From a21d355ade9ab381f7d55710b98ece547eab4997 Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Mon, 22 Jul 2019 11:00:57 -0700
Subject: [PATCH] Fix handling of potentially overlapping selectors in property
 sheets

---
 cli/src/generate/properties.rs   | 72 +++++++++++++++++++++++++-------
 cli/src/tests/properties_test.rs | 13 +++---
 2 files changed, 65 insertions(+), 20 deletions(-)

diff --git a/cli/src/generate/properties.rs b/cli/src/generate/properties.rs
index bd4a5a08..77fa29e1 100644
--- a/cli/src/generate/properties.rs
+++ b/cli/src/generate/properties.rs
@@ -407,24 +407,68 @@ impl<'a> Builder<'a> {
         left: &PropertyTransitionJSON,
         right: &PropertyTransitionJSON,
     ) -> Option<PropertyTransitionJSON> {
-        // If one transition is based on the node's type and the other
-        // is based on its field name, then create a combined transition
-        // wiht *both* criteria.
-        if let (Some(left_field), None) = (&left.field, &left.kind) {
-            if right.field.is_none() {
-                let mut result = right.clone();
-                result.field = Some(left_field.clone());
-                return Some(result);
+        let mut left_contributes = false;
+        let mut right_contributes = false;
+        let mut result = left.clone();
+
+        if let Some(left_kind) = &left.kind {
+            if let Some(right_kind) = &right.kind {
+                if left_kind != right_kind || left.named != right.named {
+                    return None;
+                }
+            } else {
+                left_contributes = true;
             }
+        } else if let Some(right_kind) = &right.kind {
+            result.kind = Some(right_kind.clone());
+            result.named = right.named;
+            right_contributes = true;
         }
-        if let (Some(right_field), None) = (&right.field, &right.kind) {
-            if left.field.is_none() {
-                let mut result = left.clone();
-                result.field = Some(right_field.clone());
-                return Some(result);
+
+        if let Some(left_field) = &left.field {
+            if let Some(right_field) = &right.field {
+                if left_field != right_field {
+                    return None;
+                }
+            } else {
+                left_contributes = true;
             }
+        } else if let Some(right_field) = &right.field {
+            result.field = Some(right_field.clone());
+            right_contributes = true;
+        }
+
+        if let Some(left_text) = &left.text {
+            if let Some(right_text) = &right.text {
+                if left_text != right_text {
+                    return None;
+                }
+            } else {
+                left_contributes = true;
+            }
+        } else if let Some(right_text) = &right.text {
+            result.text = Some(right_text.clone());
+            right_contributes = true;
+        }
+
+        if let Some(left_index) = &left.index {
+            if let Some(right_index) = &right.index {
+                if left_index != right_index {
+                    return None;
+                }
+            } else {
+                left_contributes = true;
+            }
+        } else if let Some(right_index) = &right.index {
+            result.index = Some(right_index.clone());
+            right_contributes = true;
+        }
+
+        if left_contributes && right_contributes {
+            Some(result)
+        } else {
+            None
         }
-        return None;
     }
 
     fn remove_duplicate_states(&mut self) {
diff --git a/cli/src/tests/properties_test.rs b/cli/src/tests/properties_test.rs
index 7c67a4df..51f0e820 100644
--- a/cli/src/tests/properties_test.rs
+++ b/cli/src/tests/properties_test.rs
@@ -2,9 +2,9 @@ use super::helpers::fixtures::get_language;
 use crate::generate::properties;
 use serde_derive::Deserialize;
 use serde_json;
-use tree_sitter::{Parser, PropertySheet};
-use std::collections::HashSet;
 
+use std::collections::HashSet;
+use tree_sitter::{Parser, PropertySheet};
 #[derive(Debug, Default, Deserialize, PartialEq, Eq)]
 struct Properties {
     a: Option<String>,
@@ -31,7 +31,7 @@ fn test_walk_with_properties_with_nth_child() {
                     a: z;
                 }
             ",
-        )
+        ),
     )
     .unwrap();
 
@@ -106,7 +106,7 @@ fn test_walk_with_properties_with_regexes() {
                     a: x;
                 }
             ",
-        )
+        ),
     )
     .unwrap();
 
@@ -195,7 +195,7 @@ fn test_walk_with_properties_based_on_fields() {
                     a: w;
                 }
             ",
-        )
+        ),
     )
     .unwrap();
 
@@ -260,5 +260,6 @@ fn test_walk_with_properties_based_on_fields() {
 }
 
 fn generate_property_sheet_string(path: &str, css: &str) -> String {
-    serde_json::to_string(&properties::generate_property_sheet(path, css, &HashSet::new()).unwrap()).unwrap()
+    serde_json::to_string(&properties::generate_property_sheet(path, css, &HashSet::new()).unwrap())
+        .unwrap()
 }