Fix up backtick breaking

CHANGELOG.md

@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) a
 
 ## [Unreleased]
 
+### Changed
+
+- If xstring literals (command line calls surrounded by backticks) break, then we indent and place the command on a new line. Previously, this was resulting in new lines getting added each time the code was formatted. Now this happens correctly. (Thanks to @dudeofawesome for the report.)
+
 ## [0.14.0] - 2019-07-17
 
 ### Added

src/nodes/strings.js

@@ -139,12 +139,24 @@ module.exports = {
   word_add: concatBody,
   word_new: empty,
   xstring: makeList,
-  xstring_literal: (path, opts, print) =>
-    group(
+  xstring_literal: (path, opts, print) => {
+    const parts = path.call(print, "body", 0);
+
+    if (typeof parts[0] === "string") {
+      parts[0] = parts[0].trimStart();
+    }
+
+    const lastIndex = parts.length - 1;
+    if (typeof parts[lastIndex] === "string") {
+      parts[lastIndex] = parts[lastIndex].trimEnd();
+    }
+
+    return group(
       concat([
         "`",
-        indent(concat([softline, join(softline, path.call(print, "body", 0))])),
+        indent(concat([softline, join(softline, parts)])),
         concat([softline, "`"])
       ])
-    )
+    );
+  }
 };

test/js/strings.test.js

@@ -111,6 +111,9 @@ describe("strings", () => {
 
     test("breaking %x literals with method chains", () =>
       expect(`%x[${long}].to_s`).toChangeFormat(`\`\n  ${long}\n\`.to_s`));
+
+    test("trims the start and end appropriately", () =>
+      expect(`\`\n\n${long}\n\n\``).toChangeFormat(`\`\n  ${long}\n\``));
   });
 
   describe("dynamic symbols", () => {