fix(core): correct ellipsis logic in EditTool getDescription()

[Megashubham]

Summary

Fixes a subtle display bug in EditToolInvocation.getDescription() where the ellipsis (...) suffix in the edit description snippet was incorrectly computed.

The Bug

// BEFORE (buggy):
const oldStringSnippet =
  this.params.old_string.split('\n')[0].substring(0, 30) +
  (this.params.old_string.length > 30 ? '...' : ''); // checks TOTAL string length

The code extracts the first line of old_string via .split('\n')[0] and applies .substring(0, 30) to it. However, the ellipsis decision was based on this.params.old_string.length > 30 - the length of the entire string, not the first line.

Example: old_string = "function foo() {\n return 1;\n}" (30 chars total)

• First line "function foo() {" is only 17 chars - correctly displayed
• • But old_string.length > 30 -> false -> no ... even though the edit spans multiple lines!
    The Fix

// AFTER (correct):
const oldFirstLine = this.params.old_string.split('\n')[0];
const oldStringSnippet =
  oldFirstLine.substring(0, 30) +
  (oldFirstLine.length > 30 || this.params.old_string.includes('\n')
    ? '...'
    : '');

The fix appends ... when: (1) the first line itself exceeds 30 characters (truncated by substring), or (2) the full string contains newlines (multi-line), so more content exists beyond the snippet. Same fix is applied symmetrically to new_string.

Tests

Added 5 new unit tests in edit.test.ts covering all cases: new file (empty old_string) - no ellipsis; short single-line strings - no ellipsis; multi-line string with short first line - shows ... (the regression case); long first line (> 30 chars) - shows ...; same old_string and new_string - "No file changes" message.

All 67 tests pass. TypeScript typecheck passes. ESLint + Prettier pass.

This fix has already been implemented, the tests pass, and it's ready for review.

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[github-actions]

📊 PR Size: size/M

• Lines changed: 119
• Additions: +113
• Deletions: -6
• Files changed: 2

[github-actions]

🛑 Action Required: Evaluation Approval

Steering changes have been detected in this PR. To prevent regressions, a maintainer must approve the evaluation run before this PR can be merged.

Maintainers:

1. Go to the Workflow Run Summary.
2. Click the yellow 'Review deployments' button.
3. Select the 'eval-gate' environment and click 'Approve'.

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[Megashubham]

@googlebot I signed it!

[gemini-code-assist]

Warning

Gemini encountered an error creating the summary. You can try again by commenting /gemini summary.

[Megashubham]

/gemini summary

[gemini-code-assist]

Summary of Changes

This pull request addresses a display bug in the EditTool description generation where the ellipsis suffix was incorrectly determined based on the total string length instead of the visible snippet length. The changes ensure that the UI accurately indicates when content is truncated or spans multiple lines, improving the clarity of edit descriptions.

Highlights

• Ellipsis Logic Correction: Updated the ellipsis calculation in EditToolInvocation.getDescription() to correctly account for multi-line strings rather than just the total string length.
• Improved Snippet Accuracy: Modified the logic to append an ellipsis if the first line exceeds 30 characters OR if the string contains multiple lines, ensuring a more accurate representation of the edit.
• Comprehensive Testing: Added 5 new unit tests to cover various edge cases, including empty strings, short single-line strings, multi-line strings, and long lines.

Activity

• The CLA check failed initially, but the author confirmed signing the agreement.
• The PR size was calculated as size/M with 87 lines changed.
• A maintainer approval is required for the evaluation run due to detected steering changes.
• The author requested a summary generation via the /gemini summary command.

[Megashubham]

/gemini review

[gemini-code-assist]

Code Review

This pull request updates the getDescription method in EditToolInvocation to correctly append an ellipsis when truncating multi-line strings, even if the first line is short. It also adds comprehensive unit tests to verify this behavior under various scenarios. The review feedback highlights a performance concern where using split('\n') on large files can cause high memory usage, and suggests an optimized approach using indexOf('\n') along with proper handling of multi-byte Unicode characters.

[Megashubham]

/gemini review

[gemini-code-assist]

Code Review

This pull request refactors the snippet generation logic in packages/core/src/tools/edit.ts to handle multi-line strings and multi-byte characters, and adds comprehensive unit tests in packages/core/src/tools/edit.test.ts. The review feedback correctly identifies a potential issue with Windows-style line endings (\r\n), where the carriage return (\r) is retained in the extracted first line and can cause rendering issues in terminal environments. A code suggestion is provided to normalize line endings before processing.

[Megashubham]

/gemini review

[gemini-code-assist]

Code Review

This pull request refactors the snippet generation logic in EditToolInvocation.getDescription to normalize line endings and correctly handle multi-byte characters, accompanied by comprehensive unit tests. The review feedback highlights a potential performance and memory issue where calling Array.from on extremely long lines could cause OOM crashes, and provides an optimized suggestion to check the string length before array conversion.

[Megashubham]

/gemini review

[gemini-code-assist]

Code Review

This pull request adds comprehensive unit tests for the getDescription method in edit.test.ts and refactors the snippet extraction logic in edit.ts to handle line-ending normalization and truncation. The reviewer provided valuable feedback on simplifying the getSnippet helper function by using Array.from() directly on the first line, which ensures safe truncation of multi-byte Unicode characters without splitting them.

[Megashubham]

/gemini review

[gemini-code-assist]

Code Review

This pull request refactors the snippet generation logic in EditToolInvocation.getDescription to normalize CRLF line endings and safely handle multi-byte Unicode characters when truncating strings, accompanied by comprehensive unit tests. Feedback suggests optimizing the truncation logic by using Intl.Segmenter to lazily evaluate grapheme clusters up to the 30-character limit, preventing potential performance and memory issues on extremely large single-line inputs.

[Megashubham]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a helper function getSnippet in packages/core/src/tools/edit.ts to safely extract and truncate snippets of old and new strings using Intl.Segmenter for grapheme-safe truncation, along with corresponding unit tests in packages/core/src/tools/edit.test.ts. However, a logical bug was identified in the truncation condition where chars.length is capped at 30 before checking if it exceeds 30, making the truncation block unreachable and causing tests for long lines to fail. A refactored implementation using array slicing was suggested to resolve this issue.

[Megashubham]

/gemini review

[gemini-code-assist]

Code Review

This pull request refactors the snippet generation logic in EditToolInvocation.getDescription to use Intl.Segmenter for grapheme-aware truncation and adds comprehensive unit tests. The reviewer recommends optimizing the getSnippet helper to process large inputs lazily, preventing potential performance degradation or out-of-memory errors from eager string replacement and segmentation.

[Megashubham]

/gemini review

[gemini-code-assist]

Code Review

This pull request refactors the snippet generation logic in packages/core/src/tools/edit.ts to use Intl.Segmenter for safely segmenting the first line of the edit strings up to 30 characters, handling multi-line strings, and stripping trailing carriage returns (\r). It also adds comprehensive unit tests in packages/core/src/tools/edit.test.ts to verify these behaviors under various scenarios. There are no review comments, and I have no feedback to provide.

[Megashubham]

can you check once :P
@Samee24 !

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