From efc5f91348a7de21dd3f115fcaabcc7b5e4a102e Mon Sep 17 00:00:00 2001
From: Connor Skees <connor1skees@gmail.com>
Date: Fri, 3 Jul 2020 23:49:31 -0400
Subject: [PATCH] more robustly parse empty bracketed lists

---
 CHANGELOG.md             |  4 ++++
 src/parse/value/parse.rs | 23 +++++++++++------------
 tests/list.rs            | 10 ++++++++++
 3 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f55355c..8209b50 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# TBD
+
+ - more robustly parse empty bracketed lists
+
 # 0.9.2
 
 - implement builtin functions `min` and `max`
diff --git a/src/parse/value/parse.rs b/src/parse/value/parse.rs
index bb3c012..c8a8433 100644
--- a/src/parse/value/parse.rs
+++ b/src/parse/value/parse.rs
@@ -112,17 +112,6 @@ impl<'a> Parser<'a> {
                 }
                 IntermediateValue::Bracketed(t) => {
                     last_was_whitespace = false;
-                    if t.is_empty() {
-                        space_separated.push(
-                            HigherIntermediateValue::Literal(Value::List(
-                                Vec::new(),
-                                ListSeparator::Space,
-                                Brackets::Bracketed,
-                            ))
-                            .span(val.span),
-                        );
-                        continue;
-                    }
                     space_separated.push(
                         HigherIntermediateValue::Literal(
                             match iter.parser.parse_value_from_vec(t)?.node {
@@ -509,6 +498,7 @@ impl<'a> Parser<'a> {
             }
             '[' => {
                 let mut span = self.toks.next().unwrap().pos();
+                self.whitespace_or_comment();
                 let mut inner = match read_until_closing_square_brace(self.toks) {
                     Ok(v) => v,
                     Err(e) => return Some(Err(e)),
@@ -519,7 +509,16 @@ impl<'a> Parser<'a> {
                     }
                     span = span.merge(last_tok.pos());
                 }
-                IntermediateValue::Bracketed(inner).span(span)
+                if inner.is_empty() {
+                    IntermediateValue::Value(HigherIntermediateValue::Literal(Value::List(
+                        Vec::new(),
+                        ListSeparator::Space,
+                        Brackets::Bracketed,
+                    )))
+                } else {
+                    IntermediateValue::Bracketed(inner)
+                }
+                .span(span)
             }
             '$' => {
                 self.toks.next();
diff --git a/tests/list.rs b/tests/list.rs
index a396edd..5b0b1dd 100644
--- a/tests/list.rs
+++ b/tests/list.rs
@@ -314,6 +314,16 @@ test!(
     "a {\n  color: 3;\n}\n"
 );
 test!(empty_bracketed_list, "a {\n  empty: [];\n}\n");
+test!(
+    empty_bracketed_list_equality,
+    "a {\n  color: []==[];\n}\n",
+    "a {\n  color: true;\n}\n"
+);
+test!(
+    empty_bracketed_list_whitespace,
+    "a {\n  color: [ /**/ ];\n}\n",
+    "a {\n  color: [];\n}\n"
+);
 error!(
     invalid_item_in_space_separated_list,
     "a {\n  color: red color * #abc;\n}\n", "Error: Undefined operation \"color * #abc\"."