Add write methods for input buffers to SafeBufferAccess

[devin-ai-integration]

Add write methods for input buffers to SafeBufferAccess

Summary

This PR adds four missing write methods to the SafeBufferAccess facade class that allow writing to PLC input buffers:

• write_byte_input(buffer_idx, value, thread_safe=True)
• write_int_input(buffer_idx, value, thread_safe=True)
• write_dint_input(buffer_idx, value, thread_safe=True)
• write_lint_input(buffer_idx, value, thread_safe=True)

These methods are required by the Modbus master plugin, which needs to write data it reads from remote slave devices INTO the PLC's input buffers. While inputs are traditionally read-only from a PLC program's perspective, external communication plugins like Modbus master legitimately need to populate these buffers.

This fixes the error: 'SafeBufferAccess' object has no attribute 'write_int_input'

The implementation delegates to the existing buffer_accessor.write_buffer() method, which already supports input buffer writes. The diff also includes formatting changes applied by pre-commit hooks (black, isort, ruff).

Review & Testing Checklist for Human

• Test with Modbus master plugin configured to read holding registers (FC 3) from a slave device and verify the values appear correctly in PLC input buffers (%IW, %ID, %IL)
• Verify the "SafeBufferAccess object has no attribute 'write_int_input'" error no longer appears in logs during Modbus master operation
• Run a longer duration test (similar to the original 2-hour test) to confirm stability

Notes

The new methods follow the exact same pattern as existing write_*_output and write_*_memory methods, making this a low-risk change. The underlying buffer accessor already supported this functionality - only the facade was missing the methods.

Link to Devin run: https://app.devin.ai/sessions/c0ab2357ad504b7ba3826ec9e9a16955
Requested by: Thiago Alves (@thiagoralves)

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment and CI monitoring

[Copilot]

Pull request overview

This PR adds four write methods (write_byte_input, write_int_input, write_dint_input, write_lint_input) to the SafeBufferAccess facade class to enable Modbus master plugins to write data into PLC input buffers, resolving the 'SafeBufferAccess' object has no attribute 'write_int_input' error.

Key Changes:

• Added four new write methods for input buffers (byte, int, dint, lint)
• Applied code formatting changes (import reordering, line length adjustments)

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.