Add Haml pre processor (#17051)

This PR ensures we extract candidates from Haml files.

Fixes: #17050

CHANGELOG.md

@@ -17,6 +17,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - _Experimental_: Add `user-valid` and `user-invalid` variants ([#12370](https://github.com/tailwindlabs/tailwindcss/pull/12370))
 - _Experimental_: Add `wrap-anywhere`, `wrap-break-word`, and `wrap-normal` utilities ([#12128](https://github.com/tailwindlabs/tailwindcss/pull/12128))
 
+### Fixed
+
+- Fix `haml` pre-processing ([#17051](https://github.com/tailwindlabs/tailwindcss/pull/17051))
+
 ## [4.0.12] - 2025-03-07
 
 ### Fixed
@@ -26,7 +30,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Ensure utilities are sorted based on their actual property order ([#16995](https://github.com/tailwindlabs/tailwindcss/pull/16995))
 - Ensure strings in Pug and Slim templates are handled correctly ([#17000](https://github.com/tailwindlabs/tailwindcss/pull/17000))
 - Ensure classes between `}` and `{` are properly extracted ([#17001](https://github.com/tailwindlabs/tailwindcss/pull/17001))
-- Add `razor`/`cshtml` pre processing ([#17027](https://github.com/tailwindlabs/tailwindcss/pull/17027))
+- Fix `razor`/`cshtml` pre-processing ([#17027](https://github.com/tailwindlabs/tailwindcss/pull/17027))
 - Ensure extracting candidates from JS embedded in a PHP string works as expected ([#17031](https://github.com/tailwindlabs/tailwindcss/pull/17031))
 
 ## [4.0.11] - 2025-03-06

crates/oxide/src/extractor/mod.rs

@@ -873,6 +873,55 @@ mod tests {
         );
     }
 
+    // https://github.com/tailwindlabs/tailwindcss/issues/17050
+    #[test]
+    fn test_haml_syntax() {
+        for (input, expected) in [
+            // Element with classes
+            (
+                "%body.flex.flex-col.items-center.justify-center",
+                vec!["flex", "flex-col", "items-center", "justify-center"],
+            ),
+            // Plain element
+            (
+                ".text-slate-500.xl:text-gray-500",
+                vec!["text-slate-500", "xl:text-gray-500"],
+            ),
+            // Element with hash attributes
+            (
+                ".text-black.xl:text-red-500{ data: { tailwind: 'css' } }",
+                vec!["text-black", "xl:text-red-500"],
+            ),
+            // Element with a boolean attribute
+            (
+                ".text-green-500.xl:text-blue-500(data-sidebar)",
+                vec!["text-green-500", "xl:text-blue-500"],
+            ),
+            // Element with interpreted content
+            (
+                ".text-yellow-500.xl:text-purple-500= 'Element with interpreted content'",
+                vec!["text-yellow-500", "xl:text-purple-500"],
+            ),
+            // Element with a hash at the end and an extra class.
+            (
+                ".text-orange-500.xl:text-pink-500{ class: 'bg-slate-100' }",
+                vec!["text-orange-500", "xl:text-pink-500", "bg-slate-100"],
+            ),
+            // Object reference
+            (
+                ".text-teal-500.xl:text-indigo-500[@user, :greeting]",
+                vec!["text-teal-500", "xl:text-indigo-500"],
+            ),
+            // Element with an ID
+            (
+                ".text-lime-500.xl:text-emerald-500#root",
+                vec!["text-lime-500", "xl:text-emerald-500"],
+            ),
+        ] {
+            assert_extract_candidates_contains(&pre_process_input(input, "haml"), expected);
+        }
+    }
+
     // https://github.com/tailwindlabs/tailwindcss/issues/16982
     #[test]
     fn test_arbitrary_container_queries_syntax() {
@@ -888,6 +937,7 @@ mod tests {
         );
     }
 
+    // https://github.com/tailwindlabs/tailwindcss/issues/17023
     #[test]
     fn test_js_embedded_in_php_syntax() {
         // Escaped single quotes

crates/oxide/src/extractor/pre_processors/haml.rs

@@ -0,0 +1,123 @@
+use crate::cursor;
+use crate::extractor::bracket_stack::BracketStack;
+use crate::extractor::pre_processors::pre_processor::PreProcessor;
+
+#[derive(Debug, Default)]
+pub struct Haml;
+
+impl PreProcessor for Haml {
+    fn process(&self, content: &[u8]) -> Vec<u8> {
+        let len = content.len();
+        let mut result = content.to_vec();
+        let mut cursor = cursor::Cursor::new(content);
+        let mut bracket_stack = BracketStack::default();
+
+        while cursor.pos < len {
+            match cursor.curr {
+                // Consume strings as-is
+                b'\'' | b'"' => {
+                    let len = cursor.input.len();
+                    let end_char = cursor.curr;
+
+                    cursor.advance();
+
+                    while cursor.pos < len {
+                        match cursor.curr {
+                            // Escaped character, skip ahead to the next character
+                            b'\\' => cursor.advance_twice(),
+
+                            // End of the string
+                            b'\'' | b'"' if cursor.curr == end_char => break,
+
+                            // Everything else is valid
+                            _ => cursor.advance(),
+                        };
+                    }
+                }
+
+                // Replace following characters with spaces if they are not inside of brackets
+                b'.' | b'#' | b'=' if bracket_stack.is_empty() => {
+                    result[cursor.pos] = b' ';
+                }
+
+                b'(' | b'[' | b'{' => {
+                    // Replace first bracket with a space
+                    if bracket_stack.is_empty() {
+                        result[cursor.pos] = b' ';
+                    }
+                    bracket_stack.push(cursor.curr);
+                }
+
+                b')' | b']' | b'}' => {
+                    bracket_stack.pop(cursor.curr);
+
+                    // Replace closing bracket with a space
+                    if bracket_stack.is_empty() {
+                        result[cursor.pos] = b' ';
+                    }
+                }
+
+                // Consume everything else
+                _ => {}
+            };
+
+            cursor.advance();
+        }
+
+        result
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Haml;
+    use crate::extractor::pre_processors::pre_processor::PreProcessor;
+
+    #[test]
+    fn test_haml_pre_processor() {
+        for (input, expected) in [
+            // Element with classes
+            (
+                "%body.flex.flex-col.items-center.justify-center",
+                "%body flex flex-col items-center justify-center",
+            ),
+            // Plain element
+            (
+                ".text-slate-500.xl:text-gray-500",
+                " text-slate-500 xl:text-gray-500",
+            ),
+            // Element with hash attributes
+            (
+                ".text-black.xl:text-red-500{ data: { tailwind: 'css' } }",
+                " text-black xl:text-red-500  data: { tailwind: 'css' }  ",
+            ),
+            // Element with a boolean attribute
+            (
+                ".text-green-500.xl:text-blue-500(data-sidebar)",
+                " text-green-500 xl:text-blue-500 data-sidebar ",
+            ),
+            // Element with interpreted content
+            (
+                ".text-yellow-500.xl:text-purple-500= 'Element with interpreted content'",
+                " text-yellow-500 xl:text-purple-500  'Element with interpreted content'",
+            ),
+            // Element with a hash at the end and an extra class.
+            (
+                ".text-orange-500.xl:text-pink-500{ class: 'bg-slate-100' }",
+                " text-orange-500 xl:text-pink-500  class: 'bg-slate-100'  ",
+            ),
+            // Object reference
+            (
+                ".text-teal-500.xl:text-indigo-500[@user, :greeting]",
+                " text-teal-500 xl:text-indigo-500 @user, :greeting ",
+            ),
+            // Element with an ID
+            (
+                ".text-lime-500.xl:text-emerald-500#root",
+                " text-lime-500 xl:text-emerald-500 root",
+            ),
+        ] {
+            Haml::test(input, expected);
+        }
+    }
+}

crates/oxide/src/extractor/pre_processors/mod.rs

@@ -1,3 +1,4 @@
+pub mod haml;
 pub mod pre_processor;
 pub mod pug;
 pub mod razor;
@@ -5,6 +6,7 @@ pub mod ruby;
 pub mod slim;
 pub mod svelte;
 
+pub use haml::*;
 pub use pre_processor::*;
 pub use pug::*;
 pub use razor::*;

crates/oxide/src/lib.rs

@@ -469,6 +469,7 @@ pub fn pre_process_input(content: &[u8], extension: &str) -> Vec<u8> {
 
     match extension {
         "cshtml" | "razor" => Razor.process(content),
+        "haml" => Haml.process(content),
         "pug" => Pug.process(content),
         "rb" | "erb" => Ruby.process(content),
         "slim" => Slim.process(content),