Use XDG base directories and Known Folders on Windows (#1809)

This changes logic that previously read/wrote from `~/.pkl` to use
XDG base directories (all OSes), and Known Folders locations on Windows.

For example, Pkl will look for `settings.pkl` in:

1. `$XDG_CONFIG_HOME/pkl/settings.pkl`
2. `%APPDATA/pkl/settings.pkl`
3. `~/.pkl/settings.pkl`
4. Path pkl/settings/pkl within `$XDG_CONFIG_DIRS`
5. `/etc/xdg/pkl/settings.pkl`

---------

Co-authored-by: Florin Ungur <florin@florinungur.com>

pkl-commons-cli/src/main/kotlin/org/pkl/commons/cli/CliBaseOptions.kt

@@ -77,8 +77,9 @@ data class CliBaseOptions(
 
   /**
    * The Pkl settings file to use. A settings file is a Pkl module amending the `pkl.settings`
-   * standard library module. If `null`, `~/.pkl/settings.pkl` (if present) or the defaults
-   * specified in the `pkl:settings` standard library module are used.
+   * standard library module. If `null`, `~/.config/pkl/settings.pkl` (falling back to the legacy
+   * `~/.pkl/settings.pkl`), or the defaults specified in the `pkl:settings` standard library
+   * module, are used.
    */
   private val settings: URI? = null,
 
@@ -130,8 +131,9 @@ data class CliBaseOptions(
    * The given files must contain [X.509](https://en.wikipedia.org/wiki/X.509) certificates in PEM
    * format.
    *
-   * If [caCertificates] is the empty list, the certificate files in `~/.pkl/cacerts/` are used. If
-   * `~/.pkl/cacerts/` does not exist or is empty, Pkl's built-in CA certificates are used.
+   * If [caCertificates] is the empty list, the certificate files in `~/.config/pkl/cacerts/` (or
+   * the legacy `~/.pkl/cacerts/`) are used. If that directory does not exist or is empty, Pkl's
+   * built-in CA certificates are used.
    */
   val caCertificates: List<Path> = listOf(),
 

pkl-commons-cli/src/main/kotlin/org/pkl/commons/cli/CliCommand.kt

@@ -20,6 +20,7 @@ import java.net.URI
 import java.nio.file.Files
 import java.nio.file.Path
 import java.util.regex.Pattern
+import kotlin.io.path.absolutePathString
 import kotlin.io.path.isRegularFile
 import org.pkl.core.*
 import org.pkl.core.evaluatorSettings.PklEvaluatorSettings
@@ -33,6 +34,7 @@ import org.pkl.core.project.Project
 import org.pkl.core.resource.ResourceReader
 import org.pkl.core.resource.ResourceReaders
 import org.pkl.core.settings.PklSettings
+import org.pkl.core.util.DebugLogger
 import org.pkl.core.util.IoUtils
 
 /** Building block for CLI commands. Configured programmatically to allow for embedding. */
@@ -69,7 +71,7 @@ abstract class CliCommand(protected val cliOptions: CliBaseOptions) {
       if (cliOptions.normalizedSettingsModule != null) {
         PklSettings.load(ModuleSource.uri(cliOptions.normalizedSettingsModule))
       } else {
-        PklSettings.loadFromPklHomeDir()
+        PklSettings.loadFromSystem()
       }
     } catch (e: PklException) {
       // do not use `errorRenderer` because it depends on `settings`
@@ -146,7 +148,7 @@ abstract class CliCommand(protected val cliOptions: CliBaseOptions) {
         ?: evaluatorSettings?.let { settings ->
           if (settings.noCache == true) null else settings.moduleCacheDir
         }
-        ?: IoUtils.getDefaultModuleCacheDir()
+        ?: IoUtils.getSystemModuleCacheDir()
   }
 
   protected val modulePath: List<Path> by lazy {
@@ -215,7 +217,7 @@ abstract class CliCommand(protected val cliOptions: CliBaseOptions) {
   }
 
   private fun HttpClient.Builder.addDefaultCliCertificates() {
-    val caCertsDir = IoUtils.getPklHomeDir().resolve("cacerts")
+    val caCertsDir = IoUtils.getSystemCaCertsDir()
     var certsAdded = false
     if (Files.isDirectory(caCertsDir)) {
       Files.list(caCertsDir)
@@ -225,7 +227,10 @@ abstract class CliCommand(protected val cliOptions: CliBaseOptions) {
           addCertificates(cert)
         }
     }
-    if (!certsAdded) {
+    if (certsAdded) {
+      DebugLogger.log("Loading CA certificates from ${caCertsDir.normalize().absolutePathString()}")
+    } else {
+      DebugLogger.log("Using built-in CA certificates")
       val defaultCerts =
         this@CliCommand.javaClass.classLoader.getResourceAsStream(
           "org/pkl/commons/cli/PklCARoots.pem"

pkl-commons-cli/src/test/kotlin/org/pkl/commons/cli/CliCommandTest.kt

@@ -144,7 +144,7 @@ class CliCommandTest {
     assertThat(cliTest.myRootDir).isNull()
     assertThat(builder.environmentVariables).isEqualTo(System.getenv())
     assertThat(builder.externalProperties).isEmpty()
-    assertThat(builder.moduleCacheDir).isEqualTo(IoUtils.getDefaultModuleCacheDir())
+    assertThat(builder.moduleCacheDir).isEqualTo(IoUtils.getSystemModuleCacheDir())
     assertThat(cliTest.myModulePath).isEmpty()
     assertThat(builder.color).isFalse
     assertThat(cliTest.myProxyAddress).isNull()