Fix destination overwrite issue

A previous change made the destination of the converter be the
parent folder of the recipe folder rather thant the folder itself,
leaving the decision of the folder name to the recipe (via metadata).

This change also impacted detection of existing destination folder, and
while it worked for batch conversion, it did not for single conversion.

This change fixes this, by separating the logic for single vs batch
conversion.

Single conversion expect the recipe folder to be empty, but the
parent (which is passed to the converted) can contain other things.
Overwritting will not impact the parent but the recipe folder only.

Batch conversion expect the recipe folder parent to be empty since
it's going to receive a lot of recipes. Overwritting will delete
the whole content of the parent (--destination) folder.

This also replaces all error handling to use System.exit instead
of exceptions as it's more user friendly (there's an option to
throw for debugging if needed)

Bug: N/A
Test: existing
Change-Id: Ie115ce6b8b13e4c77c0f99371f0d37d89e2f7a7b

convert-tool/app/src/main/kotlin/com/google/android/gradle_recipe/converter/ConvertTool.kt

@@ -86,14 +86,6 @@ fun main(args: Array<String>) {
                     printErrorAndTerminate("Folder does not exist: ${destinationPath.toAbsolutePath()}")
                 }
 
-                if (!destinationPath.isEmptyExceptForHidden()) {
-                    if (!overwrite) {
-                        error("the destination $destinationPath folder is not empty, call converter with --overwrite to overwrite it")
-                    } else {
-                        destinationPath.deleteNonHiddenRecursively()
-                    }
-                }
-
                 if (finalSource != null) {
                     RecipeConverter(
                         agpVersion = agpVersion,
@@ -104,9 +96,20 @@ fun main(args: Array<String>) {
                         branchRoot = branchRoot,
                     ).convert(
                         source = Path.of(finalSource),
-                        destination = destinationPath
+                        destination = destinationPath,
+                        overwrite = overwrite
                     )
                 } else if (finalSourceAll != null) {
+                    // if we do a convert all then we expect the root folder to be (mostly) empty
+                    // (hidden files, like git files, are kept)
+                    if (!destinationPath.isEmptyExceptForHidden()) {
+                        if (!overwrite) {
+                            printErrorAndTerminate("the destination $destinationPath folder is not empty, call converter with --overwrite to overwrite it")
+                        } else {
+                            destinationPath.deleteNonHiddenRecursively()
+                        }
+                    }
+
                     RecursiveConverter(
                         agpVersion = agpVersion,
                         repoLocation = repoLocation,
@@ -136,7 +139,7 @@ fun main(args: Array<String>) {
 
                 // check the env var for the SDK exist
                 if (System.getenv("ANDROID_HOME") == null) {
-                    throw RuntimeException("To run $COMMAND_VALIDATE command, the environment variable ANDROID_HOME must be set and must point to your Android SDK.")
+                    printErrorAndTerminate("To run $COMMAND_VALIDATE command, the environment variable ANDROID_HOME must be set and must point to your Android SDK.")
                 }
 
                 if (mode != null) {
@@ -233,15 +236,18 @@ private fun validateNullArg(arg: Any?, msg: String) {
     }
  }
 
-private fun printErrorAndTerminate(msg: String): Nothing {
+fun printErrorAndTerminate(msg: String): Nothing {
     System.err.println(msg)
+    if (System.getenv("CONVERT_DEBUG") != null) {
+        throw RuntimeException("error. See console output")
+    }
     exitProcess(1)
 }
 
 private fun Path.isEmptyExceptForHidden(): Boolean = !Files.list(this).anyMatch { !it.name.startsWith('.') }
 
 @OptIn(ExperimentalPathApi::class)
-private fun Path.deleteNonHiddenRecursively() {
+fun Path.deleteNonHiddenRecursively() {
     Files.list(this).filter {
         !it.name.startsWith('.')
     }.forEach {

convert-tool/app/src/main/kotlin/com/google/android/gradle_recipe/converter/converters/Converter.kt

@@ -16,6 +16,7 @@
 
 package com.google.android.gradle_recipe.converter.converters
 
+import com.google.android.gradle_recipe.converter.printErrorAndTerminate
 import com.google.android.gradle_recipe.converter.recipe.RecipeData
 import com.google.android.gradle_recipe.converter.recipe.toMajorMinor
 import java.nio.file.Files
@@ -79,7 +80,7 @@ abstract class Converter(
     fun copyGradleFolder(dest: Path) {
         val source = branchRoot.resolve(GRADLE_RESOURCES_FOLDER)
         if (!source.isDirectory()) {
-            throw RuntimeException("Unable to find gradle resources at $source")
+            printErrorAndTerminate("Unable to find gradle resources at $source")
         }
 
         dest.mkdirs()
@@ -104,11 +105,11 @@ abstract class Converter(
     protected fun getMinAgp(): String = recipeData?.minAgpVersion
         // this really should not happen
         // TODO(b/317888166) improve this
-        ?: error("recipeData not loaded in Converter")
+        ?: printErrorAndTerminate("recipeData not loaded in Converter")
 
     protected fun getVersionInfoFromAgp(agpVersion: String): VersionInfo {
         val agp = agpVersion.toMajorMinor()
         return getVersionsFromAgp(branchRoot, agp)
-            ?: throw RuntimeException("Unable to fetch VersionInfo for AGP $agp")
+            ?: printErrorAndTerminate("Unable to fetch VersionInfo for AGP $agp")
     }
 }

convert-tool/app/src/main/kotlin/com/google/android/gradle_recipe/converter/converters/ConverterUtils.kt

@@ -16,6 +16,7 @@
 
 package com.google.android.gradle_recipe.converter.converters
 
+import com.google.android.gradle_recipe.converter.printErrorAndTerminate
 import java.nio.file.Path
 
 /**
@@ -31,7 +32,7 @@ fun Path.mkdirs(): Boolean {
     val ret = file.mkdirs()
     if (!ret) {
         if (!file.isDirectory) {
-            throw RuntimeException("Unable to create folder: $this")
+            printErrorAndTerminate("Unable to create folder: $this")
         }
     }
     return ret

convert-tool/app/src/main/kotlin/com/google/android/gradle_recipe/converter/converters/RecipeConverter.kt

@@ -15,17 +15,20 @@
  */
 package com.google.android.gradle_recipe.converter.converters
 
+import com.google.android.gradle_recipe.converter.deleteNonHiddenRecursively
+import com.google.android.gradle_recipe.converter.printErrorAndTerminate
 import com.google.android.gradle_recipe.converter.recipe.RecipeData
 import com.google.android.gradle_recipe.converter.recipe.toMajorMinor
 import java.io.File
-import java.io.IOException
 import java.lang.System.err
-import java.nio.file.*
+import java.nio.file.FileVisitResult
+import java.nio.file.Files
+import java.nio.file.Path
+import java.nio.file.SimpleFileVisitor
+import java.nio.file.StandardCopyOption
 import java.nio.file.attribute.BasicFileAttributes
-import kotlin.io.path.exists
 import kotlin.io.path.isDirectory
 import kotlin.io.path.isRegularFile
-import kotlin.io.path.name
 import kotlin.io.path.readLines
 
 private const val VERSION_MAPPING = "version_mappings.txt"
@@ -57,7 +60,7 @@ private fun initAgpToGradleMap(branchRoot: Path) {
     if (!::agpToVersionsMap.isInitialized) {
         val file = branchRoot.resolve(VERSION_MAPPING)
         if (!file.isRegularFile()) {
-            throw RuntimeException("Missing AGP version mapping file at $file")
+            printErrorAndTerminate("Missing AGP version mapping file at $file")
         }
 
         val lines = file
@@ -141,7 +144,7 @@ class RecipeConverter(
 
             Mode.RELEASE -> {
                 ReleaseConverter(
-                    agpVersion = agpVersion ?: error("Must specify the AGP version for release"),
+                    agpVersion = agpVersion ?: printErrorAndTerminate("Must specify the AGP version for release"),
                     gradleVersion = gradleVersion,
                     repoLocation = repoLocation,
                     gradlePath = gradlePath,
@@ -158,15 +161,27 @@ class RecipeConverter(
      * @param destination the destination folder. A new folder will be created inside to contain the recipe
      *
      */
-    fun convert(source: Path, destination: Path): ConversionResult {
+    fun convert(source: Path, destination: Path, overwrite: Boolean = false): ConversionResult {
         if (!source.isDirectory()) {
-            error("the source $source folder is not a directory")
+            printErrorAndTerminate("Source $source is not a directory!")
         }
 
         val recipeData = RecipeData.loadFrom(source, mode)
 
         val recipeDestination = destination.resolve(recipeData.destinationFolder)
 
+        if (recipeDestination.isRegularFile()) {
+            printErrorAndTerminate("Destination $recipeDestination exist but is not a folder!")
+        }
+
+        if (recipeDestination.isDirectory() && recipeDestination.isNotEmpty()) {
+            if (!overwrite) {
+                printErrorAndTerminate("Destination $recipeDestination folder is not empty, call converter with --overwrite to overwrite it")
+            } else {
+                recipeDestination.deleteNonHiddenRecursively()
+            }
+        }
+
         val success = if (converter.isConversionCompliant(recipeData)) {
             converter.recipeData = recipeData
 
@@ -232,4 +247,6 @@ class RecipeConverter(
 
         return ConversionResult(recipeData, success)
     }
-}
+}
+
+private fun Path.isNotEmpty(): Boolean = Files.list(this).findAny().isPresent

convert-tool/app/src/main/kotlin/com/google/android/gradle_recipe/converter/converters/RecursiveConverter.kt

@@ -17,6 +17,7 @@
 package com.google.android.gradle_recipe.converter.converters
 
 import com.google.android.gradle_recipe.converter.converters.RecipeConverter.Mode
+import com.google.android.gradle_recipe.converter.printErrorAndTerminate
 import com.google.android.gradle_recipe.converter.recipe.visitRecipes
 import java.io.File
 import java.io.IOException
@@ -45,10 +46,9 @@ class RecursiveConverter(
         val link: String
     )
 
-    @Throws(IOException::class)
     fun convertAllRecipes(sourceAll: Path, destination: Path) {
         if (!sourceAll.exists()) {
-            error("the source $sourceAll folder doesn't exist")
+            printErrorAndTerminate("the source $sourceAll folder doesn't exist")
         }
 
         val recipeConverter = RecipeConverter(

convert-tool/app/src/main/kotlin/com/google/android/gradle_recipe/converter/converters/ReleaseConverter.kt

@@ -16,6 +16,7 @@
 
 package com.google.android.gradle_recipe.converter.converters
 
+import com.google.android.gradle_recipe.converter.printErrorAndTerminate
 import com.google.android.gradle_recipe.converter.recipe.RecipeData
 import java.nio.file.Files
 import java.nio.file.Path
@@ -48,8 +49,8 @@ class ReleaseConverter(
 
         } else {
             // internal CI release
-            pathToAgpRepo = repoLocation ?: error("must specify path to repo")
-            pathToGradle = gradlePath ?: error("must specify path to Gradle")
+            pathToAgpRepo = repoLocation ?: printErrorAndTerminate("must specify path to repo")
+            pathToGradle = gradlePath ?: printErrorAndTerminate("must specify path to Gradle")
         }
     }
 

convert-tool/app/src/main/kotlin/com/google/android/gradle_recipe/converter/recipe/RecipeData.kt

@@ -18,6 +18,7 @@ package com.google.android.gradle_recipe.converter.recipe
 
 import com.github.rising3.semver.SemVer
 import com.google.android.gradle_recipe.converter.converters.RecipeConverter
+import com.google.android.gradle_recipe.converter.printErrorAndTerminate
 import org.tomlj.Toml
 import org.tomlj.TomlParseResult
 import java.io.File
@@ -59,7 +60,7 @@ class RecipeData private constructor(
             if (parseResult.hasErrors()) {
                 System.err.println("TOML Parsing error(s) for $toml:")
                 parseResult.errors().forEach { error -> System.err.println(error.toString()) }
-                throw IllegalArgumentException("Unable to read $toml")
+                printErrorAndTerminate("Unable to read $toml")
             }
 
             val indexName = if (mode == RecipeConverter.Mode.RELEASE) {
@@ -80,7 +81,7 @@ class RecipeData private constructor(
                 } else {
                     // check there's no path separator in there
                     if (entry.contains('/')) {
-                        error("destinationFolder value ('$entry') cannot contain / character ($recipeFolder)")
+                        printErrorAndTerminate("destinationFolder value ('$entry') cannot contain / character ($recipeFolder)")
                     }
                     entry
                 }
@@ -92,7 +93,7 @@ class RecipeData private constructor(
                 indexName = indexName,
                 destinationFolder = destinationFolder,
                 minAgpVersion = parseResult.getString("agpVersion.min")
-                    ?: error("Did not find mandatory 'agpVersion.min' in $toml"),
+                    ?: printErrorAndTerminate("Did not find mandatory 'agpVersion.min' in $toml"),
                 maxAgpVersion = parseResult.getString("agpVersion.max"),
                 tasks = parseResult.getArray("gradleTasks.tasks")?.toList()?.map { it as String } ?: emptyList(),
                 keywords = parseResult.getArray("indexMetadata.index")?.toList()?.map { it as String } ?: emptyList()

convert-tool/app/src/main/kotlin/com/google/android/gradle_recipe/converter/recipe/RecipeUtils.kt

@@ -16,6 +16,7 @@
 
 package com.google.android.gradle_recipe.converter.recipe
 
+import com.google.android.gradle_recipe.converter.printErrorAndTerminate
 import java.nio.file.Files
 import java.nio.file.Path
 import kotlin.io.path.exists
@@ -26,7 +27,7 @@ import kotlin.io.path.isHidden
  */
 fun visitRecipes(rootFolder: Path, recipeCallback: (Path) -> Unit) {
     if (!rootFolder.exists()) {
-        error("the source $rootFolder folder doesn't exist")
+        printErrorAndTerminate("the source $rootFolder folder doesn't exist")
     }
 
     Files.walk(rootFolder).filter { currentPath: Path ->

convert-tool/app/src/main/kotlin/com/google/android/gradle_recipe/converter/validators/InternalCIValidator.kt

@@ -32,7 +32,6 @@ class InternalCIValidator(
     private val gradlePath: String,
     private val branchRoot: Path,
 ) {
-    @Throws(IOException::class)
     fun validate(sourceAll: Path, tmpFolder: Path?) {
 
         val converter = RecipeConverter(

convert-tool/app/src/main/kotlin/com/google/android/gradle_recipe/converter/validators/MinMaxCurrentAgpValidator.kt

@@ -20,6 +20,7 @@ import com.google.android.gradle_recipe.converter.converters.RecipeConverter
 import com.google.android.gradle_recipe.converter.converters.RecipeConverter.Mode
 import com.google.android.gradle_recipe.converter.converters.getMaxAgp
 import com.google.android.gradle_recipe.converter.converters.getVersionsFromAgp
+import com.google.android.gradle_recipe.converter.printErrorAndTerminate
 import com.google.android.gradle_recipe.converter.recipe.RecipeData
 import com.google.android.gradle_recipe.converter.recipe.toMajorMinor
 import java.nio.file.Path
@@ -50,7 +51,7 @@ class MinMaxCurrentAgpValidator(
         agpVersion: String,
     ) {
         val gradleVersion = getVersionsFromAgp(branchRoot, agpVersion.toMajorMinor())?.gradle
-            ?: throw RuntimeException("Unable to find Gradle version for AGP version $agpVersion - Make sure it's present in version_mappings.txt")
+            ?: printErrorAndTerminate("Unable to find Gradle version for AGP version $agpVersion - Make sure it's present in version_mappings.txt")
 
         val recipeConverter = RecipeConverter(
             agpVersion = agpVersion,