Preserve custom_modes.json for rollback if necessary

Author: mrubens

src/__tests__/migrateSettings.test.ts

@@ -167,7 +167,13 @@ describe("Settings Migration", () => {
 
 		// Verify file operations
 		expect(mockWrite).toHaveBeenCalledWith(newCustomModesYaml, expect.any(String), "utf-8")
-		expect(mockUnlink).toHaveBeenCalledWith(legacyCustomModesJson)
+		// We don't delete the original JSON file to allow for rollback
+		expect(mockUnlink).not.toHaveBeenCalled()
+
+		// Verify log message mentions preservation of original file
+		expect(mockOutputChannel.appendLine).toHaveBeenCalledWith(
+			expect.stringContaining("original JSON file preserved for rollback purposes"),
+		)
 	})
 
 	it("should handle corrupt JSON gracefully", async () => {

src/utils/migrateSettings.ts

@@ -98,15 +98,11 @@ async function migrateCustomModesToYaml(settingsDir: string, outputChannel: vsco
 			// Write YAML file
 			await fs.writeFile(newYamlPath, yamlContent, "utf-8")
 
-			try {
-				// Delete old JSON file - wrapped in try/catch to handle unlink errors
-				await fs.unlink(oldJsonPath)
-			} catch (unlinkError) {
-				// Just log the error but continue - file migration succeeded
-				outputChannel.appendLine(`Warning: Could not delete old JSON file: ${unlinkError}`)
-			}
-
-			outputChannel.appendLine("Successfully migrated custom_modes.json to YAML format")
+			// Keeping the old JSON file for backward compatibility
+			// This allows users to roll back if needed
+			outputChannel.appendLine(
+				"Successfully migrated custom_modes.json to YAML format (original JSON file preserved for rollback purposes)",
+			)
 		} catch (parseError) {
 			// Handle corrupt JSON file
 			outputChannel.appendLine(