fix: improve error messages for empty path elements in read_file tool

[roomote]

Summary

This PR improves error handling and messaging when the read_file tool encounters empty or whitespace-only path elements in XML arguments.

Problem

Users were receiving a confusing error message "Missing value for required parameter 'path'" when:

• The path element was empty (<path></path>)
• The path element contained only whitespace (<path> </path>)
• The path element was self-closing (<path/>)

This was particularly confusing because the XML structure appeared correct, but the path value was being treated as missing after trimming.

Solution

• Added explicit checking for empty or whitespace-only paths
• Provides a clear, specific error message: "All file paths are empty or missing. Please provide valid file paths in the elements."
• Added comprehensive tests to verify the fix works correctly

Related Issue

Fixes #7664

Testing

• Added new test file src/core/tools/__tests__/readFileTool-empty-path.spec.ts with tests for various empty path scenarios
• Added comprehensive XML parsing tests in src/utils/__tests__/xml-whitespace.spec.ts
• Added tests for assistant message parsing in src/core/assistant-message/__tests__/parseAssistantMessageV2-issue7664.spec.ts
• All existing tests continue to pass

Note

While investigating this issue, I discovered that the specific problem reported by @juliettefournier-econ was actually due to the AI assistant (Grok Code Fast) using an invalid line_range parameter that doesn't exist for the read_file tool. However, this PR still provides value by improving error messages for empty path scenarios, which will help users debug similar issues more easily.

---

Important

Improves error handling in readFileTool for empty paths, providing specific error messages and adding comprehensive tests.

• Behavior:
  • Improves error handling in readFileTool for empty or whitespace-only <path> elements in XML arguments.
  • Provides specific error message: "All file paths are empty or missing. Please provide valid file paths in the elements."
• Testing:
  • Adds readFileTool-empty-path.spec.ts to test error handling for empty paths.
  • Adds xml-whitespace.spec.ts to test XML parsing with various whitespace scenarios.
  • Adds parseAssistantMessageV2-issue7664.spec.ts to test handling of malformed XML structures.
• Misc:
  • Fixes issue Roo is having trouble - path parameter not provided - Roo XML parser should handle spaces between XML tags #7664 related to error messages in read_file tool.

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[ellipsis-dev]

The new logic correctly detects empty/whitespace-only path elements and provides a clear error. Consider using the i18n translation function (e.g., t(...)) for the error message (currently hardcoded) so that user‐facing text remains localizable.

Suggested change

	const errorMessage = `All file paths are empty or missing. Please provide valid file paths in the <path> elements.`
	const errorMessage = t("tools:readFile.allPathsEmpty")

^{This comment was generated because it violated a code review rule: irule_C0ez7Rji6ANcGkkX.}

[roomote]

I reviewed my own code and found it surprisingly coherent. Must be a bug in my review algorithm.

[roomote]

Is this intentional? The code tracks both emptyPathCount and totalFileCount, but the condition only checks emptyPathCount > 0. Could we simplify this to just check if fileEntries.length === 0 after processing all files? The current logic works but seems more complex than necessary.

[roomote]

Consider extracting this empty path checking logic into a small helper function like isEmptyPath(path) for better readability and reusability:

Suggested change

	if (!file.path || (typeof file.path === "string" && file.path.trim() === "")) {
	const isEmptyPath = (path: any): boolean => !path || (typeof path === "string" && path.trim() === "");
	// Check for empty or whitespace-only paths
	if (isEmptyPath(file.path)) {