Add build.gradle.kts to Gradle executor detection (#1231)

Most modern Gradle projects use the Gradle Kotlin DSL.
This change is necessary to detect projects as it's not possible
to add one of the existing filetypes without disrupting the build
configuration, especially in multi-project Gradle builds.

Fixes #846

CHANGELOG_PENDING.md

@@ -1,4 +1,5 @@
 ### Improvements
 
+- Plugin: will now automatically use the Gradle executor if build.gradle.kts is present
 
 ### Bug Fixes

pkg/internal/executors/executor_gradle.go

@@ -89,6 +89,7 @@ func (gradle) isGradleProject(dir fs.FS, opts JavaExecutorOptions) (bool, error)
 		"settings.gradle",
 		"settings.gradle.kts",
 		"build.gradle",
+		"build.gradle.kts",
 	}
 	for _, p := range gradleMarkers {
 		isGradle, err := fsys.FileExists(dir, p)

pkg/internal/executors/executor_test.go

@@ -47,8 +47,8 @@ func TestGradleKTS(t *testing.T) {
 	fsys := fsys.TestFS("app",
 		map[string]string{"gradle": "/usr/bin/gradle"},
 		fstest.MapFS{
-			"settings.gradle.kts": {},
-			"app/build.gradle":    {},
+			"settings.gradle.kts":  {},
+			"app/build.gradle.kts": {},
 		})
 	exec, err := NewJavaExecutor(JavaExecutorOptions{WD: fsys})
 	assert.NoError(t, err)
@@ -86,6 +86,24 @@ func TestGradleMultiProject(t *testing.T) {
 		exec.RunArgs)
 }
 
+func TestGradleKTSMultiProject(t *testing.T) {
+	fsys := fsys.TestFS("services/app-cluster",
+		map[string]string{"gradle": "/usr/bin/gradle"},
+		fstest.MapFS{
+			"services/app-cluster/build.gradle.kts":  {},
+			"services/mgmt-cluster/build.gradle.kts": {},
+			"gradlew":                                {},
+			"settings.gradle.kts":                    {},
+		})
+	exec, err := NewJavaExecutor(JavaExecutorOptions{WD: fsys})
+	assert.NoError(t, err)
+	assert.Equal(t, "./gradlew", exec.Cmd)
+	assert.Equal(t, ".", exec.Dir)
+	assert.Equal(t,
+		[]string{":services:app-cluster:run", "--console=plain"},
+		exec.RunArgs)
+}
+
 func TestGradleUseExecutor(t *testing.T) {
 	fs := fsys.TestFS("app",
 		map[string]string{