fix-3140

CHANGELOG.md

@@ -58,11 +58,13 @@
 
  Hint: Rename this module and try again.
  ```
+
 - New subcommand `gleam hex revert` added. ([Pi-Cla](https://github.com/Pi-Cla))
- * You can specify the options like this: `gleam hex revert --package gling --version 1.2.3`
- * A new package can be reverted or updated within 24 hours of it's initial publish,
- a new version of an existing package can be reverted or updated within one hour.
- * You could already update packages even before this release by running: `gleam publish` again.
+
+ - You can specify the options like this: `gleam hex revert --package gling --version 1.2.3`
+ - A new package can be reverted or updated within 24 hours of it's initial publish,
+ a new version of an existing package can be reverted or updated within one hour.
+ - You could already update packages even before this release by running: `gleam publish` again.
 
 - When the user tries to replace a release without the `--replace` flag
  the error message now mentions the lack of a `--replace` flag.
@@ -234,6 +236,8 @@
  Matching on a literal value is redundant since you can already tell which
  branch is going to match with this value.
 
+ ```
+
 - The compiler will now continue module analysis when there are errors in top
  level definitions. This means that when these errors occur the compiler will
  continue analysing the rest of the code to find other errors and type
@@ -413,7 +417,9 @@
  #(_, _) -> 1
  }
  ```
+
  Is rewritten to:
+
  ```
  case x, y {
  1, 2 -> 0
@@ -479,3 +485,7 @@
 
 - Fixed a bug where local path dependencies could be mishandled on Windows.
  ([Francisco Montanez](https://github.com/Francisco-Montanez))
+
+- Fixed a bug where adding a comment to a case clause would cause it to break
+ on multiple lines.
+ ([Giacomo Cavalieri](https://github.com/giacomocavalieri))

compiler-core/src/format.rs

@@ -1268,7 +1268,7 @@ impl<'comments> Formatter<'comments> {
  clauses
  .iter()
  .enumerate()
- .map(|(i, c)| self.clause(c, i as u32)),
+ .map(|(i, c)| self.clause(c, i as u32).group()),
  );
 
  // We get all remaining comments that come before the case's closing
@@ -1759,11 +1759,6 @@ impl<'comments> Formatter<'comments> {
  .append(self.clause_guard(guard).group().nest(INDENT)),
  };
 
- let clause_doc = match printed_comments(comments, false) {
- Some(comments) => comments.append(line()).append(clause_doc),
- None => clause_doc,
- };
-
  // In case there's a guard or multiple subjects, if we decide to break
  // the patterns on multiple lines we also want the arrow to end up on
  // its own line to improve legibility.
@@ -1778,6 +1773,7 @@ impl<'comments> Formatter<'comments> {
  // // for patterns with `if` guards.
  // }
  // ```
+
  let has_guard = clause.guard.is_some();
  let has_multiple_subjects = clause.pattern.len() > 1;
  let arrow_break = if has_guard || has_multiple_subjects {
@@ -1786,17 +1782,25 @@ impl<'comments> Formatter<'comments> {
  " ".to_doc()
  };
 
+ let clause_doc = clause_doc
+ .append(arrow_break)
+ .group()
+ .append("->")
+ .append(self.case_clause_value(&clause.then).group())
+ .group();
+
+ let clause_doc = match printed_comments(comments, false) {
+ Some(comments) => comments.append(line()).append(clause_doc),
+ None => clause_doc,
+ };
+
  if index == 0 {
  clause_doc
  } else if space_before {
  lines(2).append(clause_doc)
  } else {
  lines(1).append(clause_doc)
  }
- .append(arrow_break)
- .group()
- .append("->")
- .append(self.case_clause_value(&clause.then))
  }
 
  fn alternative_patterns<'a>(&mut self, clause: &'a UntypedClause) -> Document<'a> {

compiler-core/src/format/tests/cases.rs

@@ -105,3 +105,17 @@ fn case_pattern_split_on_multiple_lines_is_not_needlessly_nested() {
 "#
  );
 }
+
+// https://github.com/gleam-lang/gleam/issues/3140
+#[test]
+fn long_comment_before_case_with_multiple_subjects_doesnt_force_a_break() {
+ assert_format!(
+ r#"fn main() {
+ case a, b {
+ // a very long comment a very long comment a very long comment a very long comment
+ _, _ -> True
+ }
+}
+"#
+ );
+}