Fix `git add -p` to work when any options enabled (#323)

* Add test for input and output for diff interactive filter

* Add color_only in config struct

* Refactor should_handle false when color_only and FileMeta, CommitMeta

* Refactor handle_hunk_header_line to show raw_text with color_format when color_only

* Fix indent

* Revert the logic changes for interactive filter

* Add color only workaround in set options

* Add more test patterns for diff interactive fillter

3 files changed, 54 insertions, 10 deletions

diff --git a/src/delta.rs b/src/delta.rs
index 9c411d8e..7ff70abe 100644
--- a/src/delta.rs
+++ b/src/delta.rs
@@ -380,9 +380,6 @@ fn handle_hunk_header_line(
     plus_file: &str,
     config: &Config,
 ) -> std::io::Result<()> {
-    if config.hunk_header_style.is_omitted {
-        return Ok(());
-    }
     let decoration_ansi_term_style;
     let draw_fn = match config.hunk_header_style.decoration_style {
         DecorationStyle::Box(style) => {
@@ -432,7 +429,7 @@ fn handle_hunk_header_line(
             config.hunk_header_style,
             decoration_ansi_term_style,
         )?;
-    } else {
+    } else if !config.hunk_header_style.is_omitted {
         let line = match painter.prepare(&raw_code_fragment, false) {
             s if s.len() > 0 => format!("{} ", s),
             s => s,
@@ -466,11 +463,10 @@ fn handle_hunk_header_line(
                 config.hunk_header_style,
                 decoration_ansi_term_style,
             )?;
-            if !config.hunk_header_style.is_raw {
-                painter.output_buffer.clear()
-            };
+            painter.output_buffer.clear();
         }
     };
+
     // Emit a single line number, or prepare for full line-numbering
     if config.line_numbers {
         painter
diff --git a/src/options/set.rs b/src/options/set.rs
index a6b4f151..a9ca6be7 100644
--- a/src/options/set.rs
+++ b/src/options/set.rs
@@ -19,8 +19,8 @@ use crate::options::option_value::{OptionValue, ProvenancedOptionValue};
 use crate::options::{self, theme};
 
 macro_rules! set_options {
-	([$( $field_ident:ident ),* ],
-     $opt:expr, $builtin_features:expr, $git_config:expr, $arg_matches:expr, $expected_option_name_map:expr, $check_names:expr) => {
+    ([$( $field_ident:ident ),* ],
+    $opt:expr, $builtin_features:expr, $git_config:expr, $arg_matches:expr, $expected_option_name_map:expr, $check_names:expr) => {
         let mut option_names = HashSet::new();
         $(
             let kebab_case_field_name = stringify!($field_ident).replace("_", "-");
@@ -59,7 +59,7 @@ macro_rules! set_options {
                              &option_names - &expected_option_names));
             }
         }
-	}
+    }
 }
 
 pub fn set_options(
@@ -192,6 +192,10 @@ pub fn set_options(
     // there (does not emit lines in 1-1 correspondence with raw git output). See #274.
     if opt.color_only {
         opt.side_by_side = false;
+        opt.file_style = "raw".to_string();
+        opt.commit_style = "raw".to_string();
+        opt.hunk_header_style = "raw".to_string();
+        opt.hunk_header_decoration_style = "none".to_string();
     }
 }
 
diff --git a/src/tests/test_example_diffs.rs b/src/tests/test_example_diffs.rs
index 9f1a257f..e7a00ee3 100644
--- a/src/tests/test_example_diffs.rs
+++ b/src/tests/test_example_diffs.rs
@@ -836,6 +836,50 @@ src/align.rs
     }
 
     #[test]
+    fn test_color_only_output_is_in_one_to_one_correspondence_with_input() {
+        _do_test_output_is_in_one_to_one_correspondence_with_input(&["--color-only", "true"]);
+        _do_test_output_is_in_one_to_one_correspondence_with_input(&[
+            "--color-only",
+            "true",
+            "--file-style",
+            "blue",
+            "--commit-style",
+            "omit",
+            "--hunk-header-style",
+            "omit",
+            "--hunk-header-decoration-style",
+            "omit",
+        ]);
+        _do_test_output_is_in_one_to_one_correspondence_with_input(&[
+            "--color-only",
+            "true",
+            "--file-style",
+            "blue",
+            "--commit-style",
+            "red",
+            "--hunk-header-style",
+            "syntax",
+            "--hunk-header-decoration-style",
+            "box",
+        ]);
+    }
+
+    fn _do_test_output_is_in_one_to_one_correspondence_with_input(args: &[&str]) {
+        let config = integration_test_utils::make_config_from_args(args);
+        let output = integration_test_utils::run_delta(GIT_DIFF_SINGLE_HUNK, &config);
+
+        let output = strip_ansi_codes(&output);
+        let output_lines: Vec<&str> = output.split('\n').collect();
+        let input_lines: Vec<&str> = GIT_DIFF_SINGLE_HUNK.split('\n').collect();
+
+        assert_eq!(input_lines.len(), output_lines.len());
+
+        for n in 0..input_lines.len() {
+            assert_eq!(input_lines[n], output_lines[n]);
+        }
+    }
+
+    #[test]
     fn test_hunk_header_style_colored_input_color_is_stripped_under_normal() {
         let config = integration_test_utils::make_config_from_args(&[
             "--hunk-header-style",