From a2b0e737670a46955097a5b02fe3daa35c3f231b Mon Sep 17 00:00:00 2001
From: Bogdan Chadkin <trysound@yandex.ru>
Date: Sat, 6 Mar 2021 13:18:53 +0300
Subject: [PATCH] Preserve conditional processing attributes

---
 plugins/removeEmptyAttrs.js          | 26 ++++++++++++++------------
 test/plugins/removeEmptyAttrs.02.svg | 18 ++++++++++++++++++
 test/regression.js                   |  4 ++--
 3 files changed, 34 insertions(+), 14 deletions(-)
 create mode 100644 test/plugins/removeEmptyAttrs.02.svg

diff --git a/plugins/removeEmptyAttrs.js b/plugins/removeEmptyAttrs.js
index ae73e6c96..daad5c513 100644
--- a/plugins/removeEmptyAttrs.js
+++ b/plugins/removeEmptyAttrs.js
@@ -1,5 +1,7 @@
 'use strict';
 
+const { attrsGroups } = require('./_collections.js');
+
 exports.type = 'perItem';
 
 exports.active = true;
@@ -14,16 +16,16 @@ exports.description = 'removes empty attributes';
  *
  * @author Kir Belevich
  */
-exports.fn = function(item) {
-
-    if (item.elem) {
-
-        item.eachAttr(function(attr) {
-            if (attr.value === '') {
-                item.removeAttr(attr.name);
-            }
-        });
-
-    }
-
+exports.fn = function (item) {
+  if (item.elem) {
+    item.eachAttr(function (attr) {
+      if (
+        attr.value === '' &&
+        // empty conditional processing attributes prevents elements from rendering
+        attrsGroups.conditionalProcessing.includes(attr.name) === false
+      ) {
+        item.removeAttr(attr.name);
+      }
+    });
+  }
 };
diff --git a/test/plugins/removeEmptyAttrs.02.svg b/test/plugins/removeEmptyAttrs.02.svg
new file mode 100644
index 000000000..336c4a4f5
--- /dev/null
+++ b/test/plugins/removeEmptyAttrs.02.svg
@@ -0,0 +1,18 @@
+Empty conditional processing attributes should be preserved
+to hide elements
+
+===
+
+<svg xmlns="http://www.w3.org/2000/svg">
+    <g requiredFeatures=""/>
+    <g requiredExtensions=""/>
+    <g systemLanguage=""/>
+</svg>
+
+@@@
+
+<svg xmlns="http://www.w3.org/2000/svg">
+    <g requiredFeatures=""/>
+    <g requiredExtensions=""/>
+    <g systemLanguage=""/>
+</svg>
diff --git a/test/regression.js b/test/regression.js
index 8cc5c49ee..61ea0f29f 100644
--- a/test/regression.js
+++ b/test/regression.js
@@ -107,15 +107,15 @@ const runTests = async ({ svgFiles }) => {
       name === 'styling-css-10-f' ||
       // rect is converted to path which matches wrong styles
       name === 'styling-css-08-f' ||
-      // other cases which require complex changes
+      // external image
       name === 'struct-image-02-b' ||
+      // complex selectors are messed becase of converting shapes to paths
       name === 'struct-use-10-f' ||
       name === 'struct-use-11-f' ||
       name === 'styling-css-01-b' ||
       name === 'styling-css-03-b' ||
       name === 'styling-css-04-f' ||
       // mismatched draft cases
-      name === 'struct-cond-overview-03-f' ||
       name === 'struct-use-07-b'
     ) {
       console.info(`${name} is skipped`);