this support is
-limited to Gradle "8.1.0" and later:
-- With Gradle "8.0", the build should run successfully, but an empty dependency graph will be generated.
-- With Gradle <= "7.6.4", the plugin will cause the build to fail with configuration-cache enabled.
-
-To use this plugin with versions of Gradle older than "8.1.0", you'll need to invoke Gradle with the
-configuration-cache disabled.
+The plugin should be compatible with most versions of Gradle >= 5.2, and has been tested against 
+Gradle versions "5.2.1", "5.6.4", "6.0.1", "6.9.4", "7.1.1" and "7.6.3", as well as all patched versions of Gradle 8.x.
+
+The plugin is compatible with running Gradle with the configuration-cache enabled: this support is
+limited to Gradle "8.1.0" and later. Earlier Gradle versions will not work with `--configuration-cache`.
+Note that no dependency graph will be generated when configuration state is loaded from the configuration-cache.
+
+| Gradle version | Compatible | Compatible with configuration-cache |
+| -------------- | ------- | ------------------------ |
+| 1.x - 4.x      | :x: | :x: |
+| 5.0 - 5.1.1 | :x: | :x: |
+| 5.2 - 5.6.4 | ✅ | :x: |
+| 6.0 - 6.9.4 | ✅ | :x: |
+| 7.0 - 7.0.2 | :x: | :x: |
+| 7.1 - 7.6.3 | ✅ | :x: |
+| 8.0 - 8.0.2 | ✅ | :x: |
+| 8.1+ | ✅ | ✅ |
 
 ## Building/Testing
 

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

@@ -4,8 +4,8 @@ import org.apache.commons.io.FileUtils
 import org.gradle.util.GradleVersion
 import spock.lang.IgnoreIf
 
-// Samples aren't designed to run on Gradle 5.x
-@IgnoreIf({ GradleVersion.version(testGradleVersion) < GradleVersion.version("6.0") })
+// Samples aren't designed to run on Gradle < 6.4
+@IgnoreIf({ GradleVersion.version(testGradleVersion) < GradleVersion.version("6.4") })
 class SampleProjectDependencyExtractorTest extends BaseExtractorTest {
     def setup() {
         applyDependencyGraphPlugin()

plugin/src/main/kotlin/org/gradle/github/GitHubDependencyGraphPlugin.kt

@@ -1,8 +1,10 @@
 package org.gradle.github
 
+import org.gradle.api.GradleException
 import org.gradle.api.Plugin
 import org.gradle.api.invocation.Gradle
 import org.gradle.forceresolve.ForceDependencyResolutionPlugin
+import org.gradle.util.GradleVersion
 
 /**
  * A plugin that collects all resolved dependencies in a Gradle build for submission to the
@@ -11,6 +13,12 @@ import org.gradle.forceresolve.ForceDependencyResolutionPlugin
 @Suppress("unused")
 class GitHubDependencyGraphPlugin : Plugin<Gradle> {
     override fun apply(gradle: Gradle) {
+        val gradleVersion = GradleVersion.current().baseVersion
+        if (gradleVersion < GradleVersion.version("5.2") ||
+            (gradleVersion >= GradleVersion.version("7.0") && gradleVersion < GradleVersion.version("7.1"))) {
+            throw GradleException("${this.javaClass.simpleName} is not supported for $gradleVersion.")
+        }
+
         // Only apply the dependency extractor to the root build
         if (gradle.parent == null) {
             gradle.pluginManager.apply(GitHubDependencyExtractorPlugin::class.java)