[Feat] Have option to use tabs instead of spaces (forced override)

com.microsoft.copilot.eclipse.core.test/src/com/microsoft/copilot/eclipse/core/completion/FormatOptionProviderTests.java

@@ -10,10 +10,15 @@
 
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IProject;
+import org.eclipse.core.runtime.preferences.IEclipsePreferences;
+import org.eclipse.core.runtime.preferences.InstanceScope;
 import org.eclipse.lsp4j.FormattingOptions;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.NullSource;
+import org.junit.jupiter.params.provider.ValueSource;
 import org.mockito.junit.jupiter.MockitoExtension;
 
 import com.microsoft.copilot.eclipse.core.format.FormatOptionProvider;
@@ -25,7 +30,9 @@ class FormatOptionProviderTests {
   private IFile mockFile;
   private IProject mockProject;
 
-  private static final int PREFERENCE_DEFAULT_TAB_SIZE = 4;
+  private static final String EDITOR_PREF_NODE = "org.eclipse.ui.editors";
+  private static final String TAB_WIDTH_KEY = "tabWidth";
+  private static final String SPACES_FOR_TABS_KEY = "spacesForTabs";
 
   @BeforeEach
   void setUp() {
@@ -52,20 +59,20 @@ void testGetEclipseDefaultJavaTabCharAndSize() {
     assertEquals(tabSize, formatOptionProvider.getTabSize(mockFile));
   }
 
-  @Test
-  void testGetCopilotDefaultTabCharAndSizeForUnknownLanguage() {
-    when(mockFile.getFileExtension()).thenReturn("js");
-
-    assertTrue(formatOptionProvider.useSpace(mockFile));
-    assertEquals(PREFERENCE_DEFAULT_TAB_SIZE, formatOptionProvider.getTabSize(mockFile));
-  }
+  @ParameterizedTest @NullSource @ValueSource(strings = { "js" })
+  void testUsesEclipseTextEditorFormattingOptionsForUnknownOrNoExtension(String extension) {
+    when(mockFile.getFileExtension()).thenReturn(extension);
 
-  @Test
-  void testGetCopilotDefaultTabCharAndSizeForNoExtensionFile() {
-    when(mockFile.getFileExtension()).thenReturn(null);
+    // Set the Eclipse preferences to be something other than the default (false, 4)
+    setEditorFormattingPreferences(true, 2);
 
     assertTrue(formatOptionProvider.useSpace(mockFile));
-    assertEquals(PREFERENCE_DEFAULT_TAB_SIZE, formatOptionProvider.getTabSize(mockFile));
+    assertEquals(2, formatOptionProvider.getTabSize(mockFile));
   }
 
+  private void setEditorFormattingPreferences(boolean useSpaces, int tabSize) {
+    IEclipsePreferences prefs = InstanceScope.INSTANCE.getNode(EDITOR_PREF_NODE);
+    prefs.putBoolean(SPACES_FOR_TABS_KEY, useSpaces);
+    prefs.putInt(TAB_WIDTH_KEY, tabSize);
+  }
 }

com.microsoft.copilot.eclipse.core/src/com/microsoft/copilot/eclipse/core/format/FormatOptionProvider.java

@@ -9,6 +9,8 @@
 import org.apache.commons.lang3.StringUtils;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IProject;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.core.runtime.preferences.IPreferencesService;
 import org.eclipse.lsp4j.FormattingOptions;
 
 import com.microsoft.copilot.eclipse.core.CopilotCore;
@@ -26,6 +28,9 @@ public class FormatOptionProvider {
   private static final String CPP_LANGUAGE_ID = "cpp";
   private static final String[] CPP_LANGUAGE_EXTENSIONS = new String[] { "cpp", "c++", "cc", "cp", "cxx", "h", "h++",
       "hh", ".hpp", ".hxx", ".inc", ".inl", ".ipp", ".tcc", ".tpp" };
+  private static final String EDITOR_PREF_NODE = "org.eclipse.ui.editors";
+  private static final String TAB_WIDTH_KEY = "tabWidth";
+  private static final String SPACES_FOR_TABS_KEY = "spacesForTabs";
   private static final boolean DEFAULT_USE_SPACE = LanguageFormatReader.PREFERENCE_DEFAULT_TAB_CHAR.equals("space");
   private static final int DEFAULT_TAB_SIZE = LanguageFormatReader.PREFERENCE_DEFAULT_TAB_SIZE;
 
@@ -85,13 +90,13 @@ private FormattingOptions getLanguageFormat(IFile file) {
     IProject project = file.getProject();
     if (project == null) {
       CopilotCore.LOGGER.info("Project is null for file: " + file.getName() + "default format will be applied.");
-      return null;
+      return getEclipseTextEditorFormattingOptions();
     }
 
     String fileExtension = file.getFileExtension();
     if (StringUtils.isEmpty(fileExtension)) {
       CopilotCore.LOGGER.info("File extension is null or empty for file: " + file.getName());
-      return null;
+      return getEclipseTextEditorFormattingOptions();
     } else {
       fileExtension = fileExtension.toLowerCase();
     }
@@ -110,14 +115,46 @@ private FormattingOptions getLanguageFormat(IFile file) {
     if (languageFormatReaderForProject == null) {
       languageFormatReaderForProject = loadFormatReaderForTheProject(languageId, project);
       if (languageFormatReaderForProject == null) {
-        return new FormattingOptions(DEFAULT_TAB_SIZE, DEFAULT_USE_SPACE);
+        return getEclipseTextEditorFormattingOptions();
       }
       projectToLanguageFormatReaderMap.put(project, languageFormatReaderForProject);
     }
 
     return languageFormatReaderForProject.getFormattingOptions();
   }
 
+  /**
+   * Attempts to read the Eclipse default text editor preferences for tab size and spaces-for-tabs.
+   * Falls back to hardcoded defaults if the preferences cannot be read.
+   */
+  private FormattingOptions getEclipseTextEditorFormattingOptions() {
+    try {
+      IPreferencesService service = Platform.getPreferencesService();
+
+      boolean useSpaces = service.getBoolean(
+          EDITOR_PREF_NODE,
+          SPACES_FOR_TABS_KEY,
+          DEFAULT_USE_SPACE,
+          null
+      );
+
+      int tabSize = service.getInt(
+          EDITOR_PREF_NODE,
+          TAB_WIDTH_KEY,
+          DEFAULT_TAB_SIZE,
+          null
+      );
+
+      return new FormattingOptions(tabSize, useSpaces);
+    } catch (Exception e) {
+      CopilotCore.LOGGER.info(
+            "Failed to read Eclipse text editor preferences, using defaults");
+      return new FormattingOptions(DEFAULT_TAB_SIZE, DEFAULT_USE_SPACE);
+    }
+  }
+
+
+
   private LanguageFormatReader loadFormatReaderForTheProject(String languageId, IProject project) {
     switch (languageId) {
       case JAVA_LANGUAGE_ID:
@@ -129,4 +166,4 @@ private LanguageFormatReader loadFormatReaderForTheProject(String languageId, IP
         return null;
     }
   }
-}
+}