feat: add newlines option to handle when blank lines are added

src/cli.rs

@@ -733,6 +733,14 @@ pub struct Opt {
     /// Regular expression defining navigation stop points.
     pub navigate_regex: Option<String>,
 
+    #[arg(
+        long = "newlines",
+        default_value = "file diff",
+        value_name = "WHERE"
+    )]
+    /// Insert newlines between elements.
+    pub newlines: String,
+
     #[arg(long = "no-gitconfig")]
     /// Do not read any settings from git config.
     ///

src/config.rs

@@ -115,6 +115,9 @@ pub struct Config {
     pub minus_style: Style,
     pub navigate_regex: Option<String>,
     pub navigate: bool,
+    pub newline_after_diff: bool,
+    pub newline_after_file: bool,
+    pub newline_after_hunk_header: bool,
     pub null_style: Style,
     pub null_syntect_style: SyntectStyle,
     pub pager: Option<String>,
@@ -410,6 +413,9 @@ impl From<cli::Opt> for Config {
             minus_style: styles["minus-style"],
             navigate: opt.navigate,
             navigate_regex,
+            newline_after_diff: opt.newlines.split_whitespace().any(|s| s == "diff"),
+            newline_after_file: opt.newlines.split_whitespace().any(|s| s == "file"),
+            newline_after_hunk_header: opt.newlines.split_whitespace().any(|s| s == "hunk-header"),
             null_style: Style::new(),
             null_syntect_style: SyntectStyle::default(),
             pager: opt.pager,

src/delta.rs

@@ -112,6 +112,7 @@ pub struct StateMachine<'a> {
     pub handled_diff_header_header_line_file_pair: Option<(String, String)>,
     pub blame_key_colors: HashMap<String, String>,
     pub minus_line_counter: AmbiguousDiffMinusCounter,
+    pub in_hunk: bool,
 }
 
 pub fn delta<I>(lines: ByteLines<I>, writer: &mut dyn Write, config: &Config) -> std::io::Result<()>
@@ -140,6 +141,7 @@ impl<'a> StateMachine<'a> {
             config,
             blame_key_colors: HashMap::new(),
             minus_line_counter: AmbiguousDiffMinusCounter::not_needed(),
+            in_hunk: false,
         }
     }
 

src/handlers/commit_meta.rs

@@ -14,6 +14,7 @@ impl StateMachine<'_> {
         if !self.test_commit_meta_header_line() {
             return Ok(false);
         }
+        self.in_hunk &= self.config.commit_style.is_omitted;
         let mut handled_line = false;
         self.painter.paint_buffered_minus_and_plus_lines();
         self.handle_pending_line_with_diff_name()?;

src/handlers/diff_header.rs

@@ -63,6 +63,7 @@ impl StateMachine<'_> {
                 &mut self.painter,
                 &mut self.mode_info,
                 self.config,
+                &mut self.in_hunk,
             )?;
             Ok(true)
         } else {
@@ -206,6 +207,7 @@ impl StateMachine<'_> {
             &mut self.painter,
             &mut self.mode_info,
             self.config,
+            &mut self.in_hunk,
         )
     }
 
@@ -248,6 +250,7 @@ impl StateMachine<'_> {
                 &mut self.painter,
                 &mut self.mode_info,
                 self.config,
+                &mut self.in_hunk,
             )
         } else if !self.config.color_only
             && self.should_handle()
@@ -270,6 +273,7 @@ pub fn write_generic_diff_header_header_line(
     painter: &mut Painter,
     mode_info: &mut String,
     config: &Config,
+    in_hunk: &mut bool
 ) -> std::io::Result<()> {
     // If file_style is "omit", we'll skip the process and print nothing.
     // However in the case of color_only mode,
@@ -279,9 +283,9 @@ pub fn write_generic_diff_header_header_line(
     }
     let (mut draw_fn, pad, decoration_ansi_term_style) =
         draw::get_draw_function(config.file_style.decoration_style);
-    if !config.color_only {
-        // Maintain 1-1 correspondence between input and output lines.
+    if !config.color_only && *in_hunk && config.newline_after_diff {
         writeln!(painter.writer)?;
+        *in_hunk = false;
     }
     draw_fn(
         painter.writer,
@@ -292,6 +296,9 @@ pub fn write_generic_diff_header_header_line(
         config.file_style,
         decoration_ansi_term_style,
     )?;
+    if !config.color_only && config.newline_after_file {
+        writeln!(painter.writer)?;
+    }
     if !mode_info.is_empty() {
         mode_info.truncate(0);
     }
@@ -757,7 +764,7 @@ index 0000000..323fae0
 +++ b.lua
 @@ -1,5 +1,4 @@
  #!/usr/bin/env lua
- 
+
  print("Hello")
 --- World?
  print("..")
@@ -766,7 +773,7 @@ index 0000000..323fae0
 +++ d.lua
 @@ -1,4 +1,3 @@
  #!/usr/bin/env lua
- 
+
  print("Hello")
 --- World?
 "#;

src/handlers/hunk.rs

@@ -78,6 +78,7 @@ impl StateMachine<'_> {
         if let State::HunkHeader(_, parsed_hunk_header, line, raw_line) = &self.state.clone() {
             self.emit_hunk_header_line(parsed_hunk_header, line, raw_line)?;
         }
+        self.in_hunk = true;
         self.state = match new_line_state(&self.line, &self.raw_line, &self.state, self.config) {
             Some(HunkMinus(diff_type, raw_line)) => {
                 if let HunkPlus(_, _) = self.state {

src/handlers/hunk_header.rs

@@ -174,11 +174,12 @@ impl StateMachine<'_> {
         if self.config.hunk_header_style.is_raw {
             write_hunk_header_raw(&mut self.painter, line, raw_line, self.config)?;
         } else if self.config.hunk_header_style.is_omitted {
-            writeln!(self.painter.writer)?;
+            // TODO: I don't know how to avoid the stuttering here...
+            if !self.config.color_only && self.in_hunk && self.config.newline_after_diff {
+                writeln!(self.painter.writer)?;
+            }
         } else {
-            // Add a blank line below the hunk-header-line for readability, unless
-            // color_only mode is active.
-            if !self.config.color_only {
+            if !self.config.color_only && self.in_hunk && self.config.newline_after_diff {
                 writeln!(self.painter.writer)?;
             }
 
@@ -203,6 +204,12 @@ impl StateMachine<'_> {
                 ":",
                 self.config,
             )?;
+
+            // Add a blank line below the hunk-header-line for readability, unless
+            // color_only mode is active.
+            if !self.config.color_only && self.config.newline_after_hunk_header {
+                writeln!(self.painter.writer)?;
+            }
         };
         self.painter.set_highlighter();
         Ok(true)

src/handlers/mod.rs

@@ -46,6 +46,7 @@ impl StateMachine<'_> {
                 &mut self.painter,
                 &mut self.mode_info,
                 self.config,
+                &mut self.in_hunk,
             )?;
             handled_line = true;
         }

src/options/set.rs

@@ -191,6 +191,7 @@ pub fn set_options(
             minus_non_emph_style,
             navigate,
             navigate_regex,
+            newlines,
             line_fill_method,
             line_numbers,
             line_numbers_left_format,