Fix Trailing Newlines (SA1518)

What This Fixes

SA1518: File may not end with a newline character.

When .editorconfig has insert_final_newline = false, files must NOT end with trailing \r\n or \n characters. This skill scans all relevant files and strips any trailing newline bytes.

Target File Types

Extension	Description
.cs	C# source files
.xaml	XAML markup files
.axaml	Avalonia XAML files
.csproj	C# project files
.props	MSBuild property files
.targets	MSBuild target files
.editorconfig	Editor configuration files
.slnx	Solution XML files
.sln	Solution files
.json	JSON configuration files

Excluded Directories

The following directories are always skipped:

• bin - Build output
• obj - Intermediate build output
• .vs - Visual Studio metadata
• .git - Git repository data
• node_modules - Node.js dependencies

Execution Steps

Step 1: Verify .editorconfig Setting

Before running, confirm the project uses insert_final_newline = false:

grep -r "insert_final_newline" .editorconfig

If insert_final_newline = true or not set, warn the user that removing trailing newlines may conflict with their editor configuration.

Step 2: Run the Fix Script

Execute the bundled Python script to scan and fix all files:

python scripts/fix_trailing_newlines.py [directory]

• If no directory is specified, defaults to the current working directory
• The script reports each fixed file and provides a summary

Step 3: Review Results

The script outputs:

• Each file that was fixed (relative path)
• Total files scanned and fixed

Step 4: Verify Build

After fixing, run:

dotnet build

Ensure the build succeeds and SA1518 warnings are resolved.

Manual Alternative

If the Python script is unavailable, perform the fix manually:

1. Find all files with target extensions in the repository
2. For each file, check if it ends with \n or \r\n
3. If it does, remove all trailing newline characters from the end
4. Save the file with binary write to avoid editors re-adding newlines

Guidelines

• Always check .editorconfig before running to confirm insert_final_newline = false
• The script preserves all file content except trailing newline bytes
• Empty files are skipped (no modification needed)
• The fix is idempotent - running it multiple times produces the same result