Skill

fix-trailing-newlines

Fix SA1518 StyleCop violations by removing trailing newlines from .cs, .xaml, .axaml, .csproj, .props, .targets, .editorconfig, .slnx, .sln, and .json files. Targets projects where .editorconfig has insert_final_newline = false. Use when SA1518 violations appear, trailing newline issues occur, or to enforce insert_final_newline = false across the repository.

npx claudepluginhub atc-net/atc-agentic-toolkit --plugin dotnet

Tool Access

This skill uses the workspace's default tool permissions.

Preview

**SA1518: File may not end with a newline character.**

Supporting Assets

scripts/fix_trailing_newlines.py

SKILL.md

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Last CommitMar 19, 2026

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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:

Find all files with target extensions in the repository
For each file, check if it ends with \n or \r\n
If it does, remove all trailing newline characters from the end
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