ShadBorder sides isn't merged

[dickermoshe]

Steps to reproduce

1. Merge a ShadBorder with another ShadBorder

Expected results

2. Get a mix of the 2

Actual results

It's completely replaced!

ShadBorder sides has a default of BorderSide.none instead of null, so a copyWith will result in these values getting replaced!

shadcn_ui version

0.14.1

Platform

MacOS, Windows, Linux, Android, iOS, Web

Code sample

Code sample

ShadInput(
placeholder: const Text('Search'),
decoration: ShadDecoration(
    focusedBorder: ShadBorder(
        radius: BorderRadius.circular(16)),
    border: ShadBorder(
        radius: BorderRadius.circular(16))),
)

Screenshots or Video

Screenshots / Video demonstration

Why is the border gone

Recording.2024-10-31.144225.mp4

Logs

Logs

N/A```

</details>


### Flutter Doctor output

<details open><summary>Doctor output</summary>

```console
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, 3.24.3, on Microsoft Windows [Version 10.0.22631.4317], locale en-US)
[√] Windows Version (Installed version of Windows is version 10 or higher)
[√] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
[√] Chrome - develop for the web
[√] Visual Studio - develop Windows apps (Visual Studio Community 2022 17.11.5)
[√] Android Studio (version 2023.1)
[√] VS Code, 64-bit edition (version 1.93.1)
[!] Proxy Configuration
    ! NO_PROXY does not contain ::1
[√] Connected device (3 available)
[√] Network resources

! Doctor found issues in 1 category.

[nank1ro]

I was sure that I already addressed this issue. With ShadBorder.all do you have the same issue?

This is the default border of the input theme

border: ShadBorder.all(
  width: 2,
  color: colorScheme.border,
  radius: radius,
),

And if in the Input field I use border: ShadBorder.all(radius: BorderRadius.circular(50)) the radius is merged correctly.

[dickermoshe]

This is a broader issue. merge() should only override explicitly set properties. So there can't be defaults on themes anywhere.
I'm gonna work on a PR which will resolve all of this. The package is littered with many instances of themes with defaults.

[dickermoshe]

For this specifically, the merge is much more complex:
See the flutter code for BorderSide.merge.

https://github.com/flutter/flutter/blob/2da2332ad1be7ed6efc049155e1f47d1fde2276b/packages/flutter/lib/src/painting/borders.dart#L85-L106

[dickermoshe]

#185