Add support for preferences file override and path normalization

Allows overriding the preferences file location via the 'processing.app.preferences.file' system property. Also normalizes slashes in preference values to forward slashes. Updates tests to verify path normalization and override behavior.

Author: Stefterv

app/src/processing/app/Preferences.java

@@ -87,8 +87,13 @@ static public void init() {
       setBoolean("editor.input_method_support", true);
     }
 
+
     // next load user preferences file
     preferencesFile = Base.getSettingsFile(PREFS_FILE);
+      var preferencesFileOverride = System.getProperty("processing.app.preferences.file");
+      if (preferencesFileOverride != null && !preferencesFileOverride.isEmpty()) {
+          preferencesFile = new File(preferencesFileOverride);
+      }
     boolean firstRun = !preferencesFile.exists();
     if (!firstRun) {
       try {
@@ -179,9 +184,11 @@ static public void load(InputStream input) throws IOException {
 
     String[] lines = PApplet.loadStrings(input);  // Reads as UTF-8
     for (String line : lines) {
-      if ((line.length() == 0) ||
+        if ((line.isEmpty()) ||
           (line.charAt(0) == '#')) continue;
 
+        line = line.replace("\\", "/");  // normalize slashes in paths
+
       // this won't properly handle = signs being in the text
       int equals = line.indexOf('=');
       if (equals != -1) {

app/test/processing/app/PreferencesKtTest.kt

@@ -9,6 +9,7 @@ import java.util.*
 import kotlin.io.path.createFile
 import kotlin.io.path.createTempDirectory
 import kotlin.test.Test
+import kotlin.test.assertEquals
 
 class PreferencesKtTest{
     @OptIn(ExperimentalTestApi::class)
@@ -75,6 +76,7 @@ class PreferencesKtTest{
 
         val value = "C:\\Users\\Test\\Documents"
         tempPreferences.writeText("$testKey=$value")
+        val replacedValue = value.replace("\\", "/")
 
         setContent {
             PreferencesProvider {
@@ -83,6 +85,9 @@ class PreferencesKtTest{
             }
         }
 
-        onNodeWithTag("text").assertTextEquals(value.replace("\\", "/"))
+        onNodeWithTag("text").assertTextEquals(replacedValue)
+
+        Preferences.init()
+        assertEquals(replacedValue, Preferences.get(testKey))
     }
 }