Getline support backspace

[zhangwenjian111]

Summary

getline function support backspace, need work with apache/nuttx-apps#2664

Impact

None

Testing

sim,qemu,arm64

[nuttxpr]

[Experimental Bot, please feedback here]

This PR does not meet the NuttX requirements.

Here's why and how to improve it:

• Summary is incomplete:

  • Missing "Why": Why is getline backspace support necessary? Is there a bug report or feature request driving this?
  • Missing "How": Provide a technical explanation of how you implemented backspace support within getline.
  • Link Issues/PRs: If this relates to existing issues in NuttX or NuttX Apps, provide the links.

• Impact is too brief:

  • Even if there's no user-facing impact, you should confirm this explicitly for each category:
    • "No new features added."
    • "No changes to existing features."
    • "No changes to the build process."
    • ...and so on for all categories.
  • Consider unintended consequences: Could this change, even a seemingly small one, have unexpected side effects?

• Testing is insufficient:

  • Provide details:
    • Which simulator? (e.g., qemu-system-arm, qemu-system-riscv64)
    • Specific ARM64 board and configuration used.
  • Show, don't tell: Include snippets of your testing logs demonstrating the problem before the change and the improvement after.
  • Test breadth: Did you test different input scenarios (long lines, special characters)? Did you test on real hardware if possible?

Example of an Improved Summary:

This PR addresses [Issue #] by adding backspace support to the getline function. Previously, backspace characters were treated as regular input, making line editing impossible. The implementation modifies the internal buffer handling of getline to correctly handle backspace characters, deleting the previous character and adjusting the cursor position.

[TimJTi]

@xiaoxiang781216 @zhangwenjian111 Assuming my git bisect attempt was correct, this PR has broken the backspace on my setup (custom board, UART console, MiniCom terminal on via WSL on Windows 11) is no longer working and I can no longer delete characters.

Is there some other setting (or change of a setting) that is related to this?

[xiaoxiang781216]

@xiaoxiang781216 @zhangwenjian111 Assuming my git bisect attempt was correct, this PR has broken the backspace on my setup (custom board, UART console, MiniCom terminal on via WSL on Windows 11) is no longer working and I can no longer delete characters.

Is there some other setting (or change of a setting) that is related to this?

do you update nsh too? apache/nuttx-apps#2664

[TimJTi]

do you update nsh too? apache/nuttx-apps#2664
I thought I had - but it seems not. I've had this before so I may need to reclone/refork the repo if this happens again.

HOWEVER - perhaps this PR could have mentioned in the IMPACT section that nsh would be broken without updating to the latest nuttx-apps?

[xiaoxiang781216]

update, thanks.

[anchao]

@xiaoxiang781216 @zhangwenjian111 regression on cu command, here is fix:
apache/nuttx-apps#2968