Make hunk header code fragment display optional (#1568)

Fixes: #1032

manual/src/full---help-output.md

@@ -238,7 +238,7 @@ Options:
       --hunk-header-style <STYLE>
           Style string for the hunk-header.
 
-          See STYLES section. Special attributes 'file' and 'line-number' can be used to include the file path, and number of first hunk line, in the hunk header. The style 'omit' can be used to remove the hunk header section from the output.
+          See STYLES section. Special attributes 'file' and 'line-number' can be used to include the file path, and number of first hunk line, in the hunk header. The special attribute 'omit-code-fragment' can be used to remove the code fragment in the hunk header. The style 'omit' can be used to remove the entire hunk header section from the output.
 
           [default: "line-number syntax"]
 

src/config.rs

@@ -78,6 +78,7 @@ pub struct Config {
     pub hunk_header_line_number_style: Style,
     pub hunk_header_style_include_file_path: HunkHeaderIncludeFilePath,
     pub hunk_header_style_include_line_number: HunkHeaderIncludeLineNumber,
+    pub hunk_header_style_include_code_fragment: HunkHeaderIncludeCodeFragment,
     pub hunk_header_style: Style,
     pub hunk_label: String,
     pub hyperlinks_commit_link_format: Option<String>,
@@ -151,6 +152,12 @@ pub enum HunkHeaderIncludeLineNumber {
     No,
 }
 
+#[cfg_attr(test, derive(Clone))]
+pub enum HunkHeaderIncludeCodeFragment {
+    Yes,
+    No,
+}
+
 impl Config {
     pub fn get_style(&self, state: &State) -> &Style {
         match state {
@@ -331,6 +338,15 @@ impl From<cli::Opt> for Config {
             } else {
                 HunkHeaderIncludeLineNumber::No
             },
+            hunk_header_style_include_code_fragment: if opt
+                .hunk_header_style
+                .split(' ')
+                .any(|s| s == "omit-code-fragment")
+            {
+                HunkHeaderIncludeCodeFragment::No
+            } else {
+                HunkHeaderIncludeCodeFragment::Yes
+            },
             hyperlinks: opt.hyperlinks,
             hyperlinks_commit_link_format: opt.hyperlinks_commit_link_format,
             hyperlinks_file_link_format: opt.hyperlinks_file_link_format,

src/handlers/grep.rs

@@ -6,7 +6,8 @@ use serde::Deserialize;
 
 use crate::ansi;
 use crate::config::{
-    delta_unreachable, GrepType, HunkHeaderIncludeFilePath, HunkHeaderIncludeLineNumber,
+    delta_unreachable, GrepType, HunkHeaderIncludeCodeFragment, HunkHeaderIncludeFilePath,
+    HunkHeaderIncludeLineNumber,
 };
 use crate::delta::{State, StateMachine};
 use crate::handlers::{self, ripgrep_json};
@@ -168,6 +169,7 @@ impl<'a> StateMachine<'a> {
                 &HunkHeaderIncludeFilePath::Yes,
                 &HunkHeaderIncludeLineNumber::No,
                 &HunkHeaderIncludeHunkLabel::Yes,
+                &HunkHeaderIncludeCodeFragment::Yes,
                 "",
                 self.config,
             )?
@@ -230,6 +232,7 @@ impl<'a> StateMachine<'a> {
                 &HunkHeaderIncludeLineNumber::No
             },
             &HunkHeaderIncludeHunkLabel::No,
+            &HunkHeaderIncludeCodeFragment::Yes,
             grep_line.line_type.file_path_separator(),
             self.config,
         )
@@ -255,6 +258,7 @@ impl<'a> StateMachine<'a> {
                     &self.config.hunk_header_style_include_file_path,
                     &self.config.hunk_header_style_include_line_number,
                     &HunkHeaderIncludeHunkLabel::Yes,
+                    &HunkHeaderIncludeCodeFragment::Yes,
                     grep_line.line_type.file_path_separator(),
                     self.config,
                 )?

src/handlers/hunk_header.rs

@@ -25,7 +25,9 @@ use lazy_static::lazy_static;
 use regex::Regex;
 
 use super::draw;
-use crate::config::{Config, HunkHeaderIncludeFilePath, HunkHeaderIncludeLineNumber};
+use crate::config::{
+    Config, HunkHeaderIncludeCodeFragment, HunkHeaderIncludeFilePath, HunkHeaderIncludeLineNumber,
+};
 use crate::delta::{self, DiffType, InMergeConflict, MergeParents, State, StateMachine};
 use crate::paint::{self, BgShouldFill, Painter, StyleSectionSpecifier};
 use crate::style::{DecorationStyle, Style};
@@ -133,6 +135,7 @@ impl<'a> StateMachine<'a> {
                 &self.config.hunk_header_style_include_file_path,
                 &self.config.hunk_header_style_include_line_number,
                 &HunkHeaderIncludeHunkLabel::Yes,
+                &self.config.hunk_header_style_include_code_fragment,
                 ":",
                 self.config,
             )?;
@@ -229,13 +232,16 @@ pub fn write_line_of_code_with_optional_path_and_line_number(
     include_file_path: &HunkHeaderIncludeFilePath,
     include_line_number: &HunkHeaderIncludeLineNumber,
     include_hunk_label: &HunkHeaderIncludeHunkLabel,
+    include_code_fragment: &HunkHeaderIncludeCodeFragment,
     file_path_separator: &str,
     config: &Config,
 ) -> std::io::Result<()> {
     let (mut draw_fn, _, decoration_ansi_term_style) = draw::get_draw_function(decoration_style);
     let line = if config.color_only {
         line.to_string()
-    } else if !code_fragment.is_empty() {
+    } else if matches!(include_code_fragment, HunkHeaderIncludeCodeFragment::Yes)
+        && !code_fragment.is_empty()
+    {
         format!("{code_fragment} ")
     } else {
         "".to_string()

src/parse_style.rs

@@ -186,7 +186,7 @@ fn parse_ansi_term_style(
             style.is_strikethrough = true;
         } else if word == "ul" || word == "underline" {
             style.is_underline = true;
-        } else if word == "line-number" || word == "file" {
+        } else if word == "line-number" || word == "file" || word == "omit-code-fragment" {
             // Allow: these are meaningful in hunk-header-style.
         } else if !seen_foreground {
             if word == "syntax" {

src/tests/test_example_diffs.rs

@@ -1091,6 +1091,21 @@ src/delta.rs:1: │
         assert!(output.contains("commit 94907c0f136f46dc46ffae2dc92dca9af7eb7c2e"));
     }
 
+    #[test]
+    fn test_hunk_header_omit_code_fragment() {
+        let config = integration_test_utils::make_config_from_args(&[
+            "--hunk-header-style",
+            "line-number omit-code-fragment",
+            "--hunk-header-decoration-style",
+            "none",
+        ]);
+        let output = strip_ansi_codes(&integration_test_utils::run_delta(
+            GIT_DIFF_SINGLE_HUNK,
+            &config,
+        ));
+        assert!(output.contains("\n71: \n"));
+    }
+
     #[test]
     fn test_hunk_header_style_colored_input_color_is_stripped_under_normal() {
         let config = integration_test_utils::make_config_from_args(&[