Fix drag and drop escaping (#18965)

packages/cli/src/ui/hooks/atCommandProcessor.test.ts

@@ -145,6 +145,7 @@ describe('handleAtCommand', () => {
   afterEach(async () => {
     abortController.abort();
     await fsPromises.rm(testRootDir, { recursive: true, force: true });
+    vi.unstubAllGlobals();
   });
 
   it('should pass through query if no @ command is present', async () => {
@@ -319,6 +320,46 @@ describe('handleAtCommand', () => {
     );
   }, 10000);
 
+  it('should correctly handle double-quoted paths with spaces', async () => {
+    // Mock platform to win32 so unescapePath strips quotes
+    vi.stubGlobal(
+      'process',
+      Object.create(process, {
+        platform: {
+          get: () => 'win32',
+        },
+      }),
+    );
+
+    const fileContent = 'Content of file with spaces';
+    const filePath = await createTestFile(
+      path.join(testRootDir, 'my folder', 'my file.txt'),
+      fileContent,
+    );
+    // On Windows, the user might provide: @"path/to/my file.txt"
+    const query = `@"${filePath}"`;
+
+    const result = await handleAtCommand({
+      query,
+      config: mockConfig,
+      addItem: mockAddItem,
+      onDebugMessage: mockOnDebugMessage,
+      messageId: 126,
+      signal: abortController.signal,
+    });
+
+    const relativePath = getRelativePath(filePath);
+    expect(result).toEqual({
+      processedQuery: [
+        { text: `@${relativePath}` },
+        { text: '\n--- Content from referenced files ---' },
+        { text: `\nContent from @${relativePath}:\n` },
+        { text: fileContent },
+        { text: '\n--- End of content ---' },
+      ],
+    });
+  });
+
   it('should correctly handle file paths with narrow non-breaking space (NNBSP)', async () => {
     const nnbsp = '\u202F';
     const fileContent = 'NNBSP file content.';

packages/cli/src/ui/hooks/atCommandProcessor.ts

@@ -31,12 +31,13 @@ const REF_CONTENT_FOOTER = `\n${REFERENCE_CONTENT_END}`;
  * Regex source for the path/command part of an @ reference.
  * It uses strict ASCII whitespace delimiters to allow Unicode characters like NNBSP in filenames.
  *
- * 1. \\. matches any escaped character (e.g., \ ).
- * 2. [^ \t\n\r,;!?()\[\]{}.] matches any character that is NOT a delimiter and NOT a period.
- * 3. \.(?!$|[ \t\n\r]) matches a period ONLY if it is NOT followed by whitespace or end-of-string.
+ * 1. "(?:[^"]*)" matches a double-quoted string (for Windows paths with spaces).
+ * 2. \\. matches any escaped character (e.g., \ ).
+ * 3. [^ \t\n\r,;!?()\[\]{}.] matches any character that is NOT a delimiter and NOT a period.
+ * 4. \.(?!$|[ \t\n\r]) matches a period ONLY if it is NOT followed by whitespace or end-of-string.
  */
 export const AT_COMMAND_PATH_REGEX_SOURCE =
-  '(?:\\\\.|[^ \\t\\n\\r,;!?()\\[\\]{}.]|\\.(?!$|[ \\t\\n\\r]))+';
+  '(?:(?:"(?:[^"]*)")|(?:\\\\.|[^ \\t\\n\\r,;!?()\\[\\]{}.]|\\.(?!$|[ \\t\\n\\r])))+';
 
 interface HandleAtCommandParams {
   query: string;
@@ -85,8 +86,8 @@ function parseAllAtCommands(query: string): AtCommandPart[] {
       });
     }
 
-    // unescapePath expects the @ symbol to be present, and will handle it.
-    const atPath = unescapePath(fullMatch);
+    // We strip the @ before unescaping so that unescapePath can handle quoted paths correctly on Windows.
+    const atPath = '@' + unescapePath(fullMatch.substring(1));
     parts.push({ type: 'atPath', content: atPath });
 
     lastIndex = matchIndex + fullMatch.length;