Fix regression in transitive var import

Cargo.toml

@@ -45,6 +45,7 @@ wasm-bindgen-cli = { version = "0.2.83", artifact = "bin" }
 wasm-opt = "0.111.0"
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
+console_error_panic_hook = "0.1.7"
 js-sys = "0.3.60"
 serde-wasm-bindgen = "0.4.5"
 wasm-bindgen = { version = "0.2.83", features = ["serde-serialize"] }

src/builder.rs

@@ -95,6 +95,7 @@ impl<'a> BuildCss<'a> {
             transformers::inline_url(&srcdir.to_string_lossy())(css);
             transformers::merge_siblings(css);
             transformers::remove_mixin(css);
+            transformers::remove_var(css);
             transformers::deduplicate(css);
         }
 

src/main.rs

@@ -36,4 +36,6 @@ fn main() {
 }
 
 #[cfg(target_arch = "wasm32")]
-fn main() {}
+fn main() {
+    std::panic::set_hook(Box::new(console_error_panic_hook::hook));
+}

src/transformers/apply_var.rs

@@ -17,17 +17,11 @@ use crate::ast::*;
 pub fn apply_var<'a>(tree: &mut Tree<'a>) {
     let mut mixins: HashMap<&'a str, &'a str> = HashMap::new();
     tree.transform(|ruleset| {
-        let mut is_mixin = false;
         if let Ruleset::QualRule(QualRule(name, Some(val))) = ruleset {
             if let Some(val) = val.strip_prefix(':') {
                 mixins.insert(name, val);
-                is_mixin = true;
             }
         }
-
-        if is_mixin {
-            *ruleset = Ruleset::QualRuleset(QualRuleset(QualRule("", None), vec![]))
-        }
     });
 
     let mut mixins = mixins.iter().collect::<Vec<_>>();

src/transformers/mod.rs

@@ -35,6 +35,7 @@ mod flat_self;
 mod inline_url;
 mod merge_siblings;
 mod remove_mixin;
+mod remove_var;
 
 pub use self::apply_import::apply_import;
 pub use self::apply_mixin::apply_mixin;
@@ -45,3 +46,4 @@ pub(crate) use self::flat_self::flat_self;
 pub use self::inline_url::inline_url;
 pub use self::merge_siblings::merge_siblings;
 pub use self::remove_mixin::remove_mixin;
+pub use self::remove_var::remove_var;

src/transformers/remove_var.rs

@@ -0,0 +1,27 @@
+// ┌───────────────────────────────────────────────────────────────────────────┐
+// │                                                                           │
+// │  ██████╗ ██████╗  ██████╗   Copyright (C) 2022, The Prospective Company   │
+// │  ██╔══██╗██╔══██╗██╔═══██╗                                                │
+// │  ██████╔╝██████╔╝██║   ██║  This file is part of the Procss library,      │
+// │  ██╔═══╝ ██╔══██╗██║   ██║  distributed under the terms of the            │
+// │  ██║     ██║  ██║╚██████╔╝  Apache License 2.0.  The full license can     │
+// │  ╚═╝     ╚═╝  ╚═╝ ╚═════╝   be found in the LICENSE file.                 │
+// │                                                                           │
+// └───────────────────────────────────────────────────────────────────────────┘
+
+use crate::ast::Ruleset::{self};
+use crate::ast::*;
+
+pub fn remove_var(css: &mut Css) {
+    let reduced = css
+        .iter()
+        .filter(|&ruleset| match ruleset {
+            Ruleset::QualRule(QualRule(name, Some(val))) if val.strip_prefix(':').is_some() => {
+                false
+            }
+            _ => true,
+        })
+        .cloned();
+
+    *css = crate::ast::Css(reduced.collect())
+}

tests/apply_import.rs

@@ -16,7 +16,7 @@ use std::assert_matches::assert_matches;
 use std::collections::HashMap;
 use std::path::Path;
 
-use procss::transformers::{apply_import, apply_var};
+use procss::transformers::{apply_import, apply_var, remove_var};
 use procss::{parse, RenderCss};
 
 #[test]
@@ -63,7 +63,9 @@ fn test_import_ref() {
         .map(|mut x| {
             apply_import(&trees)(&mut x);
             apply_var(&mut x);
-            x.flatten_tree().as_css_string()
+            let mut flat = x.flatten_tree();
+            remove_var(&mut flat);
+            flat.as_css_string()
         })
         .as_deref(),
         Ok("div.open{color:#00FF00;}")

tests/apply_var.rs

@@ -14,7 +14,7 @@
 #[cfg(test)]
 use std::assert_matches::assert_matches;
 
-use procss::transformers::apply_var;
+use procss::transformers::{apply_var, remove_var};
 use procss::{parse, RenderCss};
 
 #[test]
@@ -31,7 +31,9 @@ fn test_var() {
         )
         .map(|mut x| {
             apply_var(&mut x);
-            x.flatten_tree().as_css_string()
+            let mut flat = x.flatten_tree();
+            remove_var(&mut flat);
+            flat.as_css_string()
         })
         .as_deref(),
         Ok("div.open{color:#FF1111;}")
@@ -52,7 +54,9 @@ fn test_var_overlapping_name() {
         )
         .map(|mut x| {
             apply_var(&mut x);
-            x.flatten_tree().as_css_string()
+            let mut flat = x.flatten_tree();
+            remove_var(&mut flat);
+            flat.as_css_string()
         })
         .as_deref(),
         Ok("div.open{color:#0000FF;}")