fix(css): don't eat selector namespace (#3956)

src/language-css/printer-postcss.js

@@ -309,7 +309,12 @@ function genericPrint(path, options, print) {
       return adjustStrings(node.value, options);
     }
     case "selector-tag": {
-      return adjustNumbers(node.value);
+      return concat([
+        node.namespace
+          ? concat([node.namespace === true ? "" : node.namespace.trim(), "|"])
+          : "",
+        adjustNumbers(node.value)
+      ]);
     }
     case "selector-id": {
       return concat(["#", node.value]);
@@ -358,7 +363,12 @@ function genericPrint(path, options, print) {
       return concat([leading, value]);
     }
     case "selector-universal": {
-      return node.value;
+      return concat([
+        node.namespace
+          ? concat([node.namespace === true ? "" : node.namespace.trim(), "|"])
+          : "",
+        adjustNumbers(node.value)
+      ]);
     }
     case "selector-selector": {
       return group(indent(concat(path.map(print, "nodes"))));

tests/css_selector_list/__snapshots__/jsfmt.spec.js.snap

@@ -295,6 +295,23 @@ exports[`selectors.css 1`] = `
    >>>   .child-one {}
    >>>   .child-two {}
 }
+
+/* This matches all XHTML <a> elements, as XHTML is the default unprefixed namespace */
+a {}
+
+/* This matches all SVG <a> elements */
+svg|a {}
+
+/* This matches both XHTML and SVG <a> elements */
+*|a {}
+
+|B {}
+
+ns|* {}
+
+*|* {}
+
+|* {}
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 .a,
 .b,
@@ -660,4 +677,28 @@ exports[`selectors.css 1`] = `
   }
 }
 
+/* This matches all XHTML <a> elements, as XHTML is the default unprefixed namespace */
+a {
+}
+
+/* This matches all SVG <a> elements */
+svg|a {
+}
+
+/* This matches both XHTML and SVG <a> elements */
+*|a {
+}
+
+|B {
+}
+
+ns|* {
+}
+
+*|* {
+}
+
+|* {
+}
+
 `;

tests/css_selector_list/selectors.css

@@ -292,3 +292,20 @@
    >>>   .child-one {}
    >>>   .child-two {}
 }
+
+/* This matches all XHTML <a> elements, as XHTML is the default unprefixed namespace */
+a {}
+
+/* This matches all SVG <a> elements */
+svg|a {}
+
+/* This matches both XHTML and SVG <a> elements */
+*|a {}
+
+|B {}
+
+ns|* {}
+
+*|* {}
+
+|* {}