Bug 1222291 - change getRuleText to handle token-less rules; r=bgrins

devtools/server/actors/styles.js

@@ -2084,6 +2084,13 @@ function getRuleText(initialText, line, column) {
   if (startOffset === undefined) {
     return {offset: 0, text: ""};
   }
+  // If the input didn't have any tokens between the braces (e.g.,
+  // "div {}"), then the endOffset won't have been set yet; so account
+  // for that here.
+  if (endOffset === undefined) {
+    endOffset = startOffset;
+  }
+
   // Note that this approach will preserve comments, despite the fact
   // that cssTokenizer skips them.
   return {offset: textOffset + startOffset,

devtools/server/tests/unit/test_getRuleText.js

@@ -100,6 +100,13 @@ const TEST_DATA = [
     column: 4,
     expected: {offset: 7, text: "border:1px solid red;content: '}';color:red;"}
   },
+  {
+    desc: "Rule contains no tokens",
+    input: "div{}",
+    line: 1,
+    column: 1,
+    expected: {offset: 4, text: ""}
+  },
 ];
 
 function run_test() {