no excessive highlighting

codespan-reporting/src/term/renderer.rs

@@ -240,6 +240,20 @@ impl<'writer, 'config> Renderer<'writer, 'config> {
         // FIXME: Use the number of trimmed placeholders when rendering single line carets
         let source = source.trim_end_matches(['\n', '\r', '\0'].as_ref());
 
+        // get the byte index of the first non-whitespace character
+        let text_start = source.find(|c| !char::is_whitespace(c)).unwrap_or(0);
+
+        // get the byte index of the first trailing whitespace character
+        let text_end = source
+            .char_indices()
+            .rev()
+            .take_while(|(_, c)| c.is_whitespace())
+            .last()
+            .map(|(index, _)| index)
+            .unwrap_or_else(|| source.len());
+
+        let text_range = text_start..text_end;
+
         // Write source line
         //
         // ```text
@@ -274,37 +288,43 @@ impl<'writer, 'config> Renderer<'writer, 'config> {
 
             // Write source text
             write!(self, " ")?;
-            let mut in_primary = false;
+            let mut highlighted = false;
+
+            // iterate over all characters of source code
             for (metrics, ch) in self.char_metrics(source.char_indices()) {
                 let column_range = metrics.byte_index..(metrics.byte_index + ch.len_utf8());
 
-                // Check if we are overlapping a primary label
-                let is_primary = single_labels.iter().any(|(ls, range, _)| {
-                    *ls == LabelStyle::Primary && is_overlapping(range, &column_range)
-                }) || multi_labels.iter().any(|(_, ls, label)| {
+                /*
+                A character should be highlighted only if it is part of a primary single label which does not span the whole line
+                A label already spans the whole line if it does not cover leading/trailing whitespace.
+                */
+                let should_highlight = single_labels.iter().any(|(ls, range, _)| {
                     *ls == LabelStyle::Primary
-                        && match label {
-                            MultiLabel::Top(start) => column_range.start >= *start,
-                            MultiLabel::Left => true,
-                            MultiLabel::Bottom(start, _) => column_range.end <= *start,
-                        }
+                        // is this at the current position
+                        && is_overlapping(range, &column_range)
+                        // is this not a whole line label
+                        && !(
+                            range.start <= text_range.start
+                            && range.end >= text_range.end
+                        )
                 });
 
                 // Set the source color if we are in a primary label
-                if is_primary && !in_primary {
+                if should_highlight && !highlighted {
                     self.set_color(self.styles().label(severity, LabelStyle::Primary))?;
-                    in_primary = true;
-                } else if !is_primary && in_primary {
+                    highlighted = true;
+                } else if !should_highlight && highlighted {
                     self.reset()?;
-                    in_primary = false;
+                    highlighted = false;
                 }
 
+                // actually write the character
                 match ch {
                     '\t' => (0..metrics.unicode_width).try_for_each(|_| write!(self, " "))?,
                     _ => write!(self, "{}", ch)?,
                 }
             }
-            if in_primary {
+            if highlighted {
                 self.reset()?;
             }
             writeln!(self)?;

codespan-reporting/tests/snapshots/term__highlight__rich_color.snap

@@ -0,0 +1,36 @@
+---
+source: codespan-reporting/tests/term.rs
+expression: TEST_DATA.emit_color(&config)
+---
+{fg:Green bold bright}note{bold bright}: not highlighted{/}
+  {fg:Blue}┌─{/} test.txt:1:1
+  {fg:Blue}│{/}
+{fg:Blue}1{/} {fg:Blue}│{/} This is some text.
+  {fg:Blue}│{/} {fg:Green}^^^^^^^^^^^^^^^^^^{/}
+{fg:Blue}2{/} {fg:Blue}│{/}     This is some indented text.
+  {fg:Blue}│{/}     {fg:Green}^^^^^^^^^^^^^^^^^^^^^^^^^^^{/}
+{fg:Blue}3{/} {fg:Blue}│{/}     This is some indented text with trailing whitespace.    
+  {fg:Blue}│{/}     {fg:Green}^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^{/}
+
+{fg:Green bold bright}note{bold bright}: also not highlighted{/}
+  {fg:Blue}┌─{/} test.txt:2:1
+  {fg:Blue}│{/}
+{fg:Blue}2{/} {fg:Blue}│{/}     This is some indented text.
+  {fg:Blue}│{/} {fg:Green}^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^{/}
+{fg:Blue}3{/} {fg:Blue}│{/}     This is some indented text with trailing whitespace.    
+  {fg:Blue}│{/} {fg:Green}^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^{/}
+
+{fg:Green bold bright}note{bold bright}: highlighted{/}
+  {fg:Blue}┌─{/} test.txt:1:1
+  {fg:Blue}│{/}  
+{fg:Blue}1{/} {fg:Blue}│{/}   {fg:Green}This is some text{/}.
+  {fg:Blue}│{/}   {fg:Green}^^^^^^^^^^^^^^^^^{/}
+{fg:Blue}2{/} {fg:Blue}│{/}       T{fg:Green}his is some indented text.{/}
+  {fg:Blue}│{/}        {fg:Green}^^^^^^^^^^^^^^^^^^^^^^^^^^{/}
+{fg:Blue}3{/} {fg:Blue}│{/}       {fg:Green}This{/} is some indented text with trailing whitespace.    
+  {fg:Blue}│{/}       {fg:Green}^^^^{/}
+{fg:Blue}4{/} {fg:Blue}│{/} {fg:Green}╭{/} This is some multiline text.
+{fg:Blue}5{/} {fg:Blue}│{/} {fg:Green}│{/} This is some more multiline text.
+  {fg:Blue}│{/} {fg:Green}╰{/}{fg:Green}─────────────────────────────────^{/}
+
+

codespan-reporting/tests/snapshots/term__multiline_overlapping__rich_color.snap

@@ -10,11 +10,11 @@ expression: TEST_DATA.emit_color(&config)
   {fg:Blue}│{/}   {fg:Blue}│{/}                               {fg:Blue}---------------------------------------------{/} {fg:Blue}this is found to be of type `Result<ByteIndex, LineIndexOutOfBoundsError>`{/}
 {fg:Blue}3{/} {fg:Blue}│{/}   {fg:Blue}│{/}             Ordering::Equal => Ok(self.source_span().end()),
   {fg:Blue}│{/}   {fg:Blue}│{/}                                {fg:Blue}----------------------------{/} {fg:Blue}this is found to be of type `Result<ByteIndex, LineIndexOutOfBoundsError>`{/}
-{fg:Blue}4{/} {fg:Blue}│{/}   {fg:Blue}│{/}             Ordering::Greater => {fg:Red}LineIndexOutOfBoundsError {{/}
+{fg:Blue}4{/} {fg:Blue}│{/}   {fg:Blue}│{/}             Ordering::Greater => LineIndexOutOfBoundsError {
   {fg:Blue}│{/} {fg:Red}╭{/}{fg:Red}─{/}{fg:Blue}│{/}{fg:Red}──────────────────────────────────^{/}
-{fg:Blue}5{/} {fg:Blue}│{/} {fg:Red}│{/} {fg:Blue}│{/} {fg:Red}                given: line_index,{/}
-{fg:Blue}6{/} {fg:Blue}│{/} {fg:Red}│{/} {fg:Blue}│{/} {fg:Red}                max: self.last_line_index(),{/}
-{fg:Blue}7{/} {fg:Blue}│{/} {fg:Red}│{/} {fg:Blue}│{/} {fg:Red}            }{/},
+{fg:Blue}5{/} {fg:Blue}│{/} {fg:Red}│{/} {fg:Blue}│{/}                 given: line_index,
+{fg:Blue}6{/} {fg:Blue}│{/} {fg:Red}│{/} {fg:Blue}│{/}                 max: self.last_line_index(),
+{fg:Blue}7{/} {fg:Blue}│{/} {fg:Red}│{/} {fg:Blue}│{/}             },
   {fg:Blue}│{/} {fg:Red}╰{/}{fg:Red}─{/}{fg:Blue}│{/}{fg:Red}─────────────^ expected enum `Result`, found struct `LineIndexOutOfBoundsError`{/}
 {fg:Blue}8{/} {fg:Blue}│{/}   {fg:Blue}│{/}         }
   {fg:Blue}│{/}   {fg:Blue}╰{/}{fg:Blue}─────────' `match` arms have incompatible types{/}

codespan-reporting/tests/term.rs

@@ -917,6 +917,7 @@ mod unicode_spans {
 }
 
 mod position_indicator {
+
     use super::*;
 
     lazy_static::lazy_static! {
@@ -1027,3 +1028,50 @@ mod multiline_omit {
 
     test_emit!(rich_no_color);
 }
+
+mod highlight {
+    use super::*;
+
+    lazy_static::lazy_static! {
+        static ref TEST_DATA: TestData<'static, SimpleFile<&'static str, String>> = {
+            let file = SimpleFile::new(
+                "test.txt",
+                [
+                    "This is some text.",
+                    "\tThis is some indented text.",
+                    "\tThis is some indented text with trailing whitespace. \t",
+                    "This is some multiline text.",
+                    "This is some more multiline text.",
+                ]
+                .join("\n"),
+            );
+
+            let diagnostics = vec![
+                Diagnostic::note()
+                    .with_message("not highlighted")
+                    .with_labels(vec![
+                        Label::primary((), 0..18),
+                        Label::primary((), 20..47),
+                        Label::primary((), 49..101),
+                    ]),
+                Diagnostic::note()
+                    .with_message("also not highlighted")
+                    .with_labels(vec![
+                        Label::primary((), 19..47),
+                        Label::primary((), 48..103),
+                    ]),
+                Diagnostic::note()
+                    .with_message("highlighted")
+                    .with_labels(vec![
+                        Label::primary((), 0..17),
+                        Label::primary((), 21..47),
+                        Label::primary((), 49..53),
+                        Label::primary((), 104..166),
+                    ]),
+            ];
+            TestData{files: file, diagnostics }
+        };
+    }
+
+    test_emit!(rich_color);
+}