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fix(zero length): Improve rendering for zero-length error spans 

A zero-length span at a line boundary can be associated either with the
previous or the next line. Current code prefer to use the next line,
however there isn't always a "next line" (end of source, or "no context"
configuration).
There is also the extra-special case of an empty document which has no
"next line" but also no "previous line".

This commit adds an empty newline at the end of a document if appropriate
so that there is a "next line", or use the "previous line"
This commit is contained in:
Nahor 2024-03-20 17:06:49 -07:00
parent d0c114311d
commit c7cbb07d84
3 changed files with 175 additions and 57 deletions
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131
src/handlers/graphical.rs
View File

@ -515,7 +515,19 @@ impl GraphicalReportHandler {
context: &LabeledSpan,
labels: &[LabeledSpan],
) -> fmt::Result {
let (contents, lines) = self.get_lines(source, context.inner())?;
let (contents, mut lines) = self.get_lines(source, context.inner())?;
// If the number of lines doesn't match the content's line_count, it's
// because the content is either an empty source or because the last
// line finishes with a newline. In this case, add an empty line.
if lines.len() != contents.line_count() {
lines.push(Line {
line_number: contents.line() + contents.line_count(),
offset: contents.span().offset() + contents.span().len(),
length: 0,
text: String::new(),
});
}
// only consider labels from the context as primary label
let ctx_labels = labels.iter().filter(|l| {
@ -570,6 +582,10 @@ impl GraphicalReportHandler {
self.theme.characters.hbar,
)?;
// Save that for later, since `content` might be moved before we need
// that info
let has_content = !contents.data().is_empty();
// If there is a primary label, then use its span
// as the reference point for line/column information.
let primary_contents = match primary_label {
@ -600,48 +616,53 @@ impl GraphicalReportHandler {
}
// Now it's time for the fun part--actually rendering everything!
for line in &lines {
// Line number, appropriately padded.
self.write_linum(f, linum_width, line.line_number)?;
// (but only if we have content or if we wanted content, to avoid
// pointless detailed rendering, e.g. arrows pointing to nothing in the
// middle of nothing)
if has_content || self.context_lines.is_some() {
for (line_no, line) in lines.iter().enumerate() {
// Line number, appropriately padded.
self.write_linum(f, linum_width, line.line_number)?;
// Then, we need to print the gutter, along with any fly-bys We
// have separate gutters depending on whether we're on the actual
// line, or on one of the "highlight lines" below it.
self.render_line_gutter(f, max_gutter, line, &labels)?;
// Then, we need to print the gutter, along with any fly-bys We
// have separate gutters depending on whether we're on the actual
// line, or on one of the "highlight lines" below it.
self.render_line_gutter(f, max_gutter, line, &labels)?;
// And _now_ we can print out the line text itself!
let styled_text =
StyledList::from(highlighter_state.highlight_line(&line.text)).to_string();
self.render_line_text(f, &styled_text)?;
// And _now_ we can print out the line text itself!
let styled_text =
StyledList::from(highlighter_state.highlight_line(&line.text)).to_string();
self.render_line_text(f, &styled_text)?;
// Next, we write all the highlights that apply to this particular line.
let (single_line, multi_line): (Vec<_>, Vec<_>) = labels
.iter()
.filter(|hl| line.span_applies(hl))
.partition(|hl| line.span_line_only(hl));
if !single_line.is_empty() {
// no line number!
self.write_no_linum(f, linum_width)?;
// gutter _again_
self.render_highlight_gutter(
f,
max_gutter,
line,
&labels,
LabelRenderMode::SingleLine,
)?;
self.render_single_line_highlights(
f,
line,
linum_width,
max_gutter,
&single_line,
&labels,
)?;
}
for hl in multi_line {
if hl.label().is_some() && line.span_ends(hl) && !line.span_starts(hl) {
self.render_multi_line_end(f, &labels, max_gutter, linum_width, line, hl)?;
// Next, we write all the highlights that apply to this particular line.
let (single_line, multi_line): (Vec<_>, Vec<_>) = labels
.iter()
.filter(|hl| line.span_applies(hl, line_no == (lines.len() - 1)))
.partition(|hl| line.span_line_only(hl));
if !single_line.is_empty() {
// no line number!
self.write_no_linum(f, linum_width)?;
// gutter _again_
self.render_highlight_gutter(
f,
max_gutter,
line,
&labels,
LabelRenderMode::SingleLine,
)?;
self.render_single_line_highlights(
f,
line,
linum_width,
max_gutter,
&single_line,
&labels,
)?;
}
for hl in multi_line {
if hl.label().is_some() && line.span_ends(hl) && !line.span_starts(hl) {
self.render_multi_line_end(f, &labels, max_gutter, linum_width, line, hl)?;
}
}
}
}
@ -1271,18 +1292,30 @@ impl Line {
/// Returns whether `span` should be visible on this line, either in the gutter or under the
/// text on this line
fn span_applies(&self, span: &FancySpan) -> bool {
///
/// An empty span at a line boundary will preferable apply to the start of
/// a line (i.e. the second/next line) rather than the end of one (i.e. the
/// first/previous line). However if there are no "second" line, the span
/// can only apply the "first". The `inclusive` parameter is there to
/// indicate that `self` is the last line, i.e. that there are no "second"
/// line.
fn span_applies(&self, span: &FancySpan, inclusive: bool) -> bool {
// A span applies if its start is strictly before the line's end,
// i.e. the span is not after the line, and its end is strictly after
// the line's start, i.e. the span is not before the line.
//
// One corner case: if the span length is 0, then the span also applies
// if its end is *at* the line's start, not just strictly after.
(span.offset() < self.offset + self.length)
&& match span.len() == 0 {
true => (span.offset() + span.len()) >= self.offset,
false => (span.offset() + span.len()) > self.offset,
}
// Two corner cases:
// - if `inclusive` is true, then the span also applies if its start is
// *at* the line's end, not just strictly before.
// - if the span length is 0, then the span also applies if its end is
// *at* the line's start, not just strictly after.
(match inclusive {
true => span.offset() <= self.offset + self.length,
false => span.offset() < self.offset + self.length,
}) && match span.len() == 0 {
true => (span.offset() + span.len()) >= self.offset,
false => (span.offset() + span.len()) > self.offset,
}
}
/// Returns whether `span` should be visible on this line in the gutter (so this excludes spans
@ -1290,7 +1323,7 @@ impl Line {
fn span_applies_gutter(&self, span: &FancySpan) -> bool {
// The span must covers this line and at least one of its ends must be
// on another line
self.span_applies(span)
self.span_applies(span, false)
&& ((span.offset() < self.offset)
|| ((span.offset() + span.len()) >= (self.offset + self.length)))
}

14
src/source_impls.rs
View File

@ -20,6 +20,16 @@ fn context_info<'a>(
) -> Result<MietteSpanContents<'a>, MietteError> {
let mut iter = input
.split_inclusive(|b| *b == b'\n')
.chain(
// `split_inclusive()` does not generate a line if the input is
// empty or for the "last line" if it terminates with a new line.
// This `chain` fixes that.
match input.last() {
None => Some(&input[0..0]),
Some(b'\n') => Some(&input[input.len()..input.len()]),
_ => None,
},
)
.enumerate()
.map(|(line_no, line)| {
// SAFETY:
@ -291,8 +301,8 @@ mod tests {
let contents = src.read_span(&(12, 0).into(), None, None)?;
assert_eq!("", std::str::from_utf8(contents.data()).unwrap());
assert_eq!(SourceSpan::from((12, 0)), *contents.span());
assert_eq!(2, contents.line());
assert_eq!(4, contents.column());
assert_eq!(3, contents.line());
assert_eq!(0, contents.column());
assert_eq!(1, contents.line_count());
Ok(())
}

87
tests/graphical.rs
View File

@ -288,6 +288,9 @@ fn empty_source() -> Result<(), MietteError> {
× oops!
╭─[bad_file.rs:1:1]
1 │
· ▲
· ╰── this bit here
╰────
help: try doing it better next time?
"#
@ -633,6 +636,78 @@ fn single_line_highlight_offset_end_of_line() -> Result<(), MietteError> {
Ok(())
}
#[test]
fn single_line_highlight_offset_end_of_file_no_newline() -> Result<(), MietteError> {
#[derive(Debug, Diagnostic, Error)]
#[error("oops!")]
#[diagnostic(code(oops::my::bad), help("try doing it better next time?"))]
struct MyBad {
#[source_code]
src: NamedSource<String>,
#[label("this bit here")]
highlight: SourceSpan,
}
let src = "one\ntwo\nthree".to_string();
let err = MyBad {
src: NamedSource::new("bad_file.rs", src),
highlight: (13, 0).into(),
};
let out = fmt_report(err.into());
println!("Error: {}", out);
let expected = r#"oops::my::bad
× oops!
╭─[bad_file.rs:3:6]
2 │ two
3 │ three
· ▲
· ╰── this bit here
╰────
help: try doing it better next time?
"#
.trim_start()
.to_string();
assert_eq!(expected, out);
Ok(())
}
#[test]
fn single_line_highlight_offset_end_of_file_with_newline() -> Result<(), MietteError> {
#[derive(Debug, Diagnostic, Error)]
#[error("oops!")]
#[diagnostic(code(oops::my::bad), help("try doing it better next time?"))]
struct MyBad {
#[source_code]
src: NamedSource<String>,
#[label("this bit here")]
highlight: SourceSpan,
}
let src = "one\ntwo\nthree\n".to_string();
let err = MyBad {
src: NamedSource::new("bad_file.rs", src),
highlight: (14, 0).into(),
};
let out = fmt_report(err.into());
println!("Error: {}", out);
let expected = r#"oops::my::bad
× oops!
╭─[bad_file.rs:4:1]
3 │ three
4 │
· ▲
· ╰── this bit here
╰────
help: try doing it better next time?
"#
.trim_start()
.to_string();
assert_eq!(expected, out);
Ok(())
}
#[test]
fn single_line_highlight_include_end_of_line() -> Result<(), MietteError> {
#[derive(Debug, Diagnostic, Error)]
@ -1088,9 +1163,8 @@ fn multiline_highlight_flyby() -> Result<(), MietteError> {
line2
line3
line4
line5
"#
.to_string();
line5"#
.to_string();
let len = src.len();
let err = MyBad {
src: NamedSource::new("bad_file.rs", src),
@ -1147,9 +1221,8 @@ fn multiline_highlight_no_label() -> Result<(), MietteError> {
line2
line3
line4
line5
"#
.to_string();
line5"#
.to_string();
let len = src.len();
let err = MyBad {
source: Inner(InnerInner),
@ -2267,6 +2340,8 @@ fn multi_adjacent_zero_length_no_context() -> Result<(), MietteError> {
· ▲
· ╰── this bit here
3 │ thr
· ▲
· ╰── and here
╰────
help: try doing it better next time?
"#