File format rules
Encoding, line endings and whitespace. Everything here applies to the text files an identifier directory may hold: the .htaccess, and the README in whatever name and format it carries — README.md, README.MD, a bare README, or any of the other formats GitHub renders.
That last part is deliberate. If a README name is accepted by files/only-allowed-names, it is checked here too; a file the repository is willing to keep should not escape these rules by being spelled unusually.
| Rule | Severity | What |
|---|---|---|
format/no-bom | error | No byte order mark — it makes Apache return 500 |
format/no-crlf | warning | Unix line endings, not CRLF |
format/final-newline | warning | End the file with a newline |
format/no-trailing-whitespace | warning | No trailing whitespace that does nothing |
format/no-excessive-blank-lines | warning | No long runs of blank lines, and none at the start or end |
Only format/no-bom can break an identifier. The rest are diff hygiene and readability, and your editor can handle most of them for you — see the note about EditorConfig on any of those pages. format/no-excessive-blank-lines is the exception, and says so on its own page: it is fixed by hand.
Back to the rule catalogue.