fix: Fix Unicode highlight alignment in patches

src/renderer/render.rs

@@ -1721,6 +1721,14 @@ fn emit_suggestion_default(
                     // logic to show the whole prior snippet, but the current output is not
                     // too bad to begin with, so we side-step that issue here.
                     for (i, line) in snippet.lines().enumerate() {
+                        let tabs: usize = line
+                            .chars()
+                            .take(span_start.char)
+                            .map(|ch| match ch {
+                                '\t' => 3,
+                                _ => 0,
+                            })
+                            .sum();
                         let line = normalize_whitespace(line);
                         // Going lower than buffer_offset (+ 1) would mean
                         // overwriting existing content in the buffer
@@ -1732,26 +1740,36 @@ fn emit_suggestion_default(
                         // the column of the part span end.
                         // On all others, we highlight the whole line.
                         let start = if i == 0 {
-                            (padding as isize + span_start_pos as isize) as usize
+                            (padding as isize + (span_start.char + tabs) as isize) as usize
                         } else {
                             padding
                         };
                         let end = if i == 0 {
-                            (padding as isize + span_start_pos as isize + line.len() as isize)
+                            (padding as isize
+                                + (span_start.char + tabs) as isize
+                                + line.chars().count() as isize)
                                 as usize
                         } else if i == newlines - 1 {
-                            (padding as isize + span_end_pos as isize) as usize
+                            (padding as isize + (span_end.char + tabs) as isize) as usize
                         } else {
-                            (padding as isize + line.len() as isize) as usize
+                            (padding as isize + line.chars().count() as isize) as usize
                         };
                         buffer.set_style_range(row, start, end, ElementStyle::Removal, true);
                     }
                 } else {
+                    let tabs: usize = snippet
+                        .chars()
+                        .take(span_start.char)
+                        .map(|ch| match ch {
+                            '\t' => 3,
+                            _ => 0,
+                        })
+                        .sum();
                     // The removed code fits all in one line.
                     buffer.set_style_range(
                         row_num - 2,
-                        (padding as isize + span_start_pos as isize) as usize,
-                        (padding as isize + span_end_pos as isize) as usize,
+                        (padding as isize + (span_start.char + tabs) as isize) as usize,
+                        (padding as isize + (span_end.char + tabs) as isize) as usize,
                         ElementStyle::Removal,
                         true,
                     );

tests/color/highlight_diff_line_with_wide_characters.rs

@@ -0,0 +1,44 @@
+use annotate_snippets::{renderer::DecorStyle, AnnotationKind, Level, Patch, Renderer, Snippet};
+
+use snapbox::{assert_data_eq, file};
+
+#[test]
+fn case() {
+    let source = r#"struct 啊啊啊啊 {}
+
+const 哦哦: 啊啊啊啊 = 哈哈哈哈 {}; // some comment"#;
+
+    let path = "$DIR/highlight_diff_line_with_wide_characters.rs";
+
+    let report = &[
+        Level::ERROR
+            .primary_title("cannot find struct, variant or union type `哈哈哈哈` in this scope")
+            .id("E0422")
+            .element(
+                Snippet::source(source)
+                    .path(path)
+                    .annotation(AnnotationKind::Primary.span(53..65).label("here"))
+                    .annotation(
+                        AnnotationKind::Context
+                            .span(0..22)
+                            .label("similarly named struct `啊啊啊啊` defined here"),
+                    ),
+            ),
+        Level::HELP
+            .secondary_title("a struct with a similar name exists: `啊啊啊啊`")
+            .element(
+                Snippet::source(source)
+                    .path(path)
+                    .patch(Patch::new(53..65, "啊啊啊啊")),
+            ),
+    ];
+
+    let expected_ascii = file!["highlight_diff_line_with_wide_characters.ascii.term.svg": TermSvg];
+    let renderer = Renderer::styled();
+    assert_data_eq!(renderer.render(report), expected_ascii);
+
+    let expected_unicode =
+        file!["highlight_diff_line_with_wide_characters.unicode.term.svg": TermSvg];
+    let renderer = renderer.decor_style(DecorStyle::Unicode);
+    assert_data_eq!(renderer.render(report), expected_unicode);
+}

tests/color/main.rs

@@ -9,6 +9,7 @@ mod fold_ann_multiline;
 mod fold_bad_origin_line;
 mod fold_leading;
 mod fold_trailing;
+mod highlight_diff_line_with_wide_characters;
 mod highlight_duplicated_diff_lines;
 mod highlight_source;
 mod issue_9;