Enum TrailingNewline 

pub enum TrailingNewline {
    Preserve,
    Strip,
    Ensure,
}

Trailing-newline policy applied at the document boundary.

Preserve (the default) matches the source’s trailing-newline shape: if the source ends with one or more \n bytes, the formatted output ends with exactly one \n; if the source has no trailing \n, the output has none either. This is what formatter validation needs to hold: pulldown-cmark’s HTML render of \t\x10 is <pre><code>\x10</code></pre> while its render of \t\x10\n is <pre><code>\x10\n</code></pre>; the trailing LF lives inside the code body for any document ending in an indented code block. An unconditional “ensure trailing \n” post-pass cannot avoid that class of HTML-divergence; Preserve avoids it by construction.

Strip drops every trailing \n. Ensure forces exactly one trailing \n (the pre-Preserve trailing_newline = true behaviour); kept under an explicit name so callers opt in to the foot-gun rather than getting it by default.

Variants

Preserve

Match the source: one trailing \n iff the source had any.

Strip

Drop every trailing \n.

Ensure

Force exactly one trailing \n, appending if absent.

Trait Implementations

impl Clone for TrailingNewline

fn clone(&self) -> TrailingNewline

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TrailingNewline

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for TrailingNewline

fn default() -> TrailingNewline

Returns the “default value” for a type.

impl PartialEq for TrailingNewline

fn eq(&self, other: &TrailingNewline) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for TrailingNewline

impl Eq for TrailingNewline

impl StructuralPartialEq for TrailingNewline