Log EditorConfig usage and resolved configuration to prevent silent config conflicts (#3867)

* Initial plan

* Add logging for EditorConfig usage and resolved configuration

- Log when EditorConfig support is enabled
- Log the config file path if found
- Log when settings come from .editorconfig (when no Prettier config exists)
- Log the complete resolved configuration
- Simplify logging messages in PrettierEditService

This helps users understand what configuration is being applied, especially
when .editorconfig has settings that affect formatting.

Co-authored-by: ntotten <282782+ntotten@users.noreply.github.com>

* Add logging for custom config path from VS Code settings

Also log when a custom prettier.configPath is specified in VS Code settings
to provide complete visibility into what configuration is being used.

Co-authored-by: ntotten <282782+ntotten@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: ntotten <282782+ntotten@users.noreply.github.com>

Author: Copilot

src/ModuleResolverNode.ts

@@ -402,12 +402,33 @@ export class ModuleResolver implements ModuleResolverInterface {
       return "error";
     }
 
+    // Log what config file was found (if any)
+    if (configPath) {
+      this.loggingService.logInfo(`Using config file at ${configPath}`);
+    }
+
+    // Log if editorconfig will be considered
+    if (vscodeConfig.useEditorConfig) {
+      this.loggingService.logInfo(
+        "EditorConfig support is enabled, checking for .editorconfig files",
+      );
+    }
+
     let resolvedConfig: PrettierOptions | null;
     try {
+      const customConfigPath = vscodeConfig.configPath
+        ? getWorkspaceRelativePath(fileName, vscodeConfig.configPath)
+        : undefined;
+      
+      // Log if a custom config path is specified in VS Code settings
+      if (customConfigPath) {
+        this.loggingService.logInfo(
+          `Using custom config path from settings: ${customConfigPath}`,
+        );
+      }
+
       const resolveConfigOptions: PrettierResolveConfigOptions = {
-        config: vscodeConfig.configPath
-          ? getWorkspaceRelativePath(fileName, vscodeConfig.configPath)
-          : configPath,
+        config: customConfigPath ?? configPath,
         editorconfig: vscodeConfig.useEditorConfig,
       };
       resolvedConfig = await prettierInstance.resolveConfig(
@@ -419,6 +440,24 @@ export class ModuleResolver implements ModuleResolverInterface {
       return "error";
     }
 
+    // Log what configuration was resolved
+    if (resolvedConfig) {
+      this.loggingService.logInfo("Resolved config:", resolvedConfig);
+    }
+
+    // Determine config source for better user feedback
+    if (!configPath && resolvedConfig && vscodeConfig.useEditorConfig) {
+      // Config was resolved but no Prettier config file was found
+      // This means settings came from .editorconfig
+      this.loggingService.logInfo(
+        "No Prettier config file found, but settings were loaded from .editorconfig",
+      );
+    } else if (!configPath && !resolvedConfig) {
+      this.loggingService.logInfo(
+        "No local configuration (i.e. .prettierrc or .editorconfig) detected, will fall back to VS Code configuration",
+      );
+    }
+
     if (!vscodeConfig.requireConfig) {
       return resolvedConfig;
     }

src/PrettierEditService.ts

@@ -677,8 +677,8 @@ export default class PrettierEditService implements Disposable {
 
     this.loggingService.logInfo(
       fallbackToVSCodeConfig
-        ? "No local configuration (i.e. .prettierrc or .editorconfig) detected, falling back to VS Code configuration"
-        : "Detected local configuration (i.e. .prettierrc or .editorconfig), VS Code configuration will not be used",
+        ? "Using VS Code configuration"
+        : "Using local configuration (VS Code configuration will not be used)",
     );
 
     let rangeFormattingOptions: RangeFormattingOptions | undefined;