Resolves #58 Detect indent from EditorConfig file

#58

plugin/build.gradle.kts

@@ -43,7 +43,6 @@ dependencies {
     testImplementation("io.kotlintest:kotlintest-runner-junit5:3.1.9")
 
     implementation("com.github.ben-manes:gradle-versions-plugin:0.25.0")
-
     implementation("com.squareup.okio:okio:2.1.0")
     implementation( "com.squareup.moshi:moshi:1.7.0")
     implementation("com.squareup:kotlinpoet:1.3.0")

plugin/src/main/kotlin/de/fayard/BuildSrcVersionsTask.kt

@@ -22,6 +22,9 @@ open class BuildSrcVersionsTask : DefaultTask() {
     @TaskAction
     fun taskAction() {
         val extension : BuildSrcVersionsExtension = extension ?: project.extensions.getByType()
+        if (extension.indent == PluginConfig.DEFAULT_INDENT) {
+            extension.indent = EditorConfig.findIndentForKotlin(project.file("buildSrc/src/main/kotlin")) ?: "  "
+        }
         println("""
             |Plugin configuration: $extension
             |See documentation at ${PluginConfig.issue53PluginConfiguration}

plugin/src/main/kotlin/de/fayard/EditorConfig.kt

@@ -0,0 +1,100 @@
+package de.fayard
+
+import java.io.File
+
+data class Section(val name: String, val lines: MutableList<Pair<String, String>>) {
+    operator fun get(key: String): String? {
+        return lines.firstOrNull { it.first == key }?.second
+    }
+}
+
+object EditorConfig {
+    const val NAME = ".editorconfig"
+    const val INDENT_STYLE = "indent_style"
+    const val INDENT_SIZE = "indent_size"
+    const val SPACE = "space"
+    const val TAB = "tab"
+
+    fun findIndentForKotlin(fromDir: File) : String? {
+        return findEditorConfig(fromDir)
+            .flatMap { file -> file.parseSections() }
+            .findIndentForKotlinFiles()
+    }
+
+    fun List<Section>.findIndentForKotlinFiles() : String? {
+        val section = this.sortedByDescending { it.priority() }
+            .filter { s ->
+                s[INDENT_STYLE] != null && s.priority() > 0
+            }.firstOrNull()
+        return section?.findIndent()
+    }
+
+    fun Section.findIndent() : String? {
+        val size = this[INDENT_SIZE]?.toIntOrNull()
+        val style = this[INDENT_STYLE]
+        return when {
+            style == TAB -> "\t"
+            style == SPACE && size != null -> List(size) { " " }.joinToString(separator = "")
+            else -> null
+        }
+    }
+
+
+    fun File.isRootEditorConfig() : Boolean = when {
+        name != NAME -> false
+        this.exists().not() -> false
+        else -> readLines().any { it.replace(" ", "").contains("root=true") }
+    }
+
+    fun Section.priority() = when {
+        name.contains("kt") -> 4
+        name.contains("gradle") -> 3
+        name.contains("java") -> 2
+        name == "*" -> 1
+        else -> -1
+    }
+
+    fun File.parseSections(): List<Section> {
+        assert(name == NAME)
+        assert(canRead())
+        val result = mutableListOf<Section>()
+        var currentSection: Section? = null
+        readLines().map { line ->
+            line.substringBefore("#").substringBefore(";")
+        }.forEach { line ->
+            val section = line.parseSection()
+            val split = line.split("=").map { it.trim() }
+            when {
+                section != null -> {
+                    currentSection = Section(section, mutableListOf())
+                    result.add(currentSection!!)
+                }
+                currentSection == null || line.isBlank() || split.size != 2 -> { }
+                else -> currentSection!!.lines.add(split.first() to split.last())
+            }
+        }
+        return result
+    }
+
+    fun String.parseSection() : String? {
+        val section = this.substringAfter("[", "").substringBefore("]", "").trim()
+        return if (section.isBlank()) null else section
+    }
+
+    fun findEditorConfig(fromDir: File) : List<File> {
+        val result =  mutableListOf<File>()
+        var current: File? = fromDir
+        while (current != null) {
+            val ec = current.resolve(NAME)
+            if (ec.exists()) {
+                assert(ec.name == NAME)
+                result += ec
+            }
+            if (ec.isRootEditorConfig()) {
+                break
+            }
+            current = current.parentFile
+        }
+        return result
+    }
+}

plugin/src/main/kotlin/de/fayard/PluginConfig.kt

@@ -27,7 +27,7 @@ object PluginConfig {
 
     const val DEFAULT_LIBS = "Libs"
     const val DEFAULT_VERSIONS = "Versions"
-    const val DEFAULT_INDENT = "  "
+    const val DEFAULT_INDENT = "from-editorconfig-file"
     const val BENMANES_REPORT_PATH = "build/dependencyUpdates/report.json"
 
     /** Documentation **/

plugin/src/test/kotlin/de/fayard/EditorConfigTest.kt

@@ -0,0 +1,93 @@
+package de.fayard
+
+import io.kotlintest.matchers.haveSize
+import io.kotlintest.matchers.withClue
+import io.kotlintest.should
+import io.kotlintest.shouldBe
+import io.kotlintest.specs.FreeSpec
+import io.kotlintest.tables.forAll
+import io.kotlintest.tables.headers
+import io.kotlintest.tables.row
+import io.kotlintest.tables.table
+import java.io.File
+
+
+
+class EditorConfigTest: FreeSpec({
+    val testFolder = File("src/test/resources").absoluteFile
+
+    "Project Dir" {
+        withClue(testFolder.absolutePath) {
+            testFolder.name shouldBe "resources"
+        }
+    }
+
+    "Find files" {
+        val table = table(
+            headers("path", "expected size"),
+            row("a/b/c", 3),
+            row("a/b", 2),
+            row("a", 1),
+            row("libs", 2)
+        )
+
+        table.forAll { path, expectedSize ->
+            val list = EditorConfig.findEditorConfig(testFolder.resolve(path))
+            withClue(list.toString()) { list should haveSize(expectedSize) }
+        }
+    }
+
+    "Sections" {
+        with(EditorConfig) {
+            val sections = testResourceFile("a/b/.editorconfig").parseSections()
+            withClue(sections.toString()) {
+                sections.size shouldBe 2
+                val (kotlin, python) = sections
+                python shouldBe Section("*.py", mutableListOf("indent_style" to "tab", "insert_final_newline" to "true"))
+                kotlin shouldBe Section("*.kt", mutableListOf("indent_style" to "space", "indent_size" to "4"))
+                kotlin[INDENT_STYLE] shouldBe "space"
+                kotlin[INDENT_SIZE] shouldBe "4"
+                kotlin["insert_final_newline"] shouldBe null
+            }
+        }
+    }
+
+    with(EditorConfig) {
+        "Parse Indents" - {
+            "Tabs" {
+                val section = Section("*", mutableListOf(INDENT_STYLE to TAB, "key" to "value"))
+                section.findIndent() shouldBe "\t"
+            }
+            "Four spaces" {
+                val section = Section("*", mutableListOf(INDENT_STYLE to SPACE, "key" to "value", INDENT_SIZE to "4"))
+                section.findIndent() shouldBe "    "
+            }
+            "Two spaces" {
+                val section = Section("*", mutableListOf(INDENT_STYLE to SPACE, "key" to "value", INDENT_SIZE to "2"))
+                section.findIndent() shouldBe "  "
+            }
+            "space no size: invalid" {
+                val section = Section("*", mutableListOf(INDENT_STYLE to SPACE, "key" to "value"))
+                section.findIndent() shouldBe null
+            }
+            "no information" {
+                val section = Section("*", mutableListOf( "key" to "value"))
+                section.findIndent() shouldBe null
+            }
+        }
+    }
+
+    "Find indentation for Kotlin" {
+        val table = table(
+            headers("path", "indentation"),
+            row("libs", "  "),
+            row("a", "   "),
+            row("a/b", "    "),
+            row("a/b/c", "    "),
+            row("maven", null)
+        )
+        table.forAll { path, expectedIndent ->
+            EditorConfig.findIndentForKotlin(testFolder.resolve(path)) shouldBe expectedIndent
+        }
+    }
+})

plugin/src/test/resources/.editorconfig

@@ -0,0 +1,3 @@
+[*]
+indent_style = space
+indent_size = 2

plugin/src/test/resources/a/.editorconfig

@@ -0,0 +1,7 @@
+root = true
+
+[*.{java,kt,kts}]
+indent_style = space ; comment
+indent_size = 3 # comment
+
+# comment

plugin/src/test/resources/a/b/.editorconfig

@@ -0,0 +1,11 @@
+[*.kt]
+indent_style = space
+indent_size = 4 # 2 is better
+
+# 4 space indentation
+[*.py]
+indent_style = tab
+insert_final_newline = true
+
+
+

plugin/src/test/resources/a/b/c/.editorconfig

@@ -0,0 +1,3 @@
+[*.java]
+indent_style = space
+indent_size = 5

plugin/src/test/resources/maven/.editorconfig

@@ -0,0 +1,5 @@
+root = true
+
+[*.py]
+indent_style = space
+indent_size = 2

sample-groovy/buildSrc/src/main/kotlin/Libs.kt

@@ -7,16 +7,16 @@ import kotlin.String
  *   `$ ./gradlew buildSrcVersions`
  */
 object Libs {
+  const val guava: String = "com.google.guava:guava:" + Versions.guava
+
+  const val guice: String = "com.google.inject:guice:" + Versions.guice
+
   const val io_vertx_vertx_plugin_gradle_plugin: String =
       "io.vertx.vertx-plugin:io.vertx.vertx-plugin.gradle.plugin:" +
       Versions.io_vertx_vertx_plugin_gradle_plugin
 
-  const val vertx_stack_depchain: String = "io.vertx:vertx-stack-depchain:" +
-      Versions.vertx_stack_depchain
-
   const val vertx_core: String = "io.vertx:vertx-core"
 
-  const val guava: String = "com.google.guava:guava:" + Versions.guava
-
-  const val guice: String = "com.google.inject:guice:" + Versions.guice
+  const val vertx_stack_depchain: String = "io.vertx:vertx-stack-depchain:" +
+      Versions.vertx_stack_depchain
 }

sample-groovy/buildSrc/src/main/kotlin/Versions.kt

@@ -10,15 +10,15 @@ import kotlin.String
  * YOU are responsible for updating manually the dependency version.
  */
 object Versions {
-  const val io_vertx_vertx_plugin_gradle_plugin: String = "0.3.1"
+  const val guava: String = "15.0"
 
-  const val vertx_stack_depchain: String = "3.6.2"
+  const val guice: String = "2.0"
 
-  const val vertx_core: String = "none"// No version. See buildSrcVersions#23
+  const val io_vertx_vertx_plugin_gradle_plugin: String = "0.3.1"
 
-  const val guava: String = "15.0"
+  const val vertx_core: String = "none"// No version. See buildSrcVersions#23
 
-  const val guice: String = "2.0"
+  const val vertx_stack_depchain: String = "3.6.2"
 
   /**
    *

sample-kotlin/build.gradle.kts

@@ -32,7 +32,7 @@ buildSrcVersions {
     useFqdnFor("dependency")
     renameLibs = "Libs"
     renameVersions = "Versions"
-    indent = "  "
+//    indent = "  "
     rejectVersionIf {
         isNonStable(candidate.version) && isNonStable(currentVersion).not()
     }

sample-kotlin/buildSrc/src/main/kotlin/Libs.kt

@@ -7,24 +7,24 @@ import kotlin.String
  *   `$ ./gradlew buildSrcVersions`
  */
 object Libs {
-  /**
-   * https://github.com/google/guava
-   */
-  const val guava: String = "com.google.guava:guava:" + Versions.guava
+    /**
+     * https://github.com/google/guava
+     */
+    const val guava: String = "com.google.guava:guava:" + Versions.guava
 
-  /**
-   * https://github.com/google/guice
-   */
-  const val guice: String = "com.google.inject:guice:" + Versions.guice
+    /**
+     * https://github.com/google/guice
+     */
+    const val guice: String = "com.google.inject:guice:" + Versions.guice
 
-  const val org_jetbrains_kotlin_jvm_gradle_plugin: String =
-      "org.jetbrains.kotlin.jvm:org.jetbrains.kotlin.jvm.gradle.plugin:" +
-      Versions.org_jetbrains_kotlin_jvm_gradle_plugin
+    const val org_jetbrains_kotlin_jvm_gradle_plugin: String =
+            "org.jetbrains.kotlin.jvm:org.jetbrains.kotlin.jvm.gradle.plugin:" +
+            Versions.org_jetbrains_kotlin_jvm_gradle_plugin
 
-  /**
-   * https://kotlinlang.org/
-   */
-  const val kotlin_scripting_compiler_embeddable: String =
-      "org.jetbrains.kotlin:kotlin-scripting-compiler-embeddable:" +
-      Versions.kotlin_scripting_compiler_embeddable
+    /**
+     * https://kotlinlang.org/
+     */
+    const val kotlin_scripting_compiler_embeddable: String =
+            "org.jetbrains.kotlin:kotlin-scripting-compiler-embeddable:" +
+            Versions.kotlin_scripting_compiler_embeddable
 }

sample-kotlin/buildSrc/src/main/kotlin/Versions.kt

@@ -10,20 +10,20 @@ import kotlin.String
  * YOU are responsible for updating manually the dependency version.
  */
 object Versions {
-  const val guava: String = "15.0" // available: "23.0"
+    const val guava: String = "15.0" // available: "23.0"
 
-  const val guice: String = "2.0" // available: "4.2.2"
+    const val guice: String = "2.0" // available: "4.2.2"
 
-  const val org_jetbrains_kotlin_jvm_gradle_plugin: String = "1.3.11" // available: "1.3.50"
+    const val org_jetbrains_kotlin_jvm_gradle_plugin: String = "1.3.11" // available: "1.3.50"
 
-  const val kotlin_scripting_compiler_embeddable: String = "1.3.11" // available: "1.3.50"
+    const val kotlin_scripting_compiler_embeddable: String = "1.3.11" // available: "1.3.50"
 
-  /**
-   *
-   * See issue 19: How to update Gradle itself?
-   * https://github.com/jmfayard/buildSrcVersions/issues/19
-   */
-  const val gradleLatestVersion: String = "5.6.2"
+    /**
+     *
+     * See issue 19: How to update Gradle itself?
+     * https://github.com/jmfayard/buildSrcVersions/issues/19
+     */
+    const val gradleLatestVersion: String = "5.6.2"
 
-  const val gradleCurrentVersion: String = "5.6.2"
+    const val gradleCurrentVersion: String = "5.6.2"
 }