We should not error out when agent produces range that's beyond file length

[xingyaoww]

Instead of throwing error like this:

ERROR: Invalid view_range parameter: [386, 700]. Its second element 700 should be smaller than the number of lines in the file: 600.

We should treat it as [386, max number of lines in file] and then throw a warning like "We only show up to 600 since there's only 600 lines in this file".

[xingyaoww]

@openhands-exp Please solve this issue

[openhands-ai]

I'm on it! xingyaoww can track my progress at all-hands.dev

[openhands-ai]

Summary of work completed for Issue #154

What changed

• Behavior: When view_range end exceeds file length, the editor now clamps the end to the file’s last line and returns the requested content instead of erroring.
• Warning: A clear warning is appended to the output if clamping occurs:
  • NOTE: We only show up to {num_lines} since there's only {num_lines} lines in this file
• Existing validations preserved:
  • start_line must be within [1, num_lines]
  • end_line == -1 still means “to the end of the file”
  • end_line must be >= start_line after normalization

Files modified

• openhands_aci/editor/editor.py
  • Implemented end_line normalization and warning emission
• tests/integration/editor/test_error_handling.py
  • Updated out-of-bounds view_range test to assert on the new NOTE warning

Validation

• Pre-commit hooks: Passed (ruff, ruff-format, mypy)
• Selective tests: Passed
  • tests/integration/editor/test_error_handling.py
  • tests/integration/test_oh_editor.py
  • tests/integration/editor/test_non_utf8_operations.py
• Full pytest run encountered a container MemoryError unrelated to code changes; targeted tests covering this change passed.

Checklist

• Implement clamping instead of error for out-of-range view_range end: done
• Emit a user-facing warning as requested: done
• Preserve existing validations and behaviors: done
• Keep changes minimal and focused: done
• Update tests to reflect new behavior: done
• Linting and typing checks pass: done

Branch and PR

• Branch pushed: fix/154-view-range-clamp
• Draft PR opened: Clamp view_range end to file length and emit warning instead of error (fixes #154) #157

If you’d like, I can mark the PR ready for review once you confirm.

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