fix(render): On fold, strip prefix/suffix rather than fold

As we don't show `...` on non-first lines without fold, it seems to make sense to do the same thing for fold. To show this, we likely would want to add more nuance than just `fold`. This has the benefit of offering a "magic mode" where the annotated lines get selected automatically. This was implemented by pre-processing things which should keep overhead low as other calculations down the line aren't done.

Author: epage

src/renderer/display_list.rs

@@ -696,17 +696,19 @@ impl<'a> Iterator for CursorLines<'a> {
 }
 
 fn format_message(
- snippet::Message {
+ message: snippet::Message<'_>,
+ term_width: usize,
+ anonymized_line_numbers: bool,
+ primary: bool,
+) -> Vec<DisplaySet<'_>> {
+ let snippet::Message {
  level,
  id,
  title,
  footer,
  snippets,
- }: snippet::Message<'_>,
- term_width: usize,
- anonymized_line_numbers: bool,
- primary: bool,
-) -> Vec<DisplaySet<'_>> {
+ } = message;
+
  let mut sets = vec![];
  let body = if !snippets.is_empty() || primary {
  vec![format_title(level, id, title)]
@@ -715,6 +717,7 @@ fn format_message(
  };
 
  for (idx, snippet) in snippets.into_iter().enumerate() {
+ let snippet = fold_prefix_suffix(snippet);
  sets.push(format_snippet(
  snippet,
  idx == 0,
@@ -876,6 +879,46 @@ fn format_header<'a>(
  None
 }
 
+fn fold_prefix_suffix(mut snippet: snippet::Snippet<'_>) -> snippet::Snippet<'_> {
+ if !snippet.fold {
+ return snippet;
+ }
+
+ let ann_start = snippet
+ .annotations
+ .iter()
+ .map(|ann| ann.range.start)
+ .min()
+ .unwrap_or(0);
+ if let Some(before_new_start) = snippet.source[0..ann_start].rfind('\n') {
+ let new_start = before_new_start + 1;
+
+ let line_offset = snippet.source[..new_start].lines().count();
+ snippet.line_start += line_offset;
+
+ snippet.source = &snippet.source[new_start..];
+
+ for ann in &mut snippet.annotations {
+ let range_start = ann.range.start - new_start;
+ let range_end = ann.range.end - new_start;
+ ann.range = range_start..range_end;
+ }
+ }
+
+ let ann_end = snippet
+ .annotations
+ .iter()
+ .map(|ann| ann.range.end)
+ .max()
+ .unwrap_or(snippet.source.len());
+ if let Some(end_offset) = snippet.source[ann_end..].find('\n') {
+ let new_end = ann_end + end_offset;
+ snippet.source = &snippet.source[..new_end];
+ }
+
+ snippet
+}
+
 fn fold_body(mut body: Vec<DisplayLine<'_>>) -> Vec<DisplayLine<'_>> {
  enum Line {
  Fold(usize),

tests/fixtures/no-color/fold_bad_origin_line.svg

@@ -14,7 +14,6 @@ fn test_i_29() {
 error: oops
  --> <current file>:2:8
  |
-1 | First line
 2 | Second oops line
  | ^^^^ oops
  |"#]]